Rollup merge of #35080 - jonathandturner:fix_numeric_expected_found, r=nikomatsakis

Rename _ to {integer} and {float} for unknown numeric types

This PR renames _ to {integer} or {float} for unknown numeric types, to help people parse error messages that have numeric types that haven't been nailed down.

Example:
```rust
fn main() {
    let x: String = 4;
}
```

Before:
```
error[E0308]: mismatched types
 --> quicktest.rs:2:21
  |
2 |     let x: String = 4;
  |                     ^ expected struct `std::string::String`, found integral variable
  |
  = note: expected type `std::string::String`
  = note:    found type `_`

error: aborting due to previous error
```

after:
```
error[E0308]: mismatched types
 --> quicktest.rs:2:21
  |
2 |     let x: String = 4;
  |                     ^ expected struct `std::string::String`, found integral variable
  |
  = note: expected type `std::string::String`
  = note:    found type `{integer}`

error: aborting due to previous error
```
```
This commit is contained in:
Manish Goregaokar 2016-07-30 13:44:46 +05:30 committed by GitHub
commit 26e22b8e2e
35 changed files with 43 additions and 41 deletions

View file

@ -974,7 +974,9 @@ impl fmt::Display for ty::InferTy {
ty::TyVar(ref vid) if print_var_ids => write!(f, "{:?}", vid),
ty::IntVar(ref vid) if print_var_ids => write!(f, "{:?}", vid),
ty::FloatVar(ref vid) if print_var_ids => write!(f, "{:?}", vid),
ty::TyVar(_) | ty::IntVar(_) | ty::FloatVar(_) => write!(f, "_"),
ty::TyVar(_) => write!(f, "_"),
ty::IntVar(_) => write!(f, "{}", "{integer}"),
ty::FloatVar(_) => write!(f, "{}", "{float}"),
ty::FreshTy(v) => write!(f, "FreshTy({})", v),
ty::FreshIntTy(v) => write!(f, "FreshIntTy({})", v),
ty::FreshFloatTy(v) => write!(f, "FreshFloatTy({})", v)