// DR 743: A type without linkage shall not be used as the type of a // variable or function with linkage, unless // o the variable or function has extern "C" linkage (7.5 [dcl.link]), or // o the variable or function is not used (3.2 [basic.def.odr]) or is // defined in the same translation unit. // { dg-do compile { target c++11 } } template struct B { void g(T){} void h(T); // { dg-error "never defined" } friend void i(B, T){} static T t1; // { dg-error "never defined" } static T t2; }; template T B::t2 = { }; enum { E1 } e1; // OK, defined extern enum { E2 } e2; // { dg-error "never defined" } extern "C" enum { E3 } e3; // OK, extern "C" void f() { struct A { int x; }; // no linkage A a = {1}; B ba; // declares B::g(A) and B::h(A) ba.t1 = a; // error, B::t never defined ba.t2 = a; // OK ba.g(a); // OK ba.h(a); // error, B::h never defined i(ba, a); // OK e1+e2+e3; }