diff --git a/src/librustc/error_codes.rs b/src/librustc/error_codes.rs index 968b0b9f2f2b7..8b9797f8025fd 100644 --- a/src/librustc/error_codes.rs +++ b/src/librustc/error_codes.rs @@ -1580,6 +1580,47 @@ where ``` "##, +E0495: r##" +A lifetime cannot be determined in the given situation. + +Erroneous code example: + +```compile_fail,E0495 +fn transmute_lifetime<'a, 'b, T>(t: &'a (T,)) -> &'b T { + match (&t,) { // error! + ((u,),) => u, + } +} + +let y = Box::new((42,)); +let x = transmute_lifetime(&y); +``` + +In this code, you have two ways to solve this issue: + 1. Enforce that `'a` lives at least as long as `'b`. + 2. Use the same lifetime requirement for both input and output values. + +So for the first solution, you can do it by replacing `'a` with `'a: 'b`: + +``` +fn transmute_lifetime<'a: 'b, 'b, T>(t: &'a (T,)) -> &'b T { + match (&t,) { // ok! + ((u,),) => u, + } +} +``` + +In the second you can do it by simply removing `'b` so they both use `'a`: + +``` +fn transmute_lifetime<'a, T>(t: &'a (T,)) -> &'a T { + match (&t,) { // ok! + ((u,),) => u, + } +} +``` +"##, + E0496: r##" A lifetime name is shadowing another lifetime name. Erroneous code example: @@ -2275,8 +2316,6 @@ rejected in your own crates. E0488, // lifetime of variable does not enclose its declaration E0489, // type/lifetime parameter not in scope here E0490, // a value of type `..` is borrowed for too long - E0495, // cannot infer an appropriate lifetime due to conflicting - // requirements E0566, // conflicting representation hints E0623, // lifetime mismatch where both parameters are anonymous regions E0628, // generators cannot have explicit parameters