Fix integration pipeline

This MR fixes several issues with the integration pipeline.

1. !349 (closed).

2. Fixes an oversight introduced in !344 (merged). The issue was with expressions like:

   a: scalar float = CastFunc(b: vector float, float)

   The mentioned MR used get_type_of_expression to determine whether an expression will be vectorized. That works in most cases due to type collation but fails for CastFuncs, which are always vectorized. This MR replaces get_type_of_expression by a small helper function that checks whether an expression is entirely scalar or requires additional vector casts.

pystencils/cpu/kernelcreation.py

@@ -94,7 +94,7 @@ def create_kernel(assignments: Union[NodeCollection],
     return ast_node
 
 
-def create_indexed_kernel(assignments: Union[AssignmentCollection, NodeCollection],
+def create_indexed_kernel(assignments: NodeCollection,
                           config: CreateKernelConfig) -> KernelFunction:
     """
     Similar to :func:`create_kernel`, but here not all cells of a field are updated but only cells with
@@ -115,16 +115,28 @@ def create_indexed_kernel(assignments: Union[AssignmentCollection, NodeCollectio
     fields_written = assignments.bound_fields
     fields_read = assignments.rhs_fields
 
+
+    Index_IDBefore = ""
+    for index_field in index_fields:
+        Index_IDBefore += f"index field name: {index_field.name}: {str(id(index_field))}"
+
     assignments = assignments.all_assignments
     assignments = add_types(assignments, config)
 
+
     all_fields = fields_read.union(fields_written)
+    AllFieldsIDSBefore = ""
+    for field in all_fields:
+        AllFieldsIDSBefore += f"field name: {field.name}: {str(id(field))}"
 
     for index_field in index_fields:
         index_field.field_type = FieldType.INDEXED
         assert FieldType.is_indexed(index_field)
         assert index_field.spatial_dimensions == 1, "Index fields have to be 1D"
 
+    Index_IDAfter = ""
+    for index_field in index_fields:
+        Index_IDAfter += f"index field name: {index_field.name}: {str(id(index_field))}"
     non_index_fields = [f for f in all_fields if f not in index_fields]
     spatial_coordinates = {f.spatial_dimensions for f in non_index_fields}
     assert len(spatial_coordinates) == 1, f"Non-index fields do not have the same number of spatial coordinates " \
@@ -132,7 +144,11 @@ def create_indexed_kernel(assignments: Union[AssignmentCollection, NodeCollectio
                                           f"{spatial_coordinates} and len(spatial coordiantes) is " \
                                           f"{len(spatial_coordinates)}, " \
                                           f"index_fields in config: {config.index_fields}, " \
-                                          f"extracted index fields: {index_fields} "
+                                          f"extracted index fields: {index_fields} " \
+                                          f"Index_IDBefore {Index_IDBefore} " \
+                                          f"Index_IDAfter {Index_IDAfter} " \
+                                          f"AllFieldsIDSBefore {AllFieldsIDSBefore}"
+
     spatial_coordinates = list(spatial_coordinates)[0]
 
     def get_coordinate_symbol_assignment(name):