From 12bca1c32d6655ed612938bfd4031ea488cef7e3 Mon Sep 17 00:00:00 2001
From: sebastianselander <sebastian.selander@gmail.com>
Date: Wed, 5 Apr 2023 12:56:57 +0200
Subject: [PATCH] Added small comment about incorrect subtyping

---
 src/TypeChecker/TypeCheckerHm.hs | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/src/TypeChecker/TypeCheckerHm.hs b/src/TypeChecker/TypeCheckerHm.hs
index 1b6ae4d..38582e5 100644
--- a/src/TypeChecker/TypeCheckerHm.hs
+++ b/src/TypeChecker/TypeCheckerHm.hs
@@ -595,6 +595,19 @@ fresh = do
     modify (\st -> st{count = succ (count st)})
     return $ TVar $ MkTVar $ LIdent $ show n
 
+{-
+
+The following definition of id should type check
+id : forall a. a -> a
+id x = (x : a)
+
+but not this one, according to haskell atleast
+
+id : a -> a
+id x = (x : a)
+
+currently this is not the case, the TAll pattern match is incorrectly implemented.
+-}
 -- Is the left a subtype of the right
 (<<=) :: Type -> Type -> Bool
 (<<=) (TVar _) _ = True