[clang] [clang] Extend -Wunused-but-set-variable to static globals (PR #178342)

[Yanzuo Liu via cfe-commits]

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@@ -1900,12 +1900,10 @@ bool Sema::mightHaveNonExternalLinkage(const DeclaratorDecl *D) {
   return !D->isExternallyVisible();
 }
 
-// FIXME: This needs to be refactored; some other isInMainFile users want
-// these semantics.
-static bool isMainFileLoc(const Sema &S, SourceLocation Loc) {
-  if (S.TUKind != TU_Complete || S.getLangOpts().IsHeaderFile)
+bool Sema::isMainFileLoc(SourceLocation Loc) const {
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zwuis wrote:

IMO this definition should be put in Sema.cpp because it can be used for other kinds of semantic analysis.

The declaration of `isMainFileLoc` might be moved because declarations in Sema.h are grouped by files where they are implemented.

https://github.com/llvm/llvm-project/pull/178342