Add a note why the same size int casting is a no-op
@@ -340,6 +340,7 @@ reference types and `mut` or `const` in pointer types.
#### Numeric cast
* Casting between two integers of the same size (e.g. i32 -> u32) is a no-op
+ (Rust uses 2's complement for negative values of fixed integers)
* Casting from a larger integer to a smaller integer (e.g. u32 -> u8) will
truncate
* Casting from a smaller integer to a larger integer (e.g. u8 -> u32) will
