gcc/testsuite/gdc.test/fail_compilation/diag16977.d

/*
TEST_OUTPUT:
---
fail_compilation/diag16977.d(22): Error: undefined identifier `undefined`, did you mean function `undefinedId`?
fail_compilation/diag16977.d(23): Error: cannot implicitly convert expression `"\x01string"` of type `string` to `int`
fail_compilation/diag16977.d(24): Error: template diag16977.templ cannot deduce function from argument types !()(int), candidates are:
fail_compilation/diag16977.d(17):        diag16977.templ(S)(S s) if (false)
fail_compilation/diag16977.d(25): Error: cannot implicitly convert expression `5` of type `int` to `string`
fail_compilation/diag16977.d(27): Error: template instance diag16977.test.funcTemplate!string error instantiating
---
*/

// when copying the expression of a default argument, location information is 
//   replaced by the location of the caller to improve debug information
// verify error messages are displayed for the original location only

string templ(S)(S s) if(false) { return null; }

void test()
{
    // local functions to defer evaluation into semantic3 pass
    void undefinedId(int x, int y = undefined) {}
    void badOp(int x, int y = 1 ~ "string") {}
    void lazyTemplate(int x, lazy int y = 4.templ) {}
    void funcTemplate(T)(T y = 5) {}
    
    funcTemplate!string();
    undefinedId(1);
    badOp(2);
    lazyTemplate(3);
}