diff --git a/src/librustc_error_codes/error_codes/E0631.md b/src/librustc_error_codes/error_codes/E0631.md index ad419f82250cc..6188d5f61a7f9 100644 --- a/src/librustc_error_codes/error_codes/E0631.md +++ b/src/librustc_error_codes/error_codes/E0631.md @@ -3,27 +3,25 @@ This error indicates a type mismatch in closure arguments. Erroneous code example: ```compile_fail,E0631 -fn test_strings(string_vec: Vec) -> Vec { - string_vec - .iter() - .map(|arg: &i32| arg.eq("Test String")) - .collect() +fn foo(f: F) { +} + +fn main() { + foo(|x: &str| {}); } ``` -The closure passed to `map` expects a `&String` argument, since `some_vec` -has the type `Vec`. -However, the closure argument is annotated as an `&i32`, which does not match -the type of the iterable. +The error occurs because `foo` accepts a closure that takes an `i32` argument, +but in `main`, it is passed a closure with a `&str` argument. This can be resolved by changing the type annotation or removing it entirely if it can be inferred. ``` -fn test_strings(string_vec: Vec) -> Vec { - string_vec - .iter() - .map(|arg| arg.eq("Test String")) - .collect() +fn foo(f: F) { +} + +fn main() { + foo(|x: i32| {}); } ```