KAPT: Fix an ISE when processing unresolved generic types

Error types that are generic could sometimes throw an ISE when
generating the stub.

This fixes KT-43786

core/descriptors/src/org/jetbrains/kotlin/types/TypeSubstitution.kt

@@ -19,6 +19,10 @@ package org.jetbrains.kotlin.types
 import org.jetbrains.kotlin.descriptors.TypeParameterDescriptor
 import org.jetbrains.kotlin.descriptors.annotations.Annotations
 import org.jetbrains.kotlin.descriptors.annotations.FilteredAnnotations
+import org.jetbrains.kotlin.types.checker.SimpleClassicTypeSystemContext.replaceArguments
+import org.jetbrains.kotlin.types.error.ErrorType
+import org.jetbrains.kotlin.types.error.ErrorUtils
+import org.jetbrains.kotlin.types.model.typeConstructor
 
 abstract class TypeSubstitution {
     companion object {
@@ -171,6 +175,10 @@ fun SimpleType.replace(
         return replaceAttributes(newAttributes)
     }
 
+    if (this is ErrorType) {
+        return replaceArguments(newArguments)
+    }
+
     return KotlinTypeFactory.simpleType(
         newAttributes,
         constructor,

core/descriptors/src/org/jetbrains/kotlin/types/error/ErrorType.kt

@@ -24,8 +24,11 @@ class ErrorType @JvmOverloads internal constructor(
 
     override fun replaceAttributes(newAttributes: TypeAttributes): SimpleType = this
 
+    fun replaceArguments(newArguments: List<TypeProjection>): ErrorType =
+        ErrorType(constructor, memberScope, kind, newArguments, isMarkedNullable, *formatParams)
+
     override fun makeNullableAsSpecified(newNullability: Boolean): SimpleType =
-            ErrorType(constructor, memberScope, kind, arguments, newNullability, *formatParams)
+        ErrorType(constructor, memberScope, kind, arguments, newNullability, *formatParams)
 
     @TypeRefinement
     override fun refine(kotlinTypeRefiner: KotlinTypeRefiner) = this