[Bug c++/52718] -Wzero-as-null-pointer-constant: misleading location for 0 as default argument

[jason at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=52718

--- Comment #4 from Jason Merrill <jason at gcc dot gnu.org> 2012-03-29 
16:18:34 UTC ---
Since "The names in the default argument are bound, and the semantic
constraints are checked, at the point where the default argument appears" I
think it makes sense to give this warning at that point as well.