Rakete1111 added inline comments.
================ Comment at: test/CXX/concepts-ts/temp/temp.constr/temp.constr.decl/var-template-decl.cpp:10 + +template <typename U> requires bool(U()) +int B::A = int(U()); ---------------- Quuxplusone wrote: > saar.raz wrote: > > Quuxplusone wrote: > > > For my own edification, could you explain whether, given > > > > > > #define BOOL bool > > > using typedef_for_bool = bool; > > > > > > you'd expect to diagnose a redeclaration of `B::A` with associated > > > constraint > > > > > > requires bool( U() ) // extra whitespace > > > > > > or > > > > > > requires BOOL(U()) // different spelling of `bool` > > > > > > or > > > > > > requires typedef_for_bool(U()) // different spelling of `bool` > > > > > > ? My naive reading of N4762 temp.constr.atomic/2 says that none of these > > > constraints (on line 10) would be "identical" to the constraint on line > > > 6... but then I don't understand what's the salient difference between > > > line 10 (which apparently gives no error) and line 22 (which apparently > > > gives an error). > > Line 22 has a not (!) operator in front of the bool(), I guess you missed > > that? > I saw the `!`... but I don't understand how the compiler "knows" that > `!bool(U())` is "different" from `bool(T())` in a way that doesn't equally > apply to `bool(U())`. > > Or suppose the constraint on line 10 was `requires bool(U())==true`... would > that give a diagnostic? `bool(T())` and `bool(U())` are identical because they have the same parameter mappings. The "identical" requirement applies to the actual grammar composition of the expression, so `bool(T())` would be different to `bool(T()) == true`. At least that's how I understand it. Repository: rC Clang https://reviews.llvm.org/D41284 _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org http://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
