[Bug c++/46220] [4.3/4.4/4.5/4.6 Regression] Error: invalid covariant return type generated for incomplete class type and different qualifer

[redi at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=46220

--- Comment #2 from Jonathan Wakely <redi at gcc dot gnu.org> 2010-10-29 
00:45:26 UTC ---
It certainly is a covariant return type, it meets the criteria in all three
bullet points of 10.3 [class.virtual] p5