diff options
Diffstat (limited to 'compiler/hsSyn/PlaceHolder.hs')
| -rw-r--r-- | compiler/hsSyn/PlaceHolder.hs | 27 |
1 files changed, 26 insertions, 1 deletions
diff --git a/compiler/hsSyn/PlaceHolder.hs b/compiler/hsSyn/PlaceHolder.hs index cacad7111c..7b3391d533 100644 --- a/compiler/hsSyn/PlaceHolder.hs +++ b/compiler/hsSyn/PlaceHolder.hs @@ -17,6 +17,7 @@ import ConLike (ConLike) import FieldLabel import SrcLoc (Located) import TcEvidence ( HsWrapper ) +import Outputable ( OutputableBndr ) import Data.Data hiding ( Fixity ) import BasicTypes (Fixity) @@ -97,9 +98,18 @@ In terms of actual usage, we have the following PostRn id NameSet TcId and Var are synonyms for Id + +Unfortunately the type checker termination checking conditions fail for the +DataId constraint type based on this, so even though it is safe the +UndecidableInstances pragma is required where this is used. -} type DataId id = + ( DataIdPost id + , DataIdPost (NameOrRdrName id) + ) + +type DataIdPost id = ( Data id , Data (PostRn id NameSet) , Data (PostRn id Fixity) @@ -107,7 +117,7 @@ type DataId id = , Data (PostRn id Name) , Data (PostRn id (Located Name)) , Data (PostRn id [Name]) --- , Data (PostRn id [id]) + , Data (PostRn id id) , Data (PostTc id Type) , Data (PostTc id Coercion) @@ -118,3 +128,18 @@ type DataId id = , Data (PostTc id HsWrapper) , Data (PostTc id [FieldLabel]) ) + + +-- |Follow the @id@, but never beyond Name. This is used in a 'HsMatchContext', +-- for printing messages related to a 'Match' +type family NameOrRdrName id where + NameOrRdrName Id = Name + NameOrRdrName Name = Name + NameOrRdrName RdrName = RdrName + +-- |Constraint type to bundle up the requirement for 'OutputableBndr' on both +-- the @id@ and the 'NameOrRdrName' type for it +type OutputableBndrId id = + ( OutputableBndr id + , OutputableBndr (NameOrRdrName id) + ) |