https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96309
Bug ID: 96309
Summary: Substitution failure doesn't propagate through the
typename of a template value parameter
Product: gcc
Version: 9.3.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: 171044 at vutbr dot cz
Target Milestone: ---
Created attachment 48923
--> https://gcc.gnu.org/bugzilla/attachment.cgi?id=48923&action=edit
Source code
When a substitution failure takes place in the default of a template type
parameter (as presented in the namespace conformant), everything works as
expected - the candidate is dismissed and the instantiation fails.
However, when the substitution failure takes place in the typename of a
template value parameter (as presented in the namespace defective), it behaves
in a non-standard manner - the candidate isn't dismissed and the instantiation
doesn't fail.
The enclosed source code compiles even though it shouldn't.
https://godbolt.org/z/Gs6e85
