gcc/testsuite/gdc.test/compilable/test17590.d

   1 // REQUIRED_ARGS: -o-
   2
   3 void lazyfun(scope lazy int a) @nogc;
   4
   5 // Test that returning a local _static_ struct does not lead to allocation of a closure.
   6 auto foo_static(int a, bool b) @nogc {
   7     static struct SInside {}
   8
   9     SInside res;
  10
  11     lazyfun(a);
  12
  13     return res;
  14 }
  15
  16 // Test that returning a local _non-static_ struct that does not reference any local variable does not lead to allocation of a closure.
  17 auto foo_nonstatic(int a, bool b) @nogc {
  18     struct SInside {}
  19
  20     SInside res;
  21
  22     lazyfun(a);
  23
  24     return res;
  25 }
  26
  27 // Test that returning a local non-static struct that references a local variable does lead to allocation of a closure.
  28 static assert(!__traits(compiles, () @nogc => goo(1)));
  29 static assert(__traits(compiles, () => goo(1)));
  30 auto goo(T)(T a) {
  31     struct SInside {
  32         T foo() { return a; }
  33     }
  34
  35     SInside res;
  36
  37     lazyfun(a);
  38
  39     return res;
  40 }