When tree-transforming an expression sequence, always flag expanded

variadic argument pack expansions as having changed, rather than doing
it for each changed expansion, which leaves out zero-argument packs
with catastrophic consequences.

Fixes PR10260.



git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@134483 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 7 insertions, 5 deletions

diff --git a/lib/Sema/TreeTransform.h b/lib/Sema/TreeTransform.h
index edbf1fb459..66ea7df4ee 100644
--- a/lib/Sema/TreeTransform.h
+++ b/lib/Sema/TreeTransform.h
@@ -1547,9 +1547,9 @@ public:
   /// By default, performs semantic analysis to build the new expression.
   /// Subclasses may override this routine to provide different behavior.
   ExprResult RebuildInitList(SourceLocation LBraceLoc,
-                                   MultiExprArg Inits,
-                                   SourceLocation RBraceLoc,
-                                   QualType ResultTy) {
+                             MultiExprArg Inits,
+                             SourceLocation RBraceLoc,
+                             QualType ResultTy) {
     ExprResult Result
       = SemaRef.ActOnInitList(LBraceLoc, move(Inits), RBraceLoc);
     if (Result.isInvalid() || ResultTy->isDependentType())
@@ -2476,6 +2476,10 @@ bool TreeTransform<Derived>::TransformExprs(Expr **Inputs,
         Outputs.push_back(Out.get());
         continue;
       }
+
+      // Record right away that the argument was changed.  This needs
+      // to happen even if the array expands to nothing.
+      if (ArgChanged) *ArgChanged = true;
       
       // The transform has determined that we should perform an elementwise
       // expansion of the pattern. Do so.
@@ -2492,8 +2496,6 @@ bool TreeTransform<Derived>::TransformExprs(Expr **Inputs,
             return true;
         }
         
-        if (ArgChanged)
-          *ArgChanged = true;  
         Outputs.push_back(Out.get());
       }