GHC.Rename.Utils

Ensure that a boxed or unboxed tuple has arity no larger than mAX_TUPLE_SIZE.

Ensure that a constraint tuple has arity no larger than mAX_CTUPLE_SIZE.

Whether to report deprecation warnings when registering a used GRE

There is no option to only emit declaration warnings since everywhere we emit the declaration warnings we also emit export warnings (See Note [Handling of deprecations] for details)

Checks to see if we need to warn for -Wunused-record-wildcards or -Wredundant-record-wildcards

Keeps the span given to the Name for the application head only

Throw an error message if a user attempts to quantify an inferred type variable in a place where specificity cannot be observed. For example, forall {a}. [a] -> [a] would be rejected to the inferred type variable {a}, but forall a. [a] -> [a] would be accepted. See Note [Unobservably inferred type variables].

Examines a non-outermost type for foralls or contexts, which are assumed to be nested. For example, in the following declaration:

instance forall a. forall b. C (Either a b)

The outermost forall a is fine, but the nested forall b is not. We invoke noNestedForallsContextsErr on the type forall b. C (Either a b) to catch the nested forall and create a suitable error message. noNestedForallsContextsErr returns Just err_msg if such a forall or context is found, and returns Nothing otherwise.

This is currently used in the following places:

• In GADT constructor types (in rnConDecl). See Note [GADT abstract syntax] (Wrinkle: No nested foralls or contexts) in GHC.Hs.Type.

• In instance declaration types (in rnClsIntDecl and rnSrcDerivDecl in GHC.Rename.Module and renameSig in GHC.Rename.Bind). See Note [No nested foralls or contexts in instance types] in GHC.Hs.Type.

A common way to invoke noNestedForallsContextsErr.