[clang] [analyzer] Fix false positive for mutexes inheriting mutex_base (PR #106240)

[Balazs Benics via cfe-commits]

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@@ -241,10 +241,14 @@ BlockInCriticalSectionChecker::checkDescriptorMatch(const CallEvent &Call,
   return std::nullopt;
 }
 
-static const MemRegion *skipBaseClassRegion(const MemRegion *Reg) {
-  while (const auto *BaseClassRegion = dyn_cast<CXXBaseObjectRegion>(Reg)) {
+static const MemRegion *skipStdBaseClassRegion(const MemRegion *Reg) {
+  do {
+    assert(Reg);
+    const auto *BaseClassRegion = dyn_cast<CXXBaseObjectRegion>(Reg);
+    if (!BaseClassRegion || !BaseClassRegion->getDecl()->isInStdNamespace())
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steakhal wrote:

FYI `isInStdNamespace` only works if the decl is exactly within std. Any nested namespaces beyond std, or class scopes are rejected even if their parents reside within std.
Have a look at `CallEvent.cpp:isWithinStdNamespace()`. If you think it's what we should use here, we could hoist that function into some utility header and use it.

https://github.com/llvm/llvm-project/pull/106240