Suggest adding & when a lifetime immediately precedes a type in a generic arg list

If one types

fn foo(bar: 'static SomeStruct) { ... }

the compiler could suggest adding a & before the lifetime. This can be more useful in a generic parameter, where a high concentration of special characters makes it easy to not notice the mistake:

fn foo(bar: &mut HashSet<'static SomeStruct>) { ... }

Currently, the error message is just expected one of `,` or `>`, found `SomeStruct` .

I didn't know about this issue but I fixed it in PR #139854 a year ago.

The compiler output now looks like this for your snippet:

error: expected type, found lifetime
 --> src/lib.rs:1:13
  |
1 | fn foo(bar: 'static SomeStruct) {}
  |             ^^^^^^^ expected type
  |
help: you might have meant to write a reference type here
  |
1 | fn foo(bar: &'static SomeStruct) {}
  |             +

Ah but your 2nd example has not been addressed.

Rollup merge of rust-lang#163454 - Tehforsch:fix-lifetime-preceding-t…

Unrolled build for #163454 in rollup 163695

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Suggest adding `&` when a lifetime immediately precedes a type in a generic arg list #59325

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Suggest adding & when a lifetime immediately precedes a type in a generic arg list #59325

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fmease commented on Sep 20, 2026

fmease commented on Sep 20, 2026

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Suggest adding `&` when a lifetime immediately precedes a type in a generic arg list #59325