AST: Fix NominalType::get() when given a BuiltinTupleDecl

Author: slavapestov

lib/AST/ASTContext.cpp

@@ -3726,7 +3726,9 @@ BoundGenericType *BoundGenericType::get(NominalTypeDecl *TheDecl,
 }
 
 NominalType *NominalType::get(NominalTypeDecl *D, Type Parent, const ASTContext &C) {
-  assert((isa<ProtocolDecl>(D) || !D->getGenericParams()) &&
+  assert((isa<ProtocolDecl>(D) ||
+          isa<BuiltinTupleDecl>(D) ||
+          !D->getGenericParams()) &&
          "must be a non-generic type decl");
   assert((!Parent || Parent->is<NominalType>() ||
           Parent->is<BoundGenericType>() ||
@@ -3742,6 +3744,8 @@ NominalType *NominalType::get(NominalTypeDecl *D, Type Parent, const ASTContext
     return ClassType::get(cast<ClassDecl>(D), Parent, C);
   case DeclKind::Protocol: {
     return ProtocolType::get(cast<ProtocolDecl>(D), Parent, C);
+  case DeclKind::BuiltinTuple:
+    return BuiltinTupleType::get(cast<BuiltinTupleDecl>(D), Parent, C);
   }
 
   default: