gcc/testsuite/gdc.test/fail_compilation/ice9406.d

/*
TEST_OUTPUT:
---
fail_compilation/ice9406.d(22): Error: `s1.mixin Mixin!() t1;
` has no effect
---
*/

mixin template Mixin() { }

struct S
{
    template t1()
    {
        mixin Mixin t1;
    }
}

void main()
{
    S s1;
    s1.t1!();
}