If a parameter has a default argument expression, make sure to instantiate the parameter type before checking that the expression is a valid initializer.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@79986 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Sema/SemaDeclCXX.cpp b/lib/Sema/SemaDeclCXX.cpp
index c30b974..0dbefe1 100644
--- a/lib/Sema/SemaDeclCXX.cpp
+++ b/lib/Sema/SemaDeclCXX.cpp
@@ -107,6 +107,12 @@
 {
   QualType ParamType = Param->getType();
 
+  if (RequireCompleteType(Param->getLocation(), Param->getType(),
+                          diag::err_typecheck_decl_incomplete_type)) {
+    Param->setInvalidDecl();
+    return true;
+  }
+
   Expr *Arg = (Expr *)DefaultArg.get();
   
   // C++ [dcl.fct.default]p5