[PATCH] D91037: [clang-tidy] Fix crash in bugprone-redundant-branch-condition on ExprWithCleanups

Zinovy Nis via Phabricator via cfe-commits cfe-commits at lists.llvm.org
Thu Nov 12 10:03:09 PST 2020


zinovy.nis marked an inline comment as done.
zinovy.nis added inline comments.


================
Comment at: clang-tools-extra/test/clang-tidy/checkers/bugprone-redundant-branch-condition.cpp:1092
+      // CHECK-MESSAGES: :[[@LINE-1]]:5: warning: redundant condition 'isSet' [bugprone-redundant-branch-condition]
+      // CHECK-FIXES: {{isSet}}
+    }
----------------
aaron.ballman wrote:
> zinovy.nis wrote:
> > aaron.ballman wrote:
> > > zinovy.nis wrote:
> > > > aaron.ballman wrote:
> > > > > There's not a whole lot of context for FileCheck to determine if it's been correctly applied or not (same below) -- for instance, won't this pass even if no changes are applied because FileCheck is still going to find `isSet` in the file?
> > > > Thanks. Fixed.
> > > Maybe it's just early in the morning for me, but... I was expecting the transformation to be:
> > > ```
> > > if (RetT::Test(isSet).Ok() && isSet) {
> > >   if (RetT::Test(isSet).Ok() && isSet) {
> > >   }
> > > }
> > > ```
> > > turns into
> > > ```
> > > if (RetT::Test(isSet).Ok() && isSet) {
> > > }
> > > ```
> > > Why does it remove the `&& isSet` instead? That seems like it's changing the logic here from `if (true && false)` to `if (true)`.
> > IMO it's correct.
> > `isSet` cannot change its value between `if`s while `RetT::Test(isSet).Ok()` can.
> > So we don't need to re-evaluate `isSet` and need to re-evaluate `RetT::Test(isSet).Ok()` only.
> > 
> > 
> > 
> > > That seems like it's changing the logic here from if (true && false) to if (true).
> > 
> > 
> > As I understand only the second `if` is transformed.
> Does this only trigger as a redundant branch condition if the definition of `RetT::Test()` is available? Because `Test()` takes a `bool&` so it sure seems like `isSet` could be modified between the branches if the definition isn't found because it's being passed as a non-const reference to `Test()`.
1) 
> if the definition of RetT::Test() is available?

Removing the body from RetT::Test changes nothing.

2) Turning `RetT Test(bool &_isSet)` -> `RetT Test(bool _isSet)` also changes nothing.






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https://reviews.llvm.org/D91037



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