[Bug ada/50197] Assert_Failure sinfo.adb:2738 with default generic formal parameters

[nicolas.boulenguez at free dot fr]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=50197

--- Comment #2 from nicolas.boulenguez at free dot fr ---
4.8.2 produces the expected result:
a.ads:10:10: unmatched actual "Foo"
a.ads:10:10: in instantiation of "B" declared at line 5