C++: Detect non-allocating placement new in cpp/memory-never-freed#523
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This adds a `NewOrNewArrayExpr.getPlacementPointer` predicate and uses it in `Alloc.qll` to detect when a `new`-expression is not an allocation. User-defined replacements for `operator new` may not be allocations either, but the code continues to assume that they are. It's possible that we want to change this assumption in the future or leave it up to individual queries to decide on which side to err. It's hard to statically tell whether `operator new` has been overloaded in a particular file because it can be overloaded by a definition that is not in scope but is only linked together with that file.
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The test failures will be fixed by #525. |
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I think this is good to merge. I haven't re-run the Azure tests, but I've re-run Language-Tests/CPP after #525 was merged, and it passes now. |
This was referenced Nov 29, 2023
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This addresses CPP-294. It's a more conservative solution than what we've talked about because I think a more complete solution is at risk of introducing false negatives. Therefore I'd prefer that proposals for a more complete solution should be based on actual FPs in actual projects.