each only accepts lambdas that take a single argument

[dlangBugzillaToGithub]

iamthewilsonator (@thewilsonator) reported this on 2018-10-05T06:55:35Z

Transfered from https://issues.dlang.org/show_bug.cgi?id=19287

CC List

• jrdemail2000-dlang

Description

See https://forum.dlang.org/post/tgnnsqkclbcaejhbiprn@forum.dlang.org for the motivation.

struct that contain destructors cannot be closed over (I'm not sure why but thats a different problem) and so 

CantCloseMe o; // some struct with a door
somerange.each!(e => foo(o,e)); //Error: variable `o` has scoped destruction, cannot build closure

fails. But it can't be worked around with 
somerange.each!((e,f) => foo(o,f))(o);

Fails with

Error: template somerange.each!((e,f) => foo(o,f)).each cannot deduce function from argument types !()(SomeRange, CantCloseMe), candidates are:
...

because all of the each functions take only a range or iterable.