[rustc.git] / src / librustc_error_codes / error_codes / E0687.md

In-band lifetimes cannot be used in `fn`/`Fn` syntax.

Erroneous code examples:

```compile_fail,E0687
#![feature(in_band_lifetimes)]

fn foo(x: fn(&'a u32)) {} // error!

fn bar(x: &Fn(&'a u32)) {} // error!

fn baz(x: fn(&'a u32), y: &'a u32) {} // error!

struct Foo<'a> { x: &'a u32 }

impl Foo<'a> {
    fn bar(&self, x: fn(&'a u32)) {} // error!
}
```

Lifetimes used in `fn` or `Fn` syntax must be explicitly
declared using `<...>` binders. For example:

```
fn foo<'a>(x: fn(&'a u32)) {} // ok!

fn bar<'a>(x: &Fn(&'a u32)) {} // ok!

fn baz<'a>(x: fn(&'a u32), y: &'a u32) {} // ok!

struct Foo<'a> { x: &'a u32 }

impl<'a> Foo<'a> {
    fn bar(&self, x: fn(&'a u32)) {} // ok!
}
```
Commit	Line	Data
f035d41b XL	1	In-band lifetimes cannot be used in `fn`/`Fn` syntax.
	2
	3	Erroneous code examples:
	4
	5	```compile_fail,E0687
	6	#![feature(in_band_lifetimes)]
	7
	8	fn foo(x: fn(&'a u32)) {} // error!
	9
	10	fn bar(x: &Fn(&'a u32)) {} // error!
	11
	12	fn baz(x: fn(&'a u32), y: &'a u32) {} // error!
	13
	14	struct Foo<'a> { x: &'a u32 }
	15
	16	impl Foo<'a> {
	17	fn bar(&self, x: fn(&'a u32)) {} // error!
	18	}
	19	```
	20
	21	Lifetimes used in `fn` or `Fn` syntax must be explicitly
	22	declared using `<...>` binders. For example:
	23
	24	```
	25	fn foo<'a>(x: fn(&'a u32)) {} // ok!
	26
	27	fn bar<'a>(x: &Fn(&'a u32)) {} // ok!
	28
	29	fn baz<'a>(x: fn(&'a u32), y: &'a u32) {} // ok!
	30
	31	struct Foo<'a> { x: &'a u32 }
	32
	33	impl<'a> Foo<'a> {
	34	fn bar(&self, x: fn(&'a u32)) {} // ok!
	35	}
	36	```