Change Signature: Support receiver <-> parameter conversion for function expressions

#KT-9309 Fixed

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

@@ -65,7 +65,7 @@ fun JetCallableDeclaration.setReceiverTypeReference(typeRef: JetTypeReference?):
                     oldTypeRef.replace(typeRef) as JetTypeReference
                 }
                 else {
-                    val anchor = getNameIdentifier()
+                    val anchor = getNameIdentifier() ?: valueParameterList
                     val newTypeRef = addBefore(typeRef, anchor) as JetTypeReference
                     addAfter(JetPsiFactory(getProject()).createDot(), newTypeRef)
                     newTypeRef

idea/src/org/jetbrains/kotlin/idea/refactoring/changeSignature/JetChangeSignatureUsageProcessor.java

@@ -75,6 +75,7 @@ import org.jetbrains.kotlin.resolve.scopes.JetScope;
 import org.jetbrains.kotlin.resolve.scopes.receivers.ReceiverValue;
 import org.jetbrains.kotlin.resolve.scopes.receivers.ThisReceiver;
 import org.jetbrains.kotlin.resolve.scopes.utils.ScopeUtilsKt;
+import org.jetbrains.kotlin.resolve.source.KotlinSourceElementKt;
 import org.jetbrains.kotlin.types.JetType;
 
 import java.util.*;
@@ -671,7 +672,7 @@ public class JetChangeSignatureUsageProcessor implements ChangeSignatureUsagePro
         if (function instanceof JetCallableDeclaration && newReceiverInfo != originalReceiverInfo) {
             findReceiverIntroducingConflicts(result, function, newReceiverInfo);
             findInternalExplicitReceiverConflicts(refUsages.get(), result, originalReceiverInfo);
-            findThisLabelConflicts((JetChangeInfo) info, refUsages, result, changeInfo, function);
+            findThisLabelConflicts(refUsages, result, changeInfo, (JetCallableDeclaration) function);
         }
 
         for (UsageInfo usageInfo : usageInfos) {
@@ -716,18 +717,17 @@ public class JetChangeSignatureUsageProcessor implements ChangeSignatureUsagePro
     }
 
     private static void findThisLabelConflicts(
-            JetChangeInfo info,
             Ref<UsageInfo[]> refUsages,
             MultiMap<PsiElement, String> result,
             JetChangeInfo changeInfo,
-            PsiElement function
+            JetCallableDeclaration callable
     ) {
-        JetPsiFactory psiFactory = new JetPsiFactory(function.getProject());
+        JetPsiFactory psiFactory = new JetPsiFactory(callable.getProject());
         for (UsageInfo usageInfo : refUsages.get()) {
             if (!(usageInfo instanceof JetParameterUsage)) continue;
 
             String newExprText = ((JetParameterUsage) usageInfo).getReplacementText(changeInfo);
-            if (!newExprText.startsWith("this@")) continue;
+            if (!newExprText.startsWith("this")) continue;
 
             if (usageInfo.getElement() instanceof KDocName) continue; // TODO support converting parameter to receiver in KDoc
 
@@ -737,12 +737,11 @@ public class JetChangeSignatureUsageProcessor implements ChangeSignatureUsagePro
             if (scope == null) continue;
 
             JetThisExpression newExpr = (JetThisExpression) psiFactory.createExpression(newExprText);
-            JetSimpleNameExpression labelExpr = newExpr.getTargetLabel();
-            if (labelExpr == null) continue;
 
             BindingContext newContext = AnalysisPackage.analyzeInContext(newExpr, scope, originalExpr);
 
-            if (newContext.get(BindingContext.AMBIGUOUS_LABEL_TARGET, labelExpr) != null) {
+            JetSimpleNameExpression labelExpr = newExpr.getTargetLabel();
+            if (labelExpr != null && newContext.get(BindingContext.AMBIGUOUS_LABEL_TARGET, labelExpr) != null) {
                 result.putValue(
                         originalExpr,
                         "Parameter reference can't be safely replaced with " +
@@ -751,6 +750,20 @@ public class JetChangeSignatureUsageProcessor implements ChangeSignatureUsagePro
                         labelExpr.getText() +
                         " is ambiguous in this context"
                 );
+                continue;
+            }
+
+            DeclarationDescriptor thisTarget = newContext.get(BindingContext.REFERENCE_TARGET, newExpr.getInstanceReference());
+            PsiElement thisTargetPsi = thisTarget instanceof DeclarationDescriptorWithSource
+                                 ? KotlinSourceElementKt.getPsi(((DeclarationDescriptorWithSource) thisTarget).getSource())
+                                 : null;
+            if (thisTargetPsi != null && PsiTreeUtil.isAncestor(callable, thisTargetPsi, true)) {
+                result.putValue(
+                        originalExpr,
+                        "Parameter reference can't be safely replaced with " +
+                        newExprText +
+                        " since target function can't be referenced in this context"
+                );
             }
         }
     }

idea/src/org/jetbrains/kotlin/idea/refactoring/changeSignature/usages/JetParameterUsage.kt

@@ -23,13 +23,14 @@ import org.jetbrains.kotlin.idea.refactoring.changeSignature.JetChangeInfo
 import org.jetbrains.kotlin.idea.refactoring.changeSignature.JetParameterInfo
 import org.jetbrains.kotlin.descriptors.DeclarationDescriptor
 import org.jetbrains.kotlin.idea.codeInsight.shorten.addToShorteningWaitSet
+import org.jetbrains.kotlin.idea.core.KotlinNameSuggester
 import org.jetbrains.kotlin.psi.JetQualifiedExpression
 import org.jetbrains.kotlin.psi.JetElement
 import org.jetbrains.kotlin.psi.JetThisExpression
 import org.jetbrains.kotlin.idea.util.ShortenReferences.Options
 
 // Explicit reference to function parameter or outer this
-public abstract class JetExplicitReferenceUsage<T: JetElement>(element: T) : JetUsageInfo<T>(element) {
+public abstract class JetExplicitReferenceUsage<T : JetElement>(element: T) : JetUsageInfo<T>(element) {
     abstract fun getReplacementText(changeInfo: JetChangeInfo): String
 
     protected open fun processReplacedElement(element: JetElement) {
@@ -55,10 +56,14 @@ public class JetParameterUsage(
         elementToShorten.addToShorteningWaitSet(Options(removeThis = true, removeThisLabels = true))
     }
 
-    override fun getReplacementText(changeInfo: JetChangeInfo): String =
-            if (changeInfo.receiverParameterInfo != parameterInfo) {
-                parameterInfo.getInheritedName(containingCallable)
-            } else "this@${changeInfo.getNewName()}"
+    override fun getReplacementText(changeInfo: JetChangeInfo): String {
+        if (changeInfo.receiverParameterInfo != parameterInfo) return parameterInfo.getInheritedName(containingCallable)
+
+        val newName = changeInfo.getNewName()
+        if (KotlinNameSuggester.isIdentifier(newName)) return "this@$newName"
+
+        return "this"
+    }
 }
 
 public class JetNonQualifiedOuterThisUsage(

idea/testData/intentions/convertParameterToReceiver/functionExpression.kt

@@ -0,0 +1,7 @@
+interface T {
+    val foo: Int
+}
+
+val f = fun(<caret>t: T): Int {
+    return t.foo
+}

idea/testData/intentions/convertParameterToReceiver/functionExpression.kt.after

@@ -0,0 +1,7 @@
+interface T {
+    val foo: Int
+}
+
+val f = fun T.(): Int {
+    return foo
+}

idea/testData/intentions/convertParameterToReceiver/functionExpressionWithThisConflict.kt

@@ -0,0 +1,12 @@
+// SHOULD_FAIL_WITH: Parameter reference can't be safely replaced with this since target function can't be referenced in this context
+interface T {
+    val foo: Int
+}
+
+val f = fun(<caret>t: T) {
+    object {
+        fun f(): Int {
+            return t.foo
+        }
+    }
+}

idea/testData/intentions/convertReceiverToParameter/functionExpression.kt

@@ -0,0 +1,7 @@
+interface T {
+    val foo: Int
+}
+
+val f = fun <caret>T.(): Int {
+    return foo
+}

idea/testData/intentions/convertReceiverToParameter/functionExpression.kt.after

@@ -0,0 +1,7 @@
+interface T {
+    val foo: Int
+}
+
+val f = fun(t: T): Int {
+    return t.foo
+}

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

@@ -3565,6 +3565,18 @@ public class IntentionTestGenerated extends AbstractIntentionTest {
             doTest(fileName);
         }
 
+        @TestMetadata("functionExpression.kt")
+        public void testFunctionExpression() throws Exception {
+            String fileName = JetTestUtils.navigationMetadata("idea/testData/intentions/convertParameterToReceiver/functionExpression.kt");
+            doTest(fileName);
+        }
+
+        @TestMetadata("functionExpressionWithThisConflict.kt")
+        public void testFunctionExpressionWithThisConflict() throws Exception {
+            String fileName = JetTestUtils.navigationMetadata("idea/testData/intentions/convertParameterToReceiver/functionExpressionWithThisConflict.kt");
+            doTest(fileName);
+        }
+
         @TestMetadata("lambdaParameter.kt")
         public void testLambdaParameter() throws Exception {
             String fileName = JetTestUtils.navigationMetadata("idea/testData/intentions/convertParameterToReceiver/lambdaParameter.kt");
@@ -3727,6 +3739,12 @@ public class IntentionTestGenerated extends AbstractIntentionTest {
             JetTestUtils.assertAllTestsPresentByMetadata(this.getClass(), new File("idea/testData/intentions/convertReceiverToParameter"), Pattern.compile("^([\\w\\-_]+)\\.kt$"), true);
         }
 
+        @TestMetadata("functionExpression.kt")
+        public void testFunctionExpression() throws Exception {
+            String fileName = JetTestUtils.navigationMetadata("idea/testData/intentions/convertReceiverToParameter/functionExpression.kt");
+            doTest(fileName);
+        }
+
         @TestMetadata("genericReceiver.kt")
         public void testGenericReceiver() throws Exception {
             String fileName = JetTestUtils.navigationMetadata("idea/testData/intentions/convertReceiverToParameter/genericReceiver.kt");