JVM_IR KT-44627 fix bridge signature for parameter with primitive bound

compiler/ir/backend.jvm/src/org/jetbrains/kotlin/backend/jvm/codegen/MethodSignatureMapper.kt

@@ -198,7 +198,9 @@ class MethodSignatureMapper(private val context: JvmBackendContext) {
 
     // See also: KotlinTypeMapper.forceBoxedReturnType
     private fun forceBoxedReturnType(function: IrFunction): Boolean =
-        isBoxMethodForInlineClass(function) || forceFoxedReturnTypeOnOverride(function) || forceBoxedReturnTypeOnDefaultImplFun(function) ||
+        isBoxMethodForInlineClass(function) ||
+                forceFoxedReturnTypeOnOverride(function) ||
+                forceBoxedReturnTypeOnDefaultImplFun(function) ||
                 function.isFromJava() && function.returnType.isInlined()
 
     private fun forceFoxedReturnTypeOnOverride(function: IrFunction) =

compiler/ir/backend.jvm/src/org/jetbrains/kotlin/backend/jvm/lower/BridgeLowering.kt

@@ -428,17 +428,24 @@ internal class BridgeLowering(val context: JvmBackendContext) : FileLoweringPass
             copyParametersWithErasure(this@addBridge, bridge.overridden)
             body = context.createIrBuilder(symbol, startOffset, endOffset).run { irExprBody(delegatingCall(this@apply, target)) }
 
-            // The generated bridge method overrides all of the symbols which were overridden by its overrides.
-            // This is technically wrong, but it's necessary to generate a method which maps to the same signature.
-            val inheritedOverrides = bridge.overriddenSymbols.flatMapTo(mutableSetOf()) { function ->
-                function.owner.safeAs<IrSimpleFunction>()?.overriddenSymbols ?: emptyList()
+            if (!bridge.overridden.returnType.isTypeParameterWithPrimitiveUpperBound()) {
+                // The generated bridge method overrides all of the symbols which were overridden by its overrides.
+                // This is technically wrong, but it's necessary to generate a method which maps to the same signature.
+                // In case of 'fun foo(): T', where 'T' is a type parameter with primitive upper bound (e.g., 'T : Char'),
+                // 'foo' is mapped to 'foo()C', regardless of its overrides.
+                val inheritedOverrides = bridge.overriddenSymbols.flatMapTo(mutableSetOf()) { function ->
+                    function.owner.safeAs<IrSimpleFunction>()?.overriddenSymbols ?: emptyList()
+                }
+                val redundantOverrides = inheritedOverrides.flatMapTo(mutableSetOf()) {
+                    it.owner.allOverridden().map { override -> override.symbol }
+                }
+                overriddenSymbols = inheritedOverrides.filter { it !in redundantOverrides }
             }
-            val redundantOverrides = inheritedOverrides.flatMapTo(mutableSetOf()) {
-                it.owner.allOverridden().map { override -> override.symbol }
-            }
-            overriddenSymbols = inheritedOverrides.filter { it !in redundantOverrides }
         }
 
+    private fun IrType.isTypeParameterWithPrimitiveUpperBound(): Boolean =
+        isTypeParameter() && eraseTypeParameters().isPrimitiveType()
+
     private fun IrClass.addSpecialBridge(specialBridge: SpecialBridge, target: IrSimpleFunction): IrSimpleFunction =
         addFunction {
             startOffset = this@addSpecialBridge.startOffset

compiler/testData/codegen/bytecodeListing/overrideWithPrimitiveUpperBound.kt

@@ -0,0 +1,5 @@
+open class ATChar<T : Char>(open var x: T)
+
+open class BTChar<T : Char>(override var x: T) : ATChar<T>(x)
+
+class CChar(override var x: Char) : BTChar<Char>('x')

compiler/testData/codegen/bytecodeListing/overrideWithPrimitiveUpperBound.txt

@@ -0,0 +1,27 @@
+@kotlin.Metadata
+public class ATChar {
+    // source: 'overrideWithPrimitiveUpperBound.kt'
+    private field x: char
+    public method <init>(p0: char): void
+    public method getX(): char
+    public method setX(p0: char): void
+}
+
+@kotlin.Metadata
+public class BTChar {
+    // source: 'overrideWithPrimitiveUpperBound.kt'
+    private field x: char
+    public method <init>(p0: char): void
+    public method getX(): char
+    public method setX(p0: char): void
+}
+
+@kotlin.Metadata
+public final class CChar {
+    // source: 'overrideWithPrimitiveUpperBound.kt'
+    private field x: char
+    public method <init>(p0: char): void
+    public synthetic bridge method getX(): char
+    public @org.jetbrains.annotations.NotNull method getX(): java.lang.Character
+    public method setX(p0: char): void
+}

compiler/testData/codegen/bytecodeListing/overrideWithPrimitiveUpperBound2.kt

@@ -0,0 +1,5 @@
+open class ATAny<T>(open val x: T)
+
+open class BTChar<T : Char>(override val x: T) : ATAny<T>(x)
+
+class CChar(override val x: Char) : BTChar<Char>('x')

compiler/testData/codegen/bytecodeListing/overrideWithPrimitiveUpperBound2.txt

@@ -0,0 +1,26 @@
+@kotlin.Metadata
+public class ATAny {
+    // source: 'overrideWithPrimitiveUpperBound2.kt'
+    private final field x: java.lang.Object
+    public method <init>(p0: java.lang.Object): void
+    public method getX(): java.lang.Object
+}
+
+@kotlin.Metadata
+public class BTChar {
+    // source: 'overrideWithPrimitiveUpperBound2.kt'
+    private final field x: char
+    public method <init>(p0: char): void
+    public method getX(): char
+    public synthetic bridge method getX(): java.lang.Object
+}
+
+@kotlin.Metadata
+public final class CChar {
+    // source: 'overrideWithPrimitiveUpperBound2.kt'
+    private final field x: char
+    public method <init>(p0: char): void
+    public synthetic bridge method getX(): char
+    public @org.jetbrains.annotations.NotNull method getX(): java.lang.Character
+    public synthetic bridge method getX(): java.lang.Object
+}

compiler/tests-gen/org/jetbrains/kotlin/codegen/BytecodeListingTestGenerated.java

@@ -215,6 +215,16 @@ public class BytecodeListingTestGenerated extends AbstractBytecodeListingTest {
         runTest("compiler/testData/codegen/bytecodeListing/noRemoveAtInReadOnly.kt");
     }
 
+    @TestMetadata("overrideWithPrimitiveUpperBound.kt")
+    public void testOverrideWithPrimitiveUpperBound() throws Exception {
+        runTest("compiler/testData/codegen/bytecodeListing/overrideWithPrimitiveUpperBound.kt");
+    }
+
+    @TestMetadata("overrideWithPrimitiveUpperBound2.kt")
+    public void testOverrideWithPrimitiveUpperBound2() throws Exception {
+        runTest("compiler/testData/codegen/bytecodeListing/overrideWithPrimitiveUpperBound2.kt");
+    }
+
     @TestMetadata("privateCompanionFields.kt")
     public void testPrivateCompanionFields() throws Exception {
         runTest("compiler/testData/codegen/bytecodeListing/privateCompanionFields.kt");

compiler/tests-gen/org/jetbrains/kotlin/codegen/ir/IrBytecodeListingTestGenerated.java

@@ -215,6 +215,16 @@ public class IrBytecodeListingTestGenerated extends AbstractIrBytecodeListingTes
         runTest("compiler/testData/codegen/bytecodeListing/noRemoveAtInReadOnly.kt");
     }
 
+    @TestMetadata("overrideWithPrimitiveUpperBound.kt")
+    public void testOverrideWithPrimitiveUpperBound() throws Exception {
+        runTest("compiler/testData/codegen/bytecodeListing/overrideWithPrimitiveUpperBound.kt");
+    }
+
+    @TestMetadata("overrideWithPrimitiveUpperBound2.kt")
+    public void testOverrideWithPrimitiveUpperBound2() throws Exception {
+        runTest("compiler/testData/codegen/bytecodeListing/overrideWithPrimitiveUpperBound2.kt");
+    }
+
     @TestMetadata("privateCompanionFields.kt")
     public void testPrivateCompanionFields() throws Exception {
         runTest("compiler/testData/codegen/bytecodeListing/privateCompanionFields.kt");