Add quickfix for "Interface doesn't have constructors" #KT-17687 Fixed

idea/src/org/jetbrains/kotlin/idea/quickfix/ConvertToAnonymousObjectFix.kt

@@ -0,0 +1,76 @@
+/*
+ * Copyright 2010-2018 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.quickfix
+
+import com.intellij.openapi.editor.Editor
+import com.intellij.openapi.project.Project
+import org.jetbrains.kotlin.descriptors.SimpleFunctionDescriptor
+import org.jetbrains.kotlin.diagnostics.Diagnostic
+import org.jetbrains.kotlin.diagnostics.Errors
+import org.jetbrains.kotlin.psi.*
+import org.jetbrains.kotlin.psi.psiUtil.forEachDescendantOfType
+import org.jetbrains.kotlin.resolve.DescriptorToSourceUtils
+import org.jetbrains.kotlin.resolve.calls.tower.WrongResolutionToClassifier
+import org.jetbrains.kotlin.resolve.lazy.descriptors.LazyClassDescriptor
+import org.jetbrains.kotlin.types.typeUtil.isUnit
+
+class ConvertToAnonymousObjectFix(
+    callExpression: KtCallExpression,
+    private val interfaceName: String,
+    private val functionName: String,
+    private val functionParameters: String,
+    private val functionReturnType: String?
+) : KotlinQuickFixAction<KtCallExpression>(callExpression) {
+    override fun getFamilyName() = "Convert to anonymous object"
+
+    override fun getText() = familyName
+
+    override fun invoke(project: Project, editor: Editor?, file: KtFile) {
+        val callExpression = element ?: return
+        val lambda = callExpression.lambdaArguments.singleOrNull()?.getLambdaExpression() ?: return
+
+        val psiFactory = KtPsiFactory(project)
+        val body = lambda.bodyExpression
+        if (body != null) {
+            body.forEachDescendantOfType<KtReturnExpression> {
+                if (it.getLabelName() == interfaceName) it.labeledExpression?.delete()
+            }
+            val last = body.statements.lastOrNull()
+            if (last !is KtReturnExpression) last?.replace(psiFactory.createExpressionByPattern("return $0", last))
+        }
+
+        val anonymousObject = psiFactory.buildExpression {
+            appendFixedText("object : $interfaceName {")
+            appendFixedText("override fun $functionName$functionParameters")
+            if (functionReturnType != null) appendFixedText(": $functionReturnType")
+            appendFixedText("{")
+            if (body != null) appendExpression(body)
+            appendFixedText("}")
+            appendFixedText("}")
+        }
+        callExpression.replace(anonymousObject)
+    }
+
+    companion object : KotlinSingleIntentionActionFactory() {
+        override fun createAction(diagnostic: Diagnostic): KotlinQuickFixAction<KtCallExpression>? {
+            val casted = Errors.RESOLUTION_TO_CLASSIFIER.cast(diagnostic)
+            if (casted.b != WrongResolutionToClassifier.INTERFACE_AS_FUNCTION) return null
+
+            val callExpression = casted.psiElement.parent as? KtCallExpression ?: return null
+            if (callExpression.lambdaArguments.singleOrNull()?.getLambdaExpression() == null) return null
+            val interfaceName = callExpression.calleeExpression?.text ?: return null
+
+            val classDescriptor = casted.a as? LazyClassDescriptor ?: return null
+            val function = classDescriptor.declaredCallableMembers.singleOrNull() as? SimpleFunctionDescriptor ?: return null
+            val functionDeclaration = DescriptorToSourceUtils.descriptorToDeclaration(function) as? KtNamedFunction ?: return null
+            val functionName = functionDeclaration.name ?: return null
+            val functionParameters = functionDeclaration.valueParameterList?.text ?: return null
+            val functionReturnType = function.returnType?.takeIf { !it.isUnit() }?.toString()
+
+            return ConvertToAnonymousObjectFix(callExpression, interfaceName, functionName, functionParameters, functionReturnType)
+        }
+    }
+}

idea/src/org/jetbrains/kotlin/idea/quickfix/QuickFixRegistrar.kt

@@ -572,5 +572,7 @@ class QuickFixRegistrar : QuickFixContributor {
 
         DEFAULT_VALUE_NOT_ALLOWED_IN_OVERRIDE.registerFactory(RemoveDefaultParameterValueFix)
         ACTUAL_FUNCTION_WITH_DEFAULT_ARGUMENTS.registerFactory(RemoveDefaultParameterValueFix)
+
+        RESOLUTION_TO_CLASSIFIER.registerFactory(ConvertToAnonymousObjectFix)
     }
 }