From 3c428f76d6c11d6475323173937b9ef9d516bcfe Mon Sep 17 00:00:00 2001
From: Anupam Jain <ajnsit@gmail.com>
Date: Thu, 6 Jul 2023 18:59:31 +0530
Subject: [PATCH] Use TypeRep directly instead of TypeableDict

---
 src/Data/Typeable.js   | 10 ++++------
 src/Data/Typeable.purs | 29 +++++++++--------------------
 2 files changed, 13 insertions(+), 26 deletions(-)

diff --git a/src/Data/Typeable.js b/src/Data/Typeable.js
index 584937f..0a4c8dd 100644
--- a/src/Data/Typeable.js
+++ b/src/Data/Typeable.js
@@ -1,7 +1,6 @@
 // var _tag_id_counter = 1;
 
 export function typeRepDefault0Impl(t) {
-  // if(t.__uniqueId == undefined) t.__uniqueId = _tag_id_counter++;
   return t;
 }
 
@@ -21,9 +20,9 @@ export const proxyTFromTagTImpl = pack('tagT');
 function pack(tagName) {
   return function(origTag) {
     let unwrappedTag = origTag[tagName];
-    return function(dict) {
-      if (unwrappedTag.tag) return { tag: unwrappedTag.tag, args: unwrappedTag.args.concat(dict) };
-      return { tag: origTag, args: [dict] };
+    return function(typeRep) {
+      if (unwrappedTag.tag) return { tag: unwrappedTag.tag, args: unwrappedTag.args.concat(typeRep) };
+      return { tag: origTag, args: [typeRep] };
     };
   };
 };
@@ -54,7 +53,6 @@ export const typeRowNil = { record: [] };
 
 function eqTypeRepHelper(t1, t2) {
   if (t1.tagT) return t1 === t2;
-  if (t1.tag !== t2.tag) return false;
   if (t1.record) {
     if (!t2.record) return false;
     if (t1.record.length !== t2.record.length) return false;
@@ -67,7 +65,7 @@ function eqTypeRepHelper(t1, t2) {
   if (!t1.args) return false;
   if (t1.args.length !== t2.args.length) return false;
   for (var i = 0; i < t1.args.length; i++) {
-    if (!eqTypeRepHelper(t1.args[i].typeRep, t2.args[i].typeRep)) return false;
+    if (!eqTypeRepHelper(t1.args[i], t2.args[i])) return false;
   }
   return true;
 }
diff --git a/src/Data/Typeable.purs b/src/Data/Typeable.purs
index a48ea28..979f947 100644
--- a/src/Data/Typeable.purs
+++ b/src/Data/Typeable.purs
@@ -49,9 +49,6 @@ class Typeable :: forall k. k -> Constraint
 class Typeable a where
   typeRep :: TypeRep a
 
-data TypeableDict :: forall k. k -> Type
-data TypeableDict a
-
 instance showTypeRepInstance :: Show (TypeRep a) where
   show t = showTypeRep t
 
@@ -111,27 +108,23 @@ eqSomeTypeRep s1 s2 = unwrapSomeTypeRep s1 \t1 -> unwrapSomeTypeRep s2 \t2 -> eq
 
 -- MACHINERY + INSTANCES
 
+-- Coerce must have a type sig, and must not be inlined else it won't get passed the dicts
+coerceTagDict :: forall a r. (TagTDict a -> r) -> (TagT a => r)
+coerceTagDict = unsafeCoerce
+
 -- HACK: For https://github.com/purescript/purescript/pull/4240
 typeRepDefault0 :: forall a. TagT a => TypeRep a
-typeRepDefault0 = coerce typeRepDefault0Impl
-  where
-  -- Coerce must have a type sig, and must not be inlined else it won't get passed the dicts
-  coerce :: (TagTDict a -> TypeRep a) -> (TagT a => TypeRep a)
-  coerce = unsafeCoerce
+typeRepDefault0 = coerceTagDict typeRepDefault0Impl
 
 -- typeRepDefaultImpl :: forall a. TagT a => TypeRep a
 foreign import typeRepDefault0Impl :: forall a. TagTDict a -> TypeRep a
 
 -- HACK: For https://github.com/purescript/purescript/pull/4240
 typeRepFromTag1 :: forall a b. TagT a => Typeable b => TypeRep (a b)
-typeRepFromTag1 = coerce typeRepFromTag1Impl
-  where
-  -- Coerce must have a type sig, and must not be inlined else it won't get passed the dicts
-  coerce :: (TagTDict a -> TypeableDict b -> TypeRep (a b)) -> (TagT a => Typeable b => TypeRep (a b))
-  coerce = unsafeCoerce
+typeRepFromTag1 = coerceTagDict typeRepFromTag1Impl typeRep
 
 -- typeRepFromTag1Impl :: forall a b. TagT a => Typeable b => TypeRep (a b)
-foreign import typeRepFromTag1Impl :: forall a b. TagTDict a -> TypeableDict b -> TypeRep (a b)
+foreign import typeRepFromTag1Impl :: forall a b. TagTDict a -> TypeRep b -> TypeRep (a b)
 
 foreign import showTypeRep :: forall a. TypeRep a -> String
 
@@ -153,14 +146,10 @@ data TagTDict t
 
 -- HACK: For https://github.com/purescript/purescript/pull/4240
 proxyTFromTagT :: forall t a. TagT t => Typeable a => ProxyT (t a)
-proxyTFromTagT = coerce proxyTFromTagTImpl
-  where
-  -- Coerce must have a type sig, and must not be inlined else it won't get passed the dicts
-  coerce :: (TagTDict t -> TypeableDict a -> ProxyT (t a)) -> (TagT t => Typeable a => ProxyT (t a))
-  coerce = unsafeCoerce
+proxyTFromTagT = coerceTagDict proxyTFromTagTImpl typeRep
 
 -- foreign import proxyTFromTagTImpl :: forall t a. TagT t => Typeable a => ProxyT (t a)
-foreign import proxyTFromTagTImpl :: forall t a. TagTDict t -> TypeableDict a -> ProxyT (t a)
+foreign import proxyTFromTagTImpl :: forall t a. TagTDict t -> TypeRep a -> ProxyT (t a)
 
 instance typeableRecord :: (RL.RowToList rs ls, TypeableRecordFields ls) => Typeable (Record rs) where
   typeRep = typeRowToTypeRep (typeableRecordFields (Proxy :: _ ls))