IR: keep local scope with counter maps across LDL invocations

Since LocalDeclarationsLowering is a BodyLoweringPass, local
functions inside one declaration are handled independently of local
functions in the other declaration. This can lead to name clashes, in
case a local function with the same name and signature is declared in
overloads in the same container, which results in a signature clash
error in JVM IR.

The issue became more common with the introduction of adapted function
references, where psi2ir generates a local adapter-function with a
predefined name, which can easily clash with another reference to the
same target in an overload. This led to a compilation error when
bootstrapping Kotlin with JVM IR, for example in GradleIRBuilder.kt
where there are a lot of references to the same function.

compiler/fir/fir2ir/tests/org/jetbrains/kotlin/codegen/ir/FirBlackBoxCodegenTestGenerated.java

@@ -2075,6 +2075,11 @@ public class FirBlackBoxCodegenTestGenerated extends AbstractFirBlackBoxCodegenT
                 runTest("compiler/testData/codegen/box/callableReference/adaptedReferences/noAdaptedReferencesIfNoOptimizedReferencesEnabled.kt");
             }
 
+            @TestMetadata("noNameClashForReferencesToSameFunction.kt")
+            public void testNoNameClashForReferencesToSameFunction() throws Exception {
+                runTest("compiler/testData/codegen/box/callableReference/adaptedReferences/noNameClashForReferencesToSameFunction.kt");
+            }
+
             @TestMetadata("noReflectionForAdaptedCallableReferences.kt")
             public void testNoReflectionForAdaptedCallableReferences() throws Exception {
                 runTest("compiler/testData/codegen/box/callableReference/adaptedReferences/noReflectionForAdaptedCallableReferences.kt");
@@ -11747,6 +11752,11 @@ public class FirBlackBoxCodegenTestGenerated extends AbstractFirBlackBoxCodegenT
                 runTest("compiler/testData/codegen/box/functions/localFunctions/nameClash.kt");
             }
 
+            @TestMetadata("nameClashAcrossDifferentContainers.kt")
+            public void testNameClashAcrossDifferentContainers() throws Exception {
+                runTest("compiler/testData/codegen/box/functions/localFunctions/nameClashAcrossDifferentContainers.kt");
+            }
+
             @TestMetadata("overloadedLocalFunWithoutClosure.kt")
             public void testOverloadedLocalFunWithoutClosure() throws Exception {
                 runTest("compiler/testData/codegen/box/functions/localFunctions/overloadedLocalFunWithoutClosure.kt");

compiler/ir/backend.common/src/org/jetbrains/kotlin/backend/common/ir/Ir.kt

@@ -6,6 +6,7 @@
 package org.jetbrains.kotlin.backend.common.ir
 
 import org.jetbrains.kotlin.backend.common.CommonBackendContext
+import org.jetbrains.kotlin.backend.common.lower.LocalDeclarationsLowering
 import org.jetbrains.kotlin.builtins.*
 import org.jetbrains.kotlin.descriptors.ClassDescriptor
 import org.jetbrains.kotlin.descriptors.SimpleFunctionDescriptor
@@ -34,6 +35,8 @@ abstract class Ir<out T : CommonBackendContext>(val context: T, val irModule: Ir
 
     val defaultParameterDeclarationsCache = mutableMapOf<IrFunction, IrFunction>()
 
+    internal val localScopeWithCounterMap = LocalDeclarationsLowering.LocalScopeWithCounterMap()
+
     // If irType is an inline class type, return the underlying type according to the
     // unfolding rules of the current backend. Otherwise, returns null.
     open fun unfoldInlineClassType(irType: IrType): IrType? = null

compiler/ir/backend.common/src/org/jetbrains/kotlin/backend/common/lower/LocalDeclarationsLowering.kt

@@ -39,12 +39,15 @@ import org.jetbrains.kotlin.ir.types.impl.IrSimpleTypeImpl
 import org.jetbrains.kotlin.ir.types.impl.IrTypeAbbreviationImpl
 import org.jetbrains.kotlin.ir.types.impl.IrUninitializedType
 import org.jetbrains.kotlin.ir.types.impl.makeTypeProjection
-import org.jetbrains.kotlin.ir.util.*
+import org.jetbrains.kotlin.ir.util.constructedClass
+import org.jetbrains.kotlin.ir.util.file
+import org.jetbrains.kotlin.ir.util.parentAsClass
 import org.jetbrains.kotlin.ir.visitors.IrElementTransformerVoid
 import org.jetbrains.kotlin.ir.visitors.acceptChildrenVoid
 import org.jetbrains.kotlin.ir.visitors.acceptVoid
 import org.jetbrains.kotlin.ir.visitors.transformChildrenVoid
 import org.jetbrains.kotlin.name.Name
+import org.jetbrains.kotlin.utils.addToStdlib.safeAs
 import java.util.*
 
 interface LocalNameProvider {
@@ -117,19 +120,22 @@ class LocalDeclarationsLowering(
         LocalDeclarationsTransformer(irElement, container, classesToLower).lowerLocalDeclarations()
     }
 
-    private class ScopeWithCounter(scope: Scope, irElement: IrElement) : ScopeWithIr(scope, irElement) {
+    internal class ScopeWithCounter(scope: Scope, irElement: IrElement) : ScopeWithIr(scope, irElement) {
         // Continuous numbering across all declarations in the container.
         var counter: Int = 0
+        val usedLocalFunctionNames: MutableSet<Name> = hashSetOf()
+    }
+
+    internal class LocalScopeWithCounterMap {
+        val scopeMap: MutableMap<IrSymbolOwner, ScopeWithCounter> = hashMapOf()
     }
 
-    private val scopeMap: MutableMap<IrSymbolOwner, ScopeWithCounter> = mutableMapOf()
     // Need to keep LocalFunctionContext.index
     private val IrSymbolOwner.scopeWithCounter: ScopeWithCounter
-        get() = scopeMap.getOrPut(this) {
+        get() = context.ir.localScopeWithCounterMap.scopeMap.getOrPut(this) {
             ScopeWithCounter(Scope(symbol), this)
         }
 
-
     private abstract class LocalContext {
         val capturedTypeParameterToTypeParameter: MutableMap<IrTypeParameter, IrTypeParameter> = mutableMapOf()
 
@@ -229,7 +235,6 @@ class LocalDeclarationsLowering(
         val localFunctions: MutableMap<IrFunction, LocalFunctionContext> = LinkedHashMap()
         val localClasses: MutableMap<IrClass, LocalClassContext> = LinkedHashMap()
         val localClassConstructors: MutableMap<IrConstructor, LocalClassConstructorContext> = LinkedHashMap()
-        val usedLocalFunctionNames: MutableSet<Name> = mutableSetOf()
 
         val transformedDeclarations = mutableMapOf<IrSymbolOwner, IrDeclaration>()
 
@@ -832,19 +837,17 @@ class LocalDeclarationsLowering(
         }
 
         private fun collectLocalDeclarations() {
-            val enclosingFileScope = container.file.scopeWithCounter
+            val enclosingFile = container.file
-
+            val enclosingClass = run {
-            val enclosingClassScope = run {
                 var currentParent = container as? IrClass ?: container.parent
                 while (currentParent is IrDeclaration && currentParent !is IrClass) {
                     currentParent = currentParent.parent
                 }
 
                 currentParent as? IrClass
-            }?.scopeWithCounter
+            }
 
             irElement.acceptVoid(object : IrElementVisitorVoidWithContext() {
-
                 override fun visitElement(element: IrElement) {
                     element.acceptChildrenVoid(this)
                 }
@@ -866,18 +869,16 @@ class LocalDeclarationsLowering(
                     super.visitSimpleFunction(declaration)
 
                     if (declaration.visibility == Visibilities.LOCAL) {
-                        val scopeWithIr =
+                        val enclosingScope =
-                            (currentClass ?: enclosingClassScope ?: enclosingFileScope /*file is required for K/N cause file declarations are not split by classes*/
+                            // File is required for K/N because file declarations are not split by classes.
-                            ?: error("No scope for ${declaration.dump()}"))
+                            currentClass ?: enclosingClass?.scopeWithCounter ?: enclosingFile.scopeWithCounter
+                        val index =
+                            if (enclosingScope is ScopeWithCounter &&
+                                (declaration.name.isSpecial || declaration.name in enclosingScope.usedLocalFunctionNames)
+                            ) enclosingScope.counter++ else -1
                         localFunctions[declaration] =
-                            LocalFunctionContext(
+                            LocalFunctionContext(declaration, index, enclosingScope.irElement as IrDeclarationContainer)
-                                declaration,
+                        (enclosingScope as? ScopeWithCounter)?.usedLocalFunctionNames?.add(declaration.name)
-                                if (declaration.name.isSpecial || declaration.name in usedLocalFunctionNames)
-                                    (scopeWithIr as ScopeWithCounter).counter++
-                                else -1,
-                                scopeWithIr.irElement as IrDeclarationContainer
-                            )
-                        usedLocalFunctionNames.add(declaration.name)
                     }
                 }
 
@@ -909,4 +910,4 @@ class LocalDeclarationsLowering(
 }
 
 // Local inner classes capture anything through outer
-internal fun IrClass.isLocalNotInner(): Boolean = visibility == Visibilities.LOCAL && !isInner
+internal fun IrClass.isLocalNotInner(): Boolean = visibility == Visibilities.LOCAL && !isInner

compiler/testData/codegen/box/callableReference/adaptedReferences/noNameClashForReferencesToSameFunction.kt

@@ -0,0 +1,26 @@
+// IGNORE_BACKEND_FIR: JVM_IR
+
+var result = ""
+
+class C(val token: String) {
+    fun target(): Int {
+        result += token
+        return 42
+    }
+}
+
+fun adapt(f: () -> Unit): Unit = f()
+
+fun overload() {
+    adapt(C("O")::target)
+}
+
+fun overload(unused: String) {
+    adapt(C("K")::target)
+}
+
+fun box(): String {
+    overload()
+    overload("")
+    return result
+}

compiler/testData/codegen/box/functions/localFunctions/nameClashAcrossDifferentContainers.kt

@@ -0,0 +1,53 @@
+// IGNORE_BACKEND_FIR: JVM_IR
+
+var result = ""
+
+fun overload() {
+    fun local() {
+        result += "1"
+    }
+    local()
+}
+
+fun overload(unused: String) {
+    fun local() {
+        result += "2"
+    }
+    local()
+    if ("".length < 1) {
+        fun local() {
+            result += "3"
+        }
+        local()
+    }
+}
+
+class C {
+    fun overload() {
+        fun local() {
+            result += "4"
+        }
+        local()
+    }
+
+    fun overload(unused: String) {
+        fun local() {
+            result += "5"
+        }
+        local()
+        if ("".length < 1) {
+            fun local() {
+                result += "6"
+            }
+            local()
+        }
+    }
+}
+
+fun box(): String {
+    overload()
+    overload("")
+    C().overload()
+    C().overload("")
+    return if (result == "123456") "OK" else "Fail: $result"
+}

compiler/tests/org/jetbrains/kotlin/codegen/BlackBoxCodegenTestGenerated.java

@@ -2095,6 +2095,11 @@ public class BlackBoxCodegenTestGenerated extends AbstractBlackBoxCodegenTest {
                 runTest("compiler/testData/codegen/box/callableReference/adaptedReferences/noAdaptedReferencesIfNoOptimizedReferencesEnabled.kt");
             }
 
+            @TestMetadata("noNameClashForReferencesToSameFunction.kt")
+            public void testNoNameClashForReferencesToSameFunction() throws Exception {
+                runTest("compiler/testData/codegen/box/callableReference/adaptedReferences/noNameClashForReferencesToSameFunction.kt");
+            }
+
             @TestMetadata("noReflectionForAdaptedCallableReferences.kt")
             public void testNoReflectionForAdaptedCallableReferences() throws Exception {
                 runTest("compiler/testData/codegen/box/callableReference/adaptedReferences/noReflectionForAdaptedCallableReferences.kt");
@@ -12962,6 +12967,11 @@ public class BlackBoxCodegenTestGenerated extends AbstractBlackBoxCodegenTest {
                 runTest("compiler/testData/codegen/box/functions/localFunctions/nameClash.kt");
             }
 
+            @TestMetadata("nameClashAcrossDifferentContainers.kt")
+            public void testNameClashAcrossDifferentContainers() throws Exception {
+                runTest("compiler/testData/codegen/box/functions/localFunctions/nameClashAcrossDifferentContainers.kt");
+            }
+
             @TestMetadata("overloadedLocalFunWithoutClosure.kt")
             public void testOverloadedLocalFunWithoutClosure() throws Exception {
                 runTest("compiler/testData/codegen/box/functions/localFunctions/overloadedLocalFunWithoutClosure.kt");

compiler/tests/org/jetbrains/kotlin/codegen/LightAnalysisModeTestGenerated.java

@@ -2095,6 +2095,11 @@ public class LightAnalysisModeTestGenerated extends AbstractLightAnalysisModeTes
                 runTest("compiler/testData/codegen/box/callableReference/adaptedReferences/noAdaptedReferencesIfNoOptimizedReferencesEnabled.kt");
             }
 
+            @TestMetadata("noNameClashForReferencesToSameFunction.kt")
+            public void testNoNameClashForReferencesToSameFunction() throws Exception {
+                runTest("compiler/testData/codegen/box/callableReference/adaptedReferences/noNameClashForReferencesToSameFunction.kt");
+            }
+
             @TestMetadata("noReflectionForAdaptedCallableReferences.kt")
             public void testNoReflectionForAdaptedCallableReferences() throws Exception {
                 runTest("compiler/testData/codegen/box/callableReference/adaptedReferences/noReflectionForAdaptedCallableReferences.kt");
@@ -12962,6 +12967,11 @@ public class LightAnalysisModeTestGenerated extends AbstractLightAnalysisModeTes
                 runTest("compiler/testData/codegen/box/functions/localFunctions/nameClash.kt");
             }
 
+            @TestMetadata("nameClashAcrossDifferentContainers.kt")
+            public void testNameClashAcrossDifferentContainers() throws Exception {
+                runTest("compiler/testData/codegen/box/functions/localFunctions/nameClashAcrossDifferentContainers.kt");
+            }
+
             @TestMetadata("overloadedLocalFunWithoutClosure.kt")
             public void testOverloadedLocalFunWithoutClosure() throws Exception {
                 runTest("compiler/testData/codegen/box/functions/localFunctions/overloadedLocalFunWithoutClosure.kt");

compiler/tests/org/jetbrains/kotlin/codegen/ir/IrBlackBoxCodegenTestGenerated.java

@@ -2075,6 +2075,11 @@ public class IrBlackBoxCodegenTestGenerated extends AbstractIrBlackBoxCodegenTes
                 runTest("compiler/testData/codegen/box/callableReference/adaptedReferences/noAdaptedReferencesIfNoOptimizedReferencesEnabled.kt");
             }
 
+            @TestMetadata("noNameClashForReferencesToSameFunction.kt")
+            public void testNoNameClashForReferencesToSameFunction() throws Exception {
+                runTest("compiler/testData/codegen/box/callableReference/adaptedReferences/noNameClashForReferencesToSameFunction.kt");
+            }
+
             @TestMetadata("noReflectionForAdaptedCallableReferences.kt")
             public void testNoReflectionForAdaptedCallableReferences() throws Exception {
                 runTest("compiler/testData/codegen/box/callableReference/adaptedReferences/noReflectionForAdaptedCallableReferences.kt");
@@ -11747,6 +11752,11 @@ public class IrBlackBoxCodegenTestGenerated extends AbstractIrBlackBoxCodegenTes
                 runTest("compiler/testData/codegen/box/functions/localFunctions/nameClash.kt");
             }
 
+            @TestMetadata("nameClashAcrossDifferentContainers.kt")
+            public void testNameClashAcrossDifferentContainers() throws Exception {
+                runTest("compiler/testData/codegen/box/functions/localFunctions/nameClashAcrossDifferentContainers.kt");
+            }
+
             @TestMetadata("overloadedLocalFunWithoutClosure.kt")
             public void testOverloadedLocalFunWithoutClosure() throws Exception {
                 runTest("compiler/testData/codegen/box/functions/localFunctions/overloadedLocalFunWithoutClosure.kt");

js/js.tests/test/org/jetbrains/kotlin/js/test/ir/semantics/IrJsCodegenBoxTestGenerated.java

@@ -1515,6 +1515,11 @@ public class IrJsCodegenBoxTestGenerated extends AbstractIrJsCodegenBoxTest {
                 runTest("compiler/testData/codegen/box/callableReference/adaptedReferences/manyDefaultsAndVararg.kt");
             }
 
+            @TestMetadata("noNameClashForReferencesToSameFunction.kt")
+            public void testNoNameClashForReferencesToSameFunction() throws Exception {
+                runTest("compiler/testData/codegen/box/callableReference/adaptedReferences/noNameClashForReferencesToSameFunction.kt");
+            }
+
             @TestMetadata("simpleDefaultArgument.kt")
             public void testSimpleDefaultArgument() throws Exception {
                 runTest("compiler/testData/codegen/box/callableReference/adaptedReferences/simpleDefaultArgument.kt");
@@ -10122,6 +10127,11 @@ public class IrJsCodegenBoxTestGenerated extends AbstractIrJsCodegenBoxTest {
                 runTest("compiler/testData/codegen/box/functions/localFunctions/nameClash.kt");
             }
 
+            @TestMetadata("nameClashAcrossDifferentContainers.kt")
+            public void testNameClashAcrossDifferentContainers() throws Exception {
+                runTest("compiler/testData/codegen/box/functions/localFunctions/nameClashAcrossDifferentContainers.kt");
+            }
+
             @TestMetadata("overloadedLocalFunWithoutClosure.kt")
             public void testOverloadedLocalFunWithoutClosure() throws Exception {
                 runTest("compiler/testData/codegen/box/functions/localFunctions/overloadedLocalFunWithoutClosure.kt");

js/js.tests/test/org/jetbrains/kotlin/js/test/semantics/JsCodegenBoxTestGenerated.java

@@ -1515,6 +1515,11 @@ public class JsCodegenBoxTestGenerated extends AbstractJsCodegenBoxTest {
                 runTest("compiler/testData/codegen/box/callableReference/adaptedReferences/manyDefaultsAndVararg.kt");
             }
 
+            @TestMetadata("noNameClashForReferencesToSameFunction.kt")
+            public void testNoNameClashForReferencesToSameFunction() throws Exception {
+                runTest("compiler/testData/codegen/box/callableReference/adaptedReferences/noNameClashForReferencesToSameFunction.kt");
+            }
+
             @TestMetadata("simpleDefaultArgument.kt")
             public void testSimpleDefaultArgument() throws Exception {
                 runTest("compiler/testData/codegen/box/callableReference/adaptedReferences/simpleDefaultArgument.kt");
@@ -10122,6 +10127,11 @@ public class JsCodegenBoxTestGenerated extends AbstractJsCodegenBoxTest {
                 runTest("compiler/testData/codegen/box/functions/localFunctions/nameClash.kt");
             }
 
+            @TestMetadata("nameClashAcrossDifferentContainers.kt")
+            public void testNameClashAcrossDifferentContainers() throws Exception {
+                runTest("compiler/testData/codegen/box/functions/localFunctions/nameClashAcrossDifferentContainers.kt");
+            }
+
             @TestMetadata("overloadedLocalFunWithoutClosure.kt")
             public void testOverloadedLocalFunWithoutClosure() throws Exception {
                 runTest("compiler/testData/codegen/box/functions/localFunctions/overloadedLocalFunWithoutClosure.kt");