[clang] [Lifetime Safety] Highlight lifetimebound calls in alias chain diagnostics (PR #206337)

[Gábor Horváth via cfe-commits]

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@@ -664,20 +665,44 @@ class LifetimeSafetySemaHelperImpl : public LifetimeSafetySemaHelper {
     return CurrExpr->getSourceRange() != LastExpr->getSourceRange();
   }
 
-  void reportAliasingChain(llvm::ArrayRef<const Expr *> OriginExprChain) {
+  void reportAliasingChain(llvm::ArrayRef<AliasChainEntry> OriginExprChain) {
     if (OriginExprChain.empty())
       return;
 
-    const Expr *LastExpr = OriginExprChain.back();
+    AliasChainEntry Last = OriginExprChain.back();
+    const Expr *LastExpr = Last.E;
     std::string IssueStr = getDiagSubjectDescription(LastExpr);
 
-    for (const Expr *CurrExpr : reverse(OriginExprChain.drop_back())) {
-      if (!shouldShowInAliasChain(CurrExpr, LastExpr))
+    for (AliasChainEntry Curr : reverse(OriginExprChain.drop_back())) {
+      const Expr *CurrExpr = Curr.E;
+      if (!shouldShowInAliasChain(CurrExpr, LastExpr)) {
+        if (!Last.LifetimeBound && Curr.LifetimeBound)
+          Last.LifetimeBound = Curr.LifetimeBound;
         continue;
-      S.Diag(CurrExpr->getBeginLoc(),
-             diag::note_lifetime_safety_aliases_storage)
-          << CurrExpr->getSourceRange() << getDiagSubjectDescription(CurrExpr)
-          << IssueStr;
+      }
+      if (Last.LifetimeBound) {
+        std::string LifetimeBoundSubject;
+        if (Last.LifetimeBound->IsImplicitObject) {
+          LifetimeBoundSubject = "the implicit object parameter";
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Xazax-hun wrote:

I wonder if these texts could be part of the diagnostic test instead and we could use `select` and similar to get the right variant. 

https://github.com/llvm/llvm-project/pull/206337