[clang] [LifetimeSafety] Detect iterator invalidation through container aliases (PR #195231)

[Gábor Horváth via cfe-commits]

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@@ -254,6 +253,46 @@ void IteratorUsedAfterPushBack(std::vector<int> v) {
 }
 }  // namespace SimpleInvalidIterators
 
+namespace InvalidatingThroughContainerAliases {
+void IteratorInvalidatedThroughLocalReferenceAlias() {
+  std::vector<int> vv;
+  std::vector<int> &v = vv;
+  auto it = vv.begin(); // expected-warning {{object whose reference is captured is later invalidated}}
+  v.push_back(42);      // expected-note {{invalidated here}}
+  (void)it;             // expected-note {{later used here}}
+}
+
+void IteratorInvalidatedThroughPointerParameter(std::vector<int> *v) { // expected-warning {{parameter is later invalidated}}
+  auto it = v->begin();
+  v->push_back(42); // expected-note {{invalidated here}}
+  (void)it;         // expected-note {{later used here}}
+}
+} // namespace InvalidatingThroughContainerAliases
+
+namespace ContainerObjectAliases {
+// FIXME: Distinguish owner-borrow from content-borrow.
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Xazax-hun wrote:

Are we concerned about false positives of this shape? This might be a non-trivial amount of false positives. That being said, I think we do not really recommend people to use the invalidation related diagnostics just yet. 

https://github.com/llvm/llvm-project/pull/195231