https://issues.dlang.org/show_bug.cgi?id=13572
--- Comment #8 from Steven Schveighoffer <schvei...@yahoo.com> --- @trusted means that the call should be considered @safe, but it must call some @system functions internally. However, the marking means that the @system calls are properly encapsulated such that the total call is @safe. If we marked zlib @trusted, then we would be responsible for verifying all the code is actually @safe. You are right that if you pass invalid data into a safe function, guarantees are lost. But we don't need to go there to prove the library is unsafe: the zalloc and zfree functions can do anything, and the library can call them whenever they need data. So right there, you can't mark it @trusted. --
