GHC.HsToCore.Utils

Utility functions for constructing Core syntax, principally for desugaring

Documentation

data EquationInfo

Constructors

EqnInfo

Fields

• eqn_pats :: [Pat GhcTc]

  The patterns for an equation

  NB: We have already applied decideBangHood to these patterns. See Note [decideBangHood] in GHC.HsToCore.Utils

• eqn_orig :: Origin

  Was this equation present in the user source?

  This helps us avoid warnings on patterns that GHC elaborated.

  For instance, the pattern -1 :: Word gets desugared into W# -1## :: Word, but we shouldn't warn about an overflowed literal for both of these cases.

• eqn_rhs :: MatchResult CoreExpr

  What to do after match

Instances

Outputable EquationInfo

Defined in GHC.HsToCore.Monad

Methods

ppr :: EquationInfo -> SDoc

firstPat :: EquationInfo -> Pat GhcTc

shiftEqns :: Functor f => f EquationInfo -> f EquationInfo

data MatchResult a

This is a value of type a with potentially a CoreExpr-shaped hole in it. This is used to deal with cases where we are potentially handling pattern match failure, and want to later specify how failure is handled.

Constructors

MR_Infallible (DsM a)

We represent the case where there is no hole without a function from CoreExpr, like this, because sometimes we have nothing to put in the hole and so want to be sure there is in fact no hole.

MR_Fallible (CoreExpr -> DsM a)

Instances

Applicative MatchResult

Product is an "or" on fallibility---the combined match result is infallible only if the left and right argument match results both were.

This is useful for combining a bunch of alternatives together and then getting the overall fallibility of the entire group. See mkDataConCase for an example.

Defined in GHC.HsToCore.Monad

Methods

pure :: a -> MatchResult a

(<*>) :: MatchResult (a -> b) -> MatchResult a -> MatchResult b

liftA2 :: (a -> b -> c) -> MatchResult a -> MatchResult b -> MatchResult c

(*>) :: MatchResult a -> MatchResult b -> MatchResult b

(<*) :: MatchResult a -> MatchResult b -> MatchResult a

Functor MatchResult

Defined in GHC.HsToCore.Monad

Methods

fmap :: (a -> b) -> MatchResult a -> MatchResult b

(<$) :: a -> MatchResult b -> MatchResult a

data CaseAlt a

Constructors

MkCaseAlt

Fields

• alt_pat :: a
• alt_bndrs :: [Var]
• alt_wrapper :: HsWrapper
• alt_result :: MatchResult CoreExpr

cantFailMatchResult :: CoreExpr -> MatchResult CoreExpr

alwaysFailMatchResult :: MatchResult CoreExpr

extractMatchResult :: MatchResult CoreExpr -> CoreExpr -> DsM CoreExpr

combineMatchResults :: MatchResult CoreExpr -> MatchResult CoreExpr -> MatchResult CoreExpr

adjustMatchResultDs :: (a -> DsM b) -> MatchResult a -> MatchResult b

shareFailureHandler :: MatchResult CoreExpr -> MatchResult CoreExpr

dsHandleMonadicFailure :: HsDoFlavour -> LPat GhcTc -> MatchResult CoreExpr -> FailOperator GhcTc -> DsM CoreExpr

mkCoLetMatchResult :: CoreBind -> MatchResult CoreExpr -> MatchResult CoreExpr

mkViewMatchResult :: Id -> CoreExpr -> MatchResult CoreExpr -> MatchResult CoreExpr

mkGuardedMatchResult :: CoreExpr -> MatchResult CoreExpr -> MatchResult CoreExpr

matchCanFail :: MatchResult a -> Bool

mkEvalMatchResult :: Id -> Type -> MatchResult CoreExpr -> MatchResult CoreExpr

mkCoPrimCaseMatchResult :: Id -> Type -> [(Literal, MatchResult CoreExpr)] -> MatchResult CoreExpr

mkCoAlgCaseMatchResult

Arguments

:: Id

Scrutinee

-> Type

Type of exp

-> NonEmpty (CaseAlt DataCon)

Alternatives (bndrs *include* tyvars, dicts)

-> MatchResult CoreExpr

mkCoSynCaseMatchResult :: Id -> Type -> CaseAlt PatSyn -> MatchResult CoreExpr

wrapBind :: Var -> Var -> CoreExpr -> CoreExpr

wrapBinds :: [(Var, Var)] -> CoreExpr -> CoreExpr

mkErrorAppDs :: Id -> Type -> SDoc -> DsM CoreExpr

mkCoreAppDs :: SDoc -> CoreExpr -> CoreExpr -> CoreExpr

mkCoreAppsDs :: SDoc -> CoreExpr -> [CoreExpr] -> CoreExpr

mkCastDs :: CoreExpr -> Coercion -> CoreExpr

mkFailExpr :: HsMatchContext GhcTc -> Type -> DsM CoreExpr

seqVar :: Var -> CoreExpr -> CoreExpr

mkLHsPatTup :: [LPat GhcTc] -> LPat GhcTc

mkVanillaTuplePat :: [LPat GhcTc] -> Boxity -> Pat GhcTc

mkBigLHsVarTupId :: [Id] -> LHsExpr GhcTc

mkBigLHsTupId :: [LHsExpr GhcTc] -> LHsExpr GhcTc

mkBigLHsVarPatTupId :: [Id] -> LPat GhcTc

mkBigLHsPatTupId :: [LPat GhcTc] -> LPat GhcTc

mkSelectorBinds

Arguments

:: [[CoreTickish]]

ticks to add, possibly

-> LPat GhcTc

The pattern

-> CoreExpr

Expression to which the pattern is bound

-> DsM (Id, [(Id, CoreExpr)])

Id the rhs is bound to, for desugaring strict binds (see Note [Desugar Strict binds] in GHC.HsToCore.Binds) and all the desugared binds

selectSimpleMatchVarL :: Mult -> LPat GhcTc -> DsM Id

selectMatchVars :: [(Mult, Pat GhcTc)] -> DsM [Id]

selectMatchVar :: Mult -> Pat GhcTc -> DsM Id

mkOptTickBox :: [CoreTickish] -> CoreExpr -> CoreExpr

mkBinaryTickBox :: Int -> Int -> CoreExpr -> DsM CoreExpr

decideBangHood

Arguments

:: DynFlags

-> LPat GhcTc

Original pattern

-> LPat GhcTc

Use -XStrict to add a ! or remove a ~ See Note [decideBangHood]

isTrueLHsExpr :: LHsExpr GhcTc -> Maybe (CoreExpr -> DsM CoreExpr)