On Wed, Mar 14, 2012 at 02:07:04PM -0500, Andrei Alexandrescu wrote:
[...]
> Aha! This is one of those cases in which built-in magic smells of
> putrid beef soup.
[...]
It gets worse than we first thought:
void f1(dstring x) { dstring y = x; }
void f2()(dstring x) { dstring y = x; }
void f2(U)(U x) if (!is(U==string)) { dstring y = x; }
void f3(byte[] x) { byte[] y = x; }
void f4()(byte[] x) { byte[] y = x; }
void f4(U)(U x) if (!is(U==int[])) { byte[] y = x; }
void main() {
f1("abc"); // OK: "abc" deduced as dstring
f2("abc"); // OK: "abc" defaults to string, but f2(U)(U)
// declines U==string, so f2()(dstring) is
// chosen, and "abc" is deduced as dstring
f3([1,2,3]); // OK: [1,2,3] deduced as byte[]
f4([1,2,3]); // Error: template test2.f4() does not match
any function template declaration
// Error: template test2.f4() cannot deduce
template function from argument types !()(int[])
}
WAT?? So "abc" will match f()(dstring x), but [1,2,3] doesn't match
f()(byte[] b)?
Upon further investigation:
void f5(dstring s) {}
void f6()(dstring s) {}
void f7(byte[] s) {}
void f8()(byte[] s) {}
void main() {
f5("abc"); // OK
f6("abc"); // OK (!)
f7([1,2,3]); // OK
f8([1,2,3]); // cannot deduce template function from
argument types !()(int[])
}
WAT?
T
--
"You know, maybe we don't *need* enemies." "Yeah, best friends are about all I
can take." -- Calvin & Hobbes
