PR24440: Do not silently discard a fold-expression appearing as the operand of a cast-expression.

llvm-svn: 295224

1 files changed, 7 insertions, 0 deletions

diff --git a/clang/lib/Sema/SemaTemplateVariadic.cpp b/clang/lib/Sema/SemaTemplateVariadic.cpp
index 4ea04ac143a..9f572007d8a 100644
--- a/clang/lib/Sema/SemaTemplateVariadic.cpp
+++ b/clang/lib/Sema/SemaTemplateVariadic.cpp
@@ -1015,6 +1015,11 @@ ExprResult Sema::ActOnCXXFoldExpr(SourceLocation LParenLoc, Expr *LHS,
   CheckFoldOperand(*this, LHS);
   CheckFoldOperand(*this, RHS);
 
+  auto DiscardOperands = [&] {
+    CorrectDelayedTyposInExpr(LHS);
+    CorrectDelayedTyposInExpr(RHS);
+  };
+
   // [expr.prim.fold]p3:
   //   In a binary fold, op1 and op2 shall be the same fold-operator, and
   //   either e1 shall contain an unexpanded parameter pack or e2 shall contain
@@ -1022,6 +1027,7 @@ ExprResult Sema::ActOnCXXFoldExpr(SourceLocation LParenLoc, Expr *LHS,
   if (LHS && RHS &&
       LHS->containsUnexpandedParameterPack() ==
           RHS->containsUnexpandedParameterPack()) {
+    DiscardOperands();
     return Diag(EllipsisLoc,
                 LHS->containsUnexpandedParameterPack()
                     ? diag::err_fold_expression_packs_both_sides
@@ -1035,6 +1041,7 @@ ExprResult Sema::ActOnCXXFoldExpr(SourceLocation LParenLoc, Expr *LHS,
   if (!LHS || !RHS) {
     Expr *Pack = LHS ? LHS : RHS;
     assert(Pack && "fold expression with neither LHS nor RHS");
+    DiscardOperands();
     if (!Pack->containsUnexpandedParameterPack())
       return Diag(EllipsisLoc, diag::err_pack_expansion_without_parameter_packs)
              << Pack->getSourceRange();