[clang] [analyzer] Return null from makeNode on PosteriorlyOverconstrained (PR #218472)

[Donát Nagy via cfe-commits]

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@@ -561,13 +561,13 @@ void CoreEngine::HandleVirtualBaseBranch(const CFGBlock *B,
 ExplodedNode *CoreEngine::makeNode(const ProgramPoint &Loc,
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NagyDonat wrote:

Sounds like a good idea, but I'm not too familiar with any of these (the `__nullable` attribute and the nullability checks in tidy and clang) so I'm probably not the best person to work on this. However if you (or anybody else) happen to explore this, I very much support it :smile:!

https://github.com/llvm/llvm-project/pull/218472