[clang] [LifetimeSafety] Introduce buildOriginFlowChain for use-after-scope (PR #199345)

[Gábor Horváth via cfe-commits]

================
@@ -471,13 +474,47 @@ class LifetimeSafetySemaHelperImpl : public LifetimeSafetySemaHelper {
   }
 
   std::string getDiagSubjectDescription(const Expr *E) {
+    E = E->IgnoreImpCasts();
     if (isa<MaterializeTemporaryExpr>(E))
       return "local temporary object";
----------------
Xazax-hun wrote:

Nit, I wonder if we should just say "temporary object". I am not sure if the term "local" is useful here. 

https://github.com/llvm/llvm-project/pull/199345