NOTE: Test cases have not been adjusted! It is unclear how aggressively we want to make the manifestation stage, thus if we want to duplicate attributes at call sites existing at the callee decleration.
Call site argument abstract attributes (will) serve multiple purposes:
- they allow to simplify lookups of existing call site attributes
- they allow to hide away abstract call sites (follow up patch)
- they allow to use local information (before/after) the call site (follow up patch)