Fix E0805: Extern Types Cannot Have Lifetimes

Wed, 12 Aug 2026 19:56:04 +0800

1. Symptoms

When attempting to declare an extern type with a lifetime annotation, the Rust compiler immediately halts compilation and produces error E0805. The error message clearly indicates that lifetime parameters are prohibited on extern type declarations.

The compiler output typically appears as follows:

error[E0805]: extern types cannot have lifetimes
 --> src/main.rs:3:17
  |
3 | extern "C" { type Foo<'a>; }
  |                      ^^-- lifetime used in type

In more complex scenarios involving multiple lifetime parameters or where the extern type is nested within generic structures, the error message may expand to show the full context of where the invalid lifetime annotation appears:

E0805 on ErrorVault — Developer Error Code Dictionary

Fix E0805: Extern Types Cannot Have Lifetimes

1. Symptoms