On 11/01/2013 02:36 PM, Kenji Hara wrote:

I think this is a good discovery. Currently a pure function can have
lazy parameters and it is treated as a weakly pure function.

pure int foo(lazy int x) { return x; }  // OK

We can think the lazy parameter is a limited case of scope delegate
parameter.

...

They are. I think it would be quite strange to treat them differently.

And more, I discovered that the purity may be stronger depends on the
given delegate purity.

void func(scope void delegate(int) dg) pure;

void main() {
     int num;

     // the function call has weak purity
     func((x){ num = x;});

     // the function call has strong purity
     func((x){ ; });
}

Kenji Hara

Yes. Furthermore, the first delegate should have inferred type 'void delegate(int x)pure nothrow @safe' and the second delegate should have inferred type 'void delegate(int x)pure immutable nothrow @safe'.