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impl-trait-redundant-captures leaves + if there are several items #143216

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@matthiaskrgr

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@matthiaskrgr

Using the following flags

--force-warn impl-trait-redundant-captures

this code:

fn a() -> impl Sized + use<> {}
fn b() -> impl use<> + Sized {}

caused the following diagnostics:

    Checking _snippet_0 v0.1.0 (/tmp/icemaker_global_tempdir.BLc4baxM1XwC/icemaker_clippyfix_tempdir.yaIvKRyduqKN/_snippet_0)
warning: all possible in-scope parameters are already captured, so `use<...>` syntax is redundant
 --> src/lib.rs:1:11
  |
1 | fn a() -> impl Sized + use<> {}
  |           ^^^^^^^^^^^^^-----
  |                        |
  |                        help: remove the `use<...>` syntax
  |
  = note: requested on the command line with `--force-warn impl-trait-redundant-captures`

warning: all possible in-scope parameters are already captured, so `use<...>` syntax is redundant
 --> src/lib.rs:2:11
  |
2 | fn b() -> impl use<> + Sized {}
  |           ^^^^^-----^^^^^^^^
  |                |
  |                help: remove the `use<...>` syntax

warning: `_snippet_0` (lib) generated 2 warnings (run `cargo clippy --fix --lib -p _snippet_0` to apply 2 suggestions)
    Finished `dev` profile [unoptimized + debuginfo] target(s) in 0.14s

However after applying these diagnostics, the resulting code:

fn a() -> impl Sized +  {}
fn b() -> impl  + Sized {}

no longer compiled:

    Checking _snippet_0 v0.1.0 (/tmp/icemaker_global_tempdir.BLc4baxM1XwC/icemaker_clippyfix_tempdir.yaIvKRyduqKN/_snippet_0)
error[E0178]: expected a path on the left-hand side of `+`
 --> src/lib.rs:2:11
  |
2 | fn b() -> impl  + Sized {}
  |           ^^^^ expected a path

error: at least one trait must be specified
 --> src/lib.rs:2:11
  |
2 | fn b() -> impl  + Sized {}
  |           ^^^^

For more information about this error, try `rustc --explain E0178`.
error: could not compile `_snippet_0` (lib test) due to 2 previous errors
warning: build failed, waiting for other jobs to finish...
error: could not compile `_snippet_0` (lib) due to 2 previous errors

Version:

rustc 1.90.0-nightly (ed2d75978 2025-06-29)
binary: rustc
commit-hash: ed2d759783dc9de134bbb3f01085b1e6dbf539f3
commit-date: 2025-06-29
host: x86_64-unknown-linux-gnu
release: 1.90.0-nightly
LLVM version: 20.1.7

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    A-suggestion-diagnosticsArea: Suggestions generated by the compiler applied by `cargo fix`C-bugCategory: This is a bug.D-invalid-suggestionDiagnostics: A structured suggestion resulting in incorrect code.D-papercutDiagnostics: An error or lint that needs small tweaks.T-compilerRelevant to the compiler team, which will review and decide on the PR/issue.

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