GHC.Tc.Instance.Class

Documentation

matchGlobalInst :: DynFlags -> Bool -> Class -> [Type] -> TcM ClsInstResult

data ClsInstResult

Constructors

NoInstance

OneInst

Fields

• cir_new_theta :: [TcPredType]
• cir_mk_ev :: [EvExpr] -> EvTerm
• cir_what :: InstanceWhat

NotSure

Instances

Outputable ClsInstResult

Defined in GHC.Tc.Instance.Class

Methods

ppr :: ClsInstResult -> SDoc

pprPrec :: Rational -> ClsInstResult -> SDoc

data InstanceWhat

Constructors

BuiltinInstance

BuiltinEqInstance

LocalInstance

TopLevInstance

Fields

• iw_dfun_id :: DFunId
• iw_safe_over :: SafeOverlapping

Instances

Outputable InstanceWhat

Defined in GHC.Tc.Instance.Class

Methods

ppr :: InstanceWhat -> SDoc

pprPrec :: Rational -> InstanceWhat -> SDoc

safeOverlap :: InstanceWhat -> Bool

instanceReturnsDictCon :: InstanceWhat -> Bool

data AssocInstInfo

Extra information about the parent instance declaration, needed when type-checking associated types. The Class is the enclosing class, the [TyVar] are the scoped type variable of the instance decl. The VarEnv Type maps class variables to their instance types.

Constructors

NotAssociated

InClsInst

Fields

• ai_class :: Class
• ai_tyvars :: [TyVar]

  The scoped tyvars of the instance Why scoped? See bind_me in checkConsistentFamInst

• ai_inst_env :: VarEnv Type

  Maps class tyvars to their instance types See Note [Matching in the consistent-instantiation check]

isNotAssociated :: AssocInstInfo -> Bool