Reduced version of code encountered during a tutorial:

fn main() {
    let x = 0;
    x += 1.0;
}

Compiler error message:

error: the trait bound `_: std::ops::AddAssign<_>` is not satisfied [--explain E0277]
 --> <anon>:3:5
3 |>     x += 1.0;
  |>     ^^^^^^^^
help: the following implementations were found:
help:   <f64 as std::ops::AddAssign>
help:   <f32 as std::ops::AddAssign>
help:   <u64 as std::ops::AddAssign>
help:   <i64 as std::ops::AddAssign>
help: and 21 others

error: aborting due to previous error

Namely, the error message says nothing about i32 nor f64 nor the use of let x = 0;, so a beginner really has no place to go for help here.

Can we leverage the on_unimplemented functionality to provide better feedback in the case where one is mixing i32 and f64? (Or does it not have a way to put in a more specific message depending on the types involved in this case?)

There may be an issue for this elsewhere (we all know that our error messaging when type-inference goes to numeric-fallback), but the error message here was particularly bad, and I couldn't find an existing issue quickly, so I am filing this one to make sure this doesn't fall through the cracks.