The GHC user manual includes this description of `Addr#` literals: > `"foo"#` has type `Addr#` That's the extent of the documentation. It should be mentioned that text is encoded with Modified UTF-8. Also, I am not even sure what happens to a string like `"hello\x00world"#`. Is it treated any differently than `"hello\NULworld"#`. I haven't checked, but the manual should document what byte sequences these correspond to.