clang/test/Modules/redecl-templates.cpp

   1 // RUN: rm -rf %t
   2 // RUN: %clang_cc1 -x c++ -I %S/Inputs/redecl-templates %s -verify -std=c++14
   3 // RUN: %clang_cc1 -x c++ -fmodules -fimplicit-module-maps -fmodules-cache-path=%t -I %S/Inputs/redecl-templates %s -verify -std=c++14
   4 // expected-no-diagnostics
   5
   6 template<int N> struct A {};
   7 template<int N> using X = A<N>;
   8
   9 template<int N> constexpr void f() {}
  10 template<int N> constexpr void g() { f<N>(); }
  11
  12 template<int N> extern int v;
  13 template<int N> int &w = v<N>;
  14
  15 #include "a.h"
  16
  17 // Be careful not to mention A here, that'll import the decls from "a.h".
  18 int g(X<1> *);
  19 X<1> *p = 0;
  20
  21 // This will implicitly instantiate A<1> if we haven't imported the explicit
  22 // specialization declaration from "a.h".
  23 int k = g(p);
  24 // Likewise for f and v.
  25 void h() { g<1>(); }
  26 int &x = w<1>;
  27
  28 // This is OK: we declared the explicit specialization before we triggered
  29 // instantiation of this specialization.
  30 template<> struct A<1> {};
  31 template<> constexpr void f<1>() {}
  32 template<> int v<1>;