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/gpu/kernelcreation.py

@@ -133,6 +133,11 @@ def created_indexed_cuda_kernel(assignments: NodeCollection, config: CreateKerne
     assignments = assignments.all_assignments
     assignments = add_types(assignments, config)
 
+    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"
+
     def get_coordinate_symbol_assignment(name):
         for ind_f in index_fields:
             assert isinstance(ind_f.dtype, StructType), "Index fields have to have a struct data type"