message: Switch to the new underlying type API
  Supports apple/swift#27172
diff: @@ -4412,7 +4412,7 @@ static CompilerType ValueDeclToType(swift::ValueDecl *decl,
  if (alias_decl->hasInterfaceType()) {
  swift::Type swift_type = swift::TypeAliasType::get(
  alias_decl, swift::Type(), swift::SubstitutionMap(),
  - alias_decl->getUnderlyingTypeLoc().getType());
  + alias_decl->getUnderlyingType());
  return {swift_type.getPointer()};
  }
  break;
  @@ -4474,7 +4474,7 @@ static SwiftASTContext::TypeOrDecl DeclToTypeOrDecl(swift::ASTContext *ast,
  if (alias_decl->hasInterfaceType()) {
  swift::Type swift_type = swift::TypeAliasType::get(
  alias_decl, swift::Type(), swift::SubstitutionMap(),
  - alias_decl->getUnderlyingTypeLoc().getType());
  + alias_decl->getUnderlyingType());
  return CompilerType(swift_type.getPointer());
  }
  } break;
  