Revert "PruneSymbols makes use of used_symbols and properly deletes i…

…nterstate edge contents"

This reverts commit 7021e25.

dace/transformation/passes/prune_symbols.py

@@ -59,11 +59,6 @@ def apply_pass(self, sdfg: SDFG, _) -> Optional[Set[Tuple[int, str]]]:
                 sdfg.remove_symbol(sym)
                 result.add(sym)
 
-        for e in sdfg.edges():
-            for aname in list(e.data.assignments):
-                if aname in result:
-                    del e.data.assignments[aname]
-
         if self.recursive:
             # Prune nested SDFGs recursively
             sid = sdfg.cfg_id
@@ -93,10 +88,10 @@ def used_symbols(self, sdfg: SDFG) -> Set[str]:
             result |= symbolic.symbols_in_code(code.as_string)
 
         for desc in sdfg.arrays.values():
-            result |= set(map(str, desc.used_symbols(False)))
+            result |= set(map(str, desc.free_symbols))
 
         for state in sdfg.nodes():
-            result |= state.used_symbols(False)
+            result |= state.free_symbols
             # In addition to the standard free symbols, we are conservative with other tasklet languages by
             # tokenizing their code. Since this is intersected with `sdfg.symbols`, keywords such as "if" are
             # ok to include
@@ -116,6 +111,6 @@ def used_symbols(self, sdfg: SDFG) -> Set[str]:
                                                            node.ignored_symbols)
 
         for e in sdfg.edges():
-            result |= e.data.used_symbols(False)
+            result |= e.data.free_symbols
 
         return result