================
@@ -1650,6 +1665,23 @@ namespace {
return inherited::TransformTemplateArgument(Input, Output, Uneval);
}
+ std::optional<unsigned> ComputeSizeOfPackExprWithoutSubstitution(
+ ArrayRef<TemplateArgument> PackArgs) {
+ // Don't do this when rewriting template parameters for CTAD:
+ // 1) The heuristic needs the unpacked Subst* nodes to figure out the
+ // expanded size, but this never applies since Subst* nodes are not
+ // created in rewrite scenarios.
+ //
+ // 2) The heuristic substitutes into the pattern with pack expansion
+ // suppressed, which does not meet the requirements for argument
+ // rewriting when template arguments include a non-pack matching
against
+ // a pack, particularly when rewriting an alias CTAD.
+ if (TemplateArgs.isRewrite())
+ return std::nullopt;
----------------
zyn0217 wrote:
It's not that hard to contrive an example to demonstrate the difference (though
invalid):
```cpp
template < typename... _Types >
struct variant {
template <int N = sizeof...(_Types)>
variant(_Types...);
};
template <class T>
using AstNode = variant<int, int, int>; // <-- Note here!
AstNode tree(42, 43, 44);
```
We still would end up here with a rewrite MLTAL = {int, int, int}, so we fall
through to the normal way and crash because we don't have a valid SubstIndex
for a pack
https://github.com/llvm/llvm-project/pull/132061
_______________________________________________
cfe-commits mailing list
cfe-commits@lists.llvm.org
https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
