[clang] [clang-cl] [Sema] Support MSVC non-const lvalue to user-defined temporary reference (PR #99833)

[via cfe-commits]

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@@ -7272,6 +7272,11 @@ void Clang::ConstructJob(Compilation &C, const JobAction &JA,
     CmdArgs.push_back("-fdelayed-template-parsing");
   }
 
+  if (Args.hasFlag(options::OPT_fms_reference_binding,
+                   options::OPT_fno_ms_reference_binding,
+                   IsWindowsMSVC && !HaveCxx20))
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zmodem wrote:

Could we do something better for the non-windows or c++20 cases?

We could emit a warning saying the flag is unsupported, or we could put those conditions first so that we don't call hasFlag, which would make clang warn about the unused option.

https://github.com/llvm/llvm-project/pull/99833