Summary:
This continues work for eliminating Annot.Item.t from Nullsafe low-level
code.
The introduced function `from_nullsafe_type` is called when we infer
initial type of the equation based on the function or field formal signature.
Before that, we did it via reading the annotation directly, which
complicates the logic and making introducing Unknown nullability tricky.
## Clarifying the semantics of PropagatesNullable
This diff also clarifies (and changes) the behavior of PropagatesNullable params.
Previously, if the return value of a function that has PropagatesNullable params was
annotated as Nullable, nullsafe was effectively ignoring PropagatesNullable effect.
This is especially bad because one can add Nullable annotation based on the logic "if the function can return `null`, it should be annotated with Nullable`.
In the new design, there is no possibility for such a misuse: the code that
applies the rule "any param is PropagatesNullable hence the return
value is nullable even if not explicitly annotated" lives in NullsafeType.ml, so
this will be automatically taken into account.
Meaning that now we implicitly deduce Nullable annotation for the return value, and providing it explicitly as an alternative that does not change the effect.
In the future, we might consider annotating the return value with `Nullable` explicit.
Reviewed By: jvillard
Differential Revision: D17479157
fbshipit-source-id: 66c2c8777
Summary:
1. Split into 3 subclasses for 3 major set of features we test
2. Document a known FP
3. More clear names
Reviewed By: jberdine
Differential Revision: D17285902
fbshipit-source-id: 66e3b5668
Summary:
Let's consolidate "positive" and "negative" cased together by adding an example
of not annotated class as a source of "negative" cases.
Also join the case with modelled methods to the same class.
Reviewed By: jberdine
Differential Revision: D17284101
fbshipit-source-id: e15e60691
Summary:
In next diff, we are going to introduce a new mode of nullsafe
(gradual). For testing, we are going to employ the strategy used by jvillard
for Pulse.
In this diff we split tests into two subfolders, one for the default and one for the gradual
mode.
We are planning to make the gradual mode default eventually. For that, most
new features will make sense for gradual mode, and we will mostly evolve
tests for that mode.
As for 'default' mode, we need to preserve tests mostly to ensure we don't introduce
regressions.
Occasionally, we might make changes that make sense for both modes, in
this (expected relatively rare) cases we will make changes to both set
of tests.
An alternative strategy would be to have two sets of issues.exp files,
one for gradual and one for default mode. This has an advantage of each
java file to be always tested twice, but disadvantage is that it will be
harder to write meaningful test code so that it makes sense for both
modes simultaneously.
Reviewed By: ngorogiannis
Differential Revision: D17156724
fbshipit-source-id: a92a9208f
Mitya Lyubarskiy