[Bug c++/40497] invalid std::next / std::prev declaration

[jason at gcc dot gnu dot org]

------- Comment #20 from jason at gcc dot gnu dot org  2009-07-27 05:46 -------
Actually, no.  It seems that T<X::C> being invalid doesn't result in a SFINAE
situation.

14.9.2/8:
  Only invalid types and expressions in the immediate context of the function
type and its template parameter types can result in a deduction failure. [
Note: The evaluation of the substituted types and expressions can result in
side effects such as the instantiation of class template specializations and/or
function template specializations, the generation of implicitly-defined
functions, etc. Such side effects are not in the “immediate context” and can
result in the program being ill-formed. — end note ]


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=40497