Used for emitting structured error messages and other diagnostic information.
Signifies that the compiler died with an explicit call to
Used as a return value to signify a fatal error occurred. (It is also used as the argument to panic at the moment, but that will eventually not be true.)
A handler deals with errors; certain errors (fatal, bug, unimpl) may cause immediate exit, others log errors for later reporting.
For example a note attached to an error.
See the docs on
Indicates the confidence in the correctness of a suggestion.