gcc/testsuite/gdc.test/fail_compilation/test21380.d

   1 // https://issues.dlang.org/show_bug.cgi?id=21380
   2 /*
   3 TEST_OUTPUT:
   4 ---
   5 fail_compilation/test21380.d(39): Error: partial template instance `MySerializer().serializeSinkType!int` has no value
   6 fail_compilation/test21380.d(44): Error: template instance `test21380.SupportSinkTypeSer!(MySerializer!int)` error instantiating
   7 ---
   8 */
   9
  10 template isSomeFunction(T...)
  11 if (T.length == 1)
  12 {
  13     static if (is(typeof(& T[0]) U : U*) && is(U == function) || is(typeof(& T[0]) U == delegate))
  14     {
  15         // T is a (nested) function symbol.
  16         enum bool isSomeFunction = true;
  17     }
  18     else static if (is(T[0] W) || is(typeof(T[0]) W))
  19     {
  20         // T is an expression or a type.  Take the type of it and examine.
  21         static if (is(W F : F*) && is(F == function))
  22             enum bool isSomeFunction = true; // function pointer
  23         else
  24             enum bool isSomeFunction = is(W == function) || is(W == delegate);
  25     }
  26     else
  27         enum bool isSomeFunction = false;
  28 }
  29
  30 struct MySerializer (T)
  31 {
  32         void serializeSinkType(T2) (scope auto ref T2 record) {}
  33 }
  34
  35 template SupportSinkTypeSer(SerT)
  36 {
  37     /* Note: Partial template instance because it needs inference, in this case
  38        it cannot infer 'auto ref' parameter */
  39         enum SupportSinkTypeSer = isSomeFunction!(SerT.init.serializeSinkType!int);
  40 }
  41
  42 int main()
  43 {
  44         enum x = SupportSinkTypeSer!(MySerializer!int);
  45         return 0;
  46 }