Summary: This makes the traces more readable when involving skipped functions.
Reviewed By: sblackshear
Differential Revision: D5731683
fbshipit-source-id: 49d363b
Summary:
A function can both be a sink and propagate source info, but we currently ignore the summary for any function that is also a sink.
This will cause us to under-report for (e.g.) `src1 = source(); src2 = strcpy(dest, src1); exec(src2)`.
This is both a potential buffer overflow and a potential shell injection, but we won't report the second issue.
Reviewed By: jberdine
Differential Revision: D5676167
fbshipit-source-id: 232ab2f
Summary: This check is not possible in Java as it natirally happens in the totally legit case of the `try ... finally`.
Reviewed By: sblackshear
Differential Revision: D5568802
fbshipit-source-id: 24ca074
Summary:
Instead of a whitelist and blacklist and default issue types and default
blacklist and filtering, consider a simpler semantics where
1. checkers can be individually turned on or off on the command line
2. most checkers are on by default
3. `--no-filtering` turns all issue types on, but they can then be turned off again by further arguments
This provides a more flexible CLI and is similar to other options in the infer
CLI, where "global" behaviour is generally avoided.
Dynamically created checkers (eg, AL linters) cause some complications in the
implementation but I think the semantics is still clear.
Also change the name of the option to mention "issue types" instead of
"checks", since the latter can be confused with "checkers".
Reviewed By: jberdine
Differential Revision: D5583238
fbshipit-source-id: 21de476
Summary:
We previously lumped ownership predicates in with all other predicates. That limited us to a flat ownership domain.
This diff separates out the ownership predicates so we can have a richer lattice of predicates with each access path.
This lets us be more precise; for example, we can now show that
```
needToOwnBothParams(Obj o1, Obj o2) {
Obj alias;
if (*) { alias = o1; } else { alias = o2; }
alias.f = ... // both o1 and o2 need to be owned for this to be safe
}
void ownBothParamsOk() {
needToOwnBothParams(new Obj(), new Obj()); // ok, would have complained before
}
```
is safe.
Reviewed By: jberdine
Differential Revision: D5589898
fbshipit-source-id: 9606a46
Summary:
Use jbuilder to build infer instead of ocamlbuild. This is mainly to get faster builds:
```
times in 10ms, ±differences measured in speedups, 4 cores
| | ocb total | jb | ±total | ocb user | jb | ±user | ocb cpu | jb | ±cpu | ocb sys | jb | ±sys |
|-----------------------------------+-----------+------+--------+----------+------+-------+---------+-----+------+---------+------+------|
| byte from scratch | 6428 | 2456 | 2.62 | 7743 | 6662 | 1.16 | 138 | 331 | 2.40 | 1184 | 1477 | 0.80 |
| native from scratch | 9841 | 4289 | 2.29 | 9530 | 8834 | 1.08 | 110 | 245 | 2.23 | 1373 | 1712 | 0.80 |
| byte after native | 29578 | 1602 | 18.46 | 4514 | 4640 | 0.97 | 170 | 325 | 1.91 | 543 | 576 | 0.94 |
| change infer.ml byte | 344 | 282 | 1.22 | 292 | 215 | 1.36 | 96 | 99 | 1.03 | 040 | 066 | 0.61 |
| change infer.ml native | 837 | 223 | 3.75 | 789 | 174 | 4.53 | 98 | 99 | 1.01 | 036 | 47 | 0.77 |
| change Config.ml byte | 451 | 339 | 1.33 | 382 | 336 | 1.14 | 97 | 122 | 1.26 | 056 | 80 | 0.70 |
| change Config.ml native | 4024 | 1760 | 2.29 | 4585 | 4225 | 1.09 | 127 | 276 | 2.17 | 559 | 644 | 0.87 |
| change cFrontend_config.ml byte | 348 | 643 | 0.54 | 297 | 330 | 0.90 | 96 | 67 | 0.70 | 038 | 102 | 0.37 |
| change cFrontend_config.ml native | 1480 | 584 | 2.53 | 1435 | 906 | 1.58 | 106 | 185 | 1.75 | 136 | 178 | 0.76 |
#+TBLFM: $4=$2/$3;f2::$7=$5/$6;f2::$10=$9/$8;f2::$13=$11/$12;f2
50 cores
| | ocb total | jb | ±total | ocb user | jb | ±user | ocb cpu | jb | ±cpu | ocb sys | jb | ±sys |
|---------------------+-----------+------+--------+----------+------+-------+---------+----+------+---------+------+------|
| byte from scratch | 9114 | 2061 | 4.42 | 9334 | 5133 | 1.82 | | | 0/0 | 2566 | 1726 | 1.49 |
| native from scratch | 13481 | 3967 | 3.40 | 12291 | 7608 | 1.62 | | | 0/0 | 3003 | 2100 | 1.43 |
| byte after native | 3467 | 1476 | 2.35 | 5067 | 3912 | 1.30 | | | 0/0 | 971 | 801 | 1.21 |
#+TBLFM: $4=$2/$3;f2::$7=$5/$6;f2::$10=$9/$8;f2::$13=$11/$12;f2
```
Menu:
1. Write a jbuild file, autogenerated from jbuild.in because we need to fill in
some information at build-time (really, at configure time, but TODO), such as
whether or not clang is enabled.
2. Nuke lots of stuff from infer/src/Makefile that is now in the jbuild file
3. The jbuild file lives in infer/src/ so it can see all the sources. If we put it somewhere else, eg, infer/, then `jbuilder` scans too many files (all irrelevant) and takes 2.5s to start instead of .8s. Adding irrelevant directories to jbuild-ignore does not help.
4. jbuilder does not support subdirectories, so resort to listing all the
source files in the generated jbuild (only source directories need to be
manually listed in jbuild.in though). Still, the generated .merlin is wrong
and makes merlin find source files in _build, so manually tune it to get
good merlin support. We also lose some of merlin for unit tests as it
cannot see their build artefacts anymore.
5. checkCopyright gets its own jbuild because it's standalone. Also, remove
some deprecation warnings in checkCopyright due to the new version of Core from
a while ago.
6. Drop less-used Makefile features (they had regressed anyway) such as
building individual modules. Also, building mod_dep.pdf now takes all the
source files available so they better build (before, it would only take the
source files from the config, eg with or without clang) (that's pretty minor).
7. The toplevel is now built as a custom toplevel because that was easier. It
should soon be even easier: https://github.com/janestreet/jbuilder/issues/210
8. Move BUILTINS.mli to BUILTINS.ml because jbuilder is not happy about
interface files without implementations.
In particular, I did not try to migrate too much of the Makefile logic to jbuilder,
more can be done in the future.
Reviewed By: jberdine
Differential Revision: D5573661
fbshipit-source-id: 4ca6d8f
Summary:
When a sink name is specified in `.inferconfig` or in OCaml, it might conflict with a function of the same name that has a different number of args.
We shouldn't try to create a sink in this case, and we definitely shouldn't crash.
Reviewed By: jeremydubreil
Differential Revision: D5561216
fbshipit-source-id: fa1859b
Summary: Those are not particularly relevant for the biabduction analysis. It would be easy to have a dedicated checker for this if we happen to need one day.
Reviewed By: sblackshear
Differential Revision: D5530834
fbshipit-source-id: 316e60f
Summary:
The Eradicate `Nullable` checker should now be run using:
infer -a checkers --eradicate ...
Reviewed By: mbouaziz
Differential Revision: D5529226
fbshipit-source-id: 0de2956
Summary:
This is unsound but will help the analysis to report less false alarms with the common pattern:
if (a.get() != null) {
a.get().foo();
}
Reviewed By: sblackshear
Differential Revision: D5528227
fbshipit-source-id: 750db4a
Summary: This was reusing the side effects of the `add_constraints_on_retval` for the final purpose of being angelic and just assigning a fresh value to the lhs of the load.
Reviewed By: sblackshear
Differential Revision: D5507037
fbshipit-source-id: ec1c89c
Summary:
Works the same way as read/write races on fields, except that are more relaxed (er, unsound) in deciding whether two containers may alias.
This is needed to avoid reporting a ton of FP's; full explanation in comments.
Reviewed By: da319
Differential Revision: D5493404
fbshipit-source-id: 0a5d8b1
Summary:
The way we represented container writes before was pretty hacky: just use a dummy field for the name of the method that performs the container write.
This diff introduces a new access kind for container writes that is much more structured.
This will make it easier to soundly handle aliasing between containers and support container reads in the near future.
Reviewed By: da319
Differential Revision: D5465747
fbshipit-source-id: e021ec2
Summary: Using a dedicated abstract domain, like Quandary does, is more suitable for taint analysis.
Reviewed By: sblackshear
Differential Revision: D5473794
fbshipit-source-id: c917417
Summary: We get the wrong answer on most of them for now, but that is expected
Reviewed By: ngorogiannis
Differential Revision: D5429242
fbshipit-source-id: 4899079
Summary:
This just makes the warnings silent for now. We may improve the analysis to check if the null check on the captured fields are consistent with the annotation on the corresponding parameters.
Eradicate also has the same issue. I added a test to outline this. The biabduction analysis will also probably fail on the same of annotation lookup. We may want implement the proper fix at the level of `Annotation.field_has_annot`.
Reviewed By: sblackshear
Differential Revision: D5419243
fbshipit-source-id: 6460de8
Summary: Adding to the Quandary tests, the list of tests that are already working for the bi-abduction based taint analysis.
Reviewed By: sblackshear
Differential Revision: D5395734
fbshipit-source-id: c4f2e79
Summary: We had a model for `Pools.SimplePool`, but were missing models for `Pools.Pool`. Since `SimplePool` and `SynchronizedPool` both extend `Pool`, modeling it should cover all of the cases.
Reviewed By: ngorogiannis
Differential Revision: D5236280
fbshipit-source-id: 9bbdb25
Summary:
:
No longer use deprecated reporting function for the suggest nullable checker
Depends on D5205009
Reviewed By: grievejia
Differential Revision: D5205843
fbshipit-source-id: f6dd059
Summary:
Read/write race errors should always show one trace for a read and one trace for a write.
We forget to pass the conflicting writes to the reporting function in one case, which prevented us from showing a well-formed trace.
Fixed it by making the `conflicts` parameter non-optional
Reviewed By: jberdine
Differential Revision: D5209332
fbshipit-source-id: 05da01a
Summary: We were almost always using `~report_reachable:true`, and in the cases where we weren't it is fine to do so. In general, a sink could read any state from its parameters, so it makes sense to complain if anything reachable from them is tainted.
Reviewed By: mbouaziz
Differential Revision: D5169067
fbshipit-source-id: ea7d659
Summary:
For now, we just support clearing the taint on a return value.
Ideally, we would associate a kind with the sanitizer and only clear taint that matches that kind.
However, it's fairly complicated to make that work properly with footprint sources.
I have some ideas about how to do it with passthroughs instead, but let's just do the simple thing for now.
Reviewed By: jeremydubreil
Differential Revision: D5141906
fbshipit-source-id: a5b8b5e
Summary: Using Conjunction for thread join has known false negatives. Finer grained recording of threading information fixes this.
Reviewed By: sblackshear
Differential Revision: D5111161
fbshipit-source-id: aab483c
Summary: This fixes a couple of false positives as objects of BufferedReader don't need to be closed if the wrapped reader resource gets closed correctly.
Reviewed By: sblackshear
Differential Revision: D5106596
fbshipit-source-id: 725fb80
Summary: Useful to have Eradicate and Biabduction agree on how to inform that the analysis that some objects are not null.
Reviewed By: sblackshear
Differential Revision: D5075127
fbshipit-source-id: 9e56981
Summary:
First step to be able to enable and disable the checkers to run in the following form:
> infer -a checkers --checker1 --checker2 --checker3 -- ...
and have a predefined list of checkers that are run by default with:
> infer -a checkers -- ...
Reviewed By: sblackshear
Differential Revision: D5007377
fbshipit-source-id: d7339ef
Summary:
Before we understood ownership, we needed this to avoid a mountain of Builder-related FP's.
Now that we have fairly sophisticated understanding of ownership, we can kill this hack.
Reviewed By: jaegs
Differential Revision: D4940238
fbshipit-source-id: 8d86e57
Summary: The purpose of the annotation reachability analysis is to report when a method annotated with `X` never calls, directly or indirectly, another method annotated with `Y`. However, there can be different call stacks following different execution paths from `X` to `Y`. Reporting more than one call stack ending with the same annotated procedure does not bring more signal to the end user. So the purpose of this diff is to avoid those duplicated reports and report at most one annotation reachability issue per end of call stack.
Reviewed By: sblackshear
Differential Revision: D4942765
fbshipit-source-id: 46325a7
Summary: Sawja assigns them on multiple control-flow paths, so they're not SSA.
Reviewed By: peterogithub
Differential Revision: D4896745
fbshipit-source-id: c805216
Summary:
There are false positives in the current analysis due to the
use of conjunction in the treatment of threaded. Changing conjunction to disjunction
removes these false positives. Some new false negatives arise, but all the old tests pass.
This is a stopgap towards a better solution being planned.
Reviewed By: sblackshear
Differential Revision: D4883280
fbshipit-source-id: c2a7e6e
Summary:
If we couldn't project the callee access path into the caller during summary application, we still added the corresponding trace to the caller state.
This was wasteful; it just bloats the caller with state it will never look at.
Fixed it by making `get_caller_ap_node` return `None` when the state won't be visible in the caller.
Reviewed By: jeremydubreil
Differential Revision: D4727937
fbshipit-source-id: 87665e9
Summary: This should make the reports much easier to understand. We can generalize to reporting a stack trace for all of the writes in the future if we wish.
Reviewed By: peterogithub
Differential Revision: D4845641
fbshipit-source-id: 589fdbc
Summary: If two public methods touch the same state and only one is marked `ThreadSafe`, it's reasonable to report unsafe accesses on both of them.
Reviewed By: peterogithub
Differential Revision: D4785038
fbshipit-source-id: 5a80da4
Summary:
*Unless* the unprotected write runs on the main thread and the read doesn't.
Otherwise, we'll already report on the unprotected write, and we don't want to duplicate.
Reviewed By: peterogithub
Differential Revision: D4798357
fbshipit-source-id: 5de06a0
Summary:
This is step further simplify the code to avoid cases where the summary of the procedure being analyzed can exist in two different versions:
# one version is the summary passed as parameter to every checker
# the other is a copy of the summary in the in-memory specs table
This diff implements:
# the analysis always run through the `Ondemand` module (was already the case before)
# the summary of the procedure being analyzed is created at the beginning of the on-demand analysis call
# all the checkers run in sequence, update their respective part of the payload and log errors to the error table
# the summary is store at the end of the on-demand analysis call
Reviewed By: sblackshear
Differential Revision: D4787414
fbshipit-source-id: 2d115c9
Summary:
Adds a new type and branching for a missing path of execution.
closes#575
Reviewed By: jvillard
Differential Revision: D4738681
fbshipit-source-id: f72344c
Summary:
It can be useful when debugging infer or the Makefiles themselves to see what
`make` is doing. Instead of editing Makefiles to remove `@` now you can `make
VERBOSE=1`.
This is just `git ls-files | grep -e Makefile -e '.*\.make' | xargs sed -e 's/^\t@/\t$(QUIET)/' -i`, and adding the definition of `QUIET` to Makefile.config.
Reviewed By: jeremydubreil
Differential Revision: D4779115
fbshipit-source-id: e6e4642
Summary:
No new functionality here; mostly `FN_` tests documenting our current limitations.
Will start chipping away at the false negatives in follow-up diffs.
Reviewed By: peterogithub
Differential Revision: D4780013
fbshipit-source-id: 7a0c821
Summary: Bringing the logic back to where it was before the big refactoring of the reporting logic.
Reviewed By: peterogithub
Differential Revision: D4774541
fbshipit-source-id: afeaaf8
Summary:
Move all of the reporting on top of the aggregation functionality.
This lets us delete lots of code
Reviewed By: peterogithub
Differential Revision: D4772223
fbshipit-source-id: 47cc51a
Summary:
This was the one type of races we were not yet reporting (besides ones that use the wrong synchronization :)).
Wrote new utility function to aggregate all accesses by the memory they access.
This makes it easy to say which accesses we should report and what their conflicts are.
Eventually, we can simplify the reporting of other kinds of unsafe accesses using this structure.
Reviewed By: peterogithub
Differential Revision: D4770542
fbshipit-source-id: 96d948e
Summary:
For collections whose type does not express that the collection is thread-safe (e.g., `Collections.syncrhonizedMap` and friends).
If you annotate a field holding one of these collections, we won't warn when you mutate the collection.
Reviewed By: jeremydubreil
Differential Revision: D4763565
fbshipit-source-id: 58b487a
Summary: It seems that we were not really using the `Bottom` part of the domain as a pair of (empty call map, empty tracking var map) was already acting as bottom.
Reviewed By: sblackshear
Differential Revision: D4759757
fbshipit-source-id: 53dedfe
Summary:
Most of our tests work by comparing the output of some command to a baseline
expected output. It's often needed to update that baseline.
Previously, that was crudely done by attempting to move every foo.exp.test file
to foo.exp. This does not work terribly well, in particular because
foo.exp.test might be stale.
Instead, add a `replace` target to every test that knows how to update the
baseline. This allows custom behaviours too, eg in the differential tests.
Most of the tests include base.make or differential.make, so add a replace target
there. A few tests are completely custom, add a replace target to them too.
Reviewed By: jeremydubreil
Differential Revision: D4754279
fbshipit-source-id: ec34273
Summary:
If I read off the main thread and write on the main we
could have a race. (Writes off main are already reported.)
Reviewed By: sblackshear
Differential Revision: D4746138
fbshipit-source-id: 8b6e9c5
Summary:
One limitation of Eradicate is that certain nullability patterns are not expressible using simply the `Nullable` annotation.
One such pattern is using the knowledge that a function returns null when passed null, but returns an object otherwise.
The annotation `PropagatesNullable` is a variant of `Nullable` applied to parameters when their value propagates to the return value.
A method annotated
```
B m(PropagatesNullable A x) { return x == null ? x : B(x); }
```
indicates that `m` returns null if `x` is null, or an object of class `B` if the argument is not null.
Examples with multiple parameters are in the test cases.
This diff builds some infrastructure for annotation transformers: the example above represents the identity function on nullability annotations.
Reviewed By: jvillard
Differential Revision: D4705938
fbshipit-source-id: 9f6194e
Summary:
Before, `trace_of_pname` only grabbed unprotected writes from the summary, so the traces ending in an unprotected read were truncated.
We now look at reads too when appropriate.
Reviewed By: peterogithub
Differential Revision: D4719740
fbshipit-source-id: 28f6e63
Summary: Now, running `infer -a checkers -- ...` will also run the ThreadSafety checker
Reviewed By: sblackshear
Differential Revision: D4691330
fbshipit-source-id: 04fc781
Summary: Run all the checkers one after each other, which allows the Infer AI framework to run several checkers together, including the possibility for them to collaborate.
Reviewed By: sblackshear
Differential Revision: D4621838
fbshipit-source-id: e264d67
Summary:
This makes sure that one can run `./build-infer.sh` then `make`. Otherwise it's
not always clear what one should do to recompile infer, eg when `make` will
work and when `./build-infer.sh` should be used instead, in particular when the
user doesn't have opam configured for her terminal.
Reviewed By: jberdine
Differential Revision: D4698159
fbshipit-source-id: 5df8059
Summary:
When both an unprotected write and a read/write race emanate from the same line,
undoubtedly because of interprocedurality, strip the read/write report (for now).
Perhaps report the info in more succinct form later, but keep to one report/line.
Reviewed By: sblackshear
Differential Revision: D4685102
fbshipit-source-id: 291cf20
Summary:
There was a bug where we allowed ourselves to project local variables from the callee summary into an access path in the caller.
We should only be able to project callee variables that are in the footprint.
Reviewed By: jeremydubreil
Differential Revision: D4684868
fbshipit-source-id: 53a2b9d
Summary:
Eradicate detects circular field initializations (e.g. a field initialized with itself)
by checking in the typestate at the end of the constructor whether the origin
of the field is a field name in the current class.
This has the problem that the following initialization pattern is not recognized as correct:
C(C x) { this.field = x.field }
To fix the issue, the origin information for field accesses x.f is extended
with the origin information of the inner object x.
Circularities are detected if the origin of x is "this".
Reviewed By: jberdine
Differential Revision: D4672472
fbshipit-source-id: 9277bdd
Summary: Previously, we wouldn't report races where the write was under synchronization.
Reviewed By: peterogithub
Differential Revision: D4658850
fbshipit-source-id: e9f4c41
Summary: I encountered cases where the class name part of the method name was passed as `(None, "package.Class")` instead of `("package", "Class")` and therefore incorrectly failing some inequality checks
Reviewed By: sblackshear
Differential Revision: D4662617
fbshipit-source-id: 98ee3e3
Summary:
Stop multiple reports per line happening. These come about
because of interprocedural access to multiple fields. Present one trace,
and summary information about other accesses.
Reviewed By: sblackshear
Differential Revision: D4636232
fbshipit-source-id: 9039fea
Summary:
All intermediate `.exp` files used for tests can be generated with custom info, based on what is needed for the tests purposes.
This customisation happens via command-line argument `--issues-fields`.
Reviewed By: cristianoc, jvillard
Differential Revision: D4628062
fbshipit-source-id: feaa382
Summary:
- The package declaration was wrong
- There was a leftover copy-pasted resource leak test from `CursorLeak.java`.
Reviewed By: sblackshear
Differential Revision: D4612687
fbshipit-source-id: 42c1a35
Summary: Rather than having three separate annotations related to checking/assuming thread-safety, let's just have one annotation instead.
Reviewed By: peterogithub
Differential Revision: D4605258
fbshipit-source-id: 17c935b
Summary: distinguish writes via method calls (e.g., add) from writes via assignment in the error messages
Reviewed By: sblackshear
Differential Revision: D4611748
fbshipit-source-id: 7594d3b
Summary: Report at most one read/write race or unprotected write per access path per method
Reviewed By: sblackshear, jvillard
Differential Revision: D4590815
fbshipit-source-id: 3c3a9d9
Summary:
To address a common source of false positives observed in D4494901.
We don't do anything with `release` yet, but can model it as releasing ownership in the future if we want to enforce correct usage of `SynchronizedPool`'s.
Reviewed By: peterogithub
Differential Revision: D4593635
fbshipit-source-id: 621e937
Summary: Reports on reads that have one or more conflicting writes. When you report, say which other methods race with it.
Reviewed By: sblackshear
Differential Revision: D4538793
fbshipit-source-id: 47ce700
Summary: Thread-local variables can't be shared between threads, so it's safe to mutate them outside of synchronization
Reviewed By: jeremydubreil
Differential Revision: D4568316
fbshipit-source-id: 0634cad
Summary:
I couldn't figure out why, but from within an infer release the traces we get
for this test are different than the expected ones. This is even consistent
across osx and linux.
In order to restore sanity, let's just hide this incomprehensible fact. Let's
come back to it if more tests exhibit this, maybe traces are not guaranteed to
be exactly the same across runs.
Reviewed By: sblackshear
Differential Revision: D4559405
fbshipit-source-id: dd88c59
Summary: Should stop us from reporting on benign races of fields that are caching resources.
Reviewed By: peterogithub
Differential Revision: D4538037
fbshipit-source-id: 15236b4
Summary: This annotation can then be used to suppress the warnings on non-android Java projects.
Reviewed By: sblackshear
Differential Revision: D4544858
fbshipit-source-id: 8a0b8fa
Summary:
The Java models for resources are way to complex. The main issue I am facing with these models is that small changes in the analysis can affect the generation of the models in some weird ways. For instance, I get different specs for some of the models between my devserver and my devvm, which seems to be mostly related with the backend treatment of `instanceof`.
The objective here is to simplify the models as much as possible in order to:
1) make debugging regressions easier
2) get simpler specs and less modeled methods shipped in `models.jar`
Reviewed By: sblackshear
Differential Revision: D4536115
fbshipit-source-id: 577183a
Summary: Better documentation, and could perhaps be checked instead of trusted later if the analysis understands threads better.
Reviewed By: jaegs
Differential Revision: D4537463
fbshipit-source-id: 4323c78
Summary: In some cases where a function is called directly on a formal (e.g, `def foo(o) { callSomething(o) }`, we were failing to propagate the footprint trace to the caller.
Reviewed By: jeremydubreil
Differential Revision: D4502404
fbshipit-source-id: d4d632f
Summary: This case was already working but there was no tests for it
Reviewed By: sblackshear
Differential Revision: D4529473
fbshipit-source-id: ca3ff02
Summary: This will be important for maintaining ownership of `View`'s, which involve a lot of casting.
Reviewed By: peterogithub
Differential Revision: D4520441
fbshipit-source-id: fdef226
Summary:
Previously, we would lose track of ownership in code like
```
Obj owned = new Obj();
Obj stillOwned = id(owned); // would lose ownership here
stillOwned.f = ... // would report false alarm here
```
This diff partially addresses the problem by adding a notion of "unconditional" (always owned) or "conditional" (owned if some formal at index i is owned) ownership.
Now we can handle simple examples like the one above.
I say "partially" because we still can't handle cases where there are different reasons for conditional ownership, such as
```
oneOrTwo(Obj o1, Obj o2) { if (*) return o1; else return o2; } // we won't understand that this maintains ownership if both formals are owned
Obj stillOwned = oneOrTwo(owned1, owned2);
stillOwned.f = ... // we'll report a false alarm here
```
This can be addressed in the future, but will require slightly more work
Reviewed By: peterogithub
Differential Revision: D4520069
fbshipit-source-id: 99c7418
Summary: This fixes a wrong level of indirection when performing the type substitution.
Reviewed By: sblackshear
Differential Revision: D4521008
fbshipit-source-id: 7324ea6
Jeremy Dubreil
Sam Blackshear
Jules Villard
azhdar
Kyriakos Nikolaos Gkorogiannis
Jia Chen
Peter O'Hearn
Paco Estevez Garcia
Martino Luca
Cristiano Calcagno