Represent type family instances by CoAxioms, not TyCons.

A few issues still remain to be addressed.

2 files changed, 12 insertions, 1 deletions

diff --git a/compiler/basicTypes/MkId.lhs b/compiler/basicTypes/MkId.lhs
index a40d46f8a9..f3922fe40b 100644
--- a/compiler/basicTypes/MkId.lhs
+++ b/compiler/basicTypes/MkId.lhs
@@ -26,6 +26,7 @@ module MkId (
 
         mkReboxingAlt, wrapNewTypeBody, unwrapNewTypeBody,
         wrapFamInstBody, unwrapFamInstScrut,
+        wrapTypeFamInstBody, unwrapTypeFamInstScrut,
         mkUnpackCase, mkProductBox,
 
         -- And some particular Ids; see below for why they are wired in
@@ -709,12 +710,22 @@ wrapFamInstBody tycon args body
   | otherwise
   = body
 
+-- Same as `wrapFamInstBody`, but for type family instances, which are
+-- represented by a `CoAxiom`, and not a `TyCon`
+wrapTypeFamInstBody :: CoAxiom -> [Type] -> CoreExpr -> CoreExpr
+wrapTypeFamInstBody axiom args body
+  = mkCast body (mkSymCo (mkAxInstCo axiom args))
+
 unwrapFamInstScrut :: TyCon -> [Type] -> CoreExpr -> CoreExpr
 unwrapFamInstScrut tycon args scrut
   | Just co_con <- tyConFamilyCoercion_maybe tycon
   = mkCast scrut (mkAxInstCo co_con args)
   | otherwise
   = scrut
+
+unwrapTypeFamInstScrut :: CoAxiom -> [Type] -> CoreExpr -> CoreExpr
+unwrapTypeFamInstScrut axiom args scrut
+  = mkCast scrut (mkAxInstCo axiom args)
 \end{code}
 
 
diff --git a/compiler/basicTypes/OccName.lhs b/compiler/basicTypes/OccName.lhs
index 9f8f32d1b3..faefa26dd5 100644
--- a/compiler/basicTypes/OccName.lhs
+++ b/compiler/basicTypes/OccName.lhs
@@ -371,7 +371,7 @@ sequentially starting at 0.
 
 So we can make a Unique using
 	mkUnique ns key  :: Unique
-where 'ns' is a Char reprsenting the name space.  This in turn makes it
+where 'ns' is a Char representing the name space.  This in turn makes it
 easy to build an OccEnv.
 
 \begin{code}