Users coming from other languages (namely C and C++) often expect to use a -Wall flag. Rustc doesn't support that, and previously it simply printed that it didn't recognize the "all" lint. This change makes rustc print out a help message, explaining: - Why there is no -Wall flag - How to view all the available warnings - Point out that the most commonly used warning is -Wunused - Instead of using a command-line flag, the user should consider a !#[warn(unused)] directive in the root of their crate.
NB: This crate is part of the Rust compiler. For an overview of the
compiler as a whole, see
the README.md file found in librustc
.
The driver
crate is effectively the "main" function for the rust
compiler. It orchestrates the compilation process and "knits together"
the code from the other crates within rustc. This crate itself does
not contain any of the "main logic" of the compiler (though it does
have some code related to pretty printing or other minor compiler
options).