API for building visitors from lambdas

compiler/frontend/src/org/jetbrains/kotlin/psi/VisitorWrappers.kt

@@ -0,0 +1,396 @@
+/*
+ * Copyright 2000-2018 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license
+ * that can be found in the license/LICENSE.txt file.
+ */
+
+package org.jetbrains.kotlin.psi
+
+fun classOrObjectVisitor(block: (KtClassOrObject) -> Unit) =
+    object : KtVisitorVoid() {
+        override fun visitClassOrObject(classOrObject: KtClassOrObject) {
+            block(classOrObject)
+        }
+    }
+
+fun classOrObjectRecursiveVisitor(block: (KtClassOrObject) -> Unit) =
+    object : KtTreeVisitorVoid() {
+        override fun visitClassOrObject(classOrObject: KtClassOrObject) {
+            super.visitClassOrObject(classOrObject)
+            block(classOrObject)
+        }
+    }
+
+fun classVisitor(block: (KtClass) -> Unit) =
+    object : KtVisitorVoid() {
+        override fun visitClass(klass: KtClass) {
+            block(klass)
+        }
+    }
+
+fun classRecursiveVisitor(block: (KtClass) -> Unit) =
+    object : KtTreeVisitorVoid() {
+        override fun visitClass(klass: KtClass) {
+            super.visitClass(klass)
+            block(klass)
+        }
+    }
+
+fun expressionVisitor(block: (KtExpression) -> Unit) =
+    object : KtVisitorVoid() {
+        override fun visitExpression(expression: KtExpression) {
+            block(expression)
+        }
+    }
+
+fun expressionRecursiveVisitor(block: (KtExpression) -> Unit) =
+    object : KtTreeVisitorVoid() {
+        override fun visitExpression(expression: KtExpression) {
+            super.visitExpression(expression)
+            block(expression)
+        }
+    }
+
+fun parameterVisitor(block: (KtParameter) -> Unit) =
+    object : KtVisitorVoid() {
+        override fun visitParameter(parameter: KtParameter) {
+            block(parameter)
+        }
+    }
+
+fun parameterRecursiveVisitor(block: (KtParameter) -> Unit) =
+    object : KtTreeVisitorVoid() {
+        override fun visitParameter(parameter: KtParameter) {
+            super.visitParameter(parameter)
+            block(parameter)
+        }
+    }
+
+fun propertyVisitor(block: (KtProperty) -> Unit) =
+    object : KtVisitorVoid() {
+        override fun visitProperty(property: KtProperty) {
+            block(property)
+        }
+    }
+
+fun propertyRecursiveVisitor(block: (KtProperty) -> Unit) =
+    object : KtTreeVisitorVoid() {
+        override fun visitProperty(property: KtProperty) {
+            super.visitProperty(property)
+            block(property)
+        }
+    }
+
+fun ifExpressionVisitor(block: (KtIfExpression) -> Unit) =
+    object : KtVisitorVoid() {
+        override fun visitIfExpression(ifExpression: KtIfExpression) {
+            block(ifExpression)
+        }
+    }
+
+fun ifExpressionRecursiveVisitor(block: (KtIfExpression) -> Unit) =
+    object : KtTreeVisitorVoid() {
+        override fun visitIfExpression(ifExpression: KtIfExpression) {
+            super.visitIfExpression(ifExpression)
+            block(ifExpression)
+        }
+    }
+
+fun callExpressionVisitor(block: (KtCallExpression) -> Unit) =
+    object : KtVisitorVoid() {
+        override fun visitCallExpression(callExpression: KtCallExpression) {
+            block(callExpression)
+        }
+    }
+
+fun callExpressionRecursiveVisitor(block: (KtCallExpression) -> Unit) =
+    object : KtTreeVisitorVoid() {
+        override fun visitCallExpression(callExpression: KtCallExpression) {
+            super.visitCallExpression(callExpression)
+            block(callExpression)
+        }
+    }
+
+fun primaryConstructorVisitor(block: (KtPrimaryConstructor) -> Unit) =
+    object : KtVisitorVoid() {
+        override fun visitPrimaryConstructor(primaryConstructor: KtPrimaryConstructor) {
+            block(primaryConstructor)
+        }
+    }
+
+fun primaryConstructorRecursiveVisitor(block: (KtPrimaryConstructor) -> Unit) =
+    object : KtTreeVisitorVoid() {
+        override fun visitPrimaryConstructor(primaryConstructor: KtPrimaryConstructor) {
+            super.visitPrimaryConstructor(primaryConstructor)
+            block(primaryConstructor)
+        }
+    }
+
+fun destructuringDeclarationVisitor(block: (KtDestructuringDeclaration) -> Unit) =
+    object : KtVisitorVoid() {
+        override fun visitDestructuringDeclaration(destructuringDeclaration: KtDestructuringDeclaration) {
+            block(destructuringDeclaration)
+        }
+    }
+
+fun destructuringDeclarationRecursiveVisitor(block: (KtDestructuringDeclaration) -> Unit) =
+    object : KtTreeVisitorVoid() {
+        override fun visitDestructuringDeclaration(destructuringDeclaration: KtDestructuringDeclaration) {
+            super.visitDestructuringDeclaration(destructuringDeclaration)
+            block(destructuringDeclaration)
+        }
+    }
+
+fun dotQualifiedExpressionVisitor(block: (KtDotQualifiedExpression) -> Unit) =
+    object : KtVisitorVoid() {
+        override fun visitDotQualifiedExpression(dotQualifiedExpression: KtDotQualifiedExpression) {
+            block(dotQualifiedExpression)
+        }
+    }
+
+fun dotQualifiedExpressionRecursiveVisitor(block: (KtDotQualifiedExpression) -> Unit) =
+    object : KtTreeVisitorVoid() {
+        override fun visitDotQualifiedExpression(dotQualifiedExpression: KtDotQualifiedExpression) {
+            super.visitDotQualifiedExpression(dotQualifiedExpression)
+            block(dotQualifiedExpression)
+        }
+    }
+
+fun prefixExpressionVisitor(block: (KtPrefixExpression) -> Unit) =
+    object : KtVisitorVoid() {
+        override fun visitPrefixExpression(prefixExpression: KtPrefixExpression) {
+            block(prefixExpression)
+        }
+    }
+
+fun prefixExpressionRecursiveVisitor(block: (KtPrefixExpression) -> Unit) =
+    object : KtTreeVisitorVoid() {
+        override fun visitPrefixExpression(prefixExpression: KtPrefixExpression) {
+            super.visitPrefixExpression(prefixExpression)
+            block(prefixExpression)
+        }
+    }
+
+fun namedFunctionVisitor(block: (KtNamedFunction) -> Unit) =
+    object : KtVisitorVoid() {
+        override fun visitNamedFunction(namedFunction: KtNamedFunction) {
+            block(namedFunction)
+        }
+    }
+
+fun namedFunctionRecursiveVisitor(block: (KtNamedFunction) -> Unit) =
+    object : KtTreeVisitorVoid() {
+        override fun visitNamedFunction(namedFunction: KtNamedFunction) {
+            super.visitNamedFunction(namedFunction)
+            block(namedFunction)
+        }
+    }
+
+fun annotationEntryVisitor(block: (KtAnnotationEntry) -> Unit) =
+    object : KtVisitorVoid() {
+        override fun visitAnnotationEntry(annotationEntry: KtAnnotationEntry) {
+            block(annotationEntry)
+        }
+    }
+
+fun annotationEntryRecursiveVisitor(block: (KtAnnotationEntry) -> Unit) =
+    object : KtTreeVisitorVoid() {
+        override fun visitAnnotationEntry(annotationEntry: KtAnnotationEntry) {
+            super.visitAnnotationEntry(annotationEntry)
+            block(annotationEntry)
+        }
+    }
+
+fun lambdaExpressionVisitor(block: (KtLambdaExpression) -> Unit) =
+    object : KtVisitorVoid() {
+        override fun visitLambdaExpression(lambdaExpression: KtLambdaExpression) {
+            block(lambdaExpression)
+        }
+    }
+
+fun lambdaExpressionRecursiveVisitor(block: (KtLambdaExpression) -> Unit) =
+    object : KtTreeVisitorVoid() {
+        override fun visitLambdaExpression(lambdaExpression: KtLambdaExpression) {
+            super.visitLambdaExpression(lambdaExpression)
+            block(lambdaExpression)
+        }
+    }
+
+fun enumEntryVisitor(block: (KtEnumEntry) -> Unit) =
+    object : KtVisitorVoid() {
+        override fun visitEnumEntry(enumEntry: KtEnumEntry) {
+            block(enumEntry)
+        }
+    }
+
+fun enumEntryRecursiveVisitor(block: (KtEnumEntry) -> Unit) =
+    object : KtTreeVisitorVoid() {
+        override fun visitEnumEntry(enumEntry: KtEnumEntry) {
+            super.visitEnumEntry(enumEntry)
+            block(enumEntry)
+        }
+    }
+
+fun packageDirectiveVisitor(block: (KtPackageDirective) -> Unit) =
+    object : KtVisitorVoid() {
+        override fun visitPackageDirective(packageDirective: KtPackageDirective) {
+            block(packageDirective)
+        }
+    }
+
+fun packageDirectiveRecursiveVisitor(block: (KtPackageDirective) -> Unit) =
+    object : KtTreeVisitorVoid() {
+        override fun visitPackageDirective(packageDirective: KtPackageDirective) {
+            super.visitPackageDirective(packageDirective)
+            block(packageDirective)
+        }
+    }
+
+fun binaryExpressionVisitor(block: (KtBinaryExpression) -> Unit) =
+    object : KtVisitorVoid() {
+        override fun visitBinaryExpression(binaryExpression: KtBinaryExpression) {
+            block(binaryExpression)
+        }
+    }
+
+fun binaryExpressionRecursiveVisitor(block: (KtBinaryExpression) -> Unit) =
+    object : KtTreeVisitorVoid() {
+        override fun visitBinaryExpression(binaryExpression: KtBinaryExpression) {
+            super.visitBinaryExpression(binaryExpression)
+            block(binaryExpression)
+        }
+    }
+
+fun declarationVisitor(block: (KtDeclaration) -> Unit) =
+    object : KtVisitorVoid() {
+        override fun visitDeclaration(declaration: KtDeclaration) {
+            block(declaration)
+        }
+    }
+
+fun declarationRecursiveVisitor(block: (KtDeclaration) -> Unit) =
+    object : KtTreeVisitorVoid() {
+        override fun visitDeclaration(declaration: KtDeclaration) {
+            super.visitDeclaration(declaration)
+            block(declaration)
+        }
+    }
+
+fun simpleNameExpressionVisitor(block: (KtSimpleNameExpression) -> Unit) =
+    object : KtVisitorVoid() {
+        override fun visitSimpleNameExpression(simpleNameExpression: KtSimpleNameExpression) {
+            block(simpleNameExpression)
+        }
+    }
+
+fun simpleNameExpressionRecursiveVisitor(block: (KtSimpleNameExpression) -> Unit) =
+    object : KtTreeVisitorVoid() {
+        override fun visitSimpleNameExpression(simpleNameExpression: KtSimpleNameExpression) {
+            super.visitSimpleNameExpression(simpleNameExpression)
+            block(simpleNameExpression)
+        }
+    }
+
+fun propertyAccessorVisitor(block: (KtPropertyAccessor) -> Unit) =
+    object : KtVisitorVoid() {
+        override fun visitPropertyAccessor(propertyAccessor: KtPropertyAccessor) {
+            block(propertyAccessor)
+        }
+    }
+
+fun propertyAccessorRecursiveVisitor(block: (KtPropertyAccessor) -> Unit) =
+    object : KtTreeVisitorVoid() {
+        override fun visitPropertyAccessor(propertyAccessor: KtPropertyAccessor) {
+            super.visitPropertyAccessor(propertyAccessor)
+            block(propertyAccessor)
+        }
+    }
+
+fun referenceExpressionVisitor(block: (KtReferenceExpression) -> Unit) =
+    object : KtVisitorVoid() {
+        override fun visitReferenceExpression(referenceExpression: KtReferenceExpression) {
+            block(referenceExpression)
+        }
+    }
+
+fun referenceExpressionRecursiveVisitor(block: (KtReferenceExpression) -> Unit) =
+    object : KtTreeVisitorVoid() {
+        override fun visitReferenceExpression(referenceExpression: KtReferenceExpression) {
+            super.visitReferenceExpression(referenceExpression)
+            block(referenceExpression)
+        }
+    }
+
+fun valueArgumentVisitor(block: (KtValueArgument) -> Unit) =
+    object : KtVisitorVoid() {
+        override fun visitArgument(valueArgument: KtValueArgument) {
+            block(valueArgument)
+        }
+    }
+
+fun valueArgumentRecursiveVisitor(block: (KtValueArgument) -> Unit) =
+    object : KtTreeVisitorVoid() {
+        override fun visitArgument(valueArgument: KtValueArgument) {
+            super.visitArgument(valueArgument)
+            block(valueArgument)
+        }
+    }
+
+fun whenExpressionVisitor(block: (KtWhenExpression) -> Unit) =
+    object : KtVisitorVoid() {
+        override fun visitWhenExpression(whenExpression: KtWhenExpression) {
+            block(whenExpression)
+        }
+    }
+
+fun whenExpressionRecursiveVisitor(block: (KtWhenExpression) -> Unit) =
+    object : KtTreeVisitorVoid() {
+        override fun visitWhenExpression(whenExpression: KtWhenExpression) {
+            super.visitWhenExpression(whenExpression)
+            block(whenExpression)
+        }
+    }
+
+fun modifierListVisitor(block: (KtModifierList) -> Unit) =
+    object : KtVisitorVoid() {
+        override fun visitModifierList(modifierList: KtModifierList) {
+            block(modifierList)
+        }
+    }
+
+fun modifierListRecursiveVisitor(block: (KtModifierList) -> Unit) =
+    object : KtTreeVisitorVoid() {
+        override fun visitModifierList(modifierList: KtModifierList) {
+            super.visitModifierList(modifierList)
+            block(modifierList)
+        }
+    }
+
+fun namedDeclarationVisitor(block: (KtNamedDeclaration) -> Unit) =
+    object : KtVisitorVoid() {
+        override fun visitNamedDeclaration(namedDeclaration: KtNamedDeclaration) {
+            block(namedDeclaration)
+        }
+    }
+
+fun namedDeclarationRecursiveVisitor(block: (KtNamedDeclaration) -> Unit) =
+    object : KtTreeVisitorVoid() {
+        override fun visitNamedDeclaration(namedDeclaration: KtNamedDeclaration) {
+            super.visitNamedDeclaration(namedDeclaration)
+            block(namedDeclaration)
+        }
+    }
+
+fun qualifiedExpressionVisitor(block: (KtQualifiedExpression) -> Unit) =
+    object : KtVisitorVoid() {
+        override fun visitQualifiedExpression(qualifiedExpression: KtQualifiedExpression) {
+            block(qualifiedExpression)
+        }
+    }
+
+fun qualifiedExpressionRecursiveVisitor(block: (KtQualifiedExpression) -> Unit) =
+    object : KtTreeVisitorVoid() {
+        override fun visitQualifiedExpression(qualifiedExpression: KtQualifiedExpression) {
+            super.visitQualifiedExpression(qualifiedExpression)
+            block(qualifiedExpression)
+        }
+    }

idea/src/org/jetbrains/kotlin/idea/inspections/AbstractPrimitiveRangeToInspection.kt

@@ -1,17 +1,6 @@
 /*
- * Copyright 2010-2017 JetBrains s.r.o.
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- * http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
+ * Copyright 2000-2018 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license
+ * that can be found in the license/LICENSE.txt file.
  */
 
 package org.jetbrains.kotlin.idea.inspections
@@ -23,7 +12,7 @@ import org.jetbrains.kotlin.idea.intentions.getCallableDescriptor
 import org.jetbrains.kotlin.psi.KtBinaryExpression
 import org.jetbrains.kotlin.psi.KtDotQualifiedExpression
 import org.jetbrains.kotlin.psi.KtExpression
-import org.jetbrains.kotlin.psi.KtVisitorVoid
+import org.jetbrains.kotlin.psi.expressionVisitor
 import org.jetbrains.kotlin.resolve.BindingContext
 import org.jetbrains.kotlin.resolve.calls.callUtil.getType
 import org.jetbrains.kotlin.resolve.constants.ConstantValue
@@ -34,17 +23,13 @@ import org.jetbrains.kotlin.resolve.lazy.BodyResolveMode
 abstract class AbstractPrimitiveRangeToInspection : AbstractKotlinInspection() {
 
     override fun buildVisitor(holder: ProblemsHolder, isOnTheFly: Boolean): PsiElementVisitor {
-        return object : KtVisitorVoid() {
-            override fun visitExpression(expression: KtExpression) {
-                super.visitExpression(expression)
+        return expressionVisitor { expression ->
+            if (expression !is KtBinaryExpression && expression !is KtDotQualifiedExpression) return@expressionVisitor
 
-                if (expression !is KtBinaryExpression && expression !is KtDotQualifiedExpression) return
+            val fqName = expression.getCallableDescriptor()?.fqNameUnsafe?.asString() ?: return@expressionVisitor
+            if (!fqName.matches(REGEX_RANGE_TO)) return@expressionVisitor
 
-                val fqName = expression.getCallableDescriptor()?.fqNameUnsafe?.asString() ?: return
-                if (!fqName.matches(REGEX_RANGE_TO)) return
-
-                visitRangeToExpression(expression, holder)
-            }
+            visitRangeToExpression(expression, holder)
         }
     }
 

idea/src/org/jetbrains/kotlin/idea/inspections/AddVarianceModifierInspection.kt

@@ -1,17 +1,6 @@
 /*
- * Copyright 2010-2016 JetBrains s.r.o.
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- * http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
+ * Copyright 2000-2018 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license
+ * that can be found in the license/LICENSE.txt file.
  */
 
 package org.jetbrains.kotlin.idea.inspections
@@ -60,43 +49,41 @@ class AddVarianceModifierInspection : AbstractKotlinInspection() {
     }
 
     override fun buildVisitor(holder: ProblemsHolder, isOnTheFly: Boolean, session: LocalInspectionToolSession): PsiElementVisitor {
-        return object : KtVisitorVoid() {
-
-            private fun variancePossible(
-                    klass: KtClassOrObject,
-                    parameterDescriptor: TypeParameterDescriptor,
-                    variance: Variance,
-                    context: BindingContext
-            ) = VarianceCheckerCore(
-                    context,
-                    DiagnosticSink.DO_NOTHING,
-                    ManualVariance(parameterDescriptor, variance)
-            ).checkClassOrObject(klass)
-
-            override fun visitClassOrObject(klass: KtClassOrObject) {
-                val context = klass.analyzeFully()
-                for (typeParameter in klass.typeParameters) {
-                    if (typeParameter.variance != Variance.INVARIANT) continue
-                    val parameterDescriptor =
-                            context.get(BindingContext.DECLARATION_TO_DESCRIPTOR, typeParameter) as? TypeParameterDescriptor ?: continue
-                    val variances = listOf(Variance.IN_VARIANCE, Variance.OUT_VARIANCE).filter {
-                        variancePossible(klass, parameterDescriptor, it, context)
-                    }
-                    if (variances.size == 1) {
-                        val suggested = variances.first()
-                        val fixes = variances.map(::AddVarianceFix)
-                        holder.registerProblem(
-                                typeParameter,
-                                "Type parameter can have $suggested variance",
-                                ProblemHighlightType.GENERIC_ERROR_OR_WARNING,
-                                *fixes.toTypedArray()
-                        )
-                    }
+        return classOrObjectVisitor { klass ->
+            val context = klass.analyzeFully()
+            for (typeParameter in klass.typeParameters) {
+                if (typeParameter.variance != Variance.INVARIANT) continue
+                val parameterDescriptor =
+                        context.get(BindingContext.DECLARATION_TO_DESCRIPTOR, typeParameter) as? TypeParameterDescriptor ?: continue
+                val variances = listOf(Variance.IN_VARIANCE, Variance.OUT_VARIANCE).filter {
+                    variancePossible(klass, parameterDescriptor, it, context)
+                }
+                if (variances.size == 1) {
+                    val suggested = variances.first()
+                    val fixes = variances.map(::AddVarianceFix)
+                    holder.registerProblem(
+                            typeParameter,
+                            "Type parameter can have $suggested variance",
+                            ProblemHighlightType.GENERIC_ERROR_OR_WARNING,
+                            *fixes.toTypedArray()
+                    )
                 }
             }
         }
     }
 
+    private fun variancePossible(
+        klass: KtClassOrObject,
+        parameterDescriptor: TypeParameterDescriptor,
+        variance: Variance,
+        context: BindingContext
+    ) = VarianceCheckerCore(
+        context,
+        DiagnosticSink.DO_NOTHING,
+        ManualVariance(parameterDescriptor, variance)
+    ).checkClassOrObject(klass)
+
+
     class AddVarianceFix(val variance: Variance) : LocalQuickFix {
         override fun getName() = "Add '$variance' variance"
 

idea/src/org/jetbrains/kotlin/idea/inspections/ArrayInDataClassInspection.kt

@@ -1,17 +1,6 @@
 /*
- * Copyright 2010-2016 JetBrains s.r.o.
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- * http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
+ * Copyright 2000-2018 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license
+ * that can be found in the license/LICENSE.txt file.
  */
 
 package org.jetbrains.kotlin.idea.inspections
@@ -26,7 +15,7 @@ import org.jetbrains.kotlin.idea.caches.resolve.analyze
 import org.jetbrains.kotlin.lexer.KtTokens
 import org.jetbrains.kotlin.psi.KtClass
 import org.jetbrains.kotlin.psi.KtFunction
-import org.jetbrains.kotlin.psi.KtVisitorVoid
+import org.jetbrains.kotlin.psi.classVisitor
 import org.jetbrains.kotlin.psi.psiUtil.getNonStrictParentOfType
 import org.jetbrains.kotlin.resolve.BindingContext
 import org.jetbrains.kotlin.resolve.lazy.BodyResolveMode
@@ -34,47 +23,45 @@ import org.jetbrains.kotlin.util.OperatorNameConventions
 
 class ArrayInDataClassInspection : AbstractKotlinInspection() {
     override fun buildVisitor(holder: ProblemsHolder, isOnTheFly: Boolean, session: LocalInspectionToolSession): PsiElementVisitor {
-        return object : KtVisitorVoid() {
-            override fun visitClass(klass: KtClass) {
-                if (!klass.isData()) return
-                val constructor = klass.primaryConstructor ?: return
-                if (hasOverriddenEqualsAndHashCode(klass)) return
-                val context = constructor.analyze(BodyResolveMode.PARTIAL)
-                for (parameter in constructor.valueParameters) {
-                    if (!parameter.hasValOrVar()) continue
-                    val type = context.get(BindingContext.TYPE, parameter.typeReference) ?: continue
-                    if (KotlinBuiltIns.isArray(type) || KotlinBuiltIns.isPrimitiveArray(type)) {
-                        holder.registerProblem(parameter,
-                                               "Array property in data class: it's recommended to override equals() / hashCode()",
-                                               ProblemHighlightType.GENERIC_ERROR_OR_WARNING,
-                                               GenerateEqualsAndHashcodeFix())
-                    }
+        return classVisitor { klass ->
+            if (!klass.isData()) return@classVisitor
+            val constructor = klass.primaryConstructor ?: return@classVisitor
+            if (hasOverriddenEqualsAndHashCode(klass)) return@classVisitor
+            val context = constructor.analyze(BodyResolveMode.PARTIAL)
+            for (parameter in constructor.valueParameters) {
+                if (!parameter.hasValOrVar()) continue
+                val type = context.get(BindingContext.TYPE, parameter.typeReference) ?: continue
+                if (KotlinBuiltIns.isArray(type) || KotlinBuiltIns.isPrimitiveArray(type)) {
+                    holder.registerProblem(parameter,
+                                           "Array property in data class: it's recommended to override equals() / hashCode()",
+                                           ProblemHighlightType.GENERIC_ERROR_OR_WARNING,
+                                           GenerateEqualsAndHashcodeFix())
                 }
             }
-
-            private fun hasOverriddenEqualsAndHashCode(klass: KtClass): Boolean {
-                var overriddenEquals = false
-                var overriddenHashCode = false
-                for (declaration in klass.declarations) {
-                    if (declaration !is KtFunction) continue
-                    if (!declaration.hasModifier(KtTokens.OVERRIDE_KEYWORD)) continue
-                    if (declaration.nameAsName == OperatorNameConventions.EQUALS && declaration.valueParameters.size == 1) {
-                        val parameter = declaration.valueParameters.single()
-                        val context = declaration.analyze(BodyResolveMode.PARTIAL)
-                        val type = context.get(BindingContext.TYPE, parameter.typeReference)
-                        if (type != null && KotlinBuiltIns.isNullableAny(type)) {
-                            overriddenEquals = true
-                        }
-                    }
-                    if (declaration.name == "hashCode" && declaration.valueParameters.size == 0) {
-                        overriddenHashCode = true
-                    }
-                }
-                return overriddenEquals && overriddenHashCode
-            }
         }
     }
 
+    private fun hasOverriddenEqualsAndHashCode(klass: KtClass): Boolean {
+        var overriddenEquals = false
+        var overriddenHashCode = false
+        for (declaration in klass.declarations) {
+            if (declaration !is KtFunction) continue
+            if (!declaration.hasModifier(KtTokens.OVERRIDE_KEYWORD)) continue
+            if (declaration.nameAsName == OperatorNameConventions.EQUALS && declaration.valueParameters.size == 1) {
+                val parameter = declaration.valueParameters.single()
+                val context = declaration.analyze(BodyResolveMode.PARTIAL)
+                val type = context.get(BindingContext.TYPE, parameter.typeReference)
+                if (type != null && KotlinBuiltIns.isNullableAny(type)) {
+                    overriddenEquals = true
+                }
+            }
+            if (declaration.name == "hashCode" && declaration.valueParameters.size == 0) {
+                overriddenHashCode = true
+            }
+        }
+        return overriddenEquals && overriddenHashCode
+    }
+
     class GenerateEqualsAndHashcodeFix : LocalQuickFix {
         override fun getName() = "Generate equals() and hashCode()"
 

idea/src/org/jetbrains/kotlin/idea/inspections/CanBeParameterInspection.kt

@@ -1,17 +1,6 @@
 /*
- * Copyright 2010-2016 JetBrains s.r.o.
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- * http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
+ * Copyright 2000-2018 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license
+ * that can be found in the license/LICENSE.txt file.
  */
 
 package org.jetbrains.kotlin.idea.inspections
@@ -78,46 +67,43 @@ class CanBeParameterInspection : AbstractKotlinInspection() {
     }
 
     override fun buildVisitor(holder: ProblemsHolder, isOnTheFly: Boolean): PsiElementVisitor {
-        return object : KtVisitorVoid() {
+        return parameterVisitor(fun(parameter) {
+            // Applicable to val / var parameters of a class / object primary constructors
+            val valOrVar = parameter.valOrVarKeyword ?: return
+            val name = parameter.name ?: return
+            if (parameter.hasModifier(OVERRIDE_KEYWORD)) return
+            if (parameter.annotationEntries.isNotEmpty()) return
+            val constructor = parameter.parent.parent as? KtPrimaryConstructor ?: return
+            val klass = constructor.getContainingClassOrObject() as? KtClass ?: return
+            if (klass.isData()) return
 
-            override fun visitParameter(parameter: KtParameter) {
-                // Applicable to val / var parameters of a class / object primary constructors
-                val valOrVar = parameter.valOrVarKeyword ?: return
-                val name = parameter.name ?: return
-                if (parameter.hasModifier(OVERRIDE_KEYWORD)) return
-                if (parameter.annotationEntries.isNotEmpty()) return
-                val constructor = parameter.parent.parent as? KtPrimaryConstructor ?: return
-                val klass = constructor.getContainingClassOrObject() as? KtClass ?: return
-                if (klass.isData()) return
-
-                val useScope = parameter.useScope
-                val restrictedScope = if (useScope is GlobalSearchScope) {
-                    val psiSearchHelper = PsiSearchHelper.SERVICE.getInstance(parameter.project)
-                    for (accessorName in parameter.getAccessorNames()) {
-                        when (psiSearchHelper.isCheapEnoughToSearchConsideringOperators(accessorName, useScope, null, null)) {
-                            ZERO_OCCURRENCES -> {
-                            } // go on
-                            else -> return         // accessor in use: should remain a property
-                        }
+            val useScope = parameter.useScope
+            val restrictedScope = if (useScope is GlobalSearchScope) {
+                val psiSearchHelper = PsiSearchHelper.SERVICE.getInstance(parameter.project)
+                for (accessorName in parameter.getAccessorNames()) {
+                    when (psiSearchHelper.isCheapEnoughToSearchConsideringOperators(accessorName, useScope, null, null)) {
+                        ZERO_OCCURRENCES -> {
+                        } // go on
+                        else -> return         // accessor in use: should remain a property
                     }
-                    // TOO_MANY_OCCURRENCES: too expensive
-                    // ZERO_OCCURRENCES: unused at all, reported elsewhere
-                    if (psiSearchHelper.isCheapEnoughToSearchConsideringOperators(name, useScope, null, null) != FEW_OCCURRENCES) return
-                    KotlinSourceFilterScope.projectSources(useScope, parameter.project)
                 }
-                else useScope
-                // Find all references and check them
-                val references = ReferencesSearch.search(parameter, restrictedScope)
-                if (references.none()) return
-                if (references.any { it.usedAsPropertyIn(klass) }) return
-                holder.registerProblem(
-                        valOrVar,
-                        "Constructor parameter is never used as a property",
-                        ProblemHighlightType.LIKE_UNUSED_SYMBOL,
-                        RemoveValVarFix(parameter)
-                )
+                // TOO_MANY_OCCURRENCES: too expensive
+                // ZERO_OCCURRENCES: unused at all, reported elsewhere
+                if (psiSearchHelper.isCheapEnoughToSearchConsideringOperators(name, useScope, null, null) != FEW_OCCURRENCES) return
+                KotlinSourceFilterScope.projectSources(useScope, parameter.project)
             }
-        }
+            else useScope
+            // Find all references and check them
+            val references = ReferencesSearch.search(parameter, restrictedScope)
+            if (references.none()) return
+            if (references.any { it.usedAsPropertyIn(klass) }) return
+            holder.registerProblem(
+                    valOrVar,
+                    "Constructor parameter is never used as a property",
+                    ProblemHighlightType.LIKE_UNUSED_SYMBOL,
+                    RemoveValVarFix(parameter)
+            )
+        })
     }
 
     class RemoveValVarFix(val parameter: KtParameter) : LocalQuickFix {

idea/src/org/jetbrains/kotlin/idea/inspections/CanBePrimaryConstructorPropertyInspection.kt

@@ -1,17 +1,6 @@
 /*
- * Copyright 2010-2016 JetBrains s.r.o.
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- * http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
+ * Copyright 2000-2018 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license
+ * that can be found in the license/LICENSE.txt file.
  */
 
 package org.jetbrains.kotlin.idea.inspections
@@ -25,9 +14,8 @@ import org.jetbrains.kotlin.idea.caches.resolve.analyzeFully
 import org.jetbrains.kotlin.idea.intentions.MovePropertyToConstructorIntention
 import org.jetbrains.kotlin.idea.refactoring.isInterfaceClass
 import org.jetbrains.kotlin.psi.KtParameter
-import org.jetbrains.kotlin.psi.KtProperty
 import org.jetbrains.kotlin.psi.KtReferenceExpression
-import org.jetbrains.kotlin.psi.KtVisitorVoid
+import org.jetbrains.kotlin.psi.propertyVisitor
 import org.jetbrains.kotlin.psi.psiUtil.containingClassOrObject
 import org.jetbrains.kotlin.resolve.BindingContext
 import org.jetbrains.kotlin.resolve.DescriptorToSourceUtils
@@ -35,39 +23,37 @@ import org.jetbrains.kotlin.resolve.DescriptorToSourceUtils
 class CanBePrimaryConstructorPropertyInspection : AbstractKotlinInspection() {
 
     override fun buildVisitor(holder: ProblemsHolder, isOnTheFly: Boolean): PsiElementVisitor {
-        return object : KtVisitorVoid() {
-            override fun visitProperty(property: KtProperty) {
-                if (property.isLocal) return
-                if (property.getter != null || property.setter != null || property.delegate != null) return
-                val assigned = property.initializer as? KtReferenceExpression ?: return
+        return propertyVisitor(fun(property) {
+            if (property.isLocal) return
+            if (property.getter != null || property.setter != null || property.delegate != null) return
+            val assigned = property.initializer as? KtReferenceExpression ?: return
 
-                val context = property.analyzeFully()
-                val assignedDescriptor = context.get(BindingContext.REFERENCE_TARGET, assigned) as? ValueParameterDescriptor ?: return
+            val context = property.analyzeFully()
+            val assignedDescriptor = context.get(BindingContext.REFERENCE_TARGET, assigned) as? ValueParameterDescriptor ?: return
 
-                val containingConstructor = assignedDescriptor.containingDeclaration as? ClassConstructorDescriptor ?: return
-                if (containingConstructor.containingDeclaration.isData) return
+            val containingConstructor = assignedDescriptor.containingDeclaration as? ClassConstructorDescriptor ?: return
+            if (containingConstructor.containingDeclaration.isData) return
 
-                val propertyTypeReference = property.typeReference
-                val propertyType = context.get(BindingContext.TYPE, propertyTypeReference)
-                if (propertyType != null && propertyType != assignedDescriptor.type) return
+            val propertyTypeReference = property.typeReference
+            val propertyType = context.get(BindingContext.TYPE, propertyTypeReference)
+            if (propertyType != null && propertyType != assignedDescriptor.type) return
 
-                val nameIdentifier = property.nameIdentifier ?: return
-                if (nameIdentifier.text != assignedDescriptor.name.asString()) return
+            val nameIdentifier = property.nameIdentifier ?: return
+            if (nameIdentifier.text != assignedDescriptor.name.asString()) return
 
-                val assignedParameter = DescriptorToSourceUtils.descriptorToDeclaration(assignedDescriptor) as? KtParameter ?: return
-                if (property.containingClassOrObject !== assignedParameter.containingClassOrObject) return
+            val assignedParameter = DescriptorToSourceUtils.descriptorToDeclaration(assignedDescriptor) as? KtParameter ?: return
+            if (property.containingClassOrObject !== assignedParameter.containingClassOrObject) return
 
-                if (property.containingClassOrObject?.isInterfaceClass() ?: false) return
+            if (property.containingClassOrObject?.isInterfaceClass() ?: false) return
 
-                holder.registerProblem(holder.manager.createProblemDescriptor(
-                        nameIdentifier,
-                        nameIdentifier,
-                        "Property is explicitly assigned to parameter ${assignedDescriptor.name}, can be declared directly in constructor",
-                        ProblemHighlightType.GENERIC_ERROR_OR_WARNING,
-                        isOnTheFly,
-                        MovePropertyToConstructorIntention()
-                ))
-            }
-        }
+            holder.registerProblem(holder.manager.createProblemDescriptor(
+                    nameIdentifier,
+                    nameIdentifier,
+                    "Property is explicitly assigned to parameter ${assignedDescriptor.name}, can be declared directly in constructor",
+                    ProblemHighlightType.GENERIC_ERROR_OR_WARNING,
+                    isOnTheFly,
+                    MovePropertyToConstructorIntention()
+            ))
+        })
     }
 }

idea/src/org/jetbrains/kotlin/idea/inspections/CascadeIfInspection.kt

@@ -1,17 +1,6 @@
 /*
- * Copyright 2010-2017 JetBrains s.r.o.
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- * http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
+ * Copyright 2000-2018 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license
+ * that can be found in the license/LICENSE.txt file.
  */
 
 package org.jetbrains.kotlin.idea.inspections
@@ -21,8 +10,8 @@ import com.intellij.codeInspection.LocalInspectionToolSession
 import com.intellij.codeInspection.ProblemHighlightType
 import com.intellij.codeInspection.ProblemsHolder
 import org.jetbrains.kotlin.idea.intentions.branchedTransformations.intentions.IfToWhenIntention
-import org.jetbrains.kotlin.idea.intentions.branchedTransformations.isOneLiner
 import org.jetbrains.kotlin.idea.intentions.branchedTransformations.isElseIf
+import org.jetbrains.kotlin.idea.intentions.branchedTransformations.isOneLiner
 import org.jetbrains.kotlin.idea.intentions.branches
 import org.jetbrains.kotlin.lexer.KtTokens
 import org.jetbrains.kotlin.psi.*
@@ -31,45 +20,41 @@ import org.jetbrains.kotlin.psi.psiUtil.lastBlockStatementOrThis
 
 class CascadeIfInspection : AbstractKotlinInspection() {
     override fun buildVisitor(holder: ProblemsHolder, isOnTheFly: Boolean, session: LocalInspectionToolSession) =
-            object : KtVisitorVoid() {
-                override fun visitIfExpression(expression: KtIfExpression) {
-                    super.visitIfExpression(expression)
+        ifExpressionVisitor(fun(expression) {
+            val branches = expression.branches
+            if (branches.size <= 2) return
+            if (expression.isOneLiner()) return
 
-                    val branches = expression.branches
-                    if (branches.size <= 2) return
-                    if (expression.isOneLiner()) return
+            if (branches.any {
+                it == null ||
+                it.lastBlockStatementOrThis() is KtIfExpression
+            }) return
 
-                    if (branches.any {
-                        it == null ||
-                        it.lastBlockStatementOrThis() is KtIfExpression
-                    }) return
+            if (expression.isElseIf()) return
 
-                    if (expression.isElseIf()) return
+            if (expression.anyDescendantOfType<KtExpressionWithLabel> {
+                it is KtBreakExpression || it is KtContinueExpression
+            }) return
 
-                    if (expression.anyDescendantOfType<KtExpressionWithLabel> {
-                        it is KtBreakExpression || it is KtContinueExpression
-                    }) return
-
-                    var current: KtIfExpression? = expression
-                    while (current != null) {
-                        val condition = current.condition
-                        when (condition) {
-                            is KtBinaryExpression -> when (condition.operationToken) {
-                                KtTokens.ANDAND, KtTokens.OROR -> return
-                            }
-                            is KtUnaryExpression -> when (condition.operationToken) {
-                                KtTokens.EXCL -> return
-                            }
-                        }
-                        current = current.`else` as? KtIfExpression
+            var current: KtIfExpression? = expression
+            while (current != null) {
+                val condition = current.condition
+                when (condition) {
+                    is KtBinaryExpression -> when (condition.operationToken) {
+                        KtTokens.ANDAND, KtTokens.OROR -> return
+                    }
+                    is KtUnaryExpression -> when (condition.operationToken) {
+                        KtTokens.EXCL -> return
                     }
-
-                    holder.registerProblem(
-                            expression.ifKeyword,
-                            "Cascade if should be replaced with when",
-                            ProblemHighlightType.GENERIC_ERROR_OR_WARNING,
-                            IntentionWrapper(IfToWhenIntention(), expression.containingKtFile)
-                    )
                 }
+                current = current.`else` as? KtIfExpression
             }
-}
+
+            holder.registerProblem(
+                    expression.ifKeyword,
+                    "Cascade if should be replaced with when",
+                    ProblemHighlightType.GENERIC_ERROR_OR_WARNING,
+                    IntentionWrapper(IfToWhenIntention(), expression.containingKtFile)
+            )
+        })
+}

idea/src/org/jetbrains/kotlin/idea/inspections/ConflictingExtensionPropertyInspection.kt

@@ -1,24 +1,16 @@
 /*
- * Copyright 2010-2016 JetBrains s.r.o.
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- * http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
+ * Copyright 2000-2018 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license
+ * that can be found in the license/LICENSE.txt file.
  */
 
 package org.jetbrains.kotlin.idea.inspections
 
 import com.intellij.codeInsight.FileModificationService
 import com.intellij.codeInsight.intention.LowPriorityAction
-import com.intellij.codeInspection.*
+import com.intellij.codeInspection.IntentionWrapper
+import com.intellij.codeInspection.LocalInspectionToolSession
+import com.intellij.codeInspection.ProblemHighlightType
+import com.intellij.codeInspection.ProblemsHolder
 import com.intellij.openapi.application.ModalityState
 import com.intellij.openapi.diagnostic.Logger
 import com.intellij.openapi.editor.Editor
@@ -34,8 +26,8 @@ import org.jetbrains.kotlin.descriptors.FunctionDescriptor
 import org.jetbrains.kotlin.descriptors.PropertyDescriptor
 import org.jetbrains.kotlin.idea.caches.resolve.analyze
 import org.jetbrains.kotlin.idea.caches.resolve.getResolutionFacade
-import org.jetbrains.kotlin.idea.caches.resolve.unsafeResolveToDescriptor
 import org.jetbrains.kotlin.idea.caches.resolve.resolveToDescriptorIfAny
+import org.jetbrains.kotlin.idea.caches.resolve.unsafeResolveToDescriptor
 import org.jetbrains.kotlin.idea.core.targetDescriptors
 import org.jetbrains.kotlin.idea.imports.importableFqName
 import org.jetbrains.kotlin.idea.quickfix.KotlinQuickFixAction
@@ -63,33 +55,29 @@ class ConflictingExtensionPropertyInspection : AbstractKotlinInspection() {
         val file = session.file as? KtFile ?: return PsiElementVisitor.EMPTY_VISITOR
         val resolutionFacade = file.getResolutionFacade()
 
-        return object : KtVisitorVoid() {
-            override fun visitProperty(property: KtProperty) {
-                super.visitProperty(property)
+        return propertyVisitor(fun(property: KtProperty) {
+            if (property.receiverTypeReference != null) {
+                val nameElement = property.nameIdentifier ?: return
+                val propertyDescriptor = property.resolveToDescriptorIfAny() as? PropertyDescriptor ?: return
 
-                if (property.receiverTypeReference != null) {
-                    val nameElement = property.nameIdentifier ?: return
-                    val propertyDescriptor = property.resolveToDescriptorIfAny() as? PropertyDescriptor ?: return
+                val syntheticScopes = resolutionFacade.frontendService<SyntheticScopes>()
+                val conflictingExtension = conflictingSyntheticExtension(propertyDescriptor, syntheticScopes) ?: return
 
-                    val syntheticScopes = resolutionFacade.frontendService<SyntheticScopes>()
-                    val conflictingExtension = conflictingSyntheticExtension(propertyDescriptor, syntheticScopes) ?: return
+                // don't report on hidden declarations
+                if (resolutionFacade.frontendService<DeprecationResolver>().isHiddenInResolution(propertyDescriptor)) return
 
-                    // don't report on hidden declarations
-                    if (resolutionFacade.frontendService<DeprecationResolver>().isHiddenInResolution(propertyDescriptor)) return
+                val fixes = createFixes(property, conflictingExtension, isOnTheFly)
 
-                    val fixes = createFixes(property, conflictingExtension, isOnTheFly)
-
-                    val problemDescriptor = holder.manager.createProblemDescriptor(
-                            nameElement,
-                            "This property conflicts with synthetic extension and should be removed or renamed to avoid breaking code by future changes in the compiler",
-                            true,
-                            fixes,
-                            ProblemHighlightType.GENERIC_ERROR_OR_WARNING
-                    )
-                    holder.registerProblem(problemDescriptor)
-                }
+                val problemDescriptor = holder.manager.createProblemDescriptor(
+                        nameElement,
+                        "This property conflicts with synthetic extension and should be removed or renamed to avoid breaking code by future changes in the compiler",
+                        true,
+                        fixes,
+                        ProblemHighlightType.GENERIC_ERROR_OR_WARNING
+                )
+                holder.registerProblem(problemDescriptor)
             }
-        }
+        })
     }
 
     private fun conflictingSyntheticExtension(descriptor: PropertyDescriptor, scopes: SyntheticScopes): SyntheticJavaPropertyDescriptor? {

idea/src/org/jetbrains/kotlin/idea/inspections/ConstantConditionIfInspection.kt

@@ -1,17 +1,6 @@
 /*
- * Copyright 2010-2017 JetBrains s.r.o.
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- * http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
+ * Copyright 2000-2018 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license
+ * that can be found in the license/LICENSE.txt file.
  */
 
 package org.jetbrains.kotlin.idea.inspections
@@ -37,31 +26,27 @@ import org.jetbrains.kotlin.resolve.lazy.BodyResolveMode
 class ConstantConditionIfInspection : AbstractKotlinInspection() {
 
     override fun buildVisitor(holder: ProblemsHolder, isOnTheFly: Boolean): PsiElementVisitor {
-        return object : KtVisitorVoid() {
-            override fun visitIfExpression(expression: KtIfExpression) {
-                super.visitIfExpression(expression)
+        return ifExpressionVisitor(fun(expression) {
+            val condition = expression.condition ?: return
 
-                val condition = expression.condition ?: return
+            val context = condition.analyze(BodyResolveMode.PARTIAL)
+            val constantValue = condition.constantBooleanValue(context) ?: return
 
-                val context = condition.analyze(BodyResolveMode.PARTIAL)
-                val constantValue = condition.constantBooleanValue(context) ?: return
+            val fixes = mutableListOf<LocalQuickFix>()
 
-                val fixes = mutableListOf<LocalQuickFix>()
-
-                if (expression.branch(constantValue) != null) {
-                    val keepBraces = expression.isElseIf() && expression.branch(constantValue) is KtBlockExpression
-                    fixes += SimplifyFix(constantValue, expression.isUsedAsExpression(context), keepBraces)
-                }
-
-                if (!constantValue && expression.`else` == null) {
-                    fixes += RemoveFix()
-                }
-
-                holder.registerProblem(condition,
-                                       "Condition is always '$constantValue'",
-                                       *fixes.toTypedArray())
+            if (expression.branch(constantValue) != null) {
+                val keepBraces = expression.isElseIf() && expression.branch(constantValue) is KtBlockExpression
+                fixes += SimplifyFix(constantValue, expression.isUsedAsExpression(context), keepBraces)
             }
-        }
+
+            if (!constantValue && expression.`else` == null) {
+                fixes += RemoveFix()
+            }
+
+            holder.registerProblem(condition,
+                                   "Condition is always '$constantValue'",
+                                   *fixes.toTypedArray())
+        })
     }
 
     private class SimplifyFix(

idea/src/org/jetbrains/kotlin/idea/inspections/CopyWithoutNamedArgumentsInspection.kt

@@ -1,17 +1,6 @@
 /*
- * Copyright 2010-2017 JetBrains s.r.o.
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- * http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
+ * Copyright 2000-2018 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license
+ * that can be found in the license/LICENSE.txt file.
  */
 
 package org.jetbrains.kotlin.idea.inspections
@@ -23,9 +12,8 @@ import com.intellij.psi.PsiElementVisitor
 import org.jetbrains.kotlin.descriptors.ClassDescriptor
 import org.jetbrains.kotlin.idea.caches.resolve.analyze
 import org.jetbrains.kotlin.idea.intentions.AddNamesToCallArgumentsIntention
-import org.jetbrains.kotlin.psi.KtCallExpression
 import org.jetbrains.kotlin.psi.KtNameReferenceExpression
-import org.jetbrains.kotlin.psi.KtVisitorVoid
+import org.jetbrains.kotlin.psi.callExpressionVisitor
 import org.jetbrains.kotlin.psi.psiUtil.referenceExpression
 import org.jetbrains.kotlin.resolve.BindingContext
 import org.jetbrains.kotlin.resolve.DataClassDescriptorResolver
@@ -35,29 +23,25 @@ import org.jetbrains.kotlin.resolve.lazy.BodyResolveMode
 class CopyWithoutNamedArgumentsInspection : AbstractKotlinInspection() {
 
     override fun buildVisitor(holder: ProblemsHolder, isOnTheFly: Boolean): PsiElementVisitor {
-        return object : KtVisitorVoid() {
-            override fun visitCallExpression(expression: KtCallExpression) {
-                super.visitCallExpression(expression)
+        return callExpressionVisitor(fun(expression) {
+            val reference = expression.referenceExpression() as? KtNameReferenceExpression ?: return
+            if (reference.getReferencedNameAsName() != DataClassDescriptorResolver.COPY_METHOD_NAME) return
+            if (expression.valueArguments.all { it.isNamed() }) return
 
-                val reference = expression.referenceExpression() as? KtNameReferenceExpression ?: return
-                if (reference.getReferencedNameAsName() != DataClassDescriptorResolver.COPY_METHOD_NAME) return
-                if (expression.valueArguments.all { it.isNamed() }) return
+            val context = expression.analyze(BodyResolveMode.PARTIAL)
+            val call = expression.getResolvedCall(context) ?: return
+            val receiver = call.dispatchReceiver?.type?.constructor?.declarationDescriptor as? ClassDescriptor ?: return
 
-                val context = expression.analyze(BodyResolveMode.PARTIAL)
-                val call = expression.getResolvedCall(context) ?: return
-                val receiver = call.dispatchReceiver?.type?.constructor?.declarationDescriptor as? ClassDescriptor ?: return
+            if (!receiver.isData) return
+            if (call.candidateDescriptor != context[BindingContext.DATA_CLASS_COPY_FUNCTION, receiver]) return
 
-                if (!receiver.isData) return
-                if (call.candidateDescriptor != context[BindingContext.DATA_CLASS_COPY_FUNCTION, receiver]) return
-
-                holder.registerProblem(
-                        expression.calleeExpression ?: return,
-                        "'copy' method of data class is called without named arguments",
-                        ProblemHighlightType.GENERIC_ERROR_OR_WARNING,
-                        IntentionWrapper(AddNamesToCallArgumentsIntention(), expression.containingKtFile)
-                )
-            }
-        }
+            holder.registerProblem(
+                    expression.calleeExpression ?: return,
+                    "'copy' method of data class is called without named arguments",
+                    ProblemHighlightType.GENERIC_ERROR_OR_WARNING,
+                    IntentionWrapper(AddNamesToCallArgumentsIntention(), expression.containingKtFile)
+            )
+        })
     }
 
 }

idea/src/org/jetbrains/kotlin/idea/inspections/DataClassPrivateConstructorInspection.kt

@@ -1,17 +1,6 @@
 /*
- * Copyright 2010-2017 JetBrains s.r.o.
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- * http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
+ * Copyright 2000-2018 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license
+ * that can be found in the license/LICENSE.txt file.
  */
 
 package org.jetbrains.kotlin.idea.inspections
@@ -20,29 +9,24 @@ import com.intellij.codeInspection.ProblemHighlightType
 import com.intellij.codeInspection.ProblemsHolder
 import com.intellij.psi.PsiElementVisitor
 import org.jetbrains.kotlin.lexer.KtTokens
-import org.jetbrains.kotlin.psi.KtPrimaryConstructor
-import org.jetbrains.kotlin.psi.KtVisitorVoid
+import org.jetbrains.kotlin.psi.primaryConstructorVisitor
 import org.jetbrains.kotlin.psi.psiUtil.containingClass
 import org.jetbrains.kotlin.psi.psiUtil.isPrivate
 
 class DataClassPrivateConstructorInspection : AbstractKotlinInspection() {
     override fun buildVisitor(holder: ProblemsHolder, isOnTheFly: Boolean): PsiElementVisitor {
-        return object : KtVisitorVoid() {
-            override fun visitPrimaryConstructor(constructor: KtPrimaryConstructor) {
-                super.visitPrimaryConstructor(constructor)
+        return primaryConstructorVisitor { constructor ->
+            if (constructor.containingClass()?.isData() == true && constructor.isPrivate()) {
+                val keyword = constructor.modifierList?.getModifier(KtTokens.PRIVATE_KEYWORD) ?: return@primaryConstructorVisitor
+                val problemDescriptor = holder.manager.createProblemDescriptor(
+                        keyword,
+                        keyword,
+                        "Private data class constructor is exposed via the generated 'copy' method.",
+                        ProblemHighlightType.GENERIC_ERROR_OR_WARNING,
+                        isOnTheFly
+                )
 
-                if (constructor.containingClass()?.isData() == true && constructor.isPrivate()) {
-                    val keyword = constructor.modifierList?.getModifier(KtTokens.PRIVATE_KEYWORD) ?: return
-                    val problemDescriptor = holder.manager.createProblemDescriptor(
-                            keyword,
-                            keyword,
-                            "Private data class constructor is exposed via the generated 'copy' method.",
-                            ProblemHighlightType.GENERIC_ERROR_OR_WARNING,
-                            isOnTheFly
-                    )
-
-                    holder.registerProblem(problemDescriptor)
-                }
+                holder.registerProblem(problemDescriptor)
             }
         }
     }

idea/src/org/jetbrains/kotlin/idea/inspections/DestructuringWrongNameInspection.kt

@@ -1,17 +1,6 @@
 /*
- * Copyright 2010-2017 JetBrains s.r.o.
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- * http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
+ * Copyright 2000-2018 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license
+ * that can be found in the license/LICENSE.txt file.
  */
 
 package org.jetbrains.kotlin.idea.inspections
@@ -21,42 +10,37 @@ import com.intellij.codeInspection.ProblemsHolder
 import com.intellij.psi.PsiElementVisitor
 import org.jetbrains.kotlin.descriptors.ClassDescriptor
 import org.jetbrains.kotlin.idea.caches.resolve.analyze
-import org.jetbrains.kotlin.psi.KtDestructuringDeclaration
-import org.jetbrains.kotlin.psi.KtVisitorVoid
+import org.jetbrains.kotlin.psi.destructuringDeclarationVisitor
 
 class DestructuringWrongNameInspection : AbstractKotlinInspection() {
     override fun buildVisitor(holder: ProblemsHolder, isOnTheFly: Boolean): PsiElementVisitor {
-        return object : KtVisitorVoid() {
-            override fun visitDestructuringDeclaration(destructuringDeclaration: KtDestructuringDeclaration) {
-                super.visitDestructuringDeclaration(destructuringDeclaration)
+        return destructuringDeclarationVisitor(fun(destructuringDeclaration) {
+            val initializer = destructuringDeclaration.initializer ?: return
+            val type = initializer.analyze().getType(initializer) ?: return
 
-                val initializer = destructuringDeclaration.initializer ?: return
-                val type = initializer.analyze().getType(initializer) ?: return
+            val classDescriptor = type.constructor.declarationDescriptor as? ClassDescriptor ?: return
 
-                val classDescriptor = type.constructor.declarationDescriptor as? ClassDescriptor ?: return
+            val primaryParameterNames = classDescriptor.constructors
+                                            .firstOrNull { it.isPrimary }
+                                            ?.valueParameters
+                                            ?.map { it.name.asString() } ?: return
 
-                val primaryParameterNames = classDescriptor.constructors
-                                                .firstOrNull { it.isPrimary }
-                                                ?.valueParameters
-                                                ?.map { it.name.asString() } ?: return
-
-                destructuringDeclaration.entries.forEachIndexed { entryIndex, entry ->
-                    val variableName = entry.name
-                    if (variableName != primaryParameterNames.getOrNull(entryIndex)) {
-                        for ((parameterIndex, parameterName) in primaryParameterNames.withIndex()) {
-                            if (parameterIndex == entryIndex) continue
-                            if (variableName == parameterName) {
-                                val fix = primaryParameterNames.getOrNull(entryIndex)?.let { RenameElementFix(entry, it) }
-                                holder.registerProblem(
-                                        entry,
-                                        "Variable name '$variableName' matches the name of a different component",
-                                        *listOfNotNull(fix).toTypedArray())
-                                break
-                            }
+            destructuringDeclaration.entries.forEachIndexed { entryIndex, entry ->
+                val variableName = entry.name
+                if (variableName != primaryParameterNames.getOrNull(entryIndex)) {
+                    for ((parameterIndex, parameterName) in primaryParameterNames.withIndex()) {
+                        if (parameterIndex == entryIndex) continue
+                        if (variableName == parameterName) {
+                            val fix = primaryParameterNames.getOrNull(entryIndex)?.let { RenameElementFix(entry, it) }
+                            holder.registerProblem(
+                                    entry,
+                                    "Variable name '$variableName' matches the name of a different component",
+                                    *listOfNotNull(fix).toTypedArray())
+                            break
                         }
                     }
                 }
             }
-        }
+        })
     }
-}
+}

idea/src/org/jetbrains/kotlin/idea/inspections/EqualsOrHashCodeInspection.kt

@@ -1,17 +1,6 @@
 /*
- * Copyright 2010-2015 JetBrains s.r.o.
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- * http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
+ * Copyright 2000-2018 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license
+ * that can be found in the license/LICENSE.txt file.
  */
 
 package org.jetbrains.kotlin.idea.inspections
@@ -29,10 +18,7 @@ import org.jetbrains.kotlin.idea.actions.generate.KotlinGenerateEqualsAndHashcod
 import org.jetbrains.kotlin.idea.actions.generate.findDeclaredEquals
 import org.jetbrains.kotlin.idea.actions.generate.findDeclaredHashCode
 import org.jetbrains.kotlin.idea.caches.resolve.resolveToDescriptorIfAny
-import org.jetbrains.kotlin.psi.KtClass
-import org.jetbrains.kotlin.psi.KtClassOrObject
-import org.jetbrains.kotlin.psi.KtObjectDeclaration
-import org.jetbrains.kotlin.psi.KtVisitorVoid
+import org.jetbrains.kotlin.psi.*
 import org.jetbrains.kotlin.psi.psiUtil.getStrictParentOfType
 import org.jetbrains.kotlin.resolve.source.getPsi
 
@@ -71,35 +57,33 @@ sealed class GenerateEqualsOrHashCodeFix : LocalQuickFix {
 
 class EqualsOrHashCodeInspection : AbstractKotlinInspection() {
     override fun buildVisitor(holder: ProblemsHolder, isOnTheFly: Boolean): PsiElementVisitor {
-        return object: KtVisitorVoid() {
-            override fun visitClassOrObject(classOrObject: KtClassOrObject) {
-                val nameIdentifier = classOrObject.nameIdentifier ?: return
-                val classDescriptor = classOrObject.resolveToDescriptorIfAny() as? ClassDescriptor ?: return
-                val hasEquals = classDescriptor.findDeclaredEquals(false) != null
-                val hasHashCode = classDescriptor.findDeclaredHashCode(false) != null
-                if (!hasEquals && !hasHashCode) return
+        return classOrObjectVisitor(fun(classOrObject) {
+            val nameIdentifier = classOrObject.nameIdentifier ?: return
+            val classDescriptor = classOrObject.resolveToDescriptorIfAny() as? ClassDescriptor ?: return
+            val hasEquals = classDescriptor.findDeclaredEquals(false) != null
+            val hasHashCode = classDescriptor.findDeclaredHashCode(false) != null
+            if (!hasEquals && !hasHashCode) return
 
-                when (classDescriptor.kind) {
-                    ClassKind.OBJECT -> {
-                        if (classOrObject.superTypeListEntries.isNotEmpty()) return
-                        holder.registerProblem(nameIdentifier, "equals()/hashCode() in object declaration", DeleteEqualsAndHashCodeFix)
-                    }
-                    ClassKind.CLASS -> {
-                        if (hasEquals && hasHashCode) return
-                        val description = InspectionsBundle.message(
-                                "inspection.equals.hashcode.only.one.defined.problem.descriptor",
-                                if (hasEquals) "<code>equals()</code>" else "<code>hashCode()</code>",
-                                if (hasEquals) "<code>hashCode()</code>" else "<code>equals()</code>"
-                        )
-                        holder.registerProblem(
-                                nameIdentifier,
-                                description,
-                                if (hasEquals) GenerateEqualsOrHashCodeFix.HashCode else GenerateEqualsOrHashCodeFix.Equals
-                        )
-                    }
-                    else -> return
+            when (classDescriptor.kind) {
+                ClassKind.OBJECT -> {
+                    if (classOrObject.superTypeListEntries.isNotEmpty()) return
+                    holder.registerProblem(nameIdentifier, "equals()/hashCode() in object declaration", DeleteEqualsAndHashCodeFix)
                 }
+                ClassKind.CLASS -> {
+                    if (hasEquals && hasHashCode) return
+                    val description = InspectionsBundle.message(
+                            "inspection.equals.hashcode.only.one.defined.problem.descriptor",
+                            if (hasEquals) "<code>equals()</code>" else "<code>hashCode()</code>",
+                            if (hasEquals) "<code>hashCode()</code>" else "<code>equals()</code>"
+                    )
+                    holder.registerProblem(
+                            nameIdentifier,
+                            description,
+                            if (hasEquals) GenerateEqualsOrHashCodeFix.HashCode else GenerateEqualsOrHashCodeFix.Equals
+                    )
+                }
+                else -> return
             }
-        }
+        })
     }
 }

idea/src/org/jetbrains/kotlin/idea/inspections/JavaCollectionsStaticMethodCallInspection.kt

@@ -1,17 +1,6 @@
 /*
- * Copyright 2010-2017 JetBrains s.r.o.
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- * http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
+ * Copyright 2000-2018 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license
+ * that can be found in the license/LICENSE.txt file.
  */
 
 package org.jetbrains.kotlin.idea.inspections
@@ -38,29 +27,25 @@ import org.jetbrains.kotlin.resolve.lazy.BodyResolveMode
 
 class JavaCollectionsStaticMethodInspection : AbstractKotlinInspection() {
     override fun buildVisitor(holder: ProblemsHolder, isOnTheFly: Boolean): PsiElementVisitor {
-        return object : KtVisitorVoid() {
-            override fun visitDotQualifiedExpression(expression: KtDotQualifiedExpression) {
-                super.visitDotQualifiedExpression(expression)
+        return dotQualifiedExpressionVisitor(fun(expression) {
+            val callExpression = expression.callExpression ?: return
+            val args = callExpression.valueArguments
+            val firstArg = args.firstOrNull() ?: return
+            val context = expression.analyze(BodyResolveMode.PARTIAL)
+            if (KotlinBuiltIns.FQ_NAMES.mutableList !=
+                    firstArg.getArgumentExpression()?.getType(context)?.constructor?.declarationDescriptor?.fqNameSafe) return
 
-                val callExpression = expression.callExpression ?: return
-                val args = callExpression.valueArguments
-                val firstArg = args.firstOrNull() ?: return
-                val context = expression.analyze(BodyResolveMode.PARTIAL)
-                if (KotlinBuiltIns.FQ_NAMES.mutableList !=
-                        firstArg.getArgumentExpression()?.getType(context)?.constructor?.declarationDescriptor?.fqNameSafe) return
+            val resolvedCall = expression.getResolvedCall(context) ?: return
+            val descriptor = resolvedCall.resultingDescriptor as? JavaMethodDescriptor ?: return
+            val fqName = descriptor.importableFqName?.asString() ?: return
+            if (!canReplaceWithStdLib(expression, fqName, args)) return
 
-                val resolvedCall = expression.getResolvedCall(context) ?: return
-                val descriptor = resolvedCall.resultingDescriptor as? JavaMethodDescriptor ?: return
-                val fqName = descriptor.importableFqName?.asString() ?: return
-                if (!canReplaceWithStdLib(expression, fqName, args)) return
-
-                val methodName = fqName.split(".").last()
-                holder.registerProblem(expression,
-                                       "Java Collections static method call should be replaced with Kotlin stdlib",
-                                       ProblemHighlightType.GENERIC_ERROR_OR_WARNING,
-                                       ReplaceWithStdLibFix(methodName, firstArg.text))
-            }
-        }
+            val methodName = fqName.split(".").last()
+            holder.registerProblem(expression,
+                                   "Java Collections static method call should be replaced with Kotlin stdlib",
+                                   ProblemHighlightType.GENERIC_ERROR_OR_WARNING,
+                                   ReplaceWithStdLibFix(methodName, firstArg.text))
+        })
     }
 
     private fun canReplaceWithStdLib(expression: KtDotQualifiedExpression, fqName: String, args: List<KtValueArgument>): Boolean {

idea/src/org/jetbrains/kotlin/idea/inspections/KotlinDoubleNegationInspection.kt

@@ -1,17 +1,6 @@
 /*
- * Copyright 2010-2017 JetBrains s.r.o.
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- * http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
+ * Copyright 2000-2018 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license
+ * that can be found in the license/LICENSE.txt file.
  */
 
 package org.jetbrains.kotlin.idea.inspections
@@ -23,30 +12,28 @@ import org.jetbrains.kotlin.idea.core.replaced
 import org.jetbrains.kotlin.lexer.KtTokens
 import org.jetbrains.kotlin.psi.KtParenthesizedExpression
 import org.jetbrains.kotlin.psi.KtPrefixExpression
-import org.jetbrains.kotlin.psi.KtVisitorVoid
+import org.jetbrains.kotlin.psi.prefixExpressionVisitor
 import org.jetbrains.kotlin.resolve.calls.callUtil.getType
 import org.jetbrains.kotlin.types.typeUtil.isBoolean
 
 class KotlinDoubleNegationInspection : AbstractKotlinInspection(), CleanupLocalInspectionTool {
     override fun buildVisitor(holder: ProblemsHolder, isOnTheFly: Boolean, session: LocalInspectionToolSession) =
-            object : KtVisitorVoid() {
-                override fun visitPrefixExpression(expression: KtPrefixExpression) {
-                    if (expression.operationToken != KtTokens.EXCL ||
-                        expression.baseExpression?.getType(expression.analyze())?.isBoolean() != true) {
-                        return
-                    }
-                    var parent = expression.parent
-                    while (parent is KtParenthesizedExpression) {
-                        parent = parent.parent
-                    }
-                    if (parent is KtPrefixExpression && parent.operationToken == KtTokens.EXCL) {
-                        holder.registerProblem(expression,
-                                               "Redundant double negation",
-                                               ProblemHighlightType.GENERIC_ERROR_OR_WARNING,
-                                               DoubleNegationFix())
-                    }
+            prefixExpressionVisitor(fun(expression) {
+                if (expression.operationToken != KtTokens.EXCL ||
+                    expression.baseExpression?.getType(expression.analyze())?.isBoolean() != true) {
+                    return
                 }
-            }
+                var parent = expression.parent
+                while (parent is KtParenthesizedExpression) {
+                    parent = parent.parent
+                }
+                if (parent is KtPrefixExpression && parent.operationToken == KtTokens.EXCL) {
+                    holder.registerProblem(expression,
+                                           "Redundant double negation",
+                                           ProblemHighlightType.GENERIC_ERROR_OR_WARNING,
+                                           DoubleNegationFix())
+                }
+            })
 
     private class DoubleNegationFix : LocalQuickFix {
         override fun getName() = "Remove redundant negations"

idea/src/org/jetbrains/kotlin/idea/inspections/KotlinRedundantOverrideInspection.kt

@@ -1,17 +1,6 @@
 /*
- * Copyright 2010-2017 JetBrains s.r.o.
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- * http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
+ * Copyright 2000-2018 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license
+ * that can be found in the license/LICENSE.txt file.
  */
 
 package org.jetbrains.kotlin.idea.inspections
@@ -29,52 +18,49 @@ import org.jetbrains.kotlin.types.typeUtil.isSubtypeOf
 
 class KotlinRedundantOverrideInspection : AbstractKotlinInspection(), CleanupLocalInspectionTool {
     override fun buildVisitor(holder: ProblemsHolder, isOnTheFly: Boolean, session: LocalInspectionToolSession) =
-            object : KtVisitorVoid() {
-                override fun visitNamedFunction(function: KtNamedFunction) {
-                    super.visitNamedFunction(function)
-                    val funKeyword = function.funKeyword ?: return
-                    val modifierList = function.modifierList ?: return
-                    if (!modifierList.hasModifier(KtTokens.OVERRIDE_KEYWORD)) return
-                    if (MODIFIER_EXCLUDE_OVERRIDE.any { modifierList.hasModifier(it) }) return
-                    if (function.annotationEntries.isNotEmpty()) return
-                    if (function.containingClass()?.isData() == true) return
+            namedFunctionVisitor(fun(function) {
+                val funKeyword = function.funKeyword ?: return
+                val modifierList = function.modifierList ?: return
+                if (!modifierList.hasModifier(KtTokens.OVERRIDE_KEYWORD)) return
+                if (MODIFIER_EXCLUDE_OVERRIDE.any { modifierList.hasModifier(it) }) return
+                if (function.annotationEntries.isNotEmpty()) return
+                if (function.containingClass()?.isData() == true) return
 
-                    val bodyExpression = function.bodyExpression ?: return
-                    val qualifiedExpression = when (bodyExpression) {
-                        is KtDotQualifiedExpression -> bodyExpression
-                        is KtBlockExpression -> {
-                            val body = bodyExpression.statements.singleOrNull()
-                            when (body) {
-                                is KtReturnExpression -> body.returnedExpression
-                                is KtDotQualifiedExpression -> body.takeIf {
-                                    function.typeReference.let { it == null || it.text == "Unit" }
-                                }
-                                else -> null
+                val bodyExpression = function.bodyExpression ?: return
+                val qualifiedExpression = when (bodyExpression) {
+                    is KtDotQualifiedExpression -> bodyExpression
+                    is KtBlockExpression -> {
+                        val body = bodyExpression.statements.singleOrNull()
+                        when (body) {
+                            is KtReturnExpression -> body.returnedExpression
+                            is KtDotQualifiedExpression -> body.takeIf {
+                                function.typeReference.let { it == null || it.text == "Unit" }
                             }
-
+                            else -> null
                         }
-                        else -> null
-                    } as? KtDotQualifiedExpression ?: return
 
-                    val superExpression = qualifiedExpression.receiverExpression as? KtSuperExpression ?: return
-                    if (superExpression.superTypeQualifier != null) return
+                    }
+                    else -> null
+                } as? KtDotQualifiedExpression ?: return
 
-                    val superCallElement = qualifiedExpression.selectorExpression as? KtCallElement ?: return
-                    if (!isSameFunctionName(superCallElement, function)) return
-                    if (!isSameArguments(superCallElement, function)) return
-                    if (function.isDefinedInDelegatedSuperType(qualifiedExpression)) return
+                val superExpression = qualifiedExpression.receiverExpression as? KtSuperExpression ?: return
+                if (superExpression.superTypeQualifier != null) return
 
-                    val descriptor = holder.manager.createProblemDescriptor(
-                            function,
-                            TextRange(modifierList.startOffsetInParent, funKeyword.endOffset - function.startOffset),
-                            "Redundant override",
-                            ProblemHighlightType.LIKE_UNUSED_SYMBOL,
-                            isOnTheFly,
-                            RedundantOverrideFix()
-                    )
-                    holder.registerProblem(descriptor)
-                }
-            }
+                val superCallElement = qualifiedExpression.selectorExpression as? KtCallElement ?: return
+                if (!isSameFunctionName(superCallElement, function)) return
+                if (!isSameArguments(superCallElement, function)) return
+                if (function.isDefinedInDelegatedSuperType(qualifiedExpression)) return
+
+                val descriptor = holder.manager.createProblemDescriptor(
+                        function,
+                        TextRange(modifierList.startOffsetInParent, funKeyword.endOffset - function.startOffset),
+                        "Redundant override",
+                        ProblemHighlightType.LIKE_UNUSED_SYMBOL,
+                        isOnTheFly,
+                        RedundantOverrideFix()
+                )
+                holder.registerProblem(descriptor)
+            })
 
     private fun isSameArguments(superCallElement: KtCallElement, function: KtNamedFunction): Boolean {
         val arguments = superCallElement.valueArguments

idea/src/org/jetbrains/kotlin/idea/inspections/LeakingThisInspection.kt

@@ -1,17 +1,6 @@
 /*
- * Copyright 2010-2016 JetBrains s.r.o.
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- * http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
+ * Copyright 2000-2018 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license
+ * that can be found in the license/LICENSE.txt file.
  */
 
 package org.jetbrains.kotlin.idea.inspections
@@ -28,58 +17,59 @@ import org.jetbrains.kotlin.descriptors.Modality
 import org.jetbrains.kotlin.idea.caches.resolve.analyzeFully
 import org.jetbrains.kotlin.idea.quickfix.AddModifierFix
 import org.jetbrains.kotlin.lexer.KtTokens
-import org.jetbrains.kotlin.psi.*
+import org.jetbrains.kotlin.psi.KtClass
+import org.jetbrains.kotlin.psi.KtDeclaration
+import org.jetbrains.kotlin.psi.KtThisExpression
+import org.jetbrains.kotlin.psi.expressionVisitor
 import org.jetbrains.kotlin.psi.psiUtil.containingClassOrObject
 import org.jetbrains.kotlin.resolve.BindingContext.LEAKING_THIS
 import org.jetbrains.kotlin.resolve.DescriptorToSourceUtils
 
 class LeakingThisInspection : AbstractKotlinInspection() {
     override fun buildVisitor(holder: ProblemsHolder, isOnTheFly: Boolean, session: LocalInspectionToolSession): PsiElementVisitor {
-        return object : KtVisitorVoid() {
-            override fun visitExpression(expression: KtExpression) {
-                val context = expression.analyzeFully()
-                val leakingThisDescriptor = context.get(LEAKING_THIS, expression) ?: return
-                val description = when (leakingThisDescriptor) {
-                    is NonFinalClass ->
-                        if (expression is KtThisExpression)
-                            "Leaking 'this' in constructor of non-final class ${leakingThisDescriptor.klass.name}"
-                        else
-                            return // Not supported yet
-                    is NonFinalProperty ->
-                        "Accessing non-final property ${leakingThisDescriptor.property.name} in constructor"
-                    is NonFinalFunction ->
-                        "Calling non-final function ${leakingThisDescriptor.function.name} in constructor"
-                    else -> return // Not supported yet
+        return expressionVisitor { expression ->
+            val context = expression.analyzeFully()
+            val leakingThisDescriptor = context.get(LEAKING_THIS, expression) ?: return@expressionVisitor
+            val description = when (leakingThisDescriptor) {
+                is NonFinalClass ->
+                    if (expression is KtThisExpression)
+                        "Leaking 'this' in constructor of non-final class ${leakingThisDescriptor.klass.name}"
+                    else
+                        return@expressionVisitor // Not supported yet
+                is NonFinalProperty ->
+                    "Accessing non-final property ${leakingThisDescriptor.property.name} in constructor"
+                is NonFinalFunction ->
+                    "Calling non-final function ${leakingThisDescriptor.function.name} in constructor"
+                else -> return@expressionVisitor // Not supported yet
+            }
+            val memberDescriptorToFix = when (leakingThisDescriptor) {
+                is NonFinalProperty -> leakingThisDescriptor.property
+                is NonFinalFunction -> leakingThisDescriptor.function
+                else -> null
+            }
+            val memberFix = memberDescriptorToFix?.let {
+                if (it.modality == Modality.OPEN) {
+                    val modifierListOwner = DescriptorToSourceUtils.descriptorToDeclaration(it) as? KtDeclaration
+                    createMakeFinalFix(modifierListOwner)
                 }
-                val memberDescriptorToFix = when (leakingThisDescriptor) {
-                    is NonFinalProperty -> leakingThisDescriptor.property
-                    is NonFinalFunction -> leakingThisDescriptor.function
-                    else -> null
-                }
-                val memberFix = memberDescriptorToFix?.let {
-                    if (it.modality == Modality.OPEN) {
-                        val modifierListOwner = DescriptorToSourceUtils.descriptorToDeclaration(it) as? KtDeclaration
-                        createMakeFinalFix(modifierListOwner)
+                else null
+            }
+
+            val klass = leakingThisDescriptor.classOrObject as? KtClass
+            val classFix =
+                    if (klass != null && klass.hasModifier(KtTokens.OPEN_KEYWORD)) {
+                        createMakeFinalFix(klass)
                     }
                     else null
-                }
 
-                val klass = leakingThisDescriptor.classOrObject as? KtClass
-                val classFix =
-                        if (klass != null && klass.hasModifier(KtTokens.OPEN_KEYWORD)) {
-                            createMakeFinalFix(klass)
-                        }
-                        else null
-
-                holder.registerProblem(
-                        expression, description,
-                        when (leakingThisDescriptor) {
-                            is NonFinalProperty, is NonFinalFunction -> GENERIC_ERROR_OR_WARNING
-                            else -> WEAK_WARNING
-                        },
-                        *(arrayOf(memberFix, classFix).filterNotNull().toTypedArray())
-                )
-            }
+            holder.registerProblem(
+                    expression, description,
+                    when (leakingThisDescriptor) {
+                        is NonFinalProperty, is NonFinalFunction -> GENERIC_ERROR_OR_WARNING
+                        else -> WEAK_WARNING
+                    },
+                    *(arrayOf(memberFix, classFix).filterNotNull().toTypedArray())
+            )
         }
     }
 

idea/src/org/jetbrains/kotlin/idea/inspections/MayBeConstantInspection.kt

@@ -1,17 +1,6 @@
 /*
- * Copyright 2010-2017 JetBrains s.r.o.
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- * http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
+ * Copyright 2000-2018 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license
+ * that can be found in the license/LICENSE.txt file.
  */
 
 package org.jetbrains.kotlin.idea.inspections
@@ -27,7 +16,7 @@ import org.jetbrains.kotlin.idea.quickfix.AddConstModifierFix
 import org.jetbrains.kotlin.lexer.KtTokens
 import org.jetbrains.kotlin.psi.KtObjectDeclaration
 import org.jetbrains.kotlin.psi.KtProperty
-import org.jetbrains.kotlin.psi.KtVisitorVoid
+import org.jetbrains.kotlin.psi.propertyVisitor
 import org.jetbrains.kotlin.psi.psiUtil.containingClassOrObject
 import org.jetbrains.kotlin.resolve.BindingContext
 import org.jetbrains.kotlin.resolve.constants.ErrorValue
@@ -48,21 +37,18 @@ class MayBeConstantInspection : AbstractKotlinInspection() {
     }
 
     override fun buildVisitor(holder: ProblemsHolder, isOnTheFly: Boolean): PsiElementVisitor {
-        return object : KtVisitorVoid() {
-            override fun visitProperty(property: KtProperty) {
-                super.visitProperty(property)
-                val status = property.getStatus()
-                when (status) {
-                    NONE, JVM_FIELD_MIGHT_BE_CONST_NO_INITIALIZER,
-                    MIGHT_BE_CONST_ERRONEOUS, JVM_FIELD_MIGHT_BE_CONST_ERRONEOUS -> return
-                    MIGHT_BE_CONST, JVM_FIELD_MIGHT_BE_CONST -> {
-                        holder.registerProblem(
-                                property.nameIdentifier ?: property,
-                                if (status == JVM_FIELD_MIGHT_BE_CONST) "'const' might be used instead of '@JvmField'" else "Might be 'const'",
-                                ProblemHighlightType.GENERIC_ERROR_OR_WARNING,
-                                IntentionWrapper(AddConstModifierFix(property), property.containingFile)
-                        )
-                    }
+        return propertyVisitor { property ->
+            val status = property.getStatus()
+            when (status) {
+                NONE, JVM_FIELD_MIGHT_BE_CONST_NO_INITIALIZER,
+                MIGHT_BE_CONST_ERRONEOUS, JVM_FIELD_MIGHT_BE_CONST_ERRONEOUS -> return@propertyVisitor
+                MIGHT_BE_CONST, JVM_FIELD_MIGHT_BE_CONST -> {
+                    holder.registerProblem(
+                            property.nameIdentifier ?: property,
+                            if (status == JVM_FIELD_MIGHT_BE_CONST) "'const' might be used instead of '@JvmField'" else "Might be 'const'",
+                            ProblemHighlightType.GENERIC_ERROR_OR_WARNING,
+                            IntentionWrapper(AddConstModifierFix(property), property.containingFile)
+                    )
                 }
             }
         }

idea/src/org/jetbrains/kotlin/idea/inspections/MigrateDiagnosticSuppressionInspection.kt

@@ -1,17 +1,6 @@
 /*
- * Copyright 2010-2017 JetBrains s.r.o.
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- * http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
+ * Copyright 2000-2018 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license
+ * that can be found in the license/LICENSE.txt file.
  */
 
 package org.jetbrains.kotlin.idea.inspections
@@ -25,37 +14,34 @@ import org.jetbrains.kotlin.builtins.KotlinBuiltIns
 import org.jetbrains.kotlin.diagnostics.DiagnosticFactory
 import org.jetbrains.kotlin.diagnostics.Errors.*
 import org.jetbrains.kotlin.idea.caches.resolve.analyze
-import org.jetbrains.kotlin.psi.*
+import org.jetbrains.kotlin.psi.KtPsiFactory
+import org.jetbrains.kotlin.psi.KtStringTemplateExpression
+import org.jetbrains.kotlin.psi.annotationEntryVisitor
 import org.jetbrains.kotlin.resolve.BindingContext
 import org.jetbrains.kotlin.resolve.lazy.BodyResolveMode
 
 class MigrateDiagnosticSuppressionInspection : AbstractKotlinInspection(), CleanupLocalInspectionTool {
     override fun buildVisitor(holder: ProblemsHolder, isOnTheFly: Boolean): PsiElementVisitor {
-        return object : KtVisitorVoid() {
+        return annotationEntryVisitor(fun(annotationEntry) {
+            if (annotationEntry.calleeExpression?.text != "Suppress") return
+            val context = annotationEntry.analyze(BodyResolveMode.PARTIAL)
+            val descriptor = context[BindingContext.ANNOTATION, annotationEntry] ?: return
+            if (descriptor.fqName != KotlinBuiltIns.FQ_NAMES.suppress) return
 
-            override fun visitAnnotationEntry(annotationEntry: KtAnnotationEntry) {
-                super.visitAnnotationEntry(annotationEntry)
+            for (argument in annotationEntry.valueArguments) {
+                val expression = argument.getArgumentExpression() as? KtStringTemplateExpression ?: continue
+                val text = expression.text
+                if (text.firstOrNull() != '\"' || text.lastOrNull() != '\"') continue
+                val newDiagnosticFactory = MIGRATION_MAP[StringUtil.unquoteString(text)] ?: continue
 
-                if (annotationEntry.calleeExpression?.text != "Suppress") return
-                val context = annotationEntry.analyze(BodyResolveMode.PARTIAL)
-                val descriptor = context[BindingContext.ANNOTATION, annotationEntry] ?: return
-                if (descriptor.fqName != KotlinBuiltIns.FQ_NAMES.suppress) return
-
-                for (argument in annotationEntry.valueArguments) {
-                    val expression = argument.getArgumentExpression() as? KtStringTemplateExpression ?: continue
-                    val text = expression.text
-                    if (text.firstOrNull() != '\"' || text.lastOrNull() != '\"') continue
-                    val newDiagnosticFactory = MIGRATION_MAP[StringUtil.unquoteString(text)] ?: continue
-
-                    holder.registerProblem(
-                            expression,
-                            "Diagnostic name should be replaced by the new one",
-                            ProblemHighlightType.GENERIC_ERROR_OR_WARNING,
-                            ReplaceDiagnosticNameFix(newDiagnosticFactory)
-                    )
-                }
+                holder.registerProblem(
+                        expression,
+                        "Diagnostic name should be replaced by the new one",
+                        ProblemHighlightType.GENERIC_ERROR_OR_WARNING,
+                        ReplaceDiagnosticNameFix(newDiagnosticFactory)
+                )
             }
-        }
+        })
     }
 
     class ReplaceDiagnosticNameFix(private val diagnosticFactory: DiagnosticFactory<*>) : LocalQuickFix {

idea/src/org/jetbrains/kotlin/idea/inspections/MoveSuspiciousCallableReferenceIntoParenthesesInspection.kt

@@ -1,17 +1,6 @@
 /*
- * Copyright 2010-2017 JetBrains s.r.o.
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- * http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
+ * Copyright 2000-2018 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license
+ * that can be found in the license/LICENSE.txt file.
  */
 
 package org.jetbrains.kotlin.idea.inspections
@@ -28,41 +17,39 @@ import org.jetbrains.kotlin.idea.caches.resolve.analyze
 import org.jetbrains.kotlin.idea.intentions.ConvertLambdaToReferenceIntention
 import org.jetbrains.kotlin.psi.KtCallableReferenceExpression
 import org.jetbrains.kotlin.psi.KtLambdaExpression
-import org.jetbrains.kotlin.psi.KtVisitorVoid
 import org.jetbrains.kotlin.psi.ValueArgument
+import org.jetbrains.kotlin.psi.lambdaExpressionVisitor
 import org.jetbrains.kotlin.resolve.calls.callUtil.getParameterForArgument
 import org.jetbrains.kotlin.resolve.calls.callUtil.getParentResolvedCall
 import org.jetbrains.kotlin.resolve.calls.callUtil.getResolvedCall
 
 class MoveSuspiciousCallableReferenceIntoParenthesesInspection : AbstractKotlinInspection() {
     override fun buildVisitor(holder: ProblemsHolder, isOnTheFly: Boolean, session: LocalInspectionToolSession): PsiElementVisitor {
-        return object : KtVisitorVoid() {
-            override fun visitLambdaExpression(lambdaExpression: KtLambdaExpression) {
-                val callableReference = lambdaExpression.bodyExpression?.statements?.singleOrNull() as? KtCallableReferenceExpression
-                if (callableReference != null) {
-                    val context = lambdaExpression.analyze()
-                    val parentResolvedCall = lambdaExpression.getParentResolvedCall(context)
-                    if (parentResolvedCall != null) {
-                        val originalParameterDescriptor =
-                                parentResolvedCall.getParameterForArgument(lambdaExpression.parent as? ValueArgument)?.original
-                        if (originalParameterDescriptor != null) {
-                            val expectedType = originalParameterDescriptor.type
-                            if (expectedType.isBuiltinFunctionalType) {
-                                val returnType = expectedType.getReturnTypeFromFunctionType()
-                                if (returnType.isBuiltinFunctionalTypeOrSubtype) return
-                            }
+        return lambdaExpressionVisitor(fun(lambdaExpression) {
+            val callableReference = lambdaExpression.bodyExpression?.statements?.singleOrNull() as? KtCallableReferenceExpression
+            if (callableReference != null) {
+                val context = lambdaExpression.analyze()
+                val parentResolvedCall = lambdaExpression.getParentResolvedCall(context)
+                if (parentResolvedCall != null) {
+                    val originalParameterDescriptor =
+                            parentResolvedCall.getParameterForArgument(lambdaExpression.parent as? ValueArgument)?.original
+                    if (originalParameterDescriptor != null) {
+                        val expectedType = originalParameterDescriptor.type
+                        if (expectedType.isBuiltinFunctionalType) {
+                            val returnType = expectedType.getReturnTypeFromFunctionType()
+                            if (returnType.isBuiltinFunctionalTypeOrSubtype) return
                         }
                     }
-                    holder.registerProblem(
-                            lambdaExpression,
-                            "Suspicious callable reference as the only lambda element",
-                            ProblemHighlightType.GENERIC_ERROR_OR_WARNING,
-                            IntentionWrapper(MoveIntoParenthesesIntention(), lambdaExpression.containingFile)
-                    )
-
                 }
+                holder.registerProblem(
+                        lambdaExpression,
+                        "Suspicious callable reference as the only lambda element",
+                        ProblemHighlightType.GENERIC_ERROR_OR_WARNING,
+                        IntentionWrapper(MoveIntoParenthesesIntention(), lambdaExpression.containingFile)
+                )
+
             }
-        }
+        })
     }
 
     class MoveIntoParenthesesIntention : ConvertLambdaToReferenceIntention(

idea/src/org/jetbrains/kotlin/idea/inspections/NamingConventionInspections.kt

@@ -123,11 +123,7 @@ class EnumEntryNameInspection : NamingConventionInspection(
     START_UPPER, NO_BAD_CHARACTERS_OR_UNDERSCORE
 ) {
     override fun buildVisitor(holder: ProblemsHolder, isOnTheFly: Boolean): PsiElementVisitor {
-        return object : KtVisitorVoid() {
-            override fun visitEnumEntry(enumEntry: KtEnumEntry) {
-                verifyName(enumEntry, holder)
-            }
-        }
+        return enumEntryVisitor { enumEntry -> verifyName(enumEntry, holder) }
     }
 }
 
@@ -137,11 +133,8 @@ class FunctionNameInspection : NamingConventionInspection(
     START_LOWER, NO_UNDERSCORES, NO_BAD_CHARACTERS
 ) {
     override fun buildVisitor(holder: ProblemsHolder, isOnTheFly: Boolean): PsiElementVisitor {
-        return object : KtVisitorVoid() {
-            override fun visitNamedFunction(function: KtNamedFunction) {
-                if (TestUtils.isInTestSourceContent(function)) {
-                    return
-                }
+        return namedFunctionVisitor { function ->
+            if (!TestUtils.isInTestSourceContent(function)) {
                 verifyName(function, holder)
             }
         }
@@ -154,16 +147,14 @@ class TestFunctionNameInspection : NamingConventionInspection(
     START_LOWER
 ) {
     override fun buildVisitor(holder: ProblemsHolder, isOnTheFly: Boolean): PsiElementVisitor {
-        return object : KtVisitorVoid() {
-            override fun visitNamedFunction(function: KtNamedFunction) {
-                if (!TestUtils.isInTestSourceContent(function)) {
-                    return
-                }
-                if (function.nameIdentifier?.text?.startsWith("`") == true) {
-                    return
-                }
-                verifyName(function, holder)
+        return namedFunctionVisitor { function ->
+            if (!TestUtils.isInTestSourceContent(function)) {
+                return@namedFunctionVisitor
             }
+            if (function.nameIdentifier?.text?.startsWith("`") == true) {
+                return@namedFunctionVisitor
+            }
+            verifyName(function, holder)
         }
     }
 }
@@ -178,11 +169,9 @@ abstract class PropertyNameInspectionBase protected constructor(
     protected enum class PropertyKind { NORMAL, PRIVATE, OBJECT_OR_TOP_LEVEL, CONST, LOCAL }
 
     override fun buildVisitor(holder: ProblemsHolder, isOnTheFly: Boolean): PsiElementVisitor {
-        return object : KtVisitorVoid() {
-            override fun visitProperty(property: KtProperty) {
-                if (property.getKind() == kind) {
-                    verifyName(property, holder)
-                }
+        return propertyVisitor { property ->
+            if (property.getKind() == kind) {
+                verifyName(property, holder)
             }
         }
     }
@@ -234,17 +223,15 @@ class LocalVariableNameInspection :
 class PackageNameInspection :
     NamingConventionInspection("Package", "[a-z][A-Za-z\\d]*(\\.[a-z][A-Za-z\\d]*)*", NO_UNDERSCORES) {
     override fun buildVisitor(holder: ProblemsHolder, isOnTheFly: Boolean, session: LocalInspectionToolSession): PsiElementVisitor {
-        return object : KtVisitorVoid() {
-            override fun visitPackageDirective(directive: KtPackageDirective) {
-                val qualifiedName = directive.qualifiedName
-                if (qualifiedName.isNotEmpty() && nameRegex?.matches(qualifiedName) == false) {
-                    val message = getNameMismatchMessage(qualifiedName)
-                    holder.registerProblem(
-                        directive.packageNameExpression!!,
-                        "Package name <code>#ref</code> $message #loc",
-                        RenamePackageFix()
-                    )
-                }
+        return packageDirectiveVisitor { directive ->
+            val qualifiedName = directive.qualifiedName
+            if (qualifiedName.isNotEmpty() && nameRegex?.matches(qualifiedName) == false) {
+                val message = getNameMismatchMessage(qualifiedName)
+                holder.registerProblem(
+                    directive.packageNameExpression!!,
+                    "Package name <code>#ref</code> $message #loc",
+                    RenamePackageFix()
+                )
             }
         }
     }

idea/src/org/jetbrains/kotlin/idea/inspections/NullChecksToSafeCallInspection.kt

@@ -1,17 +1,6 @@
 /*
- * Copyright 2010-2017 JetBrains s.r.o.
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- * http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
+ * Copyright 2000-2018 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license
+ * that can be found in the license/LICENSE.txt file.
  */
 
 package org.jetbrains.kotlin.idea.inspections
@@ -31,14 +20,12 @@ import org.jetbrains.kotlin.types.TypeUtils
 
 class NullChecksToSafeCallInspection : AbstractKotlinInspection() {
     override fun buildVisitor(holder: ProblemsHolder, isOnTheFly: Boolean, session: LocalInspectionToolSession) =
-            object : KtVisitorVoid() {
-                override fun visitBinaryExpression(expression: KtBinaryExpression) {
-                    if (isNullChecksToSafeCallFixAvailable(expression)) {
-                        holder.registerProblem(expression,
-                                               "Null-checks replaceable with safe-calls",
-                                               ProblemHighlightType.WEAK_WARNING,
-                                               NullChecksToSafeCallCheckFix())
-                    }
+            binaryExpressionVisitor { expression ->
+                if (isNullChecksToSafeCallFixAvailable(expression)) {
+                    holder.registerProblem(expression,
+                                           "Null-checks replaceable with safe-calls",
+                                           ProblemHighlightType.WEAK_WARNING,
+                                           NullChecksToSafeCallCheckFix())
                 }
             }
 

idea/src/org/jetbrains/kotlin/idea/inspections/NullableBooleanElvisInspection.kt

@@ -1,17 +1,6 @@
 /*
- * Copyright 2010-2017 JetBrains s.r.o.
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- * http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
+ * Copyright 2000-2018 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license
+ * that can be found in the license/LICENSE.txt file.
  */
 
 package org.jetbrains.kotlin.idea.inspections
@@ -34,36 +23,34 @@ import org.jetbrains.kotlin.types.typeUtil.isBooleanOrNullableBoolean
 
 class NullableBooleanElvisInspection : AbstractKotlinInspection(), CleanupLocalInspectionTool {
     override fun buildVisitor(holder: ProblemsHolder, isOnTheFly: Boolean, session: LocalInspectionToolSession) =
-            object : KtVisitorVoid() {
-                override fun visitBinaryExpression(expression: KtBinaryExpression) {
-                    if (expression.operationToken != KtTokens.ELVIS) return
-                    val lhs = expression.left ?: return
-                    val rhs = expression.right ?: return
-                    if (!KtPsiUtil.isBooleanConstant(rhs)) return
-                    val lhsType = lhs.analyze(BodyResolveMode.PARTIAL).getType(lhs) ?: return
-                    if (TypeUtils.isNullableType(lhsType) && lhsType.isBooleanOrNullableBoolean()) {
-                        val parentIfOrWhile = PsiTreeUtil.getParentOfType(
-                                expression, KtIfExpression::class.java, KtWhileExpressionBase::class.java)
-                        val condition = when (parentIfOrWhile) {
-                            is KtIfExpression -> parentIfOrWhile.condition
-                            is KtWhileExpressionBase -> parentIfOrWhile.condition
-                            else -> null
-                        }
-                        val (highlightType, verb) = if (condition != null && condition in expression.parentsWithSelf)
-                            GENERIC_ERROR_OR_WARNING to "should"
-                        else
-                            INFORMATION to "can"
-
-                        holder.registerProblemWithoutOfflineInformation(
-                                expression,
-                                "Equality check $verb be used instead of elvis for nullable boolean check",
-                                isOnTheFly,
-                                highlightType,
-                                ReplaceWithEqualityCheckFix()
-                        )
-                    }
+        binaryExpressionVisitor(fun(expression) {
+            if (expression.operationToken != KtTokens.ELVIS) return
+            val lhs = expression.left ?: return
+            val rhs = expression.right ?: return
+            if (!KtPsiUtil.isBooleanConstant(rhs)) return
+            val lhsType = lhs.analyze(BodyResolveMode.PARTIAL).getType(lhs) ?: return
+            if (TypeUtils.isNullableType(lhsType) && lhsType.isBooleanOrNullableBoolean()) {
+                val parentIfOrWhile = PsiTreeUtil.getParentOfType(
+                        expression, KtIfExpression::class.java, KtWhileExpressionBase::class.java)
+                val condition = when (parentIfOrWhile) {
+                    is KtIfExpression -> parentIfOrWhile.condition
+                    is KtWhileExpressionBase -> parentIfOrWhile.condition
+                    else -> null
                 }
+                val (highlightType, verb) = if (condition != null && condition in expression.parentsWithSelf)
+                    GENERIC_ERROR_OR_WARNING to "should"
+                else
+                    INFORMATION to "can"
+
+                holder.registerProblemWithoutOfflineInformation(
+                        expression,
+                        "Equality check $verb be used instead of elvis for nullable boolean check",
+                        isOnTheFly,
+                        highlightType,
+                        ReplaceWithEqualityCheckFix()
+                )
             }
+        })
 
     private class ReplaceWithEqualityCheckFix : LocalQuickFix {
         override fun getName() = "Replace with equality check"

idea/src/org/jetbrains/kotlin/idea/inspections/ProtectedInFinalInspection.kt

@@ -1,17 +1,6 @@
 /*
- * Copyright 2010-2016 JetBrains s.r.o.
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- * http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
+ * Copyright 2000-2018 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license
+ * that can be found in the license/LICENSE.txt file.
  */
 
 package org.jetbrains.kotlin.idea.inspections
@@ -24,33 +13,30 @@ import org.jetbrains.kotlin.idea.core.implicitVisibility
 import org.jetbrains.kotlin.idea.core.isInheritable
 import org.jetbrains.kotlin.lexer.KtTokens
 import org.jetbrains.kotlin.psi.KtClass
-import org.jetbrains.kotlin.psi.KtDeclaration
 import org.jetbrains.kotlin.psi.KtModifierListOwner
-import org.jetbrains.kotlin.psi.KtVisitorVoid
 import org.jetbrains.kotlin.psi.addRemoveModifier.addModifier
+import org.jetbrains.kotlin.psi.declarationVisitor
 import org.jetbrains.kotlin.psi.psiUtil.getParentOfType
 import org.jetbrains.kotlin.psi.psiUtil.visibilityModifier
 
 class ProtectedInFinalInspection  : AbstractKotlinInspection() {
     override fun buildVisitor(holder: ProblemsHolder, isOnTheFly: Boolean, session: LocalInspectionToolSession): PsiElementVisitor {
-        return object : KtVisitorVoid() {
-            override fun visitDeclaration(declaration: KtDeclaration) {
-                val visibilityModifier = declaration.visibilityModifier() ?: return
-                val modifierType = visibilityModifier.node?.elementType
-                if (modifierType == KtTokens.PROTECTED_KEYWORD) {
-                    val parentClass = declaration.getParentOfType<KtClass>(true) ?: return
-                    if (!parentClass.isInheritable() && !parentClass.isEnum() &&
-                        declaration.implicitVisibility() != KtTokens.PROTECTED_KEYWORD) {
-                        holder.registerProblem(visibilityModifier,
-                                               "'protected' visibility is effectively 'private' in a final class",
-                                               ProblemHighlightType.GENERIC_ERROR_OR_WARNING,
-                                               MakePrivateFix(),
-                                               MakeOpenFix()
-                        )
-                    }
+        return declarationVisitor(fun(declaration) {
+            val visibilityModifier = declaration.visibilityModifier() ?: return
+            val modifierType = visibilityModifier.node?.elementType
+            if (modifierType == KtTokens.PROTECTED_KEYWORD) {
+                val parentClass = declaration.getParentOfType<KtClass>(true) ?: return
+                if (!parentClass.isInheritable() && !parentClass.isEnum() &&
+                    declaration.implicitVisibility() != KtTokens.PROTECTED_KEYWORD) {
+                    holder.registerProblem(visibilityModifier,
+                                           "'protected' visibility is effectively 'private' in a final class",
+                                           ProblemHighlightType.GENERIC_ERROR_OR_WARNING,
+                                           MakePrivateFix(),
+                                           MakeOpenFix()
+                    )
                 }
             }
-        }
+        })
     }
 
     class MakePrivateFix : LocalQuickFix {

idea/src/org/jetbrains/kotlin/idea/inspections/RecursivePropertyAccessorInspection.kt

@@ -1,17 +1,6 @@
 /*
- * Copyright 2010-2017 JetBrains s.r.o.
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- * http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
+ * Copyright 2000-2018 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license
+ * that can be found in the license/LICENSE.txt file.
  */
 
 package org.jetbrains.kotlin.idea.inspections
@@ -35,20 +24,17 @@ import org.jetbrains.kotlin.synthetic.SyntheticJavaPropertyDescriptor
 class RecursivePropertyAccessorInspection : AbstractKotlinInspection() {
 
     override fun buildVisitor(holder: ProblemsHolder, isOnTheFly: Boolean, session: LocalInspectionToolSession): PsiElementVisitor {
-        return object : KtVisitorVoid() {
-            override fun visitSimpleNameExpression(expression: KtSimpleNameExpression) {
-                super.visitSimpleNameExpression(expression)
-                if (isRecursivePropertyAccess(expression)) {
-                    holder.registerProblem(expression,
-                                           "Recursive property accessor",
-                                           ProblemHighlightType.GENERIC_ERROR_OR_WARNING,
-                                           ReplaceWithFieldFix())
-                }
-                else if (isRecursiveSyntheticPropertyAccess(expression)) {
-                    holder.registerProblem(expression,
-                                           "Recursive synthetic property accessor",
-                                           ProblemHighlightType.GENERIC_ERROR_OR_WARNING)
-                }
+        return simpleNameExpressionVisitor { expression ->
+            if (isRecursivePropertyAccess(expression)) {
+                holder.registerProblem(expression,
+                                       "Recursive property accessor",
+                                       ProblemHighlightType.GENERIC_ERROR_OR_WARNING,
+                                       ReplaceWithFieldFix())
+            }
+            else if (isRecursiveSyntheticPropertyAccess(expression)) {
+                holder.registerProblem(expression,
+                                       "Recursive synthetic property accessor",
+                                       ProblemHighlightType.GENERIC_ERROR_OR_WARNING)
             }
         }
     }

idea/src/org/jetbrains/kotlin/idea/inspections/RedundantExplicitTypeInspection.kt

@@ -1,17 +1,6 @@
 /*
- * Copyright 2010-2017 JetBrains s.r.o.
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- * http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
+ * Copyright 2000-2018 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license
+ * that can be found in the license/LICENSE.txt file.
  */
 
 package org.jetbrains.kotlin.idea.inspections
@@ -29,61 +18,57 @@ import org.jetbrains.kotlin.resolve.lazy.BodyResolveMode
 
 class RedundantExplicitTypeInspection : AbstractKotlinInspection() {
     override fun buildVisitor(holder: ProblemsHolder, isOnTheFly: Boolean) =
-            object : KtVisitorVoid() {
-                override fun visitProperty(property: KtProperty) {
-                    super.visitProperty(property)
+            propertyVisitor(fun(property) {
+                if (!property.isLocal) return
+                val typeReference = property.typeReference ?: return
+                val initializer = property.initializer ?: return
 
-                    if (!property.isLocal) return
-                    val typeReference = property.typeReference ?: return
-                    val initializer = property.initializer ?: return
-
-                    val type = property.analyze(BodyResolveMode.PARTIAL)[BindingContext.TYPE, typeReference] ?: return
-                    when (initializer) {
-                        is KtConstantExpression -> {
-                            when (initializer.node.elementType) {
-                                KtNodeTypes.BOOLEAN_CONSTANT -> {
-                                    if (!KotlinBuiltIns.isBoolean(type)) return
-                                }
-                                KtNodeTypes.INTEGER_CONSTANT -> {
-                                    if (initializer.text.endsWith("L")) {
-                                        if (!KotlinBuiltIns.isLong(type)) return
-                                    }
-                                    else {
-                                        if (!KotlinBuiltIns.isInt(type)) return
-                                    }
-                                }
-                                KtNodeTypes.FLOAT_CONSTANT -> {
-                                    if (initializer.text.endsWith("f") || initializer.text.endsWith("F")) {
-                                        if (!KotlinBuiltIns.isFloat(type)) return
-                                    }
-                                    else {
-                                        if (!KotlinBuiltIns.isDouble(type)) return
-                                    }
-                                }
-                                KtNodeTypes.CHARACTER_CONSTANT -> {
-                                    if (!KotlinBuiltIns.isChar(type)) return
-                                }
-                                else -> return
+                val type = property.analyze(BodyResolveMode.PARTIAL)[BindingContext.TYPE, typeReference] ?: return
+                when (initializer) {
+                    is KtConstantExpression -> {
+                        when (initializer.node.elementType) {
+                            KtNodeTypes.BOOLEAN_CONSTANT -> {
+                                if (!KotlinBuiltIns.isBoolean(type)) return
                             }
+                            KtNodeTypes.INTEGER_CONSTANT -> {
+                                if (initializer.text.endsWith("L")) {
+                                    if (!KotlinBuiltIns.isLong(type)) return
+                                }
+                                else {
+                                    if (!KotlinBuiltIns.isInt(type)) return
+                                }
+                            }
+                            KtNodeTypes.FLOAT_CONSTANT -> {
+                                if (initializer.text.endsWith("f") || initializer.text.endsWith("F")) {
+                                    if (!KotlinBuiltIns.isFloat(type)) return
+                                }
+                                else {
+                                    if (!KotlinBuiltIns.isDouble(type)) return
+                                }
+                            }
+                            KtNodeTypes.CHARACTER_CONSTANT -> {
+                                if (!KotlinBuiltIns.isChar(type)) return
+                            }
+                            else -> return
                         }
-                        is KtStringTemplateExpression -> {
-                            if (!KotlinBuiltIns.isString(type)) return
-                        }
-                        is KtNameReferenceExpression -> {
-                            if (typeReference.text != initializer.getReferencedName()) return
-                        }
-                        is KtCallExpression -> {
-                            if (typeReference.text != initializer.calleeExpression?.text) return
-                        }
-                        else -> return
                     }
-
-                    holder.registerProblem(
-                            typeReference,
-                            "Explicitly given type is redundant here",
-                            ProblemHighlightType.LIKE_UNUSED_SYMBOL,
-                            IntentionWrapper(RemoveExplicitTypeIntention(), property.containingKtFile)
-                    )
+                    is KtStringTemplateExpression -> {
+                        if (!KotlinBuiltIns.isString(type)) return
+                    }
+                    is KtNameReferenceExpression -> {
+                        if (typeReference.text != initializer.getReferencedName()) return
+                    }
+                    is KtCallExpression -> {
+                        if (typeReference.text != initializer.calleeExpression?.text) return
+                    }
+                    else -> return
                 }
-            }
+
+                holder.registerProblem(
+                        typeReference,
+                        "Explicitly given type is redundant here",
+                        ProblemHighlightType.LIKE_UNUSED_SYMBOL,
+                        IntentionWrapper(RemoveExplicitTypeIntention(), property.containingKtFile)
+                )
+            })
 }

idea/src/org/jetbrains/kotlin/idea/inspections/RedundantGetterInspection.kt

@@ -1,17 +1,6 @@
 /*
- * Copyright 2010-2017 JetBrains s.r.o.
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- * http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
+ * Copyright 2000-2018 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license
+ * that can be found in the license/LICENSE.txt file.
  */
 
 package org.jetbrains.kotlin.idea.inspections
@@ -20,19 +9,15 @@ import com.intellij.codeInspection.*
 import com.intellij.openapi.project.Project
 import com.intellij.psi.PsiElementVisitor
 import org.jetbrains.kotlin.psi.*
-import org.jetbrains.kotlin.psi.psiUtil.getStrictParentOfType
 
 class RedundantGetterInspection : AbstractKotlinInspection(), CleanupLocalInspectionTool {
     override fun buildVisitor(holder: ProblemsHolder, isOnTheFly: Boolean, session: LocalInspectionToolSession): PsiElementVisitor {
-        return object : KtVisitorVoid() {
-            override fun visitPropertyAccessor(accessor: KtPropertyAccessor) {
-                super.visitPropertyAccessor(accessor)
-                if (accessor.isRedundantGetter()) {
-                    holder.registerProblem(accessor,
-                                           "Redundant getter",
-                                           ProblemHighlightType.GENERIC_ERROR_OR_WARNING,
-                                           RemoveRedundantGetterFix())
-                }
+        return propertyAccessorVisitor { accessor ->
+            if (accessor.isRedundantGetter()) {
+                holder.registerProblem(accessor,
+                                       "Redundant getter",
+                                       ProblemHighlightType.GENERIC_ERROR_OR_WARNING,
+                                       RemoveRedundantGetterFix())
             }
         }
     }

idea/src/org/jetbrains/kotlin/idea/inspections/RedundantIfInspection.kt

@@ -1,17 +1,6 @@
 /*
- * Copyright 2010-2016 JetBrains s.r.o.
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- * http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
+ * Copyright 2000-2018 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license
+ * that can be found in the license/LICENSE.txt file.
  */
 
 package org.jetbrains.kotlin.idea.inspections
@@ -27,18 +16,15 @@ import org.jetbrains.kotlin.psi.*
 class RedundantIfInspection : AbstractKotlinInspection(), CleanupLocalInspectionTool {
 
     override fun buildVisitor(holder: ProblemsHolder, isOnTheFly: Boolean, session: LocalInspectionToolSession): PsiElementVisitor {
-        return object : KtVisitorVoid() {
-            override fun visitIfExpression(expression: KtIfExpression) {
-                super.visitIfExpression(expression)
-                if (expression.condition == null) return
-                val (redundancyType, branchType) = RedundancyType.of(expression)
-                if (redundancyType == RedundancyType.NONE) return
+        return ifExpressionVisitor { expression ->
+            if (expression.condition == null) return@ifExpressionVisitor
+            val (redundancyType, branchType) = RedundancyType.of(expression)
+            if (redundancyType == RedundancyType.NONE) return@ifExpressionVisitor
 
-                holder.registerProblem(expression,
-                                       "Redundant 'if' statement",
-                                       ProblemHighlightType.GENERIC_ERROR_OR_WARNING,
-                                       RemoveRedundantIf(redundancyType, branchType))
-            }
+            holder.registerProblem(expression,
+                                   "Redundant 'if' statement",
+                                   ProblemHighlightType.GENERIC_ERROR_OR_WARNING,
+                                   RemoveRedundantIf(redundancyType, branchType))
         }
     }
 

idea/src/org/jetbrains/kotlin/idea/inspections/RedundantLambdaArrowInspection.kt

@@ -1,17 +1,6 @@
 /*
- * Copyright 2010-2017 JetBrains s.r.o.
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- * http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
+ * Copyright 2000-2018 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license
+ * that can be found in the license/LICENSE.txt file.
  */
 
 package org.jetbrains.kotlin.idea.inspections
@@ -23,23 +12,20 @@ import com.intellij.codeInspection.ProblemHighlightType
 import com.intellij.codeInspection.ProblemsHolder
 import com.intellij.openapi.project.Project
 import com.intellij.psi.PsiElementVisitor
-import org.jetbrains.kotlin.psi.KtLambdaExpression
-import org.jetbrains.kotlin.psi.KtVisitorVoid
+import org.jetbrains.kotlin.psi.lambdaExpressionVisitor
 
 class RedundantLambdaArrowInspection : AbstractKotlinInspection() {
     override fun buildVisitor(holder: ProblemsHolder, isOnTheFly: Boolean): PsiElementVisitor {
-        return object : KtVisitorVoid() {
-            override fun visitLambdaExpression(lambdaExpression: KtLambdaExpression) {
-                val functionLiteral = lambdaExpression.functionLiteral
-                if (functionLiteral.valueParameters.isNotEmpty()) return
-                val arrow = functionLiteral.arrow ?: return
+        return lambdaExpressionVisitor { lambdaExpression ->
+            val functionLiteral = lambdaExpression.functionLiteral
+            if (functionLiteral.valueParameters.isNotEmpty()) return@lambdaExpressionVisitor
+            val arrow = functionLiteral.arrow ?: return@lambdaExpressionVisitor
 
-                holder.registerProblem(
-                        arrow,
-                        "Redundant lambda arrow",
-                        ProblemHighlightType.LIKE_UNUSED_SYMBOL,
-                        DeleteFix())
-            }
+            holder.registerProblem(
+                    arrow,
+                    "Redundant lambda arrow",
+                    ProblemHighlightType.LIKE_UNUSED_SYMBOL,
+                    DeleteFix())
         }
     }
 

idea/src/org/jetbrains/kotlin/idea/inspections/RedundantModalityModifierInspection.kt

@@ -1,53 +1,31 @@
 /*
- * Copyright 2010-2016 JetBrains s.r.o.
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- * http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
+ * Copyright 2000-2018 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license
+ * that can be found in the license/LICENSE.txt file.
  */
 
 package org.jetbrains.kotlin.idea.inspections
 
 import com.intellij.codeInspection.*
 import com.intellij.psi.PsiElementVisitor
-import com.intellij.psi.tree.IElementType
-import org.jetbrains.kotlin.descriptors.Modality
-import org.jetbrains.kotlin.extensions.DeclarationAttributeAltererExtension
-import org.jetbrains.kotlin.idea.caches.resolve.analyze
 import org.jetbrains.kotlin.idea.core.implicitModality
-import org.jetbrains.kotlin.idea.core.mapModality
 import org.jetbrains.kotlin.idea.quickfix.RemoveModifierFix
-import org.jetbrains.kotlin.lexer.KtTokens
-import org.jetbrains.kotlin.psi.KtDeclaration
-import org.jetbrains.kotlin.psi.KtVisitorVoid
+import org.jetbrains.kotlin.psi.declarationVisitor
 import org.jetbrains.kotlin.psi.psiUtil.modalityModifier
-import org.jetbrains.kotlin.resolve.BindingContext
-import org.jetbrains.kotlin.resolve.lazy.BodyResolveMode
 
 class RedundantModalityModifierInspection : AbstractKotlinInspection(), CleanupLocalInspectionTool {
     override fun buildVisitor(holder: ProblemsHolder, isOnTheFly: Boolean, session: LocalInspectionToolSession): PsiElementVisitor {
-        return object : KtVisitorVoid() {
-            override fun visitDeclaration(declaration: KtDeclaration) {
-                val modalityModifier = declaration.modalityModifier() ?: return
-                val modalityModifierType = modalityModifier.node.elementType
-                val implicitModality = declaration.implicitModality()
+        return declarationVisitor { declaration ->
+            val modalityModifier = declaration.modalityModifier() ?: return@declarationVisitor
+            val modalityModifierType = modalityModifier.node.elementType
+            val implicitModality = declaration.implicitModality()
 
-                if (modalityModifierType != implicitModality) return
+            if (modalityModifierType != implicitModality) return@declarationVisitor
 
-                holder.registerProblem(modalityModifier,
-                                       "Redundant modality modifier",
-                                       ProblemHighlightType.LIKE_UNUSED_SYMBOL,
-                                       IntentionWrapper(RemoveModifierFix(declaration, implicitModality, isRedundant = true),
-                                                        declaration.containingFile))
-            }
+            holder.registerProblem(modalityModifier,
+                                   "Redundant modality modifier",
+                                   ProblemHighlightType.LIKE_UNUSED_SYMBOL,
+                                   IntentionWrapper(RemoveModifierFix(declaration, implicitModality, isRedundant = true),
+                                                    declaration.containingFile))
         }
     }
 }

idea/src/org/jetbrains/kotlin/idea/inspections/RedundantSamConstructorInspection.kt

@@ -1,17 +1,6 @@
 /*
- * Copyright 2010-2017 JetBrains s.r.o.
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- * http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
+ * Copyright 2000-2018 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license
+ * that can be found in the license/LICENSE.txt file.
  */
 
 package org.jetbrains.kotlin.idea.inspections
@@ -53,63 +42,60 @@ import org.jetbrains.kotlin.utils.keysToMapExceptNulls
 
 class RedundantSamConstructorInspection : AbstractKotlinInspection() {
     override fun buildVisitor(holder: ProblemsHolder, isOnTheFly: Boolean, session: LocalInspectionToolSession): PsiElementVisitor {
-        return object : KtVisitorVoid() {
-            private fun createQuickFix(expression: KtCallExpression): LocalQuickFix {
-                return object : LocalQuickFix {
-                    override fun getName() = "Remove redundant SAM-constructor"
-                    override fun getFamilyName() = name
-                    override fun applyFix(project: Project, descriptor: ProblemDescriptor) {
-                        if (!FileModificationService.getInstance().preparePsiElementForWrite(expression)) return
-                        replaceSamConstructorCall(expression)
-                    }
-                }
+        return callExpressionVisitor(fun(expression) {
+            if (expression.valueArguments.isEmpty()) return
+
+            val samConstructorCalls = samConstructorCallsToBeConverted(expression)
+            if (samConstructorCalls.isEmpty()) return
+            val single = samConstructorCalls.singleOrNull()
+            if (single != null) {
+                val calleeExpression = single.calleeExpression ?: return
+                val problemDescriptor = holder.manager.
+                        createProblemDescriptor(calleeExpression,
+                                                single.typeArgumentList ?: calleeExpression,
+                                                "Redundant SAM-constructor",
+                                                ProblemHighlightType.LIKE_UNUSED_SYMBOL,
+                                                isOnTheFly,
+                                                createQuickFix(single))
+
+                holder.registerProblem(problemDescriptor)
             }
+            else {
+                val problemDescriptor = holder.manager.
+                        createProblemDescriptor(expression.valueArgumentList!!,
+                                                "Redundant SAM-constructors",
+                                                createQuickFix(samConstructorCalls),
+                                                ProblemHighlightType.GENERIC_ERROR_OR_WARNING,
+                                                isOnTheFly)
 
-            private fun createQuickFix(expressions: Collection<KtCallExpression>): LocalQuickFix {
-                return object : LocalQuickFix {
-                    override fun getName() = "Remove redundant SAM-constructors"
-                    override fun getFamilyName() = name
-                    override fun applyFix(project: Project, descriptor: ProblemDescriptor) {
-                        for (callExpression in expressions) {
-                            if (!FileModificationService.getInstance().preparePsiElementForWrite(callExpression)) return
-                            replaceSamConstructorCall(callExpression)
-                        }
-                    }
-                }
+                holder.registerProblem(problemDescriptor)
             }
+        })
+    }
 
-            override fun visitCallExpression(expression: KtCallExpression) {
-                if (expression.valueArguments.isEmpty()) return
-
-                val samConstructorCalls = samConstructorCallsToBeConverted(expression)
-                if (samConstructorCalls.isEmpty()) return
-                val single = samConstructorCalls.singleOrNull()
-                if (single != null) {
-                    val calleeExpression = single.calleeExpression ?: return
-                    val problemDescriptor = holder.manager.
-                            createProblemDescriptor(calleeExpression,
-                                                    single.typeArgumentList ?: calleeExpression,
-                                                    "Redundant SAM-constructor",
-                                                    ProblemHighlightType.LIKE_UNUSED_SYMBOL,
-                                                    isOnTheFly,
-                                                    createQuickFix(single))
-
-                    holder.registerProblem(problemDescriptor)
-                }
-                else {
-                    val problemDescriptor = holder.manager.
-                            createProblemDescriptor(expression.valueArgumentList!!,
-                                                    "Redundant SAM-constructors",
-                                                    createQuickFix(samConstructorCalls),
-                                                    ProblemHighlightType.GENERIC_ERROR_OR_WARNING,
-                                                    isOnTheFly)
-
-                    holder.registerProblem(problemDescriptor)
-                }
+    private fun createQuickFix(expression: KtCallExpression): LocalQuickFix {
+        return object : LocalQuickFix {
+            override fun getName() = "Remove redundant SAM-constructor"
+            override fun getFamilyName() = name
+            override fun applyFix(project: Project, descriptor: ProblemDescriptor) {
+                if (!FileModificationService.getInstance().preparePsiElementForWrite(expression)) return
+                replaceSamConstructorCall(expression)
             }
         }
     }
 
+    private fun createQuickFix(expressions: Collection<KtCallExpression>): LocalQuickFix {
+        return object : LocalQuickFix {
+            override fun getName() = "Remove redundant SAM-constructors"
+            override fun getFamilyName() = name
+            override fun applyFix(project: Project, descriptor: ProblemDescriptor) {
+                for (callExpression in expressions) {
+                    if (!FileModificationService.getInstance().preparePsiElementForWrite(callExpression)) return
+                    replaceSamConstructorCall(callExpression)
+                }
+            }
+        }
+    }
     companion  object {
         fun replaceSamConstructorCall(callExpression: KtCallExpression): KtLambdaExpression {
             val functionalArgument = callExpression.samConstructorValueArgument()?.getArgumentExpression()

idea/src/org/jetbrains/kotlin/idea/inspections/RedundantSetterInspection.kt

@@ -1,17 +1,6 @@
 /*
- * Copyright 2010-2017 JetBrains s.r.o.
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- * http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
+ * Copyright 2000-2018 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license
+ * that can be found in the license/LICENSE.txt file.
  */
 
 package org.jetbrains.kotlin.idea.inspections
@@ -25,15 +14,12 @@ import org.jetbrains.kotlin.psi.*
 
 class RedundantSetterInspection : AbstractKotlinInspection(), CleanupLocalInspectionTool {
     override fun buildVisitor(holder: ProblemsHolder, isOnTheFly: Boolean, session: LocalInspectionToolSession): PsiElementVisitor {
-        return object : KtVisitorVoid() {
-            override fun visitPropertyAccessor(accessor: KtPropertyAccessor) {
-                super.visitPropertyAccessor(accessor)
-                if (accessor.isRedundantSetter()) {
-                    holder.registerProblem(accessor,
-                                           "Redundant setter",
-                                           ProblemHighlightType.GENERIC_ERROR_OR_WARNING,
-                                           RemoveRedundantSetterFix())
-                }
+        return propertyAccessorVisitor { accessor ->
+            if (accessor.isRedundantSetter()) {
+                holder.registerProblem(accessor,
+                                       "Redundant setter",
+                                       ProblemHighlightType.GENERIC_ERROR_OR_WARNING,
+                                       RemoveRedundantSetterFix())
             }
         }
     }

idea/src/org/jetbrains/kotlin/idea/inspections/RedundantSuspendModifierInspection.kt

@@ -1,17 +1,6 @@
 /*
- * Copyright 2010-2017 JetBrains s.r.o.
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- * http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
+ * Copyright 2000-2018 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license
+ * that can be found in the license/LICENSE.txt file.
  */
 
 package org.jetbrains.kotlin.idea.inspections
@@ -24,43 +13,37 @@ import com.intellij.psi.PsiElementVisitor
 import org.jetbrains.kotlin.config.LanguageFeature
 import org.jetbrains.kotlin.descriptors.Modality
 import org.jetbrains.kotlin.idea.caches.resolve.analyzeFully
-import org.jetbrains.kotlin.idea.core.getModalityFromDescriptor
 import org.jetbrains.kotlin.idea.highlighter.hasSuspendCalls
 import org.jetbrains.kotlin.idea.project.languageVersionSettings
 import org.jetbrains.kotlin.idea.quickfix.RemoveModifierFix
 import org.jetbrains.kotlin.lexer.KtTokens
 import org.jetbrains.kotlin.psi.KtExpression
-import org.jetbrains.kotlin.psi.KtNamedFunction
-import org.jetbrains.kotlin.psi.KtVisitorVoid
+import org.jetbrains.kotlin.psi.namedFunctionVisitor
 import org.jetbrains.kotlin.psi.psiUtil.anyDescendantOfType
 import org.jetbrains.kotlin.resolve.BindingContext
 
 class RedundantSuspendModifierInspection : AbstractKotlinInspection() {
     override fun buildVisitor(holder: ProblemsHolder, isOnTheFly: Boolean, session: LocalInspectionToolSession): PsiElementVisitor {
-        return object : KtVisitorVoid() {
-            override fun visitNamedFunction(function: KtNamedFunction) {
-                super.visitNamedFunction(function)
-                if (!function.languageVersionSettings.supportsFeature(LanguageFeature.Coroutines)) return
+        return namedFunctionVisitor(fun(function) {
+            if (!function.languageVersionSettings.supportsFeature(LanguageFeature.Coroutines)) return
 
-                val suspendModifier = function.modifierList?.getModifier(KtTokens.SUSPEND_KEYWORD) ?: return
-                if (!function.hasBody()) return
-                if (function.hasModifier(KtTokens.OVERRIDE_KEYWORD)) return
+            val suspendModifier = function.modifierList?.getModifier(KtTokens.SUSPEND_KEYWORD) ?: return
+            if (!function.hasBody()) return
+            if (function.hasModifier(KtTokens.OVERRIDE_KEYWORD)) return
 
-                val context = function.analyzeFully()
-                val descriptor = context[BindingContext.FUNCTION, function] ?: return
-                if (descriptor.modality == Modality.OPEN) return
-
-                if (function.anyDescendantOfType<KtExpression> { it.hasSuspendCalls(context) }) {
-                    return
-                }
-
-                holder.registerProblem(suspendModifier,
-                                       "Redundant 'suspend' modifier",
-                                       ProblemHighlightType.LIKE_UNUSED_SYMBOL,
-                                       IntentionWrapper(RemoveModifierFix(function, KtTokens.SUSPEND_KEYWORD, isRedundant = true),
-                                                        function.containingFile))
+            val context = function.analyzeFully()
+            val descriptor = context[BindingContext.FUNCTION, function] ?: return
+            if (descriptor.modality == Modality.OPEN) return
 
+            if (function.anyDescendantOfType<KtExpression> { it.hasSuspendCalls(context) }) {
+                return
             }
-        }
+
+            holder.registerProblem(suspendModifier,
+                                   "Redundant 'suspend' modifier",
+                                   ProblemHighlightType.LIKE_UNUSED_SYMBOL,
+                                   IntentionWrapper(RemoveModifierFix(function, KtTokens.SUSPEND_KEYWORD, isRedundant = true),
+                                                    function.containingFile))
+        })
     }
 }

idea/src/org/jetbrains/kotlin/idea/inspections/RedundantUnitExpressionInspection.kt

@@ -1,17 +1,6 @@
 /*
- * Copyright 2010-2017 JetBrains s.r.o.
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- * http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
+ * Copyright 2000-2018 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license
+ * that can be found in the license/LICENSE.txt file.
  */
 
 package org.jetbrains.kotlin.idea.inspections
@@ -25,27 +14,22 @@ import org.jetbrains.kotlin.psi.psiUtil.getParentOfType
 
 class RedundantUnitExpressionInspection : AbstractKotlinInspection(), CleanupLocalInspectionTool {
     override fun buildVisitor(holder: ProblemsHolder, isOnTheFly: Boolean, session: LocalInspectionToolSession): PsiElementVisitor {
-        return object : KtVisitorVoid() {
-
-            override fun visitReferenceExpression(expression: KtReferenceExpression) {
-                super.visitReferenceExpression(expression)
-
-                if (KotlinBuiltIns.FQ_NAMES.unit.shortName() != (expression as? KtNameReferenceExpression)?.getReferencedNameAsName()) {
-                    return
-                }
-
-                val parent = expression.parent
-                if (parent !is KtReturnExpression && parent !is KtBlockExpression) return
-
-                // Do not report just 'Unit' in function literals (return@label Unit is OK even in literals)
-                if (parent is KtBlockExpression && parent.getParentOfType<KtFunctionLiteral>(strict = true) != null) return
-
-                holder.registerProblem(expression,
-                                       "Redundant 'Unit'",
-                                       ProblemHighlightType.LIKE_UNUSED_SYMBOL,
-                                       RemoveRedundantUnitFix())
+        return referenceExpressionVisitor(fun(expression) {
+            if (KotlinBuiltIns.FQ_NAMES.unit.shortName() != (expression as? KtNameReferenceExpression)?.getReferencedNameAsName()) {
+                return
             }
-        }
+
+            val parent = expression.parent
+            if (parent !is KtReturnExpression && parent !is KtBlockExpression) return
+
+            // Do not report just 'Unit' in function literals (return@label Unit is OK even in literals)
+            if (parent is KtBlockExpression && parent.getParentOfType<KtFunctionLiteral>(strict = true) != null) return
+
+            holder.registerProblem(expression,
+                                   "Redundant 'Unit'",
+                                   ProblemHighlightType.LIKE_UNUSED_SYMBOL,
+                                   RemoveRedundantUnitFix())
+        })
     }
 }
 

idea/src/org/jetbrains/kotlin/idea/inspections/RedundantUnitReturnTypeInspection.kt

@@ -1,17 +1,6 @@
 /*
- * Copyright 2010-2017 JetBrains s.r.o.
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- * http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
+ * Copyright 2000-2018 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license
+ * that can be found in the license/LICENSE.txt file.
  */
 
 package org.jetbrains.kotlin.idea.inspections
@@ -24,34 +13,28 @@ import com.intellij.psi.PsiElementVisitor
 import org.jetbrains.kotlin.idea.caches.resolve.analyze
 import org.jetbrains.kotlin.idea.intentions.RemoveExplicitTypeIntention
 import org.jetbrains.kotlin.psi.KtCodeFragment
-import org.jetbrains.kotlin.psi.KtNamedFunction
-import org.jetbrains.kotlin.psi.KtVisitorVoid
+import org.jetbrains.kotlin.psi.namedFunctionVisitor
 import org.jetbrains.kotlin.resolve.BindingContext
-import org.jetbrains.kotlin.resolve.calls.callUtil.getResolvedCall
 import org.jetbrains.kotlin.resolve.lazy.BodyResolveMode
-import org.jetbrains.kotlin.types.typeUtil.isNothing
 import org.jetbrains.kotlin.types.typeUtil.isUnit
 
 class RedundantUnitReturnTypeInspection : AbstractKotlinInspection(), CleanupLocalInspectionTool {
     override fun buildVisitor(holder: ProblemsHolder, isOnTheFly: Boolean): PsiElementVisitor {
-        return object : KtVisitorVoid() {
-            override fun visitNamedFunction(function: KtNamedFunction) {
-                super.visitNamedFunction(function)
-                if (function.containingFile is KtCodeFragment) return
-                val typeElement = function.typeReference?.typeElement ?: return
-                val context = function.analyze(BodyResolveMode.PARTIAL)
-                val descriptor = context[BindingContext.FUNCTION, function] ?: return
-                if (descriptor.returnType?.isUnit() == true) {
-                    if (!function.hasBlockBody()) {
-                        return
-                    }
-
-                    holder.registerProblem(typeElement,
-                                           "Redundant 'Unit' return type",
-                                           ProblemHighlightType.LIKE_UNUSED_SYMBOL,
-                                           IntentionWrapper(RemoveExplicitTypeIntention(), function.containingKtFile))
+        return namedFunctionVisitor(fun(function) {
+            if (function.containingFile is KtCodeFragment) return
+            val typeElement = function.typeReference?.typeElement ?: return
+            val context = function.analyze(BodyResolveMode.PARTIAL)
+            val descriptor = context[BindingContext.FUNCTION, function] ?: return
+            if (descriptor.returnType?.isUnit() == true) {
+                if (!function.hasBlockBody()) {
+                    return
                 }
+
+                holder.registerProblem(typeElement,
+                                       "Redundant 'Unit' return type",
+                                       ProblemHighlightType.LIKE_UNUSED_SYMBOL,
+                                       IntentionWrapper(RemoveExplicitTypeIntention(), function.containingKtFile))
             }
-        }
+        })
     }
 }

idea/src/org/jetbrains/kotlin/idea/inspections/RedundantVisibilityModifierInspection.kt

@@ -1,17 +1,6 @@
 /*
- * Copyright 2010-2016 JetBrains s.r.o.
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- * http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
+ * Copyright 2000-2018 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license
+ * that can be found in the license/LICENSE.txt file.
  */
 
 package org.jetbrains.kotlin.idea.inspections
@@ -20,23 +9,20 @@ import com.intellij.codeInspection.*
 import com.intellij.psi.PsiElementVisitor
 import org.jetbrains.kotlin.idea.core.implicitVisibility
 import org.jetbrains.kotlin.idea.quickfix.RemoveModifierFix
-import org.jetbrains.kotlin.psi.KtDeclaration
-import org.jetbrains.kotlin.psi.KtVisitorVoid
+import org.jetbrains.kotlin.psi.declarationVisitor
 import org.jetbrains.kotlin.psi.psiUtil.visibilityModifier
 
 class RedundantVisibilityModifierInspection : AbstractKotlinInspection(), CleanupLocalInspectionTool {
     override fun buildVisitor(holder: ProblemsHolder, isOnTheFly: Boolean, session: LocalInspectionToolSession): PsiElementVisitor {
-        return object : KtVisitorVoid() {
-            override fun visitDeclaration(declaration: KtDeclaration) {
-                val visibilityModifier = declaration.visibilityModifier() ?: return
-                val implicitVisibility = declaration.implicitVisibility()
-                if (visibilityModifier.node.elementType == implicitVisibility) {
-                    holder.registerProblem(visibilityModifier,
-                                           "Redundant visibility modifier",
-                                           ProblemHighlightType.LIKE_UNUSED_SYMBOL,
-                                           IntentionWrapper(RemoveModifierFix(declaration, implicitVisibility, isRedundant = true),
-                                                            declaration.containingFile))
-                }
+        return declarationVisitor { declaration ->
+            val visibilityModifier = declaration.visibilityModifier() ?: return@declarationVisitor
+            val implicitVisibility = declaration.implicitVisibility()
+            if (visibilityModifier.node.elementType == implicitVisibility) {
+                holder.registerProblem(visibilityModifier,
+                                       "Redundant visibility modifier",
+                                       ProblemHighlightType.LIKE_UNUSED_SYMBOL,
+                                       IntentionWrapper(RemoveModifierFix(declaration, implicitVisibility, isRedundant = true),
+                                                        declaration.containingFile))
             }
         }
     }

idea/src/org/jetbrains/kotlin/idea/inspections/RemoveRedundantSpreadOperatorInspection.kt

@@ -1,17 +1,6 @@
 /*
- * Copyright 2010-2017 JetBrains s.r.o.
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- * http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
+ * Copyright 2000-2018 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license
+ * that can be found in the license/LICENSE.txt file.
  */
 
 package org.jetbrains.kotlin.idea.inspections
@@ -31,36 +20,32 @@ import org.jetbrains.kotlin.psi.psiUtil.startOffset
 
 class RemoveRedundantSpreadOperatorInspection : AbstractKotlinInspection() {
     override fun buildVisitor(holder: ProblemsHolder, isOnTheFly: Boolean): PsiElementVisitor {
-        return object : KtVisitorVoid() {
-            override fun visitArgument(argument: KtValueArgument) {
-                super.visitArgument(argument)
-
-                val spreadElement = argument.getSpreadElement() ?: return
-                if (argument.isNamed()) return
-                val argumentExpression = argument.getArgumentExpression() ?: return
-                val argumentOffset = argument.startOffset
-                val startOffset = spreadElement.startOffset - argumentOffset
-                val endOffset =
-                        when (argumentExpression) {
-                            is KtCallExpression -> {
-                                if (!argumentExpression.isArrayOfMethod()) return
-                                argumentExpression.calleeExpression!!.endOffset - argumentOffset
-                            }
-                            is KtCollectionLiteralExpression -> startOffset + 1
-                            else -> return
+        return valueArgumentVisitor(fun(argument) {
+            val spreadElement = argument.getSpreadElement() ?: return
+            if (argument.isNamed()) return
+            val argumentExpression = argument.getArgumentExpression() ?: return
+            val argumentOffset = argument.startOffset
+            val startOffset = spreadElement.startOffset - argumentOffset
+            val endOffset =
+                    when (argumentExpression) {
+                        is KtCallExpression -> {
+                            if (!argumentExpression.isArrayOfMethod()) return
+                            argumentExpression.calleeExpression!!.endOffset - argumentOffset
                         }
+                        is KtCollectionLiteralExpression -> startOffset + 1
+                        else -> return
+                    }
 
-                val problemDescriptor = holder.manager.createProblemDescriptor(
-                        argument,
-                        TextRange(startOffset, endOffset),
-                        "Remove redundant spread operator",
-                        ProblemHighlightType.LIKE_UNUSED_SYMBOL,
-                        isOnTheFly,
-                        RemoveRedundantSpreadOperatorQuickfix()
-                )
-                holder.registerProblem(problemDescriptor)
-            }
-        }
+            val problemDescriptor = holder.manager.createProblemDescriptor(
+                    argument,
+                    TextRange(startOffset, endOffset),
+                    "Remove redundant spread operator",
+                    ProblemHighlightType.LIKE_UNUSED_SYMBOL,
+                    isOnTheFly,
+                    RemoveRedundantSpreadOperatorQuickfix()
+            )
+            holder.registerProblem(problemDescriptor)
+        })
     }
 }
 

idea/src/org/jetbrains/kotlin/idea/inspections/RemoveSetterParameterTypeInspection.kt

@@ -1,17 +1,6 @@
 /*
- * Copyright 2010-2017 JetBrains s.r.o.
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- * http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
+ * Copyright 2000-2018 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license
+ * that can be found in the license/LICENSE.txt file.
  */
 
 package org.jetbrains.kotlin.idea.inspections
@@ -22,20 +11,16 @@ import com.intellij.codeInspection.ProblemsHolder
 import com.intellij.psi.PsiElementVisitor
 import org.jetbrains.kotlin.idea.intentions.RemoveExplicitTypeIntention
 import org.jetbrains.kotlin.idea.intentions.isSetterParameter
-import org.jetbrains.kotlin.psi.KtDeclaration
-import org.jetbrains.kotlin.psi.KtParameter
-import org.jetbrains.kotlin.psi.KtVisitorVoid
+import org.jetbrains.kotlin.psi.parameterVisitor
 
 class RemoveSetterParameterTypeInspection : AbstractKotlinInspection() {
     override fun buildVisitor(holder: ProblemsHolder, isOnTheFly: Boolean): PsiElementVisitor {
-        return object : KtVisitorVoid() {
-            override fun visitDeclaration(dcl: KtDeclaration) {
-                val typeReference = (dcl as? KtParameter)?.takeIf { it.isSetterParameter }?.typeReference ?: return
-                holder.registerProblem(typeReference,
-                                       "Redundant setter parameter type",
-                                       ProblemHighlightType.LIKE_UNUSED_SYMBOL,
-                                       IntentionWrapper(RemoveExplicitTypeIntention(), dcl.containingKtFile))
-            }
+        return parameterVisitor { dcl ->
+            val typeReference = dcl.takeIf { it.isSetterParameter }?.typeReference ?: return@parameterVisitor
+            holder.registerProblem(typeReference,
+                                   "Redundant setter parameter type",
+                                   ProblemHighlightType.LIKE_UNUSED_SYMBOL,
+                                   IntentionWrapper(RemoveExplicitTypeIntention(), dcl.containingKtFile))
         }
     }
 }

idea/src/org/jetbrains/kotlin/idea/inspections/RemoveToStringInStringTemplateInspection.kt

@@ -1,17 +1,6 @@
 /*
- * Copyright 2010-2016 JetBrains s.r.o.
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- * http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
+ * Copyright 2000-2018 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license
+ * that can be found in the license/LICENSE.txt file.
  */
 
 package org.jetbrains.kotlin.idea.inspections
@@ -29,27 +18,23 @@ import org.jetbrains.kotlin.resolve.lazy.BodyResolveMode
 
 class RemoveToStringInStringTemplateInspection : AbstractKotlinInspection(), CleanupLocalInspectionTool {
     override fun buildVisitor(holder: ProblemsHolder, isOnTheFly: Boolean, session: LocalInspectionToolSession) =
-            object : KtVisitorVoid() {
-                override fun visitDotQualifiedExpression(expression: KtDotQualifiedExpression) {
-                    super.visitDotQualifiedExpression(expression)
+            dotQualifiedExpressionVisitor(fun(expression) {
+                if (expression.parent !is KtBlockStringTemplateEntry) return
+                if (expression.receiverExpression is KtSuperExpression) return
+                val selectorExpression = expression.selectorExpression ?: return
+                if (!expression.isToString()) return
 
-                    if (expression.parent !is KtBlockStringTemplateEntry) return
-                    if (expression.receiverExpression is KtSuperExpression) return
-                    val selectorExpression = expression.selectorExpression ?: return
-                    if (!expression.isToString()) return
+                holder.registerProblem(selectorExpression,
+                                       "Redundant 'toString()' call in string template",
+                                       ProblemHighlightType.LIKE_UNUSED_SYMBOL,
+                                       RemoveToStringFix())
+            })
+}
 
-                    holder.registerProblem(selectorExpression,
-                                           "Redundant 'toString()' call in string template",
-                                           ProblemHighlightType.LIKE_UNUSED_SYMBOL,
-                                           RemoveToStringFix())
-                }
-
-                private fun KtDotQualifiedExpression.isToString(): Boolean {
-                    val resolvedCall = toResolvedCall(BodyResolveMode.PARTIAL) ?: return false
-                    val callableDescriptor = resolvedCall.resultingDescriptor as? CallableMemberDescriptor ?: return false
-                    return callableDescriptor.getDeepestSuperDeclarations().any { it.fqNameUnsafe.asString() == "kotlin.Any.toString" }
-                }
-            }
+private fun KtDotQualifiedExpression.isToString(): Boolean {
+    val resolvedCall = toResolvedCall(BodyResolveMode.PARTIAL) ?: return false
+    val callableDescriptor = resolvedCall.resultingDescriptor as? CallableMemberDescriptor ?: return false
+    return callableDescriptor.getDeepestSuperDeclarations().any { it.fqNameUnsafe.asString() == "kotlin.Any.toString" }
 }
 
 class RemoveToStringFix: LocalQuickFix {

idea/src/org/jetbrains/kotlin/idea/inspections/ReplaceArrayOfWithLiteralInspection.kt

@@ -1,17 +1,6 @@
 /*
- * Copyright 2010-2017 JetBrains s.r.o.
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- * http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
+ * Copyright 2000-2018 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license
+ * that can be found in the license/LICENSE.txt file.
  */
 
 package org.jetbrains.kotlin.idea.inspections
@@ -32,39 +21,35 @@ import org.jetbrains.kotlin.psi.psiUtil.getParentOfType
 class ReplaceArrayOfWithLiteralInspection : AbstractKotlinInspection() {
 
     override fun buildVisitor(holder: ProblemsHolder, isOnTheFly: Boolean): PsiElementVisitor {
-        return object : KtVisitorVoid() {
-            override fun visitCallExpression(expression: KtCallExpression) {
-                super.visitCallExpression(expression)
+        return callExpressionVisitor(fun(expression) {
+            if (!expression.languageVersionSettings.supportsFeature(ArrayLiteralsInAnnotations) &&
+                !ApplicationManager.getApplication().isUnitTestMode) return
 
-                if (!expression.languageVersionSettings.supportsFeature(ArrayLiteralsInAnnotations) &&
-                    !ApplicationManager.getApplication().isUnitTestMode) return
+            val calleeExpression = expression.calleeExpression as? KtNameReferenceExpression ?: return
+            if (!expression.isArrayOfMethod()) return
 
-                val calleeExpression = expression.calleeExpression as? KtNameReferenceExpression ?: return
-                if (!expression.isArrayOfMethod()) return
-
-                val parent = expression.parent
-                when (parent) {
-                    is KtValueArgument -> {
-                        if (parent.parent.parent !is KtAnnotationEntry) return
-                        if (parent.getSpreadElement() != null && !parent.isNamed()) return
-                    }
-                    is KtParameter -> {
-                        val constructor = parent.parent.parent as? KtPrimaryConstructor ?: return
-                        val containingClass = constructor.getContainingClassOrObject()
-                        if (!containingClass.isAnnotation()) return
-                    }
-                    else -> return
+            val parent = expression.parent
+            when (parent) {
+                is KtValueArgument -> {
+                    if (parent.parent.parent !is KtAnnotationEntry) return
+                    if (parent.getSpreadElement() != null && !parent.isNamed()) return
                 }
-
-                val calleeName = calleeExpression.getReferencedName()
-                holder.registerProblem(
-                        calleeExpression,
-                        "'$calleeName' call should be replaced with array literal [...]",
-                        ProblemHighlightType.GENERIC_ERROR_OR_WARNING,
-                        ReplaceWithArrayLiteralFix()
-                )
+                is KtParameter -> {
+                    val constructor = parent.parent.parent as? KtPrimaryConstructor ?: return
+                    val containingClass = constructor.getContainingClassOrObject()
+                    if (!containingClass.isAnnotation()) return
+                }
+                else -> return
             }
-        }
+
+            val calleeName = calleeExpression.getReferencedName()
+            holder.registerProblem(
+                calleeExpression,
+                "'$calleeName' call should be replaced with array literal [...]",
+                ProblemHighlightType.GENERIC_ERROR_OR_WARNING,
+                ReplaceWithArrayLiteralFix()
+            )
+        })
     }
 
     private class ReplaceWithArrayLiteralFix : LocalQuickFix {

idea/src/org/jetbrains/kotlin/idea/inspections/ReplaceToWithInfixFormInspection.kt

@@ -1,17 +1,6 @@
 /*
- * Copyright 2010-2017 JetBrains s.r.o.
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- * http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
+ * Copyright 2000-2018 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license
+ * that can be found in the license/LICENSE.txt file.
  */
 
 package org.jetbrains.kotlin.idea.inspections
@@ -26,7 +15,10 @@ import org.jetbrains.kotlin.descriptors.FunctionDescriptor
 import org.jetbrains.kotlin.idea.caches.resolve.analyze
 import org.jetbrains.kotlin.idea.intentions.callExpression
 import org.jetbrains.kotlin.idea.intentions.calleeName
-import org.jetbrains.kotlin.psi.*
+import org.jetbrains.kotlin.psi.KtDotQualifiedExpression
+import org.jetbrains.kotlin.psi.KtPsiFactory
+import org.jetbrains.kotlin.psi.createExpressionByPattern
+import org.jetbrains.kotlin.psi.dotQualifiedExpressionVisitor
 import org.jetbrains.kotlin.resolve.calls.callUtil.getResolvedCall
 import org.jetbrains.kotlin.resolve.lazy.BodyResolveMode
 
@@ -34,26 +26,23 @@ class ReplaceToWithInfixFormInspection : AbstractKotlinInspection() {
     private val compatibleNames = setOf("to")
 
     override fun buildVisitor(holder: ProblemsHolder, isOnTheFly: Boolean): PsiElementVisitor {
-        return object : KtVisitorVoid() {
-            override fun visitDotQualifiedExpression(expression: KtDotQualifiedExpression) {
-                super.visitDotQualifiedExpression(expression)
-                if (expression.callExpression?.valueArguments?.size != 1) return
-                if (expression.calleeName !in compatibleNames) return
+        return dotQualifiedExpressionVisitor(fun(expression) {
+            if (expression.callExpression?.valueArguments?.size != 1) return
+            if (expression.calleeName !in compatibleNames) return
 
-                val context = expression.analyze(BodyResolveMode.PARTIAL)
-                val resolvedCall = expression.getResolvedCall(context) ?: return
-                val function = resolvedCall.resultingDescriptor as? FunctionDescriptor ?: return
+            val context = expression.analyze(BodyResolveMode.PARTIAL)
+            val resolvedCall = expression.getResolvedCall(context) ?: return
+            val function = resolvedCall.resultingDescriptor as? FunctionDescriptor ?: return
 
-                if (!function.isInfix) return
+            if (!function.isInfix) return
 
-                holder.registerProblem(
-                    expression,
-                    "Replace 'to' with infix form",
-                    ProblemHighlightType.GENERIC_ERROR_OR_WARNING,
-                    ReplaceToWithInfixFormQuickfix()
-                )
-            }
-        }
+            holder.registerProblem(
+                expression,
+                "Replace 'to' with infix form",
+                ProblemHighlightType.GENERIC_ERROR_OR_WARNING,
+                ReplaceToWithInfixFormQuickfix()
+            )
+        })
     }
 }
 

idea/src/org/jetbrains/kotlin/idea/inspections/SelfAssignmentInspection.kt

@@ -1,17 +1,6 @@
 /*
- * Copyright 2010-2017 JetBrains s.r.o.
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- * http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
+ * Copyright 2000-2018 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license
+ * that can be found in the license/LICENSE.txt file.
  */
 
 package org.jetbrains.kotlin.idea.inspections
@@ -31,64 +20,59 @@ import org.jetbrains.kotlin.resolve.scopes.receivers.ImplicitReceiver
 
 class SelfAssignmentInspection : AbstractKotlinInspection(), CleanupLocalInspectionTool {
     override fun buildVisitor(holder: ProblemsHolder, isOnTheFly: Boolean, session: LocalInspectionToolSession): PsiElementVisitor {
-        return object : KtVisitorVoid() {
+        return binaryExpressionVisitor(fun(expression) {
+            if (expression.operationToken != KtTokens.EQ) return
+            val left = expression.left
+            val leftRefExpr = left?.asNameReferenceExpression() ?: return
+            val right = expression.right
+            val rightRefExpr = right?.asNameReferenceExpression() ?: return
+            // To omit analyzing too much
+            if (leftRefExpr.text != rightRefExpr.text) return
 
-            private fun KtExpression.asNameReferenceExpression(): KtNameReferenceExpression? = when (this) {
-                is KtNameReferenceExpression ->
-                    this
-                is KtDotQualifiedExpression ->
-                    (selectorExpression as? KtNameReferenceExpression)?.takeIf { receiverExpression is KtThisExpression }
-                else ->
-                    null
+            val context = expression.analyze(BodyResolveMode.PARTIAL)
+            val leftResolvedCall = left.getResolvedCall(context)
+            val leftCallee = leftResolvedCall?.resultingDescriptor as? VariableDescriptor ?: return
+            val rightResolvedCall = right.getResolvedCall(context)
+            val rightCallee = rightResolvedCall?.resultingDescriptor as? VariableDescriptor ?: return
+            if (leftCallee != rightCallee) return
+
+            if (!rightCallee.isVar) return
+            if (rightCallee is PropertyDescriptor) {
+                if (rightCallee.isOverridable) return
+                if (rightCallee.accessors.any { !it.isDefault }) return
             }
 
-            private fun KtExpression.receiverDeclarationDescriptor(
-                    resolvedCall: ResolvedCall<out CallableDescriptor>,
-                    context: BindingContext
-            ): DeclarationDescriptor? {
-                val thisExpression = (this as? KtDotQualifiedExpression)?.receiverExpression as? KtThisExpression
-                if (thisExpression != null) {
-                    return thisExpression.getResolvedCall(context)?.resultingDescriptor?.containingDeclaration
-                }
-                val implicitReceiver = with (resolvedCall) { dispatchReceiver ?: extensionReceiver } as? ImplicitReceiver
-                return implicitReceiver?.declarationDescriptor
+            if (left.receiverDeclarationDescriptor(leftResolvedCall, context) !=
+                right.receiverDeclarationDescriptor(rightResolvedCall, context)) {
+                return
             }
 
-            override fun visitBinaryExpression(expression: KtBinaryExpression) {
-                super.visitBinaryExpression(expression)
+            holder.registerProblem(right,
+                                   "Variable '${rightCallee.name}' is assigned to itself",
+                                   ProblemHighlightType.GENERIC_ERROR_OR_WARNING,
+                                   RemoveSelfAssignmentFix())
+        })
+    }
 
-                if (expression.operationToken != KtTokens.EQ) return
-                val left = expression.left
-                val leftRefExpr = left?.asNameReferenceExpression() ?: return
-                val right = expression.right
-                val rightRefExpr = right?.asNameReferenceExpression() ?: return
-                // To omit analyzing too much
-                if (leftRefExpr.text != rightRefExpr.text) return
+    private fun KtExpression.asNameReferenceExpression(): KtNameReferenceExpression? = when (this) {
+        is KtNameReferenceExpression ->
+            this
+        is KtDotQualifiedExpression ->
+            (selectorExpression as? KtNameReferenceExpression)?.takeIf { receiverExpression is KtThisExpression }
+        else ->
+            null
+    }
 
-                val context = expression.analyze(BodyResolveMode.PARTIAL)
-                val leftResolvedCall = left.getResolvedCall(context)
-                val leftCallee = leftResolvedCall?.resultingDescriptor as? VariableDescriptor ?: return
-                val rightResolvedCall = right.getResolvedCall(context)
-                val rightCallee = rightResolvedCall?.resultingDescriptor as? VariableDescriptor ?: return
-                if (leftCallee != rightCallee) return
-
-                if (!rightCallee.isVar) return
-                if (rightCallee is PropertyDescriptor) {
-                    if (rightCallee.isOverridable) return
-                    if (rightCallee.accessors.any { !it.isDefault }) return
-                }
-
-                if (left.receiverDeclarationDescriptor(leftResolvedCall, context) !=
-                    right.receiverDeclarationDescriptor(rightResolvedCall, context)) {
-                    return
-                }
-
-                holder.registerProblem(right,
-                                       "Variable '${rightCallee.name}' is assigned to itself",
-                                       ProblemHighlightType.GENERIC_ERROR_OR_WARNING,
-                                       RemoveSelfAssignmentFix())
-            }
+    private fun KtExpression.receiverDeclarationDescriptor(
+        resolvedCall: ResolvedCall<out CallableDescriptor>,
+        context: BindingContext
+    ): DeclarationDescriptor? {
+        val thisExpression = (this as? KtDotQualifiedExpression)?.receiverExpression as? KtThisExpression
+        if (thisExpression != null) {
+            return thisExpression.getResolvedCall(context)?.resultingDescriptor?.containingDeclaration
         }
+        val implicitReceiver = with (resolvedCall) { dispatchReceiver ?: extensionReceiver } as? ImplicitReceiver
+        return implicitReceiver?.declarationDescriptor
     }
 }
 

idea/src/org/jetbrains/kotlin/idea/inspections/SimplifyWhenWithBooleanConstantConditionInspection.kt

@@ -1,17 +1,6 @@
 /*
- * Copyright 2010-2017 JetBrains s.r.o.
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- * http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
+ * Copyright 2000-2018 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license
+ * that can be found in the license/LICENSE.txt file.
  */
 
 package org.jetbrains.kotlin.idea.inspections
@@ -30,22 +19,16 @@ import org.jetbrains.kotlin.resolve.bindingContextUtil.isUsedAsExpression
 class SimplifyWhenWithBooleanConstantConditionInspection : AbstractKotlinInspection() {
 
     override fun buildVisitor(holder: ProblemsHolder, isOnTheFly: Boolean, session: LocalInspectionToolSession): PsiElementVisitor {
-        return object : KtVisitorVoid() {
+        return whenExpressionVisitor(fun(expression) {
+            if (expression.closeBrace == null) return
+            if (expression.subjectExpression != null) return
+            if (expression.entries.none { it.isTrueConstantCondition() || it.isFalseConstantCondition() }) return
 
-            override fun visitWhenExpression(expression: KtWhenExpression) {
-                super.visitWhenExpression(expression)
-
-                if (expression.closeBrace == null) return
-                if (expression.subjectExpression != null) return
-                if (expression.entries.none { it.isTrueConstantCondition() || it.isFalseConstantCondition() }) return
-
-                holder.registerProblem(expression.whenKeyword,
-                                       "This 'when' is simplifiable",
-                                       ProblemHighlightType.GENERIC_ERROR_OR_WARNING,
-                                       SimplifyWhenFix())
-            }
-
-        }
+            holder.registerProblem(expression.whenKeyword,
+                                   "This 'when' is simplifiable",
+                                   ProblemHighlightType.GENERIC_ERROR_OR_WARNING,
+                                   SimplifyWhenFix())
+        })
     }
 }
 

idea/src/org/jetbrains/kotlin/idea/inspections/SuspiciousEqualsCombination.kt

@@ -1,17 +1,6 @@
 /*
- * Copyright 2010-2017 JetBrains s.r.o.
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- * http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
+ * Copyright 2000-2018 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license
+ * that can be found in the license/LICENSE.txt file.
  */
 
 package org.jetbrains.kotlin.idea.inspections
@@ -24,18 +13,16 @@ import org.jetbrains.kotlin.psi.*
 
 class SuspiciousEqualsCombination : AbstractKotlinInspection() {
     override fun buildVisitor(holder: ProblemsHolder, isOnTheFly: Boolean, session: LocalInspectionToolSession) =
-            object : KtVisitorVoid() {
-                override fun visitBinaryExpression(expression: KtBinaryExpression) {
-                    if (expression.parent is KtBinaryExpression) return
-                    val operands = expression.parseBinary()
-                    val eqeq = operands.eqEqOperands.map { it.text }
-                    val eqeqeq = operands.eqEqEqOperands.map { it.text }
-                    if (eqeq.intersect(eqeqeq).isNotEmpty()) {
-                        holder.registerProblem(expression, "Suspicious combination of == and ===",
-                                               ProblemHighlightType.GENERIC_ERROR_OR_WARNING)
-                    }
+            binaryExpressionVisitor(fun(expression) {
+                if (expression.parent is KtBinaryExpression) return
+                val operands = expression.parseBinary()
+                val eqeq = operands.eqEqOperands.map { it.text }
+                val eqeqeq = operands.eqEqEqOperands.map { it.text }
+                if (eqeq.intersect(eqeqeq).isNotEmpty()) {
+                    holder.registerProblem(expression, "Suspicious combination of == and ===",
+                                           ProblemHighlightType.GENERIC_ERROR_OR_WARNING)
                 }
-            }
+            })
 
     private fun KtBinaryExpression.parseBinary(pair: ComparisonOperands = ComparisonOperands()): ComparisonOperands {
         when (operationToken) {

idea/src/org/jetbrains/kotlin/idea/inspections/UnsafeCastFromDynamicInspection.kt

@@ -1,17 +1,6 @@
 /*
- * Copyright 2010-2016 JetBrains s.r.o.
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- * http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
+ * Copyright 2000-2018 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license
+ * that can be found in the license/LICENSE.txt file.
  */
 
 package org.jetbrains.kotlin.idea.inspections
@@ -20,8 +9,7 @@ import com.intellij.codeInspection.LocalInspectionToolSession
 import com.intellij.codeInspection.ProblemsHolder
 import com.intellij.psi.PsiElementVisitor
 import org.jetbrains.kotlin.idea.caches.resolve.analyze
-import org.jetbrains.kotlin.psi.KtExpression
-import org.jetbrains.kotlin.psi.KtVisitorVoid
+import org.jetbrains.kotlin.psi.expressionVisitor
 import org.jetbrains.kotlin.resolve.BindingContext
 import org.jetbrains.kotlin.resolve.calls.callUtil.getType
 import org.jetbrains.kotlin.resolve.lazy.BodyResolveMode
@@ -30,18 +18,14 @@ import org.jetbrains.kotlin.types.isDynamic
 
 class UnsafeCastFromDynamicInspection : AbstractKotlinInspection() {
     override fun buildVisitor(holder: ProblemsHolder, isOnTheFly: Boolean, session: LocalInspectionToolSession): PsiElementVisitor {
-        return object : KtVisitorVoid() {
-            override fun visitExpression(expression: KtExpression) {
-                super.visitExpression(expression)
+        return expressionVisitor(fun(expression) {
+            val context = expression.analyze(BodyResolveMode.PARTIAL)
+            val expectedType = context[BindingContext.EXPECTED_EXPRESSION_TYPE, expression] ?: return
+            val actualType = expression.getType(context) ?: return
 
-                val context = expression.analyze(BodyResolveMode.PARTIAL)
-                val expectedType = context[BindingContext.EXPECTED_EXPRESSION_TYPE, expression] ?: return
-                val actualType = expression.getType(context) ?: return
-
-                if (actualType.isDynamic() && !expectedType.isDynamic() && !TypeUtils.noExpectedType(expectedType)) {
-                    holder.registerProblem(expression, "Implicit (unsafe) cast from dynamic to $expectedType")
-                }
+            if (actualType.isDynamic() && !expectedType.isDynamic() && !TypeUtils.noExpectedType(expectedType)) {
+                holder.registerProblem(expression, "Implicit (unsafe) cast from dynamic to $expectedType")
             }
-        }
+        })
     }
 }

idea/src/org/jetbrains/kotlin/idea/inspections/UnusedLambdaExpressionBodyInspection.kt

@@ -1,25 +1,12 @@
 /*
- * Copyright 2010-2017 JetBrains s.r.o.
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- * http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
+ * Copyright 2000-2018 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license
+ * that can be found in the license/LICENSE.txt file.
  */
 
 package org.jetbrains.kotlin.idea.inspections
 
 import com.intellij.codeInsight.FileModificationService
-import com.intellij.codeInspection.LocalQuickFix
 import com.intellij.codeInspection.LocalQuickFixOnPsiElement
-import com.intellij.codeInspection.ProblemDescriptor
 import com.intellij.codeInspection.ProblemsHolder
 import com.intellij.openapi.project.Project
 import com.intellij.psi.PsiElement
@@ -28,7 +15,10 @@ import com.intellij.psi.PsiFile
 import org.jetbrains.kotlin.builtins.isFunctionType
 import org.jetbrains.kotlin.descriptors.CallableDescriptor
 import org.jetbrains.kotlin.idea.caches.resolve.analyze
-import org.jetbrains.kotlin.psi.*
+import org.jetbrains.kotlin.psi.KtExpression
+import org.jetbrains.kotlin.psi.KtFunction
+import org.jetbrains.kotlin.psi.KtLambdaExpression
+import org.jetbrains.kotlin.psi.callExpressionVisitor
 import org.jetbrains.kotlin.resolve.BindingContext
 import org.jetbrains.kotlin.resolve.calls.callUtil.getResolvedCall
 import org.jetbrains.kotlin.resolve.lazy.BodyResolveMode
@@ -37,28 +27,26 @@ import org.jetbrains.kotlin.resolve.source.getPsi
 
 class UnusedLambdaExpressionBodyInspection : AbstractKotlinInspection() {
     override fun buildVisitor(holder: ProblemsHolder, isOnTheFly: Boolean): PsiElementVisitor {
-        return object : KtVisitorVoid() {
-            override fun visitCallExpression(expression: KtCallExpression) {
-                val context = expression.analyze(BodyResolveMode.PARTIAL)
-                if (expression.used(context)) {
-                    return
-                }
-
-                val descriptor = expression.getResolvedCall(context)?.resultingDescriptor ?: return
-                if (!descriptor.returnsFunction()) {
-                    return
-                }
-
-                val function = descriptor.source.getPsi() as? KtFunction ?: return
-                if (function.hasBlockBody() || function.bodyExpression !is KtLambdaExpression) {
-                    return
-                }
-
-                holder.registerProblem(expression,
-                                       "Unused return value of a function with lambda expression body",
-                                       RemoveEqTokenFromFunctionDeclarationFix(function))
+        return callExpressionVisitor(fun(expression) {
+            val context = expression.analyze(BodyResolveMode.PARTIAL)
+            if (expression.used(context)) {
+                return
             }
-        }
+
+            val descriptor = expression.getResolvedCall(context)?.resultingDescriptor ?: return
+            if (!descriptor.returnsFunction()) {
+                return
+            }
+
+            val function = descriptor.source.getPsi() as? KtFunction ?: return
+            if (function.hasBlockBody() || function.bodyExpression !is KtLambdaExpression) {
+                return
+            }
+
+            holder.registerProblem(expression,
+                                   "Unused return value of a function with lambda expression body",
+                                   RemoveEqTokenFromFunctionDeclarationFix(function))
+        })
     }
 
     private fun KtExpression.used(context: BindingContext): Boolean = context[BindingContext.USED_AS_EXPRESSION, this] ?: true

idea/src/org/jetbrains/kotlin/idea/inspections/UnusedSymbolInspection.kt

@@ -1,17 +1,6 @@
 /*
- * Copyright 2010-2015 JetBrains s.r.o.
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- * http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
+ * Copyright 2000-2018 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license
+ * that can be found in the license/LICENSE.txt file.
  */
 
 package org.jetbrains.kotlin.idea.inspections
@@ -139,47 +128,44 @@ class UnusedSymbolInspection : AbstractKotlinInspection() {
     override fun runForWholeFile() = true
 
     override fun buildVisitor(holder: ProblemsHolder, isOnTheFly: Boolean, session: LocalInspectionToolSession): PsiElementVisitor {
-        return object : KtVisitorVoid() {
-            override fun visitDeclaration(declaration: KtDeclaration) {
-                if (declaration !is KtNamedDeclaration) return
-                val message = declaration.describe()?.let { "$it is never used" } ?: return
+        return namedDeclarationVisitor(fun(declaration) {
+            val message = declaration.describe()?.let { "$it is never used" } ?: return
 
-                if (!ProjectRootsUtil.isInProjectSource(declaration)) return
+            if (!ProjectRootsUtil.isInProjectSource(declaration)) return
 
-                // Simple PSI-based checks
-                if (declaration is KtObjectDeclaration && declaration.isCompanion()) return // never mark companion object as unused (there are too many reasons it can be needed for)
+            // Simple PSI-based checks
+            if (declaration is KtObjectDeclaration && declaration.isCompanion()) return // never mark companion object as unused (there are too many reasons it can be needed for)
 
-                if (declaration is KtEnumEntry) return
-                if (declaration.hasModifier(KtTokens.OVERRIDE_KEYWORD)) return
-                if (declaration is KtProperty && declaration.isLocal) return
-                if (declaration is KtParameter && (declaration.getParent().parent !is KtPrimaryConstructor || !declaration.hasValOrVar())) return
+            if (declaration is KtEnumEntry) return
+            if (declaration.hasModifier(KtTokens.OVERRIDE_KEYWORD)) return
+            if (declaration is KtProperty && declaration.isLocal) return
+            if (declaration is KtParameter && (declaration.getParent().parent !is KtPrimaryConstructor || !declaration.hasValOrVar())) return
 
-                // More expensive, resolve-based checks
-                val descriptor = declaration.resolveToDescriptorIfAny() ?: return
-                if (descriptor is FunctionDescriptor && descriptor.isOperator) return
-                if (isEntryPoint(declaration)) return
-                if (declaration is KtProperty && declaration.isSerializationImplicitlyUsedField()) return
-                if (declaration is KtNamedFunction && declaration.isSerializationImplicitlyUsedMethod()) return
-                // properties can be referred by component1/component2, which is too expensive to search, don't mark them as unused
-                if (declaration is KtParameter && declaration.dataClassComponentFunction() != null) return
+            // More expensive, resolve-based checks
+            val descriptor = declaration.resolveToDescriptorIfAny() ?: return
+            if (descriptor is FunctionDescriptor && descriptor.isOperator) return
+            if (isEntryPoint(declaration)) return
+            if (declaration is KtProperty && declaration.isSerializationImplicitlyUsedField()) return
+            if (declaration is KtNamedFunction && declaration.isSerializationImplicitlyUsedMethod()) return
+            // properties can be referred by component1/component2, which is too expensive to search, don't mark them as unused
+            if (declaration is KtParameter && declaration.dataClassComponentFunction() != null) return
 
-                // Main checks: finding reference usages && text usages
-                if (hasNonTrivialUsages(declaration, descriptor)) return
-                if (declaration is KtClassOrObject && classOrObjectHasTextUsages(declaration)) return
+            // Main checks: finding reference usages && text usages
+            if (hasNonTrivialUsages(declaration, descriptor)) return
+            if (declaration is KtClassOrObject && classOrObjectHasTextUsages(declaration)) return
 
-                val psiElement = declaration.nameIdentifier ?: (declaration as? KtConstructor<*>)?.getConstructorKeyword() ?: return
-                val problemDescriptor = holder.manager.createProblemDescriptor(
-                        psiElement,
-                        null,
-                        message,
-                        ProblemHighlightType.LIKE_UNUSED_SYMBOL,
-                        true,
-                        *createQuickFixes(declaration).toTypedArray()
-                )
+            val psiElement = declaration.nameIdentifier ?: (declaration as? KtConstructor<*>)?.getConstructorKeyword() ?: return
+            val problemDescriptor = holder.manager.createProblemDescriptor(
+                    psiElement,
+                    null,
+                    message,
+                    ProblemHighlightType.LIKE_UNUSED_SYMBOL,
+                    true,
+                    *createQuickFixes(declaration).toTypedArray()
+            )
 
-                holder.registerProblem(problemDescriptor)
-            }
-        }
+            holder.registerProblem(problemDescriptor)
+        })
     }
 
     override val suppressionKey: String get() = "unused"

idea/src/org/jetbrains/kotlin/idea/inspections/UseExpressionBodyInspection.kt

@@ -1,17 +1,6 @@
 /*
- * Copyright 2010-2017 JetBrains s.r.o.
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- * http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
+ * Copyright 2000-2018 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license
+ * that can be found in the license/LICENSE.txt file.
  */
 
 package org.jetbrains.kotlin.idea.inspections
@@ -67,35 +56,31 @@ class UseExpressionBodyInspection(private val convertEmptyToUnit: Boolean) : Abs
     }
 
     override fun buildVisitor(holder: ProblemsHolder, isOnTheFly: Boolean) =
-            object : KtVisitorVoid() {
-                override fun visitDeclaration(declaration: KtDeclaration) {
-                    super.visitDeclaration(declaration)
-
-                    declaration as? KtDeclarationWithBody ?: return
-                    val (toHighlightElement, suffix, highlightType) = statusFor(declaration) ?: return
-                    // Change range to start with left brace
-                    val hasHighlighting = highlightType != INFORMATION
-                    val toHighlightRange = toHighlightElement?.textRange?.let {
-                        if (hasHighlighting) {
-                            it
-                        }
-                        else {
-                            // Extend range to [left brace..end of highlight element]
-                            val offset = (declaration.blockExpression()?.lBrace?.startOffset ?: it.startOffset) - it.startOffset
-                            it.shiftRight(offset).grown(-offset)
-                        }
+            declarationVisitor(fun(declaration) {
+                declaration as? KtDeclarationWithBody ?: return
+                val (toHighlightElement, suffix, highlightType) = statusFor(declaration) ?: return
+                // Change range to start with left brace
+                val hasHighlighting = highlightType != INFORMATION
+                val toHighlightRange = toHighlightElement?.textRange?.let {
+                    if (hasHighlighting) {
+                        it
+                    }
+                    else {
+                        // Extend range to [left brace..end of highlight element]
+                        val offset = (declaration.blockExpression()?.lBrace?.startOffset ?: it.startOffset) - it.startOffset
+                        it.shiftRight(offset).grown(-offset)
                     }
-
-                    holder.registerProblemWithoutOfflineInformation(
-                            declaration,
-                            "Use expression body instead of $suffix",
-                            isOnTheFly,
-                            highlightType,
-                            toHighlightRange?.shiftRight(-declaration.startOffset),
-                            ConvertToExpressionBodyFix()
-                    )
                 }
-            }
+
+                holder.registerProblemWithoutOfflineInformation(
+                        declaration,
+                        "Use expression body instead of $suffix",
+                        isOnTheFly,
+                        highlightType,
+                        toHighlightRange?.shiftRight(-declaration.startOffset),
+                        ConvertToExpressionBodyFix()
+                )
+            })
 
     private fun KtDeclarationWithBody.findValueStatement(): KtExpression? {
         val body = blockExpression() ?: return null

idea/src/org/jetbrains/kotlin/idea/inspections/WhenWithOnlyElseInspection.kt

@@ -1,17 +1,6 @@
 /*
- * Copyright 2010-2017 JetBrains s.r.o.
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- * http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
+ * Copyright 2000-2018 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license
+ * that can be found in the license/LICENSE.txt file.
  */
 
 package org.jetbrains.kotlin.idea.inspections
@@ -23,24 +12,22 @@ import com.intellij.codeInspection.ProblemsHolder
 import com.intellij.openapi.project.Project
 import com.intellij.psi.PsiElementVisitor
 import org.jetbrains.kotlin.idea.caches.resolve.analyze
-import org.jetbrains.kotlin.psi.KtVisitorVoid
 import org.jetbrains.kotlin.psi.KtWhenExpression
+import org.jetbrains.kotlin.psi.whenExpressionVisitor
 import org.jetbrains.kotlin.resolve.bindingContextUtil.isUsedAsExpression
 
 class WhenWithOnlyElseInspection : AbstractKotlinInspection() {
     override fun buildVisitor(holder: ProblemsHolder, isOnTheFly: Boolean): PsiElementVisitor {
-        return object : KtVisitorVoid() {
-            override fun visitWhenExpression(expression: KtWhenExpression) {
-                val singleEntry = expression.entries.singleOrNull()
-                if (singleEntry?.isElse != true) return
+        return whenExpressionVisitor { expression ->
+            val singleEntry = expression.entries.singleOrNull()
+            if (singleEntry?.isElse != true) return@whenExpressionVisitor
 
-                val usedAsExpression = expression.isUsedAsExpression(expression.analyze())
+            val usedAsExpression = expression.isUsedAsExpression(expression.analyze())
 
-                holder.registerProblem(expression,
-                                       "'when' has only 'else' branch and should be simplified",
-                                       SimplifyFix(usedAsExpression)
-                )
-            }
+            holder.registerProblem(expression,
+                                   "'when' has only 'else' branch and should be simplified",
+                                   SimplifyFix(usedAsExpression)
+            )
         }
     }
 

idea/src/org/jetbrains/kotlin/idea/inspections/WrapUnaryOperatorInspection.kt

@@ -1,17 +1,6 @@
 /*
- * Copyright 2010-2017 JetBrains s.r.o.
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- * http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
+ * Copyright 2000-2018 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license
+ * that can be found in the license/LICENSE.txt file.
  */
 
 package org.jetbrains.kotlin.idea.inspections
@@ -34,28 +23,25 @@ class WrapUnaryOperatorInspection : AbstractKotlinInspection() {
     val numberTypes = listOf(KtNodeTypes.INTEGER_CONSTANT, KtNodeTypes.FLOAT_CONSTANT)
 
     override fun buildVisitor(holder: ProblemsHolder, isOnTheFly: Boolean): PsiElementVisitor {
-        return object : KtVisitorVoid() {
-            override fun visitPrefixExpression(expression: KtPrefixExpression) {
-                super.visitPrefixExpression(expression)
-                if (expression.operationToken.isUnaryMinusOrPlus()) {
-                    val baseExpression = expression.baseExpression
-                    if (baseExpression is KtDotQualifiedExpression) {
-                        val receiverExpression = baseExpression.receiverExpression
-                        if (receiverExpression is KtConstantExpression &&
-                            receiverExpression.node.elementType in numberTypes) {
-                            holder.registerProblem(expression,
-                                                   "Wrap unary operator and value with ()",
-                                                   ProblemHighlightType.GENERIC_ERROR_OR_WARNING,
-                                                   WrapUnaryOperatorQuickfix())
-                        }
+        return prefixExpressionVisitor { expression ->
+            if (expression.operationToken.isUnaryMinusOrPlus()) {
+                val baseExpression = expression.baseExpression
+                if (baseExpression is KtDotQualifiedExpression) {
+                    val receiverExpression = baseExpression.receiverExpression
+                    if (receiverExpression is KtConstantExpression &&
+                        receiverExpression.node.elementType in numberTypes) {
+                        holder.registerProblem(expression,
+                                               "Wrap unary operator and value with ()",
+                                               ProblemHighlightType.GENERIC_ERROR_OR_WARNING,
+                                               WrapUnaryOperatorQuickfix())
                     }
                 }
             }
-
-            private fun IElementType.isUnaryMinusOrPlus() = this == KtTokens.MINUS || this == KtTokens.PLUS
         }
     }
 
+    private fun IElementType.isUnaryMinusOrPlus() = this == KtTokens.MINUS || this == KtTokens.PLUS
+
     private class WrapUnaryOperatorQuickfix : LocalQuickFix {
         override fun getName() = "Wrap unary operator and value with ()"
 

idea/src/org/jetbrains/kotlin/idea/inspections/collections/SimplifiableCallChainInspection.kt

@@ -1,17 +1,6 @@
 /*
- * Copyright 2010-2017 JetBrains s.r.o.
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- * http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
+ * Copyright 2000-2018 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license
+ * that can be found in the license/LICENSE.txt file.
  */
 
 package org.jetbrains.kotlin.idea.inspections.collections
@@ -34,67 +23,63 @@ class SimplifiableCallChainInspection : AbstractKotlinInspection() {
 
 
     override fun buildVisitor(holder: ProblemsHolder, isOnTheFly: Boolean) =
-            object : KtVisitorVoid() {
-                override fun visitQualifiedExpression(expression: KtQualifiedExpression) {
-                    super.visitQualifiedExpression(expression)
+            qualifiedExpressionVisitor(fun(expression) {
+                val firstExpression = expression.receiverExpression
+                val firstCallExpression = getCallExpression(firstExpression) ?: return
 
-                    val firstExpression = expression.receiverExpression
-                    val firstCallExpression = getCallExpression(firstExpression) ?: return
+                val secondCallExpression = expression.selectorExpression as? KtCallExpression ?: return
 
-                    val secondCallExpression = expression.selectorExpression as? KtCallExpression ?: return
+                val firstCalleeExpression = firstCallExpression.calleeExpression ?: return
+                val secondCalleeExpression = secondCallExpression.calleeExpression ?: return
+                val actualConversions = conversionGroups[
+                        firstCalleeExpression.text to secondCalleeExpression.text
+                        ] ?: return
 
-                    val firstCalleeExpression = firstCallExpression.calleeExpression ?: return
-                    val secondCalleeExpression = secondCallExpression.calleeExpression ?: return
-                    val actualConversions = conversionGroups[
-                            firstCalleeExpression.text to secondCalleeExpression.text
-                            ] ?: return
+                val context = expression.analyze()
+                val firstResolvedCall = firstExpression.getResolvedCall(context) ?: return
+                val conversion = actualConversions.firstOrNull {
+                    firstResolvedCall.resultingDescriptor.fqNameOrNull()?.asString() == it.firstFqName
+                } ?: return
 
-                    val context = expression.analyze()
-                    val firstResolvedCall = firstExpression.getResolvedCall(context) ?: return
-                    val conversion = actualConversions.firstOrNull {
-                        firstResolvedCall.resultingDescriptor.fqNameOrNull()?.asString() == it.firstFqName
-                    } ?: return
+                val builtIns = context[BindingContext.EXPRESSION_TYPE_INFO, expression]?.type?.builtIns ?: return
 
-                    val builtIns = context[BindingContext.EXPRESSION_TYPE_INFO, expression]?.type?.builtIns ?: return
-
-                    // Do not apply on maps due to lack of relevant stdlib functions
-                    val firstReceiverType = firstResolvedCall.extensionReceiver?.type
-                    val firstReceiverRawType = firstReceiverType?.constructor?.declarationDescriptor?.defaultType
-                    if (firstReceiverRawType != null) {
-                        if (firstReceiverRawType.isSubtypeOf(builtIns.map.defaultType) ||
-                            firstReceiverRawType.isSubtypeOf(builtIns.mutableMap.defaultType)) return
-                    }
-
-                    // Do not apply for lambdas with return inside
-                    val lambdaArgument = firstCallExpression.lambdaArguments.firstOrNull()
-                    if (lambdaArgument?.anyDescendantOfType<KtReturnExpression>() == true) return
-
-                    val secondResolvedCall = expression.getResolvedCall(context) ?: return
-                    val secondResultingDescriptor = secondResolvedCall.resultingDescriptor
-                    if (secondResultingDescriptor.fqNameOrNull()?.asString() != conversion.secondFqName) return
-                    if (secondResolvedCall.valueArguments.any { (parameter, resolvedArgument) ->
-                        parameter.type.isFunctionOfAnyKind() &&
-                        resolvedArgument !is DefaultValueArgument
-                    }) return
-
-                    if (conversion.replacement.startsWith("joinTo")) {
-                        // Function parameter in map must have String result type
-                        if (!firstResolvedCall.hasLastFunctionalParameterWithResult(context) {
-                            it.isSubtypeOf(builtIns.charSequence.defaultType)
-                        }) return
-                    }
-
-                    val descriptor = holder.manager.createProblemDescriptor(
-                            expression,
-                            firstCalleeExpression.textRange.shiftRight(-expression.startOffset),
-                            "Call chain on collection type may be simplified",
-                            ProblemHighlightType.GENERIC_ERROR_OR_WARNING,
-                            isOnTheFly,
-                            SimplifyCallChainFix(conversion.replacement)
-                    )
-                    holder.registerProblem(descriptor)
+                // Do not apply on maps due to lack of relevant stdlib functions
+                val firstReceiverType = firstResolvedCall.extensionReceiver?.type
+                val firstReceiverRawType = firstReceiverType?.constructor?.declarationDescriptor?.defaultType
+                if (firstReceiverRawType != null) {
+                    if (firstReceiverRawType.isSubtypeOf(builtIns.map.defaultType) ||
+                        firstReceiverRawType.isSubtypeOf(builtIns.mutableMap.defaultType)) return
                 }
-            }
+
+                // Do not apply for lambdas with return inside
+                val lambdaArgument = firstCallExpression.lambdaArguments.firstOrNull()
+                if (lambdaArgument?.anyDescendantOfType<KtReturnExpression>() == true) return
+
+                val secondResolvedCall = expression.getResolvedCall(context) ?: return
+                val secondResultingDescriptor = secondResolvedCall.resultingDescriptor
+                if (secondResultingDescriptor.fqNameOrNull()?.asString() != conversion.secondFqName) return
+                if (secondResolvedCall.valueArguments.any { (parameter, resolvedArgument) ->
+                    parameter.type.isFunctionOfAnyKind() &&
+                    resolvedArgument !is DefaultValueArgument
+                }) return
+
+                if (conversion.replacement.startsWith("joinTo")) {
+                    // Function parameter in map must have String result type
+                    if (!firstResolvedCall.hasLastFunctionalParameterWithResult(context) {
+                        it.isSubtypeOf(builtIns.charSequence.defaultType)
+                    }) return
+                }
+
+                val descriptor = holder.manager.createProblemDescriptor(
+                        expression,
+                        firstCalleeExpression.textRange.shiftRight(-expression.startOffset),
+                        "Call chain on collection type may be simplified",
+                        ProblemHighlightType.GENERIC_ERROR_OR_WARNING,
+                        isOnTheFly,
+                        SimplifyCallChainFix(conversion.replacement)
+                )
+                holder.registerProblem(descriptor)
+            })
 
     companion object {
 

idea/src/org/jetbrains/kotlin/idea/inspections/kdoc/KDocMissingDocumentationInspection.kt

@@ -11,7 +11,6 @@ import com.intellij.codeInspection.ProblemDescriptor
 import com.intellij.codeInspection.ProblemsHolder
 import com.intellij.openapi.editor.EditorModificationUtil
 import com.intellij.openapi.project.Project
-import com.intellij.psi.PsiElement
 import com.intellij.psi.PsiElementVisitor
 import com.siyeh.ig.psiutils.TestUtils
 import org.jetbrains.kotlin.descriptors.DeclarationDescriptorWithVisibility
@@ -26,6 +25,7 @@ import org.jetbrains.kotlin.idea.kdoc.KDocElementFactory
 import org.jetbrains.kotlin.idea.kdoc.findKDoc
 import org.jetbrains.kotlin.kdoc.psi.impl.KDocSection
 import org.jetbrains.kotlin.psi.KtNamedDeclaration
+import org.jetbrains.kotlin.psi.namedDeclarationVisitor
 import org.jetbrains.kotlin.psi.psiUtil.endOffset
 import org.jetbrains.kotlin.psi.psiUtil.getChildOfType
 import org.jetbrains.kotlin.psi.psiUtil.getParentOfType
@@ -34,28 +34,22 @@ import org.jetbrains.kotlin.resolve.lazy.BodyResolveMode
 
 class KDocMissingDocumentationInspection : AbstractKotlinInspection() {
     override fun buildVisitor(holder: ProblemsHolder, isOnTheFly: Boolean): PsiElementVisitor =
-        KDocMissingDocumentationInspection(holder)
-
-    private class KDocMissingDocumentationInspection(private val holder: ProblemsHolder) : PsiElementVisitor() {
-        override fun visitElement(element: PsiElement) {
-            if (TestUtils.isInTestSourceContent(element)) {
-                return
-            }
-
-            if (element is KtNamedDeclaration) {
+            namedDeclarationVisitor { element ->
+                if (TestUtils.isInTestSourceContent(element)) {
+                    return@namedDeclarationVisitor
+                }
                 val nameIdentifier = element.nameIdentifier
                 val descriptor = element.resolveToDescriptorIfAny(BodyResolveMode.FULL)
                         as? DeclarationDescriptorWithVisibility
-                        as? MemberDescriptor ?: return
+                        as? MemberDescriptor ?: return@namedDeclarationVisitor
                 if (nameIdentifier != null && descriptor.isEffectivelyPublicApi) {
                     if (descriptor.findKDoc { DescriptorToSourceUtilsIde.getAnyDeclaration(element.project, it) } == null) {
                         val message = element.describe()?.let { "$it is missing documentation" } ?: "Missing documentation"
                         holder.registerProblem(nameIdentifier, message, AddDocumentationFix())
                     }
                 }
+
             }
-        }
-    }
 
     class AddDocumentationFix : LocalQuickFix {
         override fun getName(): String = "Add documentation"