The main types

Essentially a typed Name, that may also contain some additional information about the Var and it's use sites.

For an explanation of global vs. local Ids, see Var

Make a global Id without any extra information at all

Make a global Id with no global information but some generic IdInfo

For an explanation of global vs. local Ids, see Var

Create a local Id that is marked as exported. This prevents things attached to it from being removed as dead code. See Note [Exported LocalIds]

Create a system local Id. These are local Ids (see Var) that are created by the compiler out of thin air

Create a user local Id. These are local Ids (see Var) with a name and location that the user might recognize

Create a template local for a series of types

Create a template local for a series of type, but start from a specified template local

Create a template local: a family of system local Ids in bijection with Ints, typically used in unfoldings

Workers get local names. CoreTidy will externalise these if necessary

If the Id is that for a record selector, extract the sel_tycon and label. Panic otherwise

Not only does this set the Id Type, it also evaluates the type to try and reduce space usage

If it's a local, make it global

isImplicitId tells whether an Ids info is implied by other declarations, so we don't need to put its signature in an interface file, even if it's mentioned in some other interface unfolding.

This predicate says whether the Id has a strict demand placed on it or has a type such that it can always be evaluated strictly (i.e an unlifted type, as of GHC 7.6). We need to check separately whether the Id has a so-called "strict type" because if the demand for the given id hasn't been computed yet but id has a strict type, we still want isStrictId id to be True.

isExportedIdVar means "don't throw this away"

Get from either the worker or the wrapper Id to the DataCon. Currently used only in the desugarer.

INVARIANT: idDataCon (dataConWrapId d) = d: remember, dataConWrapId can return either the wrapper or the worker

Returns true if an application to n args would diverge

Returns True of an Id which may not have a binding, even though it is defined in this module.

Returns whether the lambda associated with the Id is certainly applied at most once This one is the "business end", called externally. It works on type variables as well as Ids, returning True Its main purpose is to encapsulate the Horrible State Hack

Returns whether the lambda associated with the Id is certainly applied at most once. You probably want to use isOneShotBndr instead

Should we apply the state hack to values of this Type?