File: match-ref-mut-invariance.rs

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rustc 1.85.0%2Bdfsg2-3
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// Check that when making a ref mut binding with type `&mut T`, the
// type `T` must match precisely the type `U` of the value being
// matched, and in particular cannot be some supertype of `U`. Issue
// #23116. This test focuses on a `match`.

#![allow(dead_code)]
struct S<'b>(&'b i32);
impl<'b> S<'b> {
    fn bar<'a>(&'a mut self) -> &'a mut &'a i32 {
        match self.0 { ref mut x => x }
        //~^ ERROR lifetime may not live long enough
    }
}

fn main() {}