Comments only.

Signed-off-by: Edward Z. Yang <ezyang@cs.stanford.edu>

Test Plan: comments only

Reviewers: simonpj, austin, goldfire

Subscribers: thomie

Differential Revision: https://phabricator.haskell.org/D820

2 files changed, 7 insertions, 1 deletions

diff --git a/compiler/typecheck/TcRnTypes.hs b/compiler/typecheck/TcRnTypes.hs
index 0cc06630e0..0d42334b87 100644
--- a/compiler/typecheck/TcRnTypes.hs
+++ b/compiler/typecheck/TcRnTypes.hs
@@ -796,6 +796,9 @@ data ArrowCtxt   -- Note [Escaping the arrow scope]
 -- TcTyThing
 ---------------------------
 
+-- | A typecheckable thing available in a local context.  Could be
+-- 'AGlobal' 'TyThing', but also lexically scoped variables, etc.
+-- See 'TcEnv' for how to retrieve a 'TyThing' given a 'Name'.
 data TcTyThing
   = AGlobal TyThing             -- Used only in the return type of a lookup
 
diff --git a/compiler/types/TypeRep.hs b/compiler/types/TypeRep.hs
index 8ed07c12d2..c91dddae45 100644
--- a/compiler/types/TypeRep.hs
+++ b/compiler/types/TypeRep.hs
@@ -352,7 +352,10 @@ as ATyCon.  You can tell the difference, and get to the class, with
 The Class and its associated TyCon have the same Name.
 -}
 
--- | A typecheckable-thing, essentially anything that has a name
+-- | A global typecheckable-thing, essentially anything that has a name.
+-- Not to be confused with a 'TcTyThing', which is also a typecheckable
+-- thing but in the *local* context.  See 'TcEnv' for how to retrieve
+-- a 'TyThing' given a 'Name'.
 data TyThing
   = AnId     Id
   | AConLike ConLike