Comment #0 by bearophile_hugs — 2014-12-16T11:05:52Z
void foo(double function(double) @safe,
double function(double) @safe) {}
void main() {
enum real y = 1;
foo(x => double(y), x => x); // line 5, OK
foo(x => y, x => x); // line 6, Error
}
dmd 2.067alpha gives:
test.d(6,8): Error: function test.foo (double function(double) @safe _param_0, double function(double) @safe _param_1) is not callable using argument types (void, void)
The line 5 is correct because the two given template lambdas match the functions in the 'foo' signature. While the line 6 is not correct because the first lambda template returns a real, that is not compatible with a function that returns a double.
In both lines the second lambda template is correct, but the error message gives a "(void, void)", so if the first lambda template doesn't match, the second isn't even tried. This doesn't help me find what of the two lambdas is the wrong one.
And even for the first lambda template, giving just a "void" when the given lambda template returns a real instead of a double seems excessive.
So ideally I'd like an error message more like:
test.d(6,8): Error: function test.foo(double function(double) @safe _param_0, double function(double) @safe _param_1) is not callable using argument types (real function(double) @safe, double function(double) @safe), the first argument doesn't match
Comment #1 by robert.schadek — 2024-12-13T18:38:29Z