Add inspection for calls of function with lambda expression body

Added "Unused return value of a function with lambda expression body" inspection with quickfix "Remove '=' token from function declaration" #KT-10393 Fixed
2017-03-13 19:56:59 +03:00
parent 087551ad61
commit b8ebc087e2
11 changed files with 173 additions and 0 deletions
@@ -0,0 +1,6 @@
+<html>
+<body>
+This inspection reports calls with unused return value when the function is defined with lambda as expression body.
+Happens when someone accidentally puts '=' between function header and body block.
+</body>
+</html>
@@ -2071,6 +2071,14 @@
                     language="kotlin"
    />

+    <localInspection implementationClass="org.jetbrains.kotlin.idea.inspections.UnusedLambdaExpressionBodyInspection"
+                     displayName="Unused return value of a function with lambda expression body"
+                     groupName="Kotlin"
+                     enabledByDefault="true"
+                     level="WARNING"
+                     language="kotlin"
+    />
+

    <referenceImporter implementation="org.jetbrains.kotlin.idea.quickfix.KotlinReferenceImporter"/>

@@ -0,0 +1,87 @@
+/*
+ * 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.
+ */
+
+package org.jetbrains.kotlin.idea.inspections
+
+import com.intellij.codeInsight.FileModificationService
+import com.intellij.codeInspection.LocalQuickFix
+import com.intellij.codeInspection.ProblemDescriptor
+import com.intellij.codeInspection.ProblemsHolder
+import com.intellij.openapi.project.Project
+import com.intellij.psi.PsiElement
+import com.intellij.psi.PsiElementVisitor
+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.resolve.BindingContext
+import org.jetbrains.kotlin.resolve.calls.callUtil.getResolvedCall
+import org.jetbrains.kotlin.resolve.lazy.BodyResolveMode
+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))
+            }
+        }
+    }
+
+    private fun KtExpression.used(context: BindingContext): Boolean = context[BindingContext.USED_AS_EXPRESSION, this] ?: true
+
+    private fun CallableDescriptor.returnsFunction() = returnType?.isFunctionType ?: false
+
+    class RemoveEqTokenFromFunctionDeclarationFix(val function: KtFunction) : LocalQuickFix {
+        override fun getName(): String = "Remove '=' token from function declaration"
+
+        override fun getFamilyName(): String = name
+
+        override fun applyFix(project: Project, descriptor: ProblemDescriptor) {
+            if (!FileModificationService.getInstance().preparePsiElementForWrite(function)) {
+                return
+            }
+
+            function.equalsToken?.apply {
+                // TODO: This should be done by formatter but there is no rule for this now
+                if (prevSibling.isSpace() && nextSibling.isSpace()) {
+                    prevSibling.delete()
+                }
+                delete()
+            }
+        }
+
+        private fun PsiElement.isSpace() = text == " "
+    }
+}
@@ -0,0 +1,18 @@
+<problems>
+    <problem>
+        <file>simple.kt</file>
+        <line>3</line>
+        <module>light_idea_test_case</module>
+        <entry_point TYPE="file" FQNAME="temp:///src/simple.kt" />
+        <problem_class severity="WARNING" attribute_key="WARNING_ATTRIBUTES">Unused return value of a function with lambda expression body</problem_class>
+        <description>Unused return value of a function with lambda expression body</description>
+    </problem>
+    <problem>
+        <file>simple.kt</file>
+        <line>6</line>
+        <module>light_idea_test_case</module>
+        <entry_point TYPE="file" FQNAME="temp:///src/simple.kt" />
+        <problem_class severity="WARNING" attribute_key="WARNING_ATTRIBUTES">Unused return value of a function with lambda expression body</problem_class>
+        <description>Unused return value of a function with lambda expression body</description>
+    </problem>
+</problems>
@@ -0,0 +1 @@
+// INSPECTION_CLASS: org.jetbrains.kotlin.idea.inspections.UnusedLambdaExpressionBodyInspection
@@ -0,0 +1,13 @@
+
+fun foo() {
+    bar()
+    val a = bar()
+    if (bar() != null) {
+        bar()
+    }
+    bar()()
+}
+
+fun bar() = {
+
+}
@@ -0,0 +1 @@
+org.jetbrains.kotlin.idea.inspections.UnusedLambdaExpressionBodyInspection
@@ -0,0 +1,9 @@
+// "Remove '=' token from function declaration" "true"
+
+fun foo() {
+    <caret>bar()
+}
+
+fun bar() = {
+
+}
@@ -0,0 +1,9 @@
+// "Remove '=' token from function declaration" "true"
+
+fun foo() {
+    bar()
+}
+
+fun bar() {
+
+}
@@ -311,6 +311,12 @@ public class InspectionTestGenerated extends AbstractInspectionTest {
            doTest(fileName);
        }

+        @TestMetadata("unusedLambdaExpressionBody/inspectionData/inspections.test")
+        public void testUnusedLambdaExpressionBody_inspectionData_Inspections_test() throws Exception {
+            String fileName = KotlinTestUtils.navigationMetadata("idea/testData/inspections/unusedLambdaExpressionBody/inspectionData/inspections.test");
+            doTest(fileName);
+        }
+
        @TestMetadata("unusedReceiverParameter/inspectionData/inspections.test")
        public void testUnusedReceiverParameter_inspectionData_Inspections_test() throws Exception {
            String fileName = KotlinTestUtils.navigationMetadata("idea/testData/inspections/unusedReceiverParameter/inspectionData/inspections.test");
@@ -7732,6 +7732,21 @@ public class QuickFixTestGenerated extends AbstractQuickFixTest {
        }
    }

+    @TestMetadata("idea/testData/quickfix/removeEqTokenFromFunctionDeclaration")
+    @TestDataPath("$PROJECT_ROOT")
+    @RunWith(JUnit3RunnerWithInners.class)
+    public static class RemoveEqTokenFromFunctionDeclaration extends AbstractQuickFixTest {
+        public void testAllFilesPresentInRemoveEqTokenFromFunctionDeclaration() throws Exception {
+            KotlinTestUtils.assertAllTestsPresentByMetadata(this.getClass(), new File("idea/testData/quickfix/removeEqTokenFromFunctionDeclaration"), Pattern.compile("^([\\w\\-_]+)\\.kt$"), TargetBackend.ANY, true);
+        }
+
+        @TestMetadata("simple.kt")
+        public void testSimple() throws Exception {
+            String fileName = KotlinTestUtils.navigationMetadata("idea/testData/quickfix/removeEqTokenFromFunctionDeclaration/simple.kt");
+            doTest(fileName);
+        }
+    }
+
    @TestMetadata("idea/testData/quickfix/removeFinalUpperBound")
    @TestDataPath("$PROJECT_ROOT")
    @RunWith(JUnit3RunnerWithInners.class)
				`@@ -0,0 +1 @@`
				`// INSPECTION_CLASS: org.jetbrains.kotlin.idea.inspections.UnusedLambdaExpressionBodyInspection`
				`@@ -0,0 +1 @@`
				`org.jetbrains.kotlin.idea.inspections.UnusedLambdaExpressionBodyInspection`