Introduce Variable: Do not replace assignment left-hand sides

#KT-14240 Fixed

ChangeLog.md

@@ -252,6 +252,7 @@ These artifacts include extensions for the types available in the latter JDKs, s
 - [`KT-14182`](https://youtrack.jetbrains.com/issue/KT-14182) Move: Show error message on applying to enum entries
 - Extract Function: Support implicit abnormal exits via Nothing-typed expressions
 - [`KT-14285`](https://youtrack.jetbrains.com/issue/KT-14285) Rename: Forbid on backing field reference
+- [`KT-14240`](https://youtrack.jetbrains.com/issue/KT-14240) Introduce Variable: Do not replace assignment left-hand sides
 
 ##### New features
 

idea/src/org/jetbrains/kotlin/idea/refactoring/introduce/introduceVariable/KotlinIntroduceVariableHandler.kt

@@ -320,11 +320,18 @@ object KotlinIntroduceVariableHandler : RefactoringActionHandler {
         return commonContainer.allChildren.lastOrNull { it.textRange.contains(startOffset) } ?: return null
     }
 
+    private fun PsiElement.isAssignmentLHS(): Boolean {
+        return parents.any { KtPsiUtil.isAssignment(it) && (it as KtBinaryExpression).left == this }
+    }
+
     private fun KtExpression.findOccurrences(occurrenceContainer: PsiElement): List<KtExpression> {
         return toRange()
                 .match(occurrenceContainer, KotlinPsiUnifier.DEFAULT)
                 .mapNotNull {
                     val candidate = it.range.elements.first()
+
+                    if (candidate.isAssignmentLHS()) return@mapNotNull null
+
                     when (candidate) {
                         is KtExpression -> candidate
                         is KtStringTemplateEntryWithExpression -> candidate.expression
@@ -694,6 +701,10 @@ object KotlinIntroduceVariableHandler : RefactoringActionHandler {
         val expression = expressionToExtract?.let { KtPsiUtil.safeDeparenthesize(it) }
                          ?: return showErrorHint(project, editor, KotlinRefactoringBundle.message("cannot.refactor.no.expression"))
 
+        if (expression.isAssignmentLHS()) {
+            return showErrorHint(project, editor, KotlinRefactoringBundle.message("cannot.refactor.no.expression"))
+        }
+
         val physicalExpression = expression.substringContextOrThis
 
         val resolutionFacade = physicalExpression.getResolutionFacade()

idea/testData/refactoring/introduceVariable/arrayAssignment.kt

@@ -0,0 +1,8 @@
+// WITH_RUNTIME
+class Foo(var bar: IntArray)
+
+fun test() {
+    val foo = Foo(IntArray(1) { 1 })
+    println(<selection>foo.bar</selection>)
+    foo.bar[0] = foo.bar[0] + 1
+}

idea/testData/refactoring/introduceVariable/arrayAssignment.kt.after

@@ -0,0 +1,9 @@
+// WITH_RUNTIME
+class Foo(var bar: IntArray)
+
+fun test() {
+    val foo = Foo(IntArray(1) { 1 })
+    val message = foo.bar
+    println(message)
+    message[0] = message[0] + 1
+}

idea/testData/refactoring/introduceVariable/onAssignmentLHS.kt

@@ -0,0 +1,8 @@
+// WITH_RUNTIME
+class Foo(var bar: Int)
+
+fun test() {
+    val foo = Foo(1)
+    println(foo.bar)
+    <selection>foo.bar</selection> = foo.bar + 1
+}

idea/testData/refactoring/introduceVariable/onAssignmentLHS.kt.conflicts

@@ -0,0 +1 @@
+Cannot perform refactoring without an expression

idea/testData/refactoring/introduceVariable/selectorAssignment.kt

@@ -0,0 +1,9 @@
+// WITH_RUNTIME
+class Foo(var bar: Bar)
+class Bar(var baz: Int)
+
+fun test() {
+    val foo = Foo(Bar(1))
+    println(<selection>foo.bar</selection>)
+    foo.bar.baz = foo.bar.baz + 1
+}

idea/testData/refactoring/introduceVariable/selectorAssignment.kt.after

@@ -0,0 +1,10 @@
+// WITH_RUNTIME
+class Foo(var bar: Bar)
+class Bar(var baz: Int)
+
+fun test() {
+    val foo = Foo(Bar(1))
+    val message = foo.bar
+    println(message)
+    message.baz = message.baz + 1
+}

idea/testData/refactoring/introduceVariable/skipUsageInAssignmentLHS.kt

@@ -0,0 +1,8 @@
+// WITH_RUNTIME
+class Foo(var bar: Int)
+
+fun test() {
+    val foo = Foo(1)
+    println(<selection>foo.bar</selection>)
+    foo.bar = foo.bar + 1
+}

idea/testData/refactoring/introduceVariable/skipUsageInAssignmentLHS.kt.after

@@ -0,0 +1,9 @@
+// WITH_RUNTIME
+class Foo(var bar: Int)
+
+fun test() {
+    val foo = Foo(1)
+    val message = foo.bar
+    println(message)
+    foo.bar = message + 1
+}

idea/tests/org/jetbrains/kotlin/idea/refactoring/introduce/ExtractionTestGenerated.java

@@ -43,6 +43,12 @@ public class ExtractionTestGenerated extends AbstractExtractionTest {
             doIntroduceVariableTest(fileName);
         }
 
+        @TestMetadata("arrayAssignment.kt")
+        public void testArrayAssignment() throws Exception {
+            String fileName = KotlinTestUtils.navigationMetadata("idea/testData/refactoring/introduceVariable/arrayAssignment.kt");
+            doIntroduceVariableTest(fileName);
+        }
+
         @TestMetadata("callUnderSmartCast.kt")
         public void testCallUnderSmartCast() throws Exception {
             String fileName = KotlinTestUtils.navigationMetadata("idea/testData/refactoring/introduceVariable/callUnderSmartCast.kt");
@@ -337,6 +343,12 @@ public class ExtractionTestGenerated extends AbstractExtractionTest {
             doIntroduceVariableTest(fileName);
         }
 
+        @TestMetadata("onAssignmentLHS.kt")
+        public void testOnAssignmentLHS() throws Exception {
+            String fileName = KotlinTestUtils.navigationMetadata("idea/testData/refactoring/introduceVariable/onAssignmentLHS.kt");
+            doIntroduceVariableTest(fileName);
+        }
+
         @TestMetadata("OneExplicitReceiver.kt")
         public void testOneExplicitReceiver() throws Exception {
             String fileName = KotlinTestUtils.navigationMetadata("idea/testData/refactoring/introduceVariable/OneExplicitReceiver.kt");
@@ -367,6 +379,12 @@ public class ExtractionTestGenerated extends AbstractExtractionTest {
             doIntroduceVariableTest(fileName);
         }
 
+        @TestMetadata("selectorAssignment.kt")
+        public void testSelectorAssignment() throws Exception {
+            String fileName = KotlinTestUtils.navigationMetadata("idea/testData/refactoring/introduceVariable/selectorAssignment.kt");
+            doIntroduceVariableTest(fileName);
+        }
+
         @TestMetadata("Simple.kt")
         public void testSimple() throws Exception {
             String fileName = KotlinTestUtils.navigationMetadata("idea/testData/refactoring/introduceVariable/Simple.kt");
@@ -385,6 +403,12 @@ public class ExtractionTestGenerated extends AbstractExtractionTest {
             doIntroduceVariableTest(fileName);
         }
 
+        @TestMetadata("skipUsageInAssignmentLHS.kt")
+        public void testSkipUsageInAssignmentLHS() throws Exception {
+            String fileName = KotlinTestUtils.navigationMetadata("idea/testData/refactoring/introduceVariable/skipUsageInAssignmentLHS.kt");
+            doIntroduceVariableTest(fileName);
+        }
+
         @TestMetadata("StringInjection.kt")
         public void testStringInjection() throws Exception {
             String fileName = KotlinTestUtils.navigationMetadata("idea/testData/refactoring/introduceVariable/StringInjection.kt");