Fix array indirection to memlet subset promotion (#1406)

The current solution is rather hacky. I want to run the tests first to
see the impacts of this change.
Additionally, there is no test yet, because validation doesn't catch the
erroneous SDFG yet.

Overall, it's not clear currently how to solve the issue and the PR
might change as we progress...

dace/transformation/passes/scalar_to_symbol.py

@@ -323,6 +323,7 @@ def __init__(self, in_edges: Dict[str, mm.Memlet], out_edges: Dict[str, mm.Memle
 
     def visit_Subscript(self, node: ast.Subscript) -> Any:
         # Convert subscript to symbol name
+        node = self.generic_visit(node)
         node_name = astutils.rname(node)
         if node_name in self.in_edges:
             self.latest[node_name] += 1
@@ -346,7 +347,7 @@ def visit_Subscript(self, node: ast.Subscript) -> Any:
                 return ast.copy_location(ast.Name(id=new_name, ctx=ast.Store()), node)
             else:
                 self.do_not_remove.add(node_name)
-        return self.generic_visit(node)
+        return node
 
 
 def _range_is_promotable(subset: subsets.Range, defined: Set[str]) -> bool:

tests/passes/scalar_to_symbol_test.py

@@ -1,14 +1,12 @@
-# Copyright 2019-2021 ETH Zurich and the DaCe authors. All rights reserved.
+# Copyright 2019-2024 ETH Zurich and the DaCe authors. All rights reserved.
 """ Tests the scalar to symbol promotion functionality. """
 import dace
 from dace.transformation.passes import scalar_to_symbol
-from dace.sdfg.state import SDFGState
 from dace.transformation import transformation as xf, interstate as isxf
 from dace.transformation.interstate import loop_detection as ld
-from dace import registry
-from dace.transformation import helpers as xfh
 
 import collections
+from sympy import core as sympy_core
 import numpy as np
 import pytest
 
@@ -692,6 +690,45 @@ def test_ternary_expression(compile_time_evaluatable):
     sdfg.compile()
 
 
+def test_double_index_bug():
+
+    sdfg = dace.SDFG('test_')
+    state = sdfg.add_state()
+
+    sdfg.add_array('A', shape=(10, ), dtype=dace.float64)
+    sdfg.add_array('table', shape=(10, 2), dtype=dace.int64)
+    sdfg.add_array('B', shape=(10, ), dtype=dace.float64)
+    sdfg.add_scalar('idx', dace.int64, transient=True)
+    idx_node = state.add_access('idx')
+    set_tlet = state.add_tasklet('set_idx', code="_idx=0", inputs={}, outputs={"_idx"})
+    state.add_mapped_tasklet('map',
+                             map_ranges={'i': "0:10"},
+                             inputs={
+                                 'inp': dace.Memlet("A[0:10]"),
+                                 '_idx': dace.Memlet('idx[0]'),
+                                 'indices': dace.Memlet('table[0:10, 0:2]')
+                             },
+                             code="out = inp[indices[i,_idx]]",
+                             outputs={'out': dace.Memlet("B[i]")},
+                             external_edges=True,
+                             input_nodes={'idx': idx_node})
+
+    state.add_edge(set_tlet, '_idx', idx_node, None, dace.Memlet('idx[0]'))
+
+    sdfg.simplify()
+
+    # Check that `indices` (which is an array) is not used in a memlet subset
+    for state in sdfg.states():
+        for memlet in state.edges():
+            subset = memlet.data.subset
+            if not isinstance(subset, dace.subsets.Range):
+                continue
+            for range in subset.ranges:
+                for part in range:
+                    for sympy_node in sympy_core.preorder_traversal(part):
+                        assert getattr(sympy_node, "name", None) != "indices"
+
+
 if __name__ == '__main__':
     test_find_promotable()
     test_promote_simple()
@@ -715,3 +752,4 @@ def test_ternary_expression(compile_time_evaluatable):
     test_dynamic_mapind()
     test_ternary_expression(False)
     test_ternary_expression(True)
+    test_double_index_bug()