[PATCH] D138329: [-Wunsafe-buffer-usage] Add a new recursive matcher to replace `forEachDescendant` in unsafe buffer check

[Artem Dergachev via Phabricator via cfe-commits]

NoQ added inline comments.


================
Comment at: clang/lib/Analysis/UnsafeBufferUsage.cpp:54-55
+  bool TraverseDecl(Decl *Node) {
+    if (!Node)
+      return true;
+    if (!match(*Node))
----------------
ziqingluo-90 wrote:
> steakhal wrote:
> > Can `Node` be ever null if the visitor is initiated only be `AST_MATCHER_P`?
> Honestly I do not know the exact answer to your question.  I was imagining that an AST node could have a null to be one of its children.
> 
> Our plan later is to make this matcher a general alternative to `forEachDescendant`, so I think the check for null here is not over-defensive.
There can definitely be null children in the AST. Eg. `for(;;) {}` has null initializer, null condition, null increment, non-null body. I guess this is more about whether `RecursiveASTVisitor` checks for that automatically before invoking callbacks.


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D138329/new/

https://reviews.llvm.org/D138329