ASTDemangler: Fix import-as-member types

When an enum is imported as an error, the imported type itself becomes
a nested type 'Code' of its wrapper type, so you get a type like
'MyError.Code'. However in the mangling grammar the type is a
child of a module and not another type.

This was tripping up TypeDecoder, which would check parent types for
validity and throw out the demangling since it looked invalid.

However since this case really is valid, just skip the whole parent
type mess when the type is imported and non-generic.

Author: slavapestov

lib/AST/ASTDemangler.cpp

@@ -79,6 +79,12 @@ Type ASTBuilder::createNominalType(NominalTypeDecl *decl, Type parent) {
   if (decl->getGenericParams())
     return Type();
 
+  // Imported types can be renamed to be members of other (non-generic)
+  // types, but the mangling does not have a parent type. Just use the
+  // declared type directly in this case and skip the parent check below.
+  if (decl->hasClangNode() && !decl->isGenericContext())
+    return decl->getDeclaredType();
+
   // Validate the parent type.
   if (!validateNominalParent(decl, parent))
     return Type();

test/RemoteAST/Inputs/custom-modules/ErrorEnums.h renamed to test/Inputs/custom-modules/ErrorEnums.h

@@ -1,3 +1,7 @@
 module ObjCRuntimeVisible {
   header "ObjCRuntimeVisible.h"
 }
+
+module ErrorEnums {
+  header "ErrorEnums.h"
+}

test/Inputs/custom-modules/module.map

@@ -1,4 +1,4 @@
-// RUN: %target-swift-remoteast-test-with-sdk -I %S/../ClangImporter/Inputs/custom-modules -I %S/Inputs/custom-modules %s | %FileCheck %s
+// RUN: %target-swift-remoteast-test-with-sdk -I %S/../ClangImporter/Inputs/custom-modules -I %S/../Inputs/custom-modules %s | %FileCheck %s
 
 // REQUIRES: swift-remoteast-test
 // REQUIRES: objc_interop

test/RemoteAST/Inputs/custom-modules/module.modulemap

@@ -0,0 +1,65 @@
+// RUN: %empty-directory(%t)
+
+// RUN: %target-build-swift -I %S/../ClangImporter/Inputs/custom-modules -I %S/../Inputs/custom-modules -emit-executable -emit-module %s -g -o %t/foreign_types
+// RUN: sed -ne '/\/\/ *DEMANGLE: /s/\/\/ *DEMANGLE: *//p' < %s > %t/input
+// RUN: %lldb-moduleimport-test-with-sdk %t/foreign_types -type-from-mangled=%t/input | %FileCheck %s
+
+// REQUIRES: objc_interop
+
+import Foundation
+import CoreCooling
+import ErrorEnums
+
+/*
+do {
+    let x1 = CCRefrigeratorCreate(kCCPowerStandard)
+    let x2 = MyError.good
+    let x3 = MyError.Code.good
+    let x4 = RenamedError.good
+    let x5 = RenamedError.Code.good
+    let x6 = Wrapper.MemberEnum.A
+    let x7 = WrapperByAttribute(0)
+}
+
+do {
+    let x1 = CCRefrigerator.self
+    let x2 = MyError.self
+    let x3 = MyError.Code.self
+    let x4 = RenamedError.self
+    let x5 = RenamedError.Code.self
+    let x6 = Wrapper.MemberEnum.self
+    let x7 = WrapperByAttribute.self
+}
+*/
+
+// DEMANGLE: $sSo17CCRefrigeratorRefaD
+// DEMANGLE: $sSo7MyErrorVD
+// DEMANGLE: $sSo7MyErrorLeVD
+// DEMANGLE: $sSo14MyRenamedErrorVD
+// DEMANGLE: $sSo14MyRenamedErrorLeVD
+// DEMANGLE: $sSo12MyMemberEnumVD
+// DEMANGLE: $sSo18WrapperByAttributeaD
+
+// CHECK: CCRefrigerator
+// CHECK: MyError.Code
+// CHECK: MyError
+// CHECK: RenamedError.Code
+// CHECK: RenamedError
+// CHECK: Wrapper.MemberEnum
+// CHECK: WrapperByAttribute
+
+// DEMANGLE: $sSo17CCRefrigeratorRefamD
+// DEMANGLE: $sSo7MyErrorVmD
+// DEMANGLE: $sSC7MyErrorLeVmD
+// DEMANGLE: $sSo14MyRenamedErrorVmD
+// DEMANGLE: $sSC14MyRenamedErrorLeVmD
+// DEMANGLE: $sSo12MyMemberEnumVmD
+// DEMANGLE: $sSo18WrapperByAttributeamD
+
+// CHECK: CCRefrigerator.Type
+// CHECK: MyError.Code.Type
+// CHECK: MyError.Type
+// CHECK: RenamedError.Code.Type
+// CHECK: RenamedError.Type
+// CHECK: Wrapper.MemberEnum.Type
+// CHECK: WrapperByAttribute.Type