On Wednesday, 11 April 2018 at 14:33:06 UTC, Adam D. Ruppe wrote:
On Wednesday, 11 April 2018 at 14:26:53 UTC, ixid wrote:
Is it possible to infer a template's return type from what
it's assigned to? If not is this a difficult or worthless
feature to add?
Not really. The function call needs to make sense by itself:
needs to be a complete thing for a lot of things in the
language to work. Type checking assumes it is there, inference
assumes it is there, overloading assumes it s there, etc.
foo(fun(a)); // what happens?
So I don't say anything is impossible that isn't a paradox...
but the effort level to solve all these problems would be
really high for D.
I am sure there are all sorts of thorns involved but for your
example a somewhat arbitrarily defined fallback hierarchy of
types from most complex to most simple, with it matching the most
'simple' that it can.