From f969fb5d6172761a2148221b68a0384b53368f8c Mon Sep 17 00:00:00 2001
From: Tom Smeding <tom@tomsmeding.com>
Date: Fri, 16 May 2025 12:25:44 +0200
Subject: Revert "Remove the KnownNat constraint from (:5509)"

This reverts commit 8890526cac9e6c4d5583d00fce55f32ba613cf31.

Removing a _provided_ KnownNat constraint if we cannot remove the actual
Nat information from the data type is rather pointless.
---
 src/Data/Array/Nested/Shaped/Shape.hs | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

(limited to 'src/Data/Array/Nested')

diff --git a/src/Data/Array/Nested/Shaped/Shape.hs b/src/Data/Array/Nested/Shaped/Shape.hs
index 8553b56..5a1003f 100644
--- a/src/Data/Array/Nested/Shaped/Shape.hs
+++ b/src/Data/Array/Nested/Shaped/Shape.hs
@@ -229,11 +229,11 @@ ixsRank (IxS l) = listsRank l
 
 ixsZero :: ShS sh -> IIxS sh
 ixsZero ZSS = ZIS
-ixsZero (SNat :$$ sh) = 0 :.$ ixsZero sh
+ixsZero (_ :$$ sh) = 0 :.$ ixsZero sh
 
 ixsFromIxX :: ShS sh -> IIxX (MapJust sh) -> IIxS sh
 ixsFromIxX ZSS ZIX = ZIS
-ixsFromIxX (SNat :$$ sh) (n :.% idx) = n :.$ ixsFromIxX sh idx
+ixsFromIxX (_ :$$ sh) (n :.% idx) = n :.$ ixsFromIxX sh idx
 
 ixxFromIxS :: IIxS sh -> IIxX (MapJust sh)
 ixxFromIxS ZIS = ZIX
@@ -280,10 +280,10 @@ pattern ZSS = ShS ZS
 
 pattern (:$$)
   :: forall {sh1}.
-     forall n sh. n : sh ~ sh1
+     forall n sh. (KnownNat n, n : sh ~ sh1)
   => SNat n -> ShS sh -> ShS sh1
 pattern i :$$ shl <- ShS (listsUncons -> Just (UnconsListSRes (ShS -> shl) i))
-  where i@SNat :$$ ShS shl = ShS (i ::$ shl)
+  where i :$$ ShS shl = ShS (i ::$ shl)
 
 infixr 3 :$$
 
@@ -400,7 +400,7 @@ instance KnownShS sh => IsList (ListS sh (Const i)) where
     where
       go :: ShS sh' -> [i] -> ListS sh' (Const i)
       go ZSS [] = ZS
-      go (SNat :$$ sh) (i : is) = Const i ::$ go sh is
+      go (_ :$$ sh) (i : is) = Const i ::$ go sh is
       go _ _ = error $ "IsList(ListS): Mismatched list length (type says "
                          ++ show (shsLength (knownShS @sh)) ++ ", list has length "
                          ++ show (length topl) ++ ")"
@@ -419,7 +419,7 @@ instance KnownShS sh => IsList (ShS sh) where
     where
       go :: ShS sh' -> [Int] -> ListS sh' SNat
       go ZSS [] = ZS
-      go (sn@SNat :$$ sh) (i : is)
+      go (sn :$$ sh) (i : is)
         | i == fromSNat' sn = sn ::$ go sh is
         | otherwise = error $ "IsList(ShS): Value does not match typing (type says "
                                 ++ show (fromSNat' sn) ++ ", list contains " ++ show i ++ ")"
-- 
cgit v1.2.3-70-g09d2