"Simplify using destructuring declaration" is now applicable for function literals #KT-13941 Fixed

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

@@ -244,15 +244,16 @@ class KtPsiFactory(private val project: Project) {
         return (createFunction("fun foo() {$text}").bodyExpression as KtBlockExpression).statements.first() as KtDestructuringDeclaration
     }
 
-    fun createDestructuringDeclarationInFor(text: String): KtDestructuringDeclaration {
-        return ((createFunction("fun foo() {for ($text in foo) {} }").bodyExpression as KtBlockExpression).statements.first() as KtForExpression).destructuringParameter!!
-    }
-
     fun createDestructuringParameter(text: String): KtDestructuringDeclaration {
         val dummyFun = createFunction("fun foo() { for ($text in foo) {} }")
         return ((dummyFun.bodyExpression as KtBlockExpression).statements.first() as KtForExpression).destructuringParameter!!
     }
 
+    fun createDestructuringParameterForLambda(text: String): KtParameter {
+        val dummyFun = createFunction("fun foo() = { $text -> }")
+        return (dummyFun.bodyExpression as KtLambdaExpression).functionLiteral.valueParameters.first()
+    }
+
     fun <TDeclaration : KtDeclaration> createDeclaration(text: String): TDeclaration {
         val file = createFile(text)
         val declarations = file.declarations

idea/src/org/jetbrains/kotlin/idea/intentions/DestructureIntention.kt

@@ -46,6 +46,8 @@ class DestructureIntention : SelfTargetingRangeIntention<KtParameter>(
 ) {
     override fun applyTo(element: KtParameter, editor: Editor?) {
         val forLoop = element.parent as? KtForExpression
+        val functionLiteral = element.parent?.parent as? KtFunctionLiteral
+        if (forLoop == null && functionLiteral == null) return
         val (usagesToRemove, removeSelectorInLoopRange) = collectUsagesToRemove(element, forLoop) ?: return
 
         val loopRange = forLoop?.loopRange
@@ -62,16 +64,23 @@ class DestructureIntention : SelfTargetingRangeIntention<KtParameter>(
             }
             names.add(name)
         }
-        element.replace(factory.createDestructuringDeclarationInFor("(${names.joinToString()})"))
+        if (forLoop != null) {
+            element.replace(factory.createDestructuringParameter("(${names.joinToString()})"))
 
-        if (removeSelectorInLoopRange && loopRange is KtDotQualifiedExpression) {
-            loopRange.replace(loopRange.receiverExpression)
+            if (removeSelectorInLoopRange && loopRange is KtDotQualifiedExpression) {
+                loopRange.replace(loopRange.receiverExpression)
+            }
+        }
+        else if (functionLiteral != null) {
+            element.replace(factory.createDestructuringParameterForLambda("(${names.joinToString()})"))
         }
     }
 
     override fun applicabilityRange(element: KtParameter): TextRange? {
-        val forLoop = element.parent as? KtForExpression ?: return null
-        val usagesToRemove = collectUsagesToRemove(element, forLoop)
+        val forLoopIfAny = element.parent as? KtForExpression
+        if (forLoopIfAny == null && element.parent?.parent !is KtFunctionLiteral) return null
+
+        val usagesToRemove = collectUsagesToRemove(element, forLoopIfAny)
         if (usagesToRemove != null && usagesToRemove.first.isNotEmpty()) {
             return element.textRange
         }

idea/testData/intentions/destructuringInLambda/.intention

@@ -0,0 +1 @@
+org.jetbrains.kotlin.idea.intentions.DestructureIntention

idea/testData/intentions/destructuringInLambda/dependentLocal.kt

@@ -0,0 +1,11 @@
+// WITH_RUNTIME
+
+data class XY(val x: Int, val y: Int)
+fun test(xys: Array<XY>) {
+    xys.forEach { xy<caret> ->
+        val x = xy.x
+        println(x)
+        val y = xy.y + x
+        println(y)
+    }
+}

idea/testData/intentions/destructuringInLambda/dependentLocal.kt.after

@@ -0,0 +1,10 @@
+// WITH_RUNTIME
+
+data class XY(val x: Int, val y: Int)
+fun test(xys: Array<XY>) {
+    xys.forEach { (x, y) ->
+        println(x)
+        val y = y + x
+        println(y)
+    }
+}

idea/testData/intentions/destructuringInLambda/firstProperties.kt

@@ -0,0 +1,11 @@
+// WITH_RUNTIME
+
+fun foo() {
+    val list = listOf(MyClass(1, 2, 3), MyClass(2, 3, 4))
+    list.forEach { klass<caret> ->
+        val a = klass.a
+        val b = klass.b
+    }
+}
+
+data class MyClass(val a: Int, val b: Int, val c: Int)

idea/testData/intentions/destructuringInLambda/firstProperties.kt.after

@@ -0,0 +1,9 @@
+// WITH_RUNTIME
+
+fun foo() {
+    val list = listOf(MyClass(1, 2, 3), MyClass(2, 3, 4))
+    list.forEach { (a, b) ->
+    }
+}
+
+data class MyClass(val a: Int, val b: Int, val c: Int)

idea/testData/intentions/destructuringInLambda/fold.kt

@@ -0,0 +1,5 @@
+// WITH_RUNTIME
+
+data class XY(val x: String, val y: String)
+
+fun foo(list: List<XY>) = list.fold("") { prev, <caret>xy -> prev + xy.x + xy.y }

idea/testData/intentions/destructuringInLambda/fold.kt.after

@@ -0,0 +1,5 @@
+// WITH_RUNTIME
+
+data class XY(val x: String, val y: String)
+
+fun foo(list: List<XY>) = list.fold("") { prev, (x, y) -> prev + x + y }

idea/testData/intentions/destructuringInLambda/last.kt

@@ -0,0 +1,9 @@
+// WITH_RUNTIME
+
+data class My(val first: String, val second: Int)
+
+fun foo(list: List<My>) {
+    list.forEach { my<caret> ->
+        println(my.second)
+    }
+}

idea/testData/intentions/destructuringInLambda/last.kt.after

@@ -0,0 +1,9 @@
+// WITH_RUNTIME
+
+data class My(val first: String, val second: Int)
+
+fun foo(list: List<My>) {
+    list.forEach { (first, second) ->
+        println(second)
+    }
+}

idea/testData/intentions/destructuringInLambda/list.kt

@@ -0,0 +1,5 @@
+// WITH_RUNTIME
+
+data class XY(val x: String, val y: String)
+
+fun foo(list: List<XY>) = list.map { <caret>it -> it.x + it.y }

idea/testData/intentions/destructuringInLambda/list.kt.after

@@ -0,0 +1,5 @@
+// WITH_RUNTIME
+
+data class XY(val x: String, val y: String)
+
+fun foo(list: List<XY>) = list.map { (x, y) -> x + y }

idea/testData/intentions/destructuringInLambda/nullable.kt

@@ -0,0 +1,11 @@
+// IS_APPLICABLE: false
+// WITH_RUNTIME
+
+data class XY(val x: String, val y: String)
+fun test(xys: Array<XY?>) {
+    xys.forEach { xy<caret> ->
+        val x = xy?.x
+        val y = xy?.y
+        println(x + y)
+    }
+}

idea/testData/intentions/destructuringInLambda/simple.kt

@@ -0,0 +1,5 @@
+data class XY(val x: String, val y: String)
+
+fun convert(xy: XY, foo: (XY) -> String) = foo(xy)
+
+fun foo(xy: XY) = convert(xy) { <caret>it -> it.x + it.y }

idea/testData/intentions/destructuringInLambda/simple.kt.after

@@ -0,0 +1,5 @@
+data class XY(val x: String, val y: String)
+
+fun convert(xy: XY, foo: (XY) -> String) = foo(xy)
+
+fun foo(xy: XY) = convert(xy) { (x, y) -> x + y }

idea/testData/intentions/destructuringInLambda/variables.kt

@@ -0,0 +1,9 @@
+data class XY(val x: String, val y: String)
+
+fun convert(xy: XY, foo: (XY) -> String) = foo(xy)
+
+fun foo(xy: XY) = convert(xy) { <caret>it ->
+    val x = it.x
+    val y = it.y
+    x + y
+}

idea/testData/intentions/destructuringInLambda/variables.kt.after

@@ -0,0 +1,7 @@
+data class XY(val x: String, val y: String)
+
+fun convert(xy: XY, foo: (XY) -> String) = foo(xy)
+
+fun foo(xy: XY) = convert(xy) { (x, y) ->
+    x + y
+}

idea/tests/org/jetbrains/kotlin/idea/intentions/IntentionTestGenerated.java

@@ -6244,6 +6244,63 @@ public class IntentionTestGenerated extends AbstractIntentionTest {
 
     }
 
+    @TestMetadata("idea/testData/intentions/destructuringInLambda")
+    @TestDataPath("$PROJECT_ROOT")
+    @RunWith(JUnit3RunnerWithInners.class)
+    public static class DestructuringInLambda extends AbstractIntentionTest {
+        public void testAllFilesPresentInDestructuringInLambda() throws Exception {
+            KotlinTestUtils.assertAllTestsPresentByMetadata(this.getClass(), new File("idea/testData/intentions/destructuringInLambda"), Pattern.compile("^([\\w\\-_]+)\\.kt$"), true);
+        }
+
+        @TestMetadata("dependentLocal.kt")
+        public void testDependentLocal() throws Exception {
+            String fileName = KotlinTestUtils.navigationMetadata("idea/testData/intentions/destructuringInLambda/dependentLocal.kt");
+            doTest(fileName);
+        }
+
+        @TestMetadata("firstProperties.kt")
+        public void testFirstProperties() throws Exception {
+            String fileName = KotlinTestUtils.navigationMetadata("idea/testData/intentions/destructuringInLambda/firstProperties.kt");
+            doTest(fileName);
+        }
+
+        @TestMetadata("fold.kt")
+        public void testFold() throws Exception {
+            String fileName = KotlinTestUtils.navigationMetadata("idea/testData/intentions/destructuringInLambda/fold.kt");
+            doTest(fileName);
+        }
+
+        @TestMetadata("last.kt")
+        public void testLast() throws Exception {
+            String fileName = KotlinTestUtils.navigationMetadata("idea/testData/intentions/destructuringInLambda/last.kt");
+            doTest(fileName);
+        }
+
+        @TestMetadata("list.kt")
+        public void testList() throws Exception {
+            String fileName = KotlinTestUtils.navigationMetadata("idea/testData/intentions/destructuringInLambda/list.kt");
+            doTest(fileName);
+        }
+
+        @TestMetadata("nullable.kt")
+        public void testNullable() throws Exception {
+            String fileName = KotlinTestUtils.navigationMetadata("idea/testData/intentions/destructuringInLambda/nullable.kt");
+            doTest(fileName);
+        }
+
+        @TestMetadata("simple.kt")
+        public void testSimple() throws Exception {
+            String fileName = KotlinTestUtils.navigationMetadata("idea/testData/intentions/destructuringInLambda/simple.kt");
+            doTest(fileName);
+        }
+
+        @TestMetadata("variables.kt")
+        public void testVariables() throws Exception {
+            String fileName = KotlinTestUtils.navigationMetadata("idea/testData/intentions/destructuringInLambda/variables.kt");
+            doTest(fileName);
+        }
+    }
+
     @TestMetadata("idea/testData/intentions/ifNullToElvis")
     @TestDataPath("$PROJECT_ROOT")
     @RunWith(JUnit3RunnerWithInners.class)