Rename: Support retargeting/shadowing conflict checking for functions

#KT-22564 Fixed

idea/src/org/jetbrains/kotlin/idea/refactoring/KotlinRefactoringSupportProvider.kt

@@ -58,9 +58,6 @@ class KotlinRefactoringSupportProvider : RefactoringSupportProvider() {
                 if (element.isLocal) return true
             }
             is KtDestructuringDeclarationEntry -> return true
-            is KtFunction -> {
-                if (element.isLocal && element.nameIdentifier != null) return true
-            }
             is KtParameter -> {
                 val parent = element.parent
                 if (parent is KtForExpression) {

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

@@ -96,7 +96,11 @@ class RenameKotlinFunctionProcessor : RenameKotlinPsiProcessor() {
         val declaration = element.unwrapped as? KtNamedFunction ?: return
         val descriptor = declaration.unsafeResolveToDescriptor()
         checkConflictsAndReplaceUsageInfos(element, allRenames, result)
-        checkRedeclarations(descriptor, newName, result)
+        result += SmartList<UsageInfo>().also { collisions ->
+            checkRedeclarations(descriptor, newName, collisions)
+            checkOriginalUsagesRetargeting(declaration, newName, result, collisions)
+            checkNewNameUsagesRetargeting(declaration, newName, collisions)
+        }
     }
 
     class FunctionWithSupersWrapper(
@@ -229,6 +233,8 @@ class RenameKotlinFunctionProcessor : RenameKotlinPsiProcessor() {
 
         RenameUtil.doRenameGenericNamedElement(element, newName, simpleUsages.toTypedArray(), listener)
 
+        usages.forEach { (it as? KtResolvableCollisionUsageInfo)?.apply() }
+
         (element.unwrapped as? KtNamedDeclaration)?.let(::dropOverrideKeywordIfNecessary)
     }
 

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

@@ -35,6 +35,7 @@ import org.jetbrains.kotlin.idea.references.mainReference
 import org.jetbrains.kotlin.idea.search.and
 import org.jetbrains.kotlin.idea.search.restrictToKotlinSources
 import org.jetbrains.kotlin.idea.util.IdeDescriptorRenderers
+import org.jetbrains.kotlin.idea.util.getAllAccessibleFunctions
 import org.jetbrains.kotlin.idea.util.getAllAccessibleVariables
 import org.jetbrains.kotlin.idea.util.getResolutionScope
 import org.jetbrains.kotlin.incremental.components.NoLookupLocation
@@ -166,6 +167,7 @@ private fun LexicalScope.getRelevantDescriptors(
     val nameAsName = Name.identifier(name)
     return when (declaration) {
         is KtProperty, is KtParameter, is PsiField -> getAllAccessibleVariables(nameAsName)
+        is KtNamedFunction -> getAllAccessibleFunctions(nameAsName)
         is KtClassOrObject, is PsiClass -> listOfNotNull(findClassifier(nameAsName, NoLookupLocation.FROM_IDE))
         else -> emptyList()
     }

idea/testData/refactoring/rename/inplace/AddThis.kt

@@ -0,0 +1,10 @@
+class A {
+    fun foo() {}
+
+    fun goo() {
+        fun <caret>innerGoo() {
+            foo()
+        }
+        innerGoo()
+    }
+}

idea/testData/refactoring/rename/inplace/AddThis.kt.after

@@ -0,0 +1,10 @@
+class A {
+    fun foo() {}
+
+    fun goo() {
+        fun foo() {
+            this.foo()
+        }
+        foo()
+    }
+}

idea/testData/refactoring/rename/inplace/QualifyFun.kt

@@ -0,0 +1,8 @@
+package test
+
+fun foo() {
+    fun <caret>innerGoo() {
+        foo()
+    }
+    innerGoo()
+}

idea/testData/refactoring/rename/inplace/QualifyFun.kt.after

@@ -0,0 +1,8 @@
+package test
+
+fun foo() {
+    fun foo() {
+        test.foo()
+    }
+    innerGoo()
+}

idea/tests/org/jetbrains/kotlin/idea/refactoring/InplaceRenameTest.kt

@@ -55,7 +55,7 @@ class InplaceRenameTest : LightPlatformCodeInsightTestCase() {
     }
 
     fun testLocalFunction() {
-        doTestInplaceRename("bar")
+        doTestMemberInplaceRename("bar")
     }
 
     fun testFunctionParameterNotInplace() {
@@ -71,7 +71,7 @@ class InplaceRenameTest : LightPlatformCodeInsightTestCase() {
     }
 
     fun testLabelFromFunction() {
-        doTestInplaceRename("foo")
+        doTestMemberInplaceRename("foo")
     }
 
     fun testMultiDeclaration() {
@@ -130,6 +130,10 @@ class InplaceRenameTest : LightPlatformCodeInsightTestCase() {
         doTestMemberInplaceRename("is")
     }
 
+    fun testAddThis() {
+        doTestMemberInplaceRename("foo")
+    }
+
     private fun doTestImplicitLambdaParameter(newName: String) {
         configureByFile(getTestName(false) + ".kt")