diff --git a/clang/lib/Sema/SemaTemplateInstantiate.cpp b/clang/lib/Sema/SemaTemplateInstantiate.cpp
index d75be4b..701be04 100644
--- a/clang/lib/Sema/SemaTemplateInstantiate.cpp
+++ b/clang/lib/Sema/SemaTemplateInstantiate.cpp
@@ -2226,8 +2226,10 @@
   CheckCompletedCXXClass(Instantiation);
 
   // Default arguments are parsed, if not instantiated. We can go instantiate
-  // default arg exprs for default constructors if necessary now.
-  ActOnFinishCXXNonNestedClass(Instantiation);
+  // default arg exprs for default constructors if necessary now. Unless we're
+  // parsing a class, in which case wait until that's finished.
+  if (ParsingClassDepth == 0)
+    ActOnFinishCXXNonNestedClass();
 
   // Instantiate late parsed attributes, and attach them to their decls.
   // See Sema::InstantiateAttrs