Incorrect overflowing literals error with saturating_sub

[bjorn3]

fn main() {
    assert_eq!(i8::min_value(), -128i8);
    println!("{}", -128i8.saturating_sub(-1));
}

(Playground)

Errors:

   Compiling playground v0.0.1 (/playground)
error: literal out of range for `i8`
 --> src/main.rs:3:21
  |
3 |     println!("{}", -128i8.saturating_sub(-1));
  |                     ^^^^^
  |
  = note: #[deny(overflowing_literals)] on by default

error: aborting due to previous error

error: Could not compile `playground`.

To learn more, run the command again with --verbose.

-128 is not out of range for i8, however the lint claims it is. This doesn't happen when printing a plain -128i8 without .saturating_sub. It also doesn't happen when the -128i8 is passed as arg to .saturating_sub.

[bjorn3]

Never mind. Operator precedence was confusing. The - gets applied after calling saturating_sub.

[hellow554]

Could a hint be emitted? E.g.

help: did you mean (-128i8).saturating_sub(-1)?

[Centril]

I'm not in favor of a general lint to suggest parenthesizing -$lit.method() but adding a hint to the existing overflow lint would be fine.

[oli-obk]

This has been solved in #69995