Remove unnecessary checks and unused variable in Scan rewrites

Author: ricardoV94

pytensor/scan/rewriting.py

@@ -220,9 +220,6 @@ def scan_push_out_non_seq(fgraph, node):
     it to the outer function to be executed only once, before the `Scan` `Op`,
     reduces the amount of computation that needs to be performed.
     """
-    if not isinstance(node.op, Scan):
-        return False
-
     node_inputs, node_outputs = node.op.inner_inputs, node.op.inner_outputs
 
     local_fgraph_topo = io_toposort(node_inputs, node_outputs)
@@ -430,9 +427,6 @@ def scan_push_out_seq(fgraph, node):
     many times on many smaller tensors. In many cases, this optimization can
     increase memory usage but, in some specific cases, it can also decrease it.
     """
-    if not isinstance(node.op, Scan):
-        return False
-
     node_inputs, node_outputs = node.op.inner_inputs, node.op.inner_outputs
 
     local_fgraph_topo = io_toposort(node_inputs, node_outputs)
@@ -696,7 +690,6 @@ def push_out_inner_vars(
     old_scan_args: ScanArgs,
 ) -> tuple[list[Variable], ScanArgs, dict[Variable, Variable]]:
     tmp_outer_vars: list[Variable | None] = []
-    new_scan_node = old_scan_node
     new_scan_args = old_scan_args
     replacements: dict[Variable, Variable] = {}
 
@@ -843,10 +836,11 @@ def scan_push_out_add(fgraph, node):
     # Don't perform the optimization on `as_while` `Scan`s. Because these
     # `Scan`s don't run for a predetermined number of steps, handling them is
     # more complicated and this optimization doesn't support it at the moment.
-    if not (isinstance(node.op, Scan) and not node.op.info.as_while):
+    op = node.op
+    if op.info.as_while:
         return False
 
-    op = node.op
+    # apply_ancestors(args.inner_outputs)
 
     # Use `ScanArgs` to parse the inputs and outputs of scan for ease of
     # use