Reapply 81096, now with a fix. Spot the bug:

      for (unsigned i = numargs; i < NumArgs; ++i)
        Args[0] = 0;

;)


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@81123 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/AST/ExprCXX.cpp b/lib/AST/ExprCXX.cpp
index 0ffb152..c532b8c 100644
--- a/lib/AST/ExprCXX.cpp
+++ b/lib/AST/ExprCXX.cpp
@@ -403,6 +403,8 @@
       Args = new (C) Stmt*[NumArgs];
       for (unsigned i = 0; i < numargs; ++i)
         Args[i] = args[i];
+      for (unsigned i = numargs; i < NumArgs; ++i)
+        Args[i] = 0;
     }
 }
 
diff --git a/lib/Sema/SemaDeclCXX.cpp b/lib/Sema/SemaDeclCXX.cpp
index 3ee40e8..89acfd1 100644
--- a/lib/Sema/SemaDeclCXX.cpp
+++ b/lib/Sema/SemaDeclCXX.cpp
@@ -2899,8 +2899,8 @@
                                         QualType DeclInitType, 
                                         Expr **Exprs, unsigned NumExprs) {
   OwningExprResult TempResult = 
-    BuildCXXConstructExpr(/*FIXME: ConstructLoc*/ SourceLocation(),
-                          DeclInitType, Constructor, Exprs, NumExprs);
+    BuildCXXConstructExpr(VD->getLocation(), DeclInitType, Constructor, 
+                          Exprs, NumExprs);
   if (TempResult.isInvalid())
     return true;
   
diff --git a/test/SemaTemplate/default-expr-arguments.cpp b/test/SemaTemplate/default-expr-arguments.cpp
index 925d52f..d689cc8 100644
--- a/test/SemaTemplate/default-expr-arguments.cpp
+++ b/test/SemaTemplate/default-expr-arguments.cpp
@@ -20,7 +20,7 @@
 }
 
 template<typename T> struct F {
-  F(T t = 10);
+  F(T t = 10); // expected-error{{cannot initialize 't' with an rvalue of type 'int'}}
   void f(T t = 10); // expected-error{{cannot initialize 't' with an rvalue of type 'int'}}
 };
 
@@ -34,6 +34,9 @@
 void g3(F<int> f, F<struct S> s) {
   f.f();
   s.f(); // expected-note{{in instantiation of default function argument expression for 'f<struct S>' required here}}
+  
+  F<int> f2;
+  F<S> s2; // expected-note{{in instantiation of default function argument expression for 'F<struct S>' required here}}
 }
 
 template<typename T> struct G {