On 12/31/2015 11:04 AM, Nathan Sidwell wrote:
Jason, https://gcc.gnu.org/bugzilla/show_bug.cgi?id=58583It's noticed that the testcase passes with enable-checking build but fails with enable-checking=release. Looking at what is happening, I think the checking build is changing the instantiation point of a template. The failure manifests in this snippet: template<int> struct A // { dg-error "has been parsed" } { int i = (A<0>(), 0); // { dg-error "has been parsed" } }; with a checking build we get the two diagnostics. That's due to the following bit of build_non_dependent_expr (pt.c) /* Try to get a constant value for all non-dependent expressions in order to expose bugs in *_dependent_expression_p and constexpr. */ if (flag_checking && cxx_dialect >= cxx11) fold_non_dependent_expr (expr); Notice the 'flag_checking' check. It's trying to fold the functional cast 'A<0> ()'. That is a non-dependent expression, because 'A<0>' is non-dependent (no no bug in *_D_E_p). The instantiation fails though, because we want the default ctor, but that requires a completed NSDMI. Requiring an instantiation (for instance, declaring a global var of type 'A<0>') causes the release build to issue a 'recursive instantiation' diagnostic (on the NSDMI line). I suppose I can add dg-bogus and/or xfails to get the testcase to not fail on either build, but the change in instantiation point worries me. thoughts?
Maybe disable the fold if parsing_nsdmi()? Jason
