JVM IR: keep original KotlinType in eraseTypeParameters

Otherwise EnhancedNullability annotation instance is lost (for some
reason it's not translated to IR elements), and in the newly added test,
the wrapper type in Java is confused with primitive, and this causes
a platform declaration clash error.

Also make IrTypeArgument.eraseTypeParameters private, since it's not
used outside.

compiler/ir/backend.jvm/src/org/jetbrains/kotlin/backend/jvm/ir/IrUtils.kt

@@ -30,6 +30,7 @@ import org.jetbrains.kotlin.ir.types.*
 import org.jetbrains.kotlin.ir.types.impl.IrSimpleTypeImpl
 import org.jetbrains.kotlin.ir.types.impl.IrStarProjectionImpl
 import org.jetbrains.kotlin.ir.types.impl.makeTypeProjection
+import org.jetbrains.kotlin.ir.types.impl.originalKotlinType
 import org.jetbrains.kotlin.ir.util.*
 import org.jetbrains.kotlin.ir.visitors.IrElementTransformerVoid
 import org.jetbrains.kotlin.load.java.JavaVisibilities
@@ -53,6 +54,7 @@ fun IrType.eraseTypeParameters() = when (this) {
     is IrSimpleType ->
         when (val owner = classifier.owner) {
             is IrClass -> IrSimpleTypeImpl(
+                originalKotlinType,
                 classifier,
                 hasQuestionMark,
                 arguments.map { it.eraseTypeParameters() },
@@ -72,7 +74,7 @@ fun IrType.eraseTypeParameters() = when (this) {
     else -> error("Unknown IrType kind: $this")
 }
 
-fun IrTypeArgument.eraseTypeParameters(): IrTypeArgument = when (this) {
+private fun IrTypeArgument.eraseTypeParameters(): IrTypeArgument = when (this) {
     is IrStarProjection -> this
     is IrTypeProjection -> makeTypeProjection(type.eraseTypeParameters(), variance)
     else -> error("Unknown IrTypeArgument kind: $this")

compiler/testData/codegen/box/typeMapping/enhancedPrimitiveInReturnType.kt

@@ -0,0 +1,16 @@
+// TARGET_BACKEND: JVM
+
+// FILE: E.java
+
+public interface E {
+    @org.jetbrains.annotations.NotNull
+    Integer getId();
+}
+
+// FILE: box.kt
+
+class EImpl : E {
+    override fun getId(): Int = 314
+}
+
+fun box(): String = if (EImpl().getId() == 314) "OK" else "Fail"

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

@@ -28169,6 +28169,11 @@ public class BlackBoxCodegenTestGenerated extends AbstractBlackBoxCodegenTest {
             KotlinTestUtils.assertAllTestsPresentByMetadataWithExcluded(this.getClass(), new File("compiler/testData/codegen/box/typeMapping"), Pattern.compile("^(.+)\\.kt$"), null, TargetBackend.JVM, true);
         }
 
+        @TestMetadata("enhancedPrimitiveInReturnType.kt")
+        public void testEnhancedPrimitiveInReturnType() throws Exception {
+            runTest("compiler/testData/codegen/box/typeMapping/enhancedPrimitiveInReturnType.kt");
+        }
+
         @TestMetadata("enhancedPrimitives.kt")
         public void testEnhancedPrimitives() throws Exception {
             runTest("compiler/testData/codegen/box/typeMapping/enhancedPrimitives.kt");

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

@@ -26986,6 +26986,11 @@ public class LightAnalysisModeTestGenerated extends AbstractLightAnalysisModeTes
             KotlinTestUtils.assertAllTestsPresentByMetadataWithExcluded(this.getClass(), new File("compiler/testData/codegen/box/typeMapping"), Pattern.compile("^(.+)\\.kt$"), null, TargetBackend.JVM, true);
         }
 
+        @TestMetadata("enhancedPrimitiveInReturnType.kt")
+        public void testEnhancedPrimitiveInReturnType() throws Exception {
+            runTest("compiler/testData/codegen/box/typeMapping/enhancedPrimitiveInReturnType.kt");
+        }
+
         @TestMetadata("enhancedPrimitives.kt")
         public void testEnhancedPrimitives() throws Exception {
             runTest("compiler/testData/codegen/box/typeMapping/enhancedPrimitives.kt");

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

@@ -26678,6 +26678,11 @@ public class FirBlackBoxCodegenTestGenerated extends AbstractFirBlackBoxCodegenT
             KotlinTestUtils.assertAllTestsPresentByMetadataWithExcluded(this.getClass(), new File("compiler/testData/codegen/box/typeMapping"), Pattern.compile("^(.+)\\.kt$"), null, TargetBackend.JVM_IR, true);
         }
 
+        @TestMetadata("enhancedPrimitiveInReturnType.kt")
+        public void testEnhancedPrimitiveInReturnType() throws Exception {
+            runTest("compiler/testData/codegen/box/typeMapping/enhancedPrimitiveInReturnType.kt");
+        }
+
         @TestMetadata("enhancedPrimitives.kt")
         public void testEnhancedPrimitives() throws Exception {
             runTest("compiler/testData/codegen/box/typeMapping/enhancedPrimitives.kt");

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

@@ -26678,6 +26678,11 @@ public class IrBlackBoxCodegenTestGenerated extends AbstractIrBlackBoxCodegenTes
             KotlinTestUtils.assertAllTestsPresentByMetadataWithExcluded(this.getClass(), new File("compiler/testData/codegen/box/typeMapping"), Pattern.compile("^(.+)\\.kt$"), null, TargetBackend.JVM_IR, true);
         }
 
+        @TestMetadata("enhancedPrimitiveInReturnType.kt")
+        public void testEnhancedPrimitiveInReturnType() throws Exception {
+            runTest("compiler/testData/codegen/box/typeMapping/enhancedPrimitiveInReturnType.kt");
+        }
+
         @TestMetadata("enhancedPrimitives.kt")
         public void testEnhancedPrimitives() throws Exception {
             runTest("compiler/testData/codegen/box/typeMapping/enhancedPrimitives.kt");