[clang] [clang] Constant-evaluate format strings as last resort (PR #135864)

[Aaron Ballman via cfe-commits]

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@@ -265,6 +265,9 @@ related warnings within the method body.
   ``format_matches`` accepts an example valid format string as its third
   argument. For more information, see the Clang attributes documentation.
 
+- Format string checking now supports the compile-time evaluation of format
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AaronBallman wrote:

It may help users to understand the improvement if there's a small code example showing what wasn't checked and is now correctly caught. WDYT?

https://github.com/llvm/llvm-project/pull/135864