[clang] [Clang] fix crash by avoiding invalidation of extern main declaration during strictness checks (PR #104594)

[Alexander Kornienko via cfe-commits]

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@@ -12233,7 +12233,6 @@ void Sema::CheckMain(FunctionDecl *FD, const DeclSpec &DS) {
        FD->getDeclContext()->getRedeclContext()->isTranslationUnit())) {
     Diag(FD->getLocation(), diag::ext_main_invalid_linkage_specification)
         << FD->getLanguageLinkage();
-    FD->setInvalidDecl();
     return;
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alexfh wrote:

Should we proceed with other checks after this one? 

https://github.com/llvm/llvm-project/pull/104594