Err package:ghc
A command-line error message
A type of kind
ErrorMessage (from the
TypeError
module).
A collection of error messages.
INVARIANT: Each
GhcMessage in the collection should have
SevError
severity.
A predicate with its arising location; used to encapsulate a
constraint that will give rise to a diagnostic.
Additional context to include in an error message, e.g. "In the type
signature ...", "In the ambiguity check for ...", etc.
Output an error to the screen. Does not cause the compiler to die.