bjoernager/rust
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Rollup merge of #87458 - ibraheemdev:help-msg-block-borrow, r=oli-obk

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Fix help message for modification to &T created by &{t}

Previous:
```rust
error[E0594]: cannot assign to `*x` which is behind a `&` reference
 --> src/main.rs:3:5
  |
2 |     let x: &usize = &mut{0};
  |                     ------- help: consider changing this to be a mutable reference: `&mut mut{0}`
3 |     *x = 1;
  |     ^^^^^^ `x` is a `&` reference, so the data it refers to cannot be written
```
This commit is contained in:
Guillaume Gomez 2021-07-26 16:04:36 +02:00 • committed by GitHub
commit f9d00b4a78
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3 changed files with 37 additions and 7 deletions
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10
compiler/rustc_mir/src/borrow_check/diagnostics/mutability_errors.rs
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@ -905,6 +905,8 @@ fn suggest_ampmut<'tcx>(
Some(c) if c.is_whitespace() => true,
// e.g. `&mut(x)`
Some('(') => true,
// e.g. `&mut{x}`
Some('{') => true,
// e.g. `&mutablevar`
_ => false,
}
@ -912,9 +914,7 @@ fn suggest_ampmut<'tcx>(
false
}
};
if let (true, Some(ws_pos)) =
(src.starts_with("&'"), src.find(|c: char| -> bool { c.is_whitespace() }))
{
if let (true, Some(ws_pos)) = (src.starts_with("&'"), src.find(char::is_whitespace)) {
let lt_name = &src[1..ws_pos];
let ty = src[ws_pos..].trim_start();
if !is_mutbl(ty) {
@ -940,9 +940,7 @@ fn suggest_ampmut<'tcx>(
};
if let Ok(src) = tcx.sess.source_map().span_to_snippet(highlight_span) {
if let (true, Some(ws_pos)) =
(src.starts_with("&'"), src.find(|c: char| -> bool { c.is_whitespace() }))
{
if let (true, Some(ws_pos)) = (src.starts_with("&'"), src.find(char::is_whitespace)) {
let lt_name = &src[1..ws_pos];
let ty = &src[ws_pos..];
return (highlight_span, format!("&{} mut{}", lt_name, ty));