compiler/rustc_error_codes/src/error_codes/E0007.md

   1 This error indicates that the bindings in a match arm would require a value to
   2 be moved into more than one location, thus violating unique ownership. Code
   3 like the following is invalid as it requires the entire `Option<String>` to be
   4 moved into a variable called `op_string` while simultaneously requiring the
   5 inner `String` to be moved into a variable called `s`.
   6
   7 Erroneous code example:
   8
   9 ```compile_fail,E0007
  10 let x = Some("s".to_string());
  11
  12 match x {
  13     op_string @ Some(s) => {}, // error: cannot bind by-move with sub-bindings
  14     None => {},
  15 }
  16 ```
  17
  18 See also the error E0303.