In-band lifetimes were mixed with explicit lifetime binders.
Erroneous code example:
#![feature(in_band_lifetimes)]
fn foo<'a>(x: &'a u32, y: &'b u32) {} // error!
struct Foo<'a> { x: &'a u32 }
impl Foo<'a> {
fn bar<'b>(x: &'a u32, y: &'b u32, z: &'c u32) {} // error!
}
impl<'b> Foo<'a> { // error!
fn baz() {}
}In-band lifetimes cannot be mixed with explicit lifetime binders. For example:
fn foo<'a, 'b>(x: &'a u32, y: &'b u32) {} // ok!
struct Foo<'a> { x: &'a u32 }
impl<'a> Foo<'a> {
fn bar<'b,'c>(x: &'a u32, y: &'b u32, z: &'c u32) {} // ok!
}
impl<'a> Foo<'a> { // ok!
fn baz() {}
}