src/librustc_error_codes/error_codes/E0663.md

   1 An invalid input operand constraint was passed to the `llvm_asm` macro
   2 (third line).
   3
   4 Erroneous code example:
   5
   6 ```compile_fail,E0663
   7 llvm_asm!("xor %eax, %eax"
   8           :
   9           : "+test"("a")
  10          );
  11 ```
  12
  13 Considering that this would be a long explanation, we instead recommend you
  14 take a look at the [`asm`] chapter of the Unstable book:
  15
  16 [asm]: https://doc.rust-lang.org/stable/unstable-book/library-features/asm.html