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Rollup merge of #129408 - Urgau:macro-arg-drop_copy, r=compiler-errors

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Fix handling of macro arguments within the `dropping_copy_types` lint

This PR fixes the handling of spans with different context (aka macro arguments) than the primary expression within the different `{drop,forget}ing_copy_types` and `{drop,forget}ing_references` lints.

<details>
<summary>Before</summary>

```
warning: calls to `std::mem::drop` with a value that implements `Copy` does nothing
 --> drop_writeln.rs:5:5
  |
5 |     drop(writeln!(&mut msg, "test"));
  |     ^^^^^--------------------------^
  |          |
  |          argument has type `Result<(), std::fmt::Error>`
  |
  = note: `#[warn(dropping_copy_types)]` on by default
help: use `let _ = ...` to ignore the expression or result
 --> /home/[..]/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/core/src/macros/mod.rs:688:9
  |
68|         let _ =
  |         ~~~~~~~
```

</details>

<details>
<summary>With this PR</summary>

```
warning: calls to `std::mem::drop` with a value that implements `Copy` does nothing
 --> drop_writeln.rs:5:5
  |
5 |     drop(writeln!(&mut msg, "test"));
  |     ^^^^^--------------------------^
  |          |
  |          argument has type `Result<(), std::fmt::Error>`
  |
  = note: `#[warn(dropping_copy_types)]` on by default
help: use `let _ = ...` to ignore the expression or result
  |
5 -     drop(writeln!(&mut msg, "test"));
5 +     let _ = writeln!(&mut msg, "test");
  |
```

</details>

``````@rustbot`````` label +L-dropping_copy_types
This commit is contained in:
Guillaume Gomez 2024-08-23 12:32:16 +02:00 • committed by GitHub
commit 81aca633bb
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4 changed files with 48 additions and 2 deletions
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5
compiler/rustc_lint/src/drop_forget_useless.rs
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@ -151,10 +151,11 @@ impl<'tcx> LateLintPass<'tcx> for DropForgetUseless {
&& let Node::Stmt(stmt) = node
&& let StmtKind::Semi(e) = stmt.kind
&& e.hir_id == expr.hir_id
&& let Some(arg_span) = arg.span.find_ancestor_inside(expr.span)
{
UseLetUnderscoreIgnoreSuggestion::Suggestion {
start_span: expr.span.shrink_to_lo().until(arg.span),
end_span: arg.span.shrink_to_hi().until(expr.span.shrink_to_hi()),
start_span: expr.span.shrink_to_lo().until(arg_span),
end_span: arg_span.shrink_to_hi().until(expr.span.shrink_to_hi()),
}
} else {
UseLetUnderscoreIgnoreSuggestion::Note