Hide type hints for constructor return values

[jplatte]

It would be nice if rust-analyzer could omit the type hint for infallible constructors, for example

let mut builder = MyUsefulThingyBuilder::new();

and maybe for fallible constructors in conjunction with the ? operator too:

let thing = AnotherPrettyLongType::new(arg_a, arg_b)?;

as the type hints can cause the actual expression to go off screen and don't add anything in these cases. I'm not entirely certain what would be good criteria for considering something a constructor, but as a conservative approach only functions returning Self, Option<Self> or Result<Self, E> could be considered. Although IMHO it would be nice for conversions to also not receive type hints if invoked like a constructor:

let x = Type::from(something);
let y = Type::try_from(something)?;

[bjorn3]

Note for implementation: sometimes the new method returns a builder instead of the type itself, so it would be necessary to check for this before ommitting the type hint.

[kjeremy]

Is this just a display issue?

[flodiebold]

I think it's reasonable to leave out the type hint in any instance of the pattern

let x = Type::some_method(...arguments...);

or the same with ? if x is of type Type. Though it becomes more interesting when there are type arguments...

[Veetaha]

As a sidenote, see the configurable heuristics reference of Intelij, where they describe the ways to disable type name hints for certain patterns.