Summary:
Currently, we have NullsafeRules.ml responsible for detecting the
violation fact. All other logic: what should be the error type,
severity, and error message, is in TypeErr.ml.
In this diff, we move logic from NullsafeRules.ml and TypeErr.ml to
dedicated modules like AssignmentRule.ml etc.
Each such module is responsible for:
- detecting the violation fact (this is moved from NullsafeRules.ml)
- rendering the violation error (this is moved from TypeErr.ml).
This approach makes sense for two reasons:
1. The violation fact and the way we show error are logically related to
each other.
2. In future diffs, we will support more features guiding rule behavior,
such as a) decision whether to hide or show the error depending on type
information and mode; b) the way we render error depending on type
information and role.
Having dedicated modules incapsulating knowledge about rules is a natural way to support 2.
Reviewed By: artempyanykh
Differential Revision: D17977891
fbshipit-source-id: a53d916d3
Mitya Lyubarskiy