GHC.Core.ConLike

A constructor-like thing

Is this a 'vanilla' constructor-like thing (no existentials, no provided constraints)?

Number of value arguments

Number of visible arguments

Names of fields used for selectors

The ConInfo (arity and field labels) associated to a ConLike.

Returns just the instantiated value argument types of a ConLike, (excluding dictionary args)

TyVarBinders for the type variables of the ConLike. For pattern synonyms, this will always consist of the universally quantified variables followed by the existentially quantified type variables. For data constructors, the situation is slightly more complicated—see Note [DataCon user type variable binders] in GHC.Core.DataCon.

Existentially quantified type/coercion variables

The "stupid theta" of the ConLike, such as data Eq a in:

data Eq a => T a = ...

It is empty for PatSynCon as they do not allow such contexts. See Note [The stupid context] in GHC.Core.DataCon.

Returns the strictness information for each constructor

The "full signature" of the ConLike returns, in order:

1) The universally quantified type variables

2) The existentially quantified type/coercion variables

3) The equality specification

4) The provided theta (the constraints provided by a match)

5) The required theta (the constraints required for a match)

6) The original argument types (i.e. before any change of the representation of the type)

7) The original result type

Returns the type of the whole pattern

Extract the type for any given labelled field of the ConLike

conLikeHasBuilder returns True except for uni-directional pattern synonyms, which have no builder

Is this record field a naughty record field due to the presence of existential type variables?

Different from isNaughtyRecordSelector because the latter is also true in the presence of -XNoFieldSelectors.

See Note [Naughty record selectors] in GHC.Tc.TyCl.Utils.