[clang] [clang] fix some places where used decls were not marked as referenced (PR #191848)

[Erich Keane via cfe-commits]

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@@ -3795,6 +3795,10 @@ QualType Sema::CheckTemplateIdType(ElaboratedTypeKeyword Keyword,
                                 /*UpdateArgsWithConversions=*/true))
     return QualType();
 
+  // Diagnose uses of this template.
+  (void)DiagnoseUseOfDecl(Template, TemplateLoc);
+  MarkAnyDeclReferenced(TemplateLoc, Template, /*OdrUse=*/false);
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erichkeane wrote:

Can we have tests for the `use-of-decl` additions here and below? 

https://github.com/llvm/llvm-project/pull/191848