Consider warning for struct/enum constructors without effect.

[Kimundi]

struct Warns;
struct WarnsNot1 { a: uint }
struct WarnsNot2(uint);

fn main() {
    Warns;
    WarnsNot1 { a: 0 };
    WarnsNot2(0u);
}

This produces a #[warn(path_statement)] warning for the Warns statement, but not for the WarnsNotX statements.

This is somewhat understandable, as the later two can have side effects as part of evaluating their arguments, and also expected of functions in general.

But it might be useful to have a lint for struct and enum constructors whose result is discarded like this.

[SiegeLord]

Isn't this the same situation as ignoring function returns? To that end, I'd imagine you would simply decorate the two structs with #[must_use].

[Kimundi]

@SiegeLord: Well, both structs constructors have no side effects and only exist to return a value. So I guess what I want is something like #[must_use] automatically applied to all of them :P

[sanxiyn]

Implemented in Clippy.