On Sunday, 17 December 2017 at 14:44:15 UTC, Alexandru Ermicioi
wrote:
Suppose:
--------
struct F {
static void foo(T)(T i, int o) {}
}
enum bool check(T) = is(F.foo!T == void function(Z, int), Z);
enum correct = check!int;
--------
Upon running it will return false, though, by logic is
expression could deduce that F.foo is conformat to function
signature in check test.
Here, `F.foo!T` is the function itself, not its type. You forgot
`typeof`.
It is interesting that it will not work with global functions
as well:
--------
void foo(int i, double d) {};
enum bool check = is(typeof(foo) == void function(int, double));
--------
It will be as well evaluated to false.
Write `typeof(&foo)` to make it work.
There are two kinds of function types in D:
1) "Proper" function types, e.g. `typeof(foo)` which gets printed
as "void(int i, double d)", and
2) function pointer types, e.g. `typeof(&foo)` which gets printed
as "void function(int i, double d)".
As you see, the second kind is the one you're comparing against.
I don't think you can use the first kind directly in an
IsExpression. The first kind is really rather useless, as far as
I know. Argubaly, the language would be nicer without it.
