src/librustc_error_codes/error_codes/E0201.md

   1 It is an error to define two associated items (like methods, associated types,
   2 associated functions, etc.) with the same identifier.
   3
   4 For example:
   5
   6 ```compile_fail,E0201
   7 struct Foo(u8);
   8
   9 impl Foo {
  10     fn bar(&self) -> bool { self.0 > 5 }
  11     fn bar() {} // error: duplicate associated function
  12 }
  13
  14 trait Baz {
  15     type Quux;
  16     fn baz(&self) -> bool;
  17 }
  18
  19 impl Baz for Foo {
  20     type Quux = u32;
  21
  22     fn baz(&self) -> bool { true }
  23
  24     // error: duplicate method
  25     fn baz(&self) -> bool { self.0 > 5 }
  26
  27     // error: duplicate associated type
  28     type Quux = u32;
  29 }
  30 ```
  31
  32 Note, however, that items with the same name are allowed for inherent `impl`
  33 blocks that don't overlap:
  34
  35 ```
  36 struct Foo<T>(T);
  37
  38 impl Foo<u8> {
  39     fn bar(&self) -> bool { self.0 > 5 }
  40 }
  41
  42 impl Foo<bool> {
  43     fn bar(&self) -> bool { self.0 }
  44 }
  45 ```