Change Signature/Rename: Fix renaming of extension function parameter

idea/src/org/jetbrains/kotlin/idea/refactoring/changeSignature/usages/JetFunctionDefinitionUsage.java

@@ -204,7 +204,7 @@ public class JetFunctionDefinitionUsage<T extends PsiElement> extends JetUsageIn
             processParameterListWithStructuralChanges(changeInfo, element, parameterList, psiFactory);
         }
         else if (parameterList != null) {
-            int paramIndex = 0;
+            int paramIndex = originalFunctionDescriptor.getExtensionReceiverParameter() != null ? 1 : 0;
 
             for (JetParameter parameter : parameterList.getParameters()) {
                 JetParameterInfo parameterInfo = changeInfo.getNewParameters()[paramIndex];

idea/src/org/jetbrains/kotlin/idea/refactoring/rename/RenameKotlinParameterProcessor.kt

@@ -51,7 +51,8 @@ public class RenameKotlinParameterProcessor : RenameKotlinPsiProcessor() {
 
         val changeSignatureConfiguration = object : JetChangeSignatureConfiguration {
             override fun configure(originalDescriptor: JetMethodDescriptor, bindingContext: BindingContext): JetMethodDescriptor {
-                return originalDescriptor.modify { it.renameParameter(paramIndex, newName) }
+                val paramInfoIndex = if (functionDescriptor.getExtensionReceiverParameter() != null) paramIndex + 1 else paramIndex
+                return originalDescriptor.modify { it.renameParameter(paramInfoIndex, newName) }
             }
 
             override fun performSilently(affectedFunctions: Collection<PsiElement>) = true

idea/testData/refactoring/changeSignature/RenameExtensionParameterAfter.kt

@@ -0,0 +1,3 @@
+fun Int.foo(b: Int): Int {
+    return this + b
+}

idea/testData/refactoring/changeSignature/RenameExtensionParameterBefore.kt

@@ -0,0 +1,3 @@
+fun Int.<caret>foo(a: Int): Int {
+    return this + a
+}

idea/testData/refactoring/rename/automaticRenamerParameterInExtension/after/JavaSub.java

@@ -0,0 +1,4 @@
+class JavaSub extends testing.Middle {
+    void foo(int receiver, int aa, String b) {
+    }
+}

idea/testData/refactoring/rename/automaticRenamerParameterInExtension/after/main.kt

@@ -0,0 +1,21 @@
+package testing
+
+trait Trait {
+    open fun Int.foo(aa: Int, b: String) {
+    }
+}
+
+open class Super {
+    open fun Int.foo(aa: Int, b: String) {
+    }
+}
+
+open class Middle : Super(), Trait {
+    override fun Int.foo(/*rename*/aa: Int, b: String) {
+    }
+}
+
+class Sub : Middle() {
+    override fun Int.foo(aa: Int, b: String) {
+    }
+}

idea/testData/refactoring/rename/automaticRenamerParameterInExtension/before/JavaSub.java

@@ -0,0 +1,4 @@
+class JavaSub extends testing.Middle {
+    void foo(int receiver, int a, String b) {
+    }
+}

idea/testData/refactoring/rename/automaticRenamerParameterInExtension/before/main.kt

@@ -0,0 +1,21 @@
+package testing
+
+trait Trait {
+    open fun Int.foo(a: Int, b: String) {
+    }
+}
+
+open class Super {
+    open fun Int.foo(a: Int, b: String) {
+    }
+}
+
+open class Middle : Super(), Trait {
+    override fun Int.foo(/*rename*/a: Int, b: String) {
+    }
+}
+
+class Sub : Middle() {
+    override fun Int.foo(a: Int, b: String) {
+    }
+}

idea/testData/refactoring/rename/automaticRenamerParameterInExtension/parameter.test

@@ -0,0 +1,5 @@
+{
+  "type": "MARKED_ELEMENT",
+  "newName": "aa",
+  "mainFile": "main.kt"
+}

idea/tests/org/jetbrains/kotlin/idea/refactoring/changeSignature/JetChangeSignatureTest.java

@@ -918,6 +918,12 @@ public class JetChangeSignatureTest extends KotlinCodeInsightTestCase {
         doTest(changeInfo);
     }
 
+    public void testRenameExtensionParameter() throws Exception {
+        JetChangeInfo changeInfo = getChangeInfo();
+        changeInfo.getNewParameters()[1].setName("b");
+        doTest(changeInfo);
+    }
+
     @NotNull
     @Override
     protected String getTestDataPath() {

idea/tests/org/jetbrains/kotlin/idea/refactoring/rename/RenameTestGenerated.java

@@ -83,6 +83,12 @@ public class RenameTestGenerated extends AbstractRenameTest {
         doTest(fileName);
     }
 
+    @TestMetadata("automaticRenamerParameterInExtension/parameter.test")
+    public void testAutomaticRenamerParameterInExtension_Parameter() throws Exception {
+        String fileName = JetTestUtils.navigationMetadata("idea/testData/refactoring/rename/automaticRenamerParameterInExtension/parameter.test");
+        doTest(fileName);
+    }
+
     @TestMetadata("defaultObject/defaultObject.test")
     public void testDefaultObject_DefaultObject() throws Exception {
         String fileName = JetTestUtils.navigationMetadata("idea/testData/refactoring/rename/defaultObject/defaultObject.test");