JVM_IR: skip synthetic enum parameters in signatures

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

@@ -68,11 +68,11 @@ open class FunctionCodegen(
                 functionView,
                 signature.asmMethod.returnType
             )
-        }
-
-
-        if (irFunction !is IrConstructor || !irFunction.parentAsClass.shouldNotGenerateConstructorParameterAnnotations()) {
-            generateParameterAnnotations(functionView, methodVisitor, signature, classCodegen, context)
+            // Not generating parameter annotations for default stubs fixes KT-7892, though
+            // this certainly looks like a workaround for a javac bug.
+            if (irFunction !is IrConstructor || !irFunction.parentAsClass.shouldNotGenerateConstructorParameterAnnotations()) {
+                generateParameterAnnotations(functionView, methodVisitor, signature, classCodegen, context)
+            }
         }
 
         if (!state.classBuilderMode.generateBodies || flags.and(Opcodes.ACC_ABSTRACT) != 0 || irFunction.isExternal) {

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

@@ -214,6 +214,7 @@ class MethodSignatureMapper(private val context: JvmBackendContext) {
         for (parameter in function.valueParameters) {
             val kind = when (parameter.origin) {
                 JvmLoweredDeclarationOrigin.FIELD_FOR_OUTER_THIS -> JvmMethodParameterKind.OUTER
+                JvmLoweredDeclarationOrigin.ENUM_CONSTRUCTOR_SYNTHETIC_PARAMETER -> JvmMethodParameterKind.ENUM_NAME_OR_ORDINAL
                 else -> JvmMethodParameterKind.VALUE
             }
             val type = if (forceSingleValueParameterBoxing(function.descriptor)) parameter.type.makeNullable() else parameter.type

compiler/testData/codegen/box/reflection/mapping/types/constructors.kt

@@ -12,10 +12,13 @@ class A(d: Double, s: String, parent: A?) {
     inner class Inner(nested: Nested)
 }
 
+enum class E(val i: Int) { ENTRY(1) }
+
 fun box(): String {
     assertEquals(listOf(java.lang.Double.TYPE, String::class.java, A::class.java), ::A.parameters.map { it.type.javaType })
     assertEquals(listOf(A::class.java), A::Nested.parameters.map { it.type.javaType })
     assertEquals(listOf(A::class.java, A.Nested::class.java), A::Inner.parameters.map { it.type.javaType })
+    assertEquals(listOf(java.lang.Integer.TYPE), E::class.constructors.single().parameters.map { it.type.javaType })
 
     assertEquals(A::class.java, ::A.returnType.javaType)
     assertEquals(A.Nested::class.java, A::Nested.returnType.javaType)