On Sunday, 22 March 2015 at 12:58:25 UTC, Stefan Koch wrote:
dmd infers function closures impure if impure functions are
defined within them.
even if those are never called and can never be accessed
outside of the closure.
Example :
int a;
void closure() pure {
impure_function() {
a++;
}
}
t.d(4): Error: pure function 't.closure.impure_function' cannot
access mutable static data 'a'
is this intended ?
I think this was not intended and is simply a side effect of
limited D call graph analysis. Relaxing that limitation makes
sense to me because unused impure function can be used for
compile-time reflection or returned from pure function as a
result (you need to ensure it does not capture pure functions as
closure context in that case)
