src/librustc_error_codes/error_codes/E0437.md

   1 An associated type whose name does not match any of the associated types
   2 in the trait was used when implementing the trait.
   3
   4 Erroneous code example:
   5
   6 ```compile_fail,E0437
   7 trait Foo {}
   8
   9 impl Foo for i32 {
  10     type Bar = bool;
  11 }
  12 ```
  13
  14 Trait implementations can only implement associated types that are members of
  15 the trait in question.
  16
  17 The solution to this problem is to remove the extraneous associated type:
  18
  19 ```
  20 trait Foo {}
  21
  22 impl Foo for i32 {}
  23 ```