Properly reference type parameter descriptors

'descriptor -> descriptor.original' relation is often inconsistent
wrt 'containingDeclaration', parameters, and type parameters,
we have to introduce some workarounds here.

compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/symbols/impl/IrSymbolBase.kt

@@ -32,10 +32,17 @@ abstract class IrBindableSymbolBase<out D : DeclarationDescriptor, B : IrSymbolO
         assert(isOriginalDescriptor(descriptor)) {
             "Substituted descriptor $descriptor for ${descriptor.original}"
         }
+        if (descriptor !is WrappedDeclarationDescriptor<*>) {
+            val containingDeclaration = descriptor.containingDeclaration
+            assert(containingDeclaration == null || isOriginalDescriptor(containingDeclaration)) {
+                "Substituted containing declaration: $containingDeclaration\nfor descriptor: $descriptor"
+            }
+        }
     }
 
     private fun isOriginalDescriptor(descriptor: DeclarationDescriptor): Boolean =
         descriptor is WrappedDeclarationDescriptor<*> ||
+                // TODO fix declaring/referencing value parameters: compute proper original descriptor
                 descriptor is ValueParameterDescriptor && isOriginalDescriptor(descriptor.containingDeclaration) ||
                 descriptor == descriptor.original
 

compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/util/DeclarationStubGenerator.kt

@@ -24,13 +24,11 @@ import org.jetbrains.kotlin.ir.declarations.impl.IrValueParameterImpl
 import org.jetbrains.kotlin.ir.declarations.lazy.*
 import org.jetbrains.kotlin.ir.descriptors.WrappedDeclarationDescriptor
 import org.jetbrains.kotlin.ir.descriptors.WrappedPropertyDescriptor
-import org.jetbrains.kotlin.ir.expressions.impl.IrConstImpl
 import org.jetbrains.kotlin.ir.expressions.impl.IrErrorExpressionImpl
 import org.jetbrains.kotlin.ir.expressions.impl.IrExpressionBodyImpl
 import org.jetbrains.kotlin.ir.symbols.IrFieldSymbol
 import org.jetbrains.kotlin.ir.symbols.IrSymbol
 import org.jetbrains.kotlin.ir.symbols.IrTypeParameterSymbol
-import org.jetbrains.kotlin.ir.types.*
 import org.jetbrains.kotlin.resolve.BindingContext
 import org.jetbrains.kotlin.resolve.DescriptorUtils
 import org.jetbrains.kotlin.serialization.deserialization.descriptors.DescriptorWithContainerSource

compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/util/TypeTranslator.kt

@@ -14,6 +14,7 @@ import org.jetbrains.kotlin.descriptors.TypeParameterDescriptor
 import org.jetbrains.kotlin.descriptors.annotations.Annotations
 import org.jetbrains.kotlin.ir.declarations.IrTypeParametersContainer
 import org.jetbrains.kotlin.ir.expressions.IrConstructorCall
+import org.jetbrains.kotlin.ir.symbols.IrTypeParameterSymbol
 import org.jetbrains.kotlin.ir.types.IrType
 import org.jetbrains.kotlin.ir.types.IrTypeAbbreviation
 import org.jetbrains.kotlin.ir.types.IrTypeProjection
@@ -54,9 +55,11 @@ class TypeTranslator(
         return result
     }
 
-    private fun resolveTypeParameter(typeParameterDescriptor: TypeParameterDescriptor) =
-        typeParametersResolver.resolveScopedTypeParameter(typeParameterDescriptor)
-            ?: symbolTable.referenceTypeParameter(typeParameterDescriptor)
+    private fun resolveTypeParameter(typeParameterDescriptor: TypeParameterDescriptor): IrTypeParameterSymbol {
+        val originalTypeParameter = typeParameterDescriptor.originalTypeParameter
+        return typeParametersResolver.resolveScopedTypeParameter(originalTypeParameter)
+            ?: symbolTable.referenceTypeParameter(originalTypeParameter)
+    }
 
     fun translateType(kotlinType: KotlinType): IrType =
         translateType(kotlinType, kotlinType, Variance.INVARIANT).type

compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/util/originalDescriptors.kt

@@ -0,0 +1,26 @@
+/*
+ * Copyright 2010-2019 JetBrains s.r.o. and Kotlin Programming Language contributors.
+ * Use of this source code is governed by the Apache 2.0 license that can be found in the license/LICENSE.txt file.
+ */
+
+package org.jetbrains.kotlin.ir.util
+
+import org.jetbrains.kotlin.descriptors.CallableDescriptor
+import org.jetbrains.kotlin.descriptors.ClassifierDescriptorWithTypeParameters
+import org.jetbrains.kotlin.descriptors.TypeParameterDescriptor
+import org.jetbrains.kotlin.ir.descriptors.WrappedTypeParameterDescriptor
+
+val TypeParameterDescriptor.originalTypeParameter: TypeParameterDescriptor
+    get() =
+        if (this is WrappedTypeParameterDescriptor) {
+            original
+        } else {
+            when (val container = containingDeclaration.original) {
+                is ClassifierDescriptorWithTypeParameters ->
+                    container.declaredTypeParameters[index]
+                is CallableDescriptor ->
+                    container.typeParameters[index]
+                else ->
+                    throw AssertionError("Unexpected type parameter container: $container")
+            }
+        }