Do not show default types in function and closure return values

[SomeoneToIgnore]

Avoid things like

[GrayJack]

I actually like that it shows up the default types

[SomeoneToIgnore]

Do you know any other cases when they are displayed? I'll gladly remove those too 😄

I personally don't think we should display the default generics at all, since they bloat the hints significantly with no immediate bonus to the reader.
Additionally, hover can display those already:

If you still want to display those in the hints, I think we'd better come up with a separate issue and good design due to the following reasons:

• Inline type hints could become too long sometimes #1946, Optimize the user experience when line gets too long after inlay hints are inserted. #3138 — a number of people have an opposite opinion and don't want extra hints displayed
• this particular PR only polishes the work that had started on omitting the default types: Omit default parameter types #2594, Omit default parameters for references #2894, Omit closure parameters in closure type display strings #2657 and changing it back would require some effort
• ideally, we should discuss other display option: display type aliases or types, shorten iterator types like Flatten<Chain<Chain<Once<Map<{unknown}, fn to_string<{unknown}>(&{unknown}) -> String>>, {unknown}>, Once<Option<String>>>> into impl Iterator<Item = String> or not, display closure parameters or not, etc., etc., etc.

[GrayJack]

I personally don't think we should display the default generics at all, since they bloat the hints significantly with no immediate bonus to the reader.

Yeah, agree with that, that it should not show them in the inlay hints, I misinterpreted and thought you mean not show then at all in any form of hints, hover or inlay

[matklad]

bors r+

[bors]

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