rust/rustc_typeck at 89c98cd6b4d92e0237a91eb18754d03dbe64fb6a - rust

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History

Rollup merge of #78063 - camelid:improve-cannot-multiply-error, r=estebank

Improve wording of "cannot multiply" type error

For example, if you had this code:

    fn foo(x: i32, y: f32) -> f32 {
        x * y
    }

You would get this error:

    error[E0277]: cannot multiply `f32` to `i32`
     --> src/lib.rs:2:7
      |
    2 |     x * y
      |       ^ no implementation for `i32 * f32`
      |
      = help: the trait `Mul<f32>` is not implemented for `i32`

However, that's not usually how people describe multiplication. People
usually describe multiplication like how the division error words it:

    error[E0277]: cannot divide `i32` by `f32`
     --> src/lib.rs:2:7
      |
    2 |     x / y
      |       ^ no implementation for `i32 / f32`
      |
      = help: the trait `Div<f32>` is not implemented for `i32`

So that's what this change does. It changes this:

    error[E0277]: cannot multiply `f32` to `i32`
     --> src/lib.rs:2:7
      |
    2 |     x * y
      |       ^ no implementation for `i32 * f32`
      |
      = help: the trait `Mul<f32>` is not implemented for `i32`

To this:

    error[E0277]: cannot multiply `i32` by `f32`
     --> src/lib.rs:2:7
      |
    2 |     x * y
      |       ^ no implementation for `i32 * f32`
      |
      = help: the trait `Mul<f32>` is not implemented for `i32`

2020-10-21 13:59:39 +09:00

src

Rollup merge of #78063 - camelid:improve-cannot-multiply-error, r=estebank

2020-10-21 13:59:39 +09:00

Cargo.toml

Replace some trivial struct_span_err!s in typeck.

2020-09-01 23:05:56 +10:00

README.md

…

README.md

For high-level intro to how type checking works in rustc, see the type checking chapter of the rustc dev guide.