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Support Option and similar enums as type of static variable with linkage attribute.

Compiler MCP:
https://github.com/rust-lang/compiler-team/issues/565
This commit is contained in:
Peter Collingbourne 2022-11-23 18:15:50 -08:00
parent 5873ebeef3
commit f44a0153bc
7 changed files with 67 additions and 5 deletions

View file

@ -494,6 +494,7 @@ E0786: include_str!("./error_codes/E0786.md"),
E0787: include_str!("./error_codes/E0787.md"),
E0788: include_str!("./error_codes/E0788.md"),
E0790: include_str!("./error_codes/E0790.md"),
E0791: include_str!("./error_codes/E0791.md"),
;
// E0006, // merged with E0005
// E0008, // cannot bind by-move into a pattern guard

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@ -0,0 +1,41 @@
Static variables with the `#[linkage]` attribute within external blocks
must have one of the following types, which are equivalent to a nullable
pointer in C:
* `*mut T` or `*const T`, where `T` may be any type.
* An enumerator type with no `#[repr]` attribute and with two variants, where
one of the variants has no fields, and the other has a single field of one of
the following non-nullable types:
* Reference type
* Function pointer type
The variants can appear in either order.
For example, the following declaration is invalid:
```compile_fail,E0791
#![feature(linkage)]
extern "C" {
#[linkage = "extern_weak"]
static foo: i8;
}
```
The following declarations are valid:
```
#![feature(linkage)]
extern "C" {
#[linkage = "extern_weak"]
static foo: Option<unsafe extern "C" fn()>;
#[linkage = "extern_weak"]
static bar: Option<&'static i8>;
#[linkage = "extern_weak"]
static baz: *mut i8;
}
```