Data.Constraint.Trivial

Documentation

class Unconstrained t

Intended to be used as an argument for some type constructor which expects kind k -> Constraint, when you do not actually wish to constrain anything with it.

Unconstrained t can always be added to the constraint list of any signature, without changing anything.

Instances

Unconstrained (t :: k)

Defined in Data.Constraint.Trivial

class TypeError (Disallowed "Impossible") => Impossible t where

This constraint can never be fulfilled. Might be useful e.g. as a default for a class-associated constraint; this basically disables any method with that constraint (so it can safely be left undefined).

Methods

absurdible :: proxy t -> a

Ex falso quodlibet. If you have Impossible t, you can do anything.

Might be useful e.g. if you are inside a function wiht an Impossible t => constraint, and you want to do something impossible, like the constraint implies.

Analogous to absurd.

class Unconstrained2 t s

Like Unconstrained, but with kind signature k -> k -> Constraint (two unconstrained types).

Instances

Unconstrained2 (t :: k2) (s :: k1)

Defined in Data.Constraint.Trivial

class TypeError (Disallowed "Impossible2") => Impossible2 t s where

Methods

absurdible2 :: proxy t -> proxy s -> a

class Unconstrained3 t s r

Instances

Unconstrained3 (t :: k3) (s :: k2) (r :: k1)

Defined in Data.Constraint.Trivial

class TypeError (Disallowed "Impossible3") => Impossible3 t s r where

Methods

absurdible3 :: proxy t -> proxy s -> proxy r -> a

class Unconstrained4 t s r q

Instances

Unconstrained4 (t :: k4) (s :: k3) (r :: k2) (q :: k1)

Defined in Data.Constraint.Trivial

class TypeError (Disallowed "Impossible4") => Impossible4 t s r q where

Methods

absurdible4 :: proxy t -> proxy s -> proxy r -> proxy q -> a

class Unconstrained5 t s r q p

Instances

Unconstrained5 (t :: k5) (s :: k4) (r :: k3) (q :: k2) (p :: k1)

Defined in Data.Constraint.Trivial

class TypeError (Disallowed "Impossible5") => Impossible5 t s r q p where

Methods

absurdible5 :: proxy t -> proxy s -> proxy r -> proxy q -> proxy p -> a

class Unconstrained6 t s r q p o

Instances

Unconstrained6 (t :: k6) (s :: k5) (r :: k4) (q :: k3) (p :: k2) (o :: k1)

Defined in Data.Constraint.Trivial

class TypeError (Disallowed "Impossible6") => Impossible6 t s r q p o where

Methods

absurdible6 :: proxy t -> proxy s -> proxy r -> proxy q -> proxy p -> proxy o -> a

class Unconstrained7 t s r q p o n

Instances

Unconstrained7 (t :: k7) (s :: k6) (r :: k5) (q :: k4) (p :: k3) (o :: k2) (n :: k1)

Defined in Data.Constraint.Trivial

class TypeError (Disallowed "Impossible7") => Impossible7 t s r q p o n where

Methods

absurdible7 :: proxy t -> proxy s -> proxy r -> proxy q -> proxy p -> proxy o -> proxy n -> a

class Unconstrained8 t s r q p o n m

Instances

Unconstrained8 (t :: k8) (s :: k7) (r :: k6) (q :: k5) (p :: k4) (o :: k3) (n :: k2) (m :: k1)

Defined in Data.Constraint.Trivial

class TypeError (Disallowed "Impossible8") => Impossible8 t s r q p o n m where

Methods

absurdible8 :: proxy t -> proxy s -> proxy r -> proxy q -> proxy p -> proxy o -> proxy n -> proxy m -> a

class Unconstrained9 t s r q p o n m l

Instances

Unconstrained9 (t :: k9) (s :: k8) (r :: k7) (q :: k6) (p :: k5) (o :: k4) (n :: k3) (m :: k2) (l :: k1)

Defined in Data.Constraint.Trivial

class TypeError (Disallowed "Impossible9") => Impossible9 t s r q p o n m l where

Methods

absurdible9 :: proxy t -> proxy s -> proxy r -> proxy q -> proxy p -> proxy o -> proxy n -> proxy m -> proxy l -> a