[clang] Suppress noreturn warning if last statement in a function is a throw (PR #145166)

[Erich Keane via cfe-commits]

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@@ -624,8 +624,29 @@ struct CheckFallThroughDiagnostics {
   }
 };
 
-} // anonymous namespace
+bool isKnownToAlwaysThrow(const FunctionDecl *FD) {
+  if (!FD->hasBody())
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erichkeane wrote:

It seems we have the ability to try A  LOT harder in this function, so I'd like a FIXME at the top of it that says something like:

"This is always going to be a best effort, at the moment it only handles a function that contains only a single-expression that is a 'throw', and then only in limited circumstances'.

https://github.com/llvm/llvm-project/pull/145166