fail package:ghc-lib-parser

Which instance coverage condition failed? Was it the liberal coverage condition?

Failed the instance coverage condition (ICC)

Failed the liberal instance coverage condition (LICC)

FailedToLookupThInstName is a Template Haskell error that occurrs when looking up an instance fails. Example(s): Test cases: showIfaceshould_failTHPutDocNonExistent

The fail operator This is used for `.. <-` "bind statements" in do notation, including non-monadic "binds" in applicative. The fail operator is 'Just expr' if it potentially fail monadically. if the pattern match cannot fail, or shouldn't fail monadically (regular incomplete pattern exception), it is Nothing. See Note [Monad fail : Rebindable syntax, overloaded strings] for the type of expression in the Just case, and why it is so. See Note [Failing pattern matches in Stmts] for which contexts for 'BindStmt's should use the monadic fail and which shouldn't.