[clang] [Clang] Introduce OverflowBehaviorType for fine-grained overflow control (PR #148914)

[Eli Friedman via cfe-commits]

================
@@ -1480,6 +1480,14 @@ class DeclRefExpr final
     return DeclRefExprBits.IsImmediateEscalating;
   }
 
+  bool isOverflowBehaviorDiscarded() const {
----------------
efriedma-quic wrote:

I guess that makes sense.  But the number of bits we have available in Expr is really limited; if we start using them for very narrow diagnostics like this, we'll run out, and blow up the size of the AST.

Is there some way we can pass this down as an argument to CheckCompletedExpr or something like that?

https://github.com/llvm/llvm-project/pull/148914