rust-lang / rust-lang/rust

Resolve elided lifetimes in extern/foreign statics to `'static`

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A-FFI A-lifetimes C-enhancement T-lang
Dominant language
Rust
Stars
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Description

The following code gives compiler error.

unsafe extern "C" {
    static WORLD: &str;
}
error[E0106]: missing lifetime specifier
 --> src\bin\runner.rs:6:24
  |
6 |     static WORLD: &str;
  |                   ^ expected named lifetime parameter

For more information about this error, try `rustc --explain E0106`.
error: could not compile `extern_test` (bin "runner") due to 1 previous error

What I expected: The compiler should automatically infer the lifetime of WORLD as 'static.

The bug is still there in nightly toolchain.

P.S. The imported library is a rust cdylib compiled together (and with the same compiler version).

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Research direction

Reproduce the issue from src\bin\runner.rs using the shown unsafe extern "C" declaration on a nightly toolchain, then trace the E0106 diagnostic for the elided lifetime. Done means the extern static declaration compiles with its lifetime inferred as 'static and the relevant compiler tests pass.

Written by the indexing model from the issue text.

Assessment

Tech stack
rust
Domain
compilers
Issue type
Bug
Difficulty
4/5
Estimated time
3-5 days
Activity status
Stale
Clarity
Mostly clear
Newbie friendliness
35/100

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