Safe Haskell	Safe-Inferred
Language	Haskell2010

GHC.Tc.Utils.Unify

Description

Type subsumption and unification

Synopsis

tcWrapResult :: HsExpr GhcRn -> HsExpr GhcTc -> TcSigmaType -> ExpRhoType -> TcM (HsExpr GhcTc)
tcWrapResultO :: CtOrigin -> HsExpr GhcRn -> HsExpr GhcTc -> TcSigmaType -> ExpRhoType -> TcM (HsExpr GhcTc)
tcWrapResultMono :: HsExpr GhcRn -> HsExpr GhcTc -> TcRhoType -> ExpRhoType -> TcM (HsExpr GhcTc)
tcTopSkolemise :: UserTypeCtxt -> TcSigmaType -> (TcType -> TcM result) -> TcM (HsWrapper, result)
tcSkolemiseScoped :: UserTypeCtxt -> TcSigmaType -> (TcType -> TcM result) -> TcM (HsWrapper, result)
tcSkolemiseExpType :: UserTypeCtxt -> ExpSigmaType -> (ExpRhoType -> TcM result) -> TcM (HsWrapper, result)
tcSubType :: CtOrigin -> UserTypeCtxt -> TcSigmaType -> ExpRhoType -> TcM HsWrapper
tcSubTypeSigma :: CtOrigin -> UserTypeCtxt -> TcSigmaType -> TcSigmaType -> TcM HsWrapper
tcSubTypePat :: CtOrigin -> UserTypeCtxt -> ExpSigmaType -> TcSigmaType -> TcM HsWrapper
tcSubTypeDS :: HsExpr GhcRn -> TcRhoType -> ExpRhoType -> TcM HsWrapper
tcSubTypeAmbiguity :: UserTypeCtxt -> TcSigmaType -> TcSigmaType -> TcM HsWrapper
tcSubMult :: CtOrigin -> Mult -> Mult -> TcM HsWrapper
checkConstraints :: SkolemInfoAnon -> [TcTyVar] -> [EvVar] -> TcM result -> TcM (TcEvBinds, result)
checkTvConstraints :: SkolemInfo -> [TcTyVar] -> TcM result -> TcM result
buildImplicationFor :: TcLevel -> SkolemInfoAnon -> [TcTyVar] -> [EvVar] -> WantedConstraints -> TcM (Bag Implication, TcEvBinds)
buildTvImplication :: SkolemInfoAnon -> [TcTyVar] -> TcLevel -> WantedConstraints -> TcM Implication
emitResidualTvConstraint :: SkolemInfo -> [TcTyVar] -> TcLevel -> WantedConstraints -> TcM ()
unifyType :: Maybe TypedThing -> TcTauType -> TcTauType -> TcM TcCoercionN
unifyKind :: Maybe TypedThing -> TcKind -> TcKind -> TcM CoercionN
unifyExpectedType :: HsExpr GhcRn -> TcRhoType -> ExpRhoType -> TcM TcCoercionN
uType :: TypeOrKind -> CtOrigin -> TcType -> TcType -> TcM CoercionN
promoteTcType :: TcLevel -> TcType -> TcM (TcCoercionN, TcType)
swapOverTyVars :: Bool -> TcTyVar -> TcTyVar -> Bool
startSolvingByUnification :: MetaInfo -> TcType -> TcM (Maybe TcType)
tcInfer :: (ExpSigmaType -> TcM a) -> TcM (a, TcSigmaType)
matchExpectedListTy :: TcRhoType -> TcM (TcCoercionN, TcRhoType)
matchExpectedTyConApp :: TyCon -> TcRhoType -> TcM (TcCoercionN, [TcSigmaType])
matchExpectedAppTy :: TcRhoType -> TcM (TcCoercion, (TcSigmaType, TcSigmaType))
matchExpectedFunTys :: forall a. ExpectedFunTyOrigin -> UserTypeCtxt -> Arity -> ExpRhoType -> ([Scaled ExpSigmaTypeFRR] -> ExpRhoType -> TcM a) -> TcM (HsWrapper, a)
matchExpectedFunKind :: TypedThing -> Arity -> TcKind -> TcM Coercion
matchActualFunTySigma :: ExpectedFunTyOrigin -> Maybe TypedThing -> (Arity, [Scaled TcSigmaType]) -> TcRhoType -> TcM (HsWrapper, Scaled TcSigmaTypeFRR, TcSigmaType)
matchActualFunTysRho :: ExpectedFunTyOrigin -> CtOrigin -> Maybe TypedThing -> Arity -> TcSigmaType -> TcM (HsWrapper, [Scaled TcSigmaTypeFRR], TcRhoType)
checkTyVarEq :: TcTyVar -> TcType -> CheckTyEqResult
checkTyFamEq :: TyCon -> [TcType] -> TcType -> CheckTyEqResult
checkTypeEq :: CanEqLHS -> TcType -> CheckTyEqResult

Documentation

tcWrapResult :: HsExpr GhcRn -> HsExpr GhcTc -> TcSigmaType -> ExpRhoType -> TcM (HsExpr GhcTc) Source #

tcWrapResultO :: CtOrigin -> HsExpr GhcRn -> HsExpr GhcTc -> TcSigmaType -> ExpRhoType -> TcM (HsExpr GhcTc) Source #

tcWrapResultMono :: HsExpr GhcRn -> HsExpr GhcTc -> TcRhoType -> ExpRhoType -> TcM (HsExpr GhcTc) Source #

tcTopSkolemise Source #

Arguments

:: UserTypeCtxt
-> TcSigmaType
-> (TcType -> TcM result)
-> TcM (HsWrapper, result)	The wrapper has type: spec_ty ~> expected_ty See Note [Skolemisation] for the differences between tcSkolemiseScoped and tcTopSkolemise

tcSkolemiseScoped Source #

Arguments

:: UserTypeCtxt
-> TcSigmaType
-> (TcType -> TcM result)
-> TcM (HsWrapper, result)	The wrapper has type: spec_ty ~> expected_ty See Note [Skolemisation] for the differences between tcSkolemiseScoped and tcTopSkolemise

tcSkolemiseExpType :: UserTypeCtxt -> ExpSigmaType -> (ExpRhoType -> TcM result) -> TcM (HsWrapper, result) Source #

Variant of tcTopSkolemise that takes an ExpType

tcSubType Source #

Arguments

:: CtOrigin
-> UserTypeCtxt
-> TcSigmaType	Actual
-> ExpRhoType	Expected
-> TcM HsWrapper

tcSubTypeSigma :: CtOrigin -> UserTypeCtxt -> TcSigmaType -> TcSigmaType -> TcM HsWrapper Source #

tcSubTypePat :: CtOrigin -> UserTypeCtxt -> ExpSigmaType -> TcSigmaType -> TcM HsWrapper Source #

tcSubTypeDS :: HsExpr GhcRn -> TcRhoType -> ExpRhoType -> TcM HsWrapper Source #

tcSubTypeAmbiguity :: UserTypeCtxt -> TcSigmaType -> TcSigmaType -> TcM HsWrapper Source #

tcSubMult :: CtOrigin -> Mult -> Mult -> TcM HsWrapper Source #

checkConstraints :: SkolemInfoAnon -> [TcTyVar] -> [EvVar] -> TcM result -> TcM (TcEvBinds, result) Source #

checkTvConstraints :: SkolemInfo -> [TcTyVar] -> TcM result -> TcM result Source #

buildImplicationFor :: TcLevel -> SkolemInfoAnon -> [TcTyVar] -> [EvVar] -> WantedConstraints -> TcM (Bag Implication, TcEvBinds) Source #

buildTvImplication :: SkolemInfoAnon -> [TcTyVar] -> TcLevel -> WantedConstraints -> TcM Implication Source #

emitResidualTvConstraint :: SkolemInfo -> [TcTyVar] -> TcLevel -> WantedConstraints -> TcM () Source #

unifyType Source #

Arguments

:: Maybe TypedThing	If present, the thing that has type ty1
-> TcTauType
-> TcTauType
-> TcM TcCoercionN

unifyKind :: Maybe TypedThing -> TcKind -> TcKind -> TcM CoercionN Source #

unifyExpectedType :: HsExpr GhcRn -> TcRhoType -> ExpRhoType -> TcM TcCoercionN Source #

uType :: TypeOrKind -> CtOrigin -> TcType -> TcType -> TcM CoercionN Source #

promoteTcType :: TcLevel -> TcType -> TcM (TcCoercionN, TcType) Source #

swapOverTyVars :: Bool -> TcTyVar -> TcTyVar -> Bool Source #

startSolvingByUnification :: MetaInfo -> TcType -> TcM (Maybe TcType) Source #

Checks (TYVAR-TV), (COERCION-HOLE) and (CONCRETE) of Note [Unification preconditions]; returns True if these conditions are satisfied. But see the Note for other preconditions, too.

tcInfer :: (ExpSigmaType -> TcM a) -> TcM (a, TcSigmaType) Source #

Infer a type using a fresh ExpType See also Note [ExpType] in GHC.Tc.Utils.TcMType

Use tcInferFRR if you require the type to have a fixed runtime representation.

matchExpectedListTy :: TcRhoType -> TcM (TcCoercionN, TcRhoType) Source #

matchExpectedTyConApp :: TyCon -> TcRhoType -> TcM (TcCoercionN, [TcSigmaType]) Source #

matchExpectedAppTy :: TcRhoType -> TcM (TcCoercion, (TcSigmaType, TcSigmaType)) Source #

matchExpectedFunTys :: forall a. ExpectedFunTyOrigin -> UserTypeCtxt -> Arity -> ExpRhoType -> ([Scaled ExpSigmaTypeFRR] -> ExpRhoType -> TcM a) -> TcM (HsWrapper, a) Source #

Use this function to split off arguments types when you have an "expected" type.

This function skolemises at each polytype.

Invariant: this function only applies the provided function to a list of argument types which all have a syntactically fixed RuntimeRep in the sense of Note [Fixed RuntimeRep] in GHC.Tc.Utils.Concrete. See Note [Return arguments with a fixed RuntimeRep].

matchExpectedFunKind Source #

Arguments

:: TypedThing	type, only for errors
-> Arity	n: number of desired arrows
-> TcKind	fun_kind
-> TcM Coercion	co :: fun_kind ~ (arg1 -> ... -> argn -> res)

Breaks apart a function kind into its pieces.

matchActualFunTySigma Source #

Arguments

:: ExpectedFunTyOrigin	See Note [Herald for matchExpectedFunTys]
-> Maybe TypedThing	The thing with type TcSigmaType
-> (Arity, [Scaled TcSigmaType])	Total number of value args in the call, and types of values args to which function has been applied already (reversed) (Both are used only for error messages)
-> TcRhoType	Type to analyse: a TcRhoType
-> TcM (HsWrapper, Scaled TcSigmaTypeFRR, TcSigmaType)

matchActualFunTySigma looks for just one function arrow, returning an uninstantiated sigma-type.

Invariant: the returned argument type has a syntactically fixed RuntimeRep in the sense of Note [Fixed RuntimeRep] in GHC.Tc.Utils.Concrete.

See Note [Return arguments with a fixed RuntimeRep].

matchActualFunTysRho Source #

Arguments

:: ExpectedFunTyOrigin	See Note [Herald for matchExpectedFunTys]
-> CtOrigin
-> Maybe TypedThing	the thing with type TcSigmaType
-> Arity
-> TcSigmaType
-> TcM (HsWrapper, [Scaled TcSigmaTypeFRR], TcRhoType)

Like matchExpectedFunTys, but used when you have an "actual" type, for example in function application.

INVARIANT: the returned argument types all have a syntactically fixed RuntimeRep in the sense of Note [Fixed RuntimeRep] in GHC.Tc.Utils.Concrete. See Note [Return arguments with a fixed RuntimeRep].

checkTyVarEq :: TcTyVar -> TcType -> CheckTyEqResult Source #

checkTyFamEq :: TyCon -> [TcType] -> TcType -> CheckTyEqResult Source #

checkTypeEq :: CanEqLHS -> TcType -> CheckTyEqResult Source #