trait Bazinga {} impl Bazinga for F {} fn produce1<'a>(data: &'a u32) -> impl Bazinga + 'a { let x = move || { let _data: &'a u32 = data; }; x } fn produce2<'a>(data: &'a mut Vec<&'a u32>, value: &'a u32) -> impl Bazinga + 'a { let x = move || { let value: &'a u32 = value; data.push(value); }; x } fn produce3<'a, 'b: 'a>(data: &'a mut Vec<&'a u32>, value: &'b u32) -> impl Bazinga + 'a { let x = move || { let value: &'a u32 = value; data.push(value); }; x } fn produce_err<'a, 'b: 'a>(data: &'b mut Vec<&'b u32>, value: &'a u32) -> impl Bazinga + 'b { let x = move || { let value: &'a u32 = value; data.push(value); //~ ERROR lifetime may not live long enough }; x } fn main() {}