diff --git a/src/HordeAd/Core/Ast.hs b/src/HordeAd/Core/Ast.hs
index a34bba625..e0f37eab6 100644
--- a/src/HordeAd/Core/Ast.hs
+++ b/src/HordeAd/Core/Ast.hs
@@ -413,6 +413,7 @@ data AstTensor :: AstMethodOfSharing -> AstSpanType -> TensorKindType
   AstSFromX :: (KnownShS sh, KnownShX sh', Rank sh ~ Rank sh', TensorKind r)
             => AstTensor ms s (TKX2 sh' r) -> AstTensor ms s (TKS2 sh r)
 
+  -- Nesting/unnesting
   AstXNestR :: (KnownShX sh1, KnownNat m, TensorKind x)
             => AstTensor ms s (TKX2 (sh1 ++ Replicate m Nothing) x)
             -> AstTensor ms s (TKX2 sh1 (TKR2 m x))
diff --git a/src/HordeAd/Core/Ops.hs b/src/HordeAd/Core/Ops.hs
index 059b16472..2fc26a862 100644
--- a/src/HordeAd/Core/Ops.hs
+++ b/src/HordeAd/Core/Ops.hs
@@ -68,6 +68,7 @@ import Data.Array.Nested
   , type (++)
   )
 import Data.Array.Nested qualified as Nested
+import Data.Array.Nested.Internal.Lemmas
 import Data.Array.Nested.Internal.Shape
   ( shCvtSX
   , shrAppend
@@ -1398,7 +1399,7 @@ class ( Num (IntOf target)
          => ShS sh1 -> target (TKX2 (MapJust sh1 ++ Replicate m Nothing) x)
          -> target (TKS2 sh1 (TKR2 m x))
   snestR sh1 =
-    gcastWith (unsafeCoerceRefl :: Rank (MapJust sh1) :~: Rank sh1) $
+    gcastWith (lemRankMapJust sh1) $
     withKnownShS sh1 $
     withKnownShX (ssxFromShape (shCvtSX sh1)) $
     sfromX . xnestR (ssxFromShape (shCvtSX sh1))
@@ -1407,7 +1408,7 @@ class ( Num (IntOf target)
         => ShS sh1 -> target (TKS2 (sh1 ++ sh2) x)
         -> target (TKS2 sh1 (TKS2 sh2 x))
   snest sh1 =
-    gcastWith (unsafeCoerceRefl :: Rank (MapJust sh1) :~: Rank sh1) $
+    gcastWith (lemRankMapJust sh1) $
     gcastWith (unsafeCoerceRefl :: Rank (MapJust sh1 ++ MapJust sh2)
                                     :~: Rank (sh1 ++ sh2)) $
     withKnownShS sh1 $
@@ -1421,7 +1422,7 @@ class ( Num (IntOf target)
          => ShS sh1 -> target (TKX2 (MapJust sh1 ++ sh2) x)
          -> target (TKS2 sh1 (TKX2 sh2 x))
   snestX sh1 =
-    gcastWith (unsafeCoerceRefl :: Rank (MapJust sh1) :~: Rank sh1) $
+    gcastWith (lemRankMapJust sh1) $
     withKnownShS sh1 $
     withKnownShX (ssxFromShape (shCvtSX sh1)) $
     sfromX . xnest (ssxFromShape (shCvtSX sh1))
@@ -1471,14 +1472,14 @@ class ( Num (IntOf target)
            => target (TKS2 sh1 (TKR2 m x))
            -> target (TKX2 (MapJust sh1 ++ Replicate m Nothing) x)
   sunNestR =
-    gcastWith (unsafeCoerceRefl :: Rank (MapJust sh1) :~: Rank sh1) $
+    gcastWith (lemRankMapJust (knownShS @sh1)) $
     withKnownShX (ssxFromShape (shCvtSX (knownShS @sh1))) $
     xunNestR . xfromS @_ @_ @(MapJust sh1)
   sunNest :: forall sh1 sh2 x.
              (TensorKind x, KnownShS sh1, KnownShS sh2)
           => target (TKS2 sh1 (TKS2 sh2 x)) -> target (TKS2 (sh1 ++ sh2) x)
   sunNest =
-    gcastWith (unsafeCoerceRefl :: Rank (MapJust sh1) :~: Rank sh1) $
+    gcastWith (lemRankMapJust (knownShS @sh1)) $
     gcastWith (unsafeCoerceRefl
                :: Rank (MapJust sh1 ++ MapJust sh2) :~: Rank (sh1 ++ sh2)) $
     withKnownShS (knownShS @sh1 `shsAppend` knownShS @sh2) $
@@ -1491,7 +1492,7 @@ class ( Num (IntOf target)
            => target (TKS2 sh1 (TKX2 sh2 x))
            -> target (TKX2 (MapJust sh1 ++ sh2) x)
   sunNestX =
-    gcastWith (unsafeCoerceRefl :: Rank (MapJust sh1) :~: Rank sh1) $
+    gcastWith (lemRankMapJust (knownShS @sh1)) $
     withKnownShX (ssxFromShape (shCvtSX (knownShS @sh1))) $
     withKnownShX (ssxFromShape (shCvtSX (knownShS @sh1))
                   `ssxAppend` knownShX @sh2) $
diff --git a/src/HordeAd/Core/OpsAst.hs b/src/HordeAd/Core/OpsAst.hs
index ca077c653..0c00df098 100644
--- a/src/HordeAd/Core/OpsAst.hs
+++ b/src/HordeAd/Core/OpsAst.hs
@@ -653,15 +653,9 @@ instance AstSpan s => BaseTensor (AstTensor AstMethodLet s) where
   sfromX = astSFromX
 
   -- Nesting/unnesting
-  xnestR sh =
-    withKnownShX sh $
-    astXNestR
-  xnestS sh =
-    withKnownShX sh $
-    astXNestS
-  xnest sh =
-    withKnownShX sh $
-    astXNest
+  xnestR sh = withKnownShX sh $ astXNestR
+  xnestS sh = withKnownShX sh $ astXNestS
+  xnest sh = withKnownShX sh $ astXNest
   xunNestR = astXUnNestR
   xunNestS = astXUnNestS
   xunNest = astXUnNest
@@ -1247,15 +1241,9 @@ instance AstSpan s => BaseTensor (AstRaw s) where
   xfromS @_ @sh' @x = AstRaw . AstFromS (stensorKind @(TKX2 sh' x)) . unAstRaw
 
   -- Nesting/unnesting
-  xnestR sh =
-    withKnownShX sh $
-    AstRaw . AstXNestR . unAstRaw
-  xnestS sh =
-    withKnownShX sh $
-    AstRaw . AstXNestS . unAstRaw
-  xnest sh =
-    withKnownShX sh $
-    AstRaw . AstXNest . unAstRaw
+  xnestR sh = withKnownShX sh $ AstRaw . AstXNestR . unAstRaw
+  xnestS sh = withKnownShX sh $ AstRaw . AstXNestS . unAstRaw
+  xnest sh = withKnownShX sh $ AstRaw . AstXNest . unAstRaw
   xunNestR = AstRaw . AstXUnNestR . unAstRaw
   xunNestS = AstRaw . AstXUnNestS . unAstRaw
   xunNest = AstRaw . AstXUnNest . unAstRaw