Remove untangling of ComponentTensor from apply_derivatives

ufl/algorithms/apply_derivatives.py

@@ -219,28 +219,12 @@ def variable(self, o, df, unused_l):
 
     # --- Indexing and component handling
 
-    def indexed(self, o, Ap, ii):  # TODO: (Partially) duplicated in nesting rules
+    def indexed(self, o, Ap, ii):
         """Differentiate an indexed."""
         # Propagate zeros
         if isinstance(Ap, Zero):
             return self.independent_operator(o)
 
-        # Untangle as_tensor(C[kk], jj)[ii] -> C[ll] to simplify
-        # resulting expression
-        if isinstance(Ap, ComponentTensor):
-            B, jj = Ap.ufl_operands
-            if isinstance(B, Indexed):
-                C, kk = B.ufl_operands
-                kk = list(kk)
-                if all(j in kk for j in jj):
-                    rep = dict(zip(jj, ii))
-                    Cind = tuple(rep.get(k, k) for k in kk)
-                    expr = Indexed(C, MultiIndex(Cind))
-                    assert expr.ufl_free_indices == o.ufl_free_indices
-                    assert expr.ufl_shape == o.ufl_shape
-                    return expr
-
-        # Otherwise a more generic approach
         r = len(Ap.ufl_shape) - len(ii)
         if r:
             kk = indices(r)
@@ -1450,29 +1434,12 @@ def base_form_coordinate_derivative(self, o, f, dummy_w, dummy_v, dummy_cd):
             o_[3],
         )
 
-    def indexed(self, o, Ap, ii):  # TODO: (Partially) duplicated in generic rules
+    def indexed(self, o, Ap, ii):
         """Apply to an indexed."""
         # Reuse if untouched
         if Ap is o.ufl_operands[0]:
             return o
 
-        # Untangle as_tensor(C[kk], jj)[ii] -> C[ll] to simplify
-        # resulting expression
-        if isinstance(Ap, ComponentTensor):
-            B, jj = Ap.ufl_operands
-            if isinstance(B, Indexed):
-                C, kk = B.ufl_operands
-
-                kk = list(kk)
-                if all(j in kk for j in jj):
-                    rep = dict(zip(jj, ii))
-                    Cind = tuple(rep.get(k, k) for k in kk)
-                    expr = Indexed(C, MultiIndex(Cind))
-                    assert expr.ufl_free_indices == o.ufl_free_indices
-                    assert expr.ufl_shape == o.ufl_shape
-                    return expr
-
-        # Otherwise a more generic approach
         r = len(Ap.ufl_shape) - len(ii)
         if r:
             kk = indices(r)