More clearly Error Message: Calculating with different types

[StefanoD]

This yields with rust 1.9

let result = -0.25 % 2;

following error message:

:7:18: 7:27 error: the trait bound _: std::ops::Rem<_> is not satisfied [E0277]
:7 let result = -0.25 % 2;
^~~~~~~~~
:7:18: 7:27 help: see the detailed explanation for E0277
:7:18: 7:27 help: the following implementations were found:
:7:18: 7:27 help:
:7:18: 7:27 help: <&'a f64 as std::ops::Rem>
:7:18: 7:27 help: <f64 as std::ops::Rem<&'a f64>>
:7:18: 7:27 help: <&'b f64 as std::ops::Rem<&'a f64>>
:7:18: 7:27 help: and 54 others
error: aborting due to previous error

This is the fix:

let result = -0.25 % 2.0;

This is a really compilicated error message for the fact, that calucating with different types are not allowed.

[brson]

cc @jonathandturner

[sophiajt]

cc @nikomatsakis - who was thinking about better type error reporting

[Mark-Simulacrum]

Fixed today, I think. We don't give a suggestion as to float % float but I don't really think that's feasible.

rustc 1.19.0-dev (5dfcd85fd 2017-05-19)
error[E0277]: the trait bound `{float}: std::ops::Rem<{integer}>` is not satisfied
 --> test.rs:2:14
  |
2 | let result = -0.25 % 2;}
  |              ^^^^^^^^^ the trait `std::ops::Rem<{integer}>` is not implemented for `{float}`
  |
  = note: no implementation for `{float} % {integer}`

error: aborting due to previous error