GHC.Core.TyCo.Compare

Type equality and comparison

Type comparison

eqType :: Type -> Type -> Bool

Type equality on source types. Does not look through newtypes, PredTypes or type families, but it does look through type synonyms. This first checks that the kinds of the types are equal and then checks whether the types are equal, ignoring casts and coercions. (The kind check is a recursive call, but since all kinds have type Type, there is no need to check the types of kinds.) See also Note [Non-trivial definitional equality] in GHC.Core.TyCo.Rep.

eqTypeX :: RnEnv2 -> Type -> Type -> Bool

Compare types with respect to a (presumably) non-empty RnEnv2.

eqTypes :: [Type] -> [Type] -> Bool

Type equality on lists of types, looking through type synonyms but not newtypes.

nonDetCmpType :: Type -> Type -> Ordering

nonDetCmpTypes :: [Type] -> [Type] -> Ordering

nonDetCmpTypeX :: RnEnv2 -> Type -> Type -> Ordering

nonDetCmpTypesX :: RnEnv2 -> [Type] -> [Type] -> Ordering

nonDetCmpTc :: TyCon -> TyCon -> Ordering

Compare two TyCons. See Note [nonDetCmpType nondeterminism]

eqVarBndrs :: RnEnv2 -> [Var] -> [Var] -> Maybe RnEnv2

pickyEqType :: Type -> Type -> Bool

Like pickyEqTypeVis, but returns a Bool for convenience

tcEqType :: HasDebugCallStack => Type -> Type -> Bool

tcEqType implements typechecker equality It behaves just like eqType, but is implemented differently (for now)

tcEqKind :: HasDebugCallStack => Kind -> Kind -> Bool

tcEqTypeNoKindCheck :: Type -> Type -> Bool

Just like tcEqType, but will return True for types of different kinds as long as their non-coercion structure is identical.

tcEqTypeVis :: Type -> Type -> Bool

Like tcEqType, but returns True if the visible part of the types are equal, even if they are really unequal (in the invisible bits)

tcEqTyConApps :: TyCon -> [Type] -> TyCon -> [Type] -> Bool

Check whether two TyConApps are the same; if the number of arguments are different, just checks the common prefix of arguments.

Visiblity comparision

eqForAllVis :: ForAllTyFlag -> ForAllTyFlag -> Bool

Do these denote the same level of visibility? Required arguments are visible, others are not. So this function equates Specified and Inferred. Used for printing.

cmpForAllVis :: ForAllTyFlag -> ForAllTyFlag -> Ordering

Do these denote the same level of visibility? Required arguments are visible, others are not. So this function equates Specified and Inferred. Used for printing.