https://gcc.gnu.org/bugzilla/show_bug.cgi?id=59759
--- Comment #14 from Gereon Kremer <gereon.kremer at cs dot rwth-aachen.de> --- I upgraded to 5.3 and sure enough, the bug still fires: $ g++ --version g++ (GCC) 5.3.0 Test_GCC.cpp: In substitution of ‘template<class T> void f(const A<T>*) [with T = <missing>]’: Test_GCC.cpp:25:7: required from here Test_GCC.cpp:25:7: internal compiler error: in unify, at cp/pt.c:18727 f(map);