[Clang][Sema] Add a nullptr check in template name (#162377)

shafik · web-flow · commit 37af81fbb54a · 2025-10-08T13:57:16.000-07:00
Static analysis flagged that when calling ActOnTemplateName, `S` can be
a `nullptr`
and we call `isTemplateName` which unconditionally dereferences the `S`
argument at
some point. I added a `nullptr` check to assure we don't dereference `S`
in
`isTemplateName` if it is a `nullptr`.
diff --git a/clang/lib/Sema/SemaTemplate.cpp b/clang/lib/Sema/SemaTemplate.cpp
@@ -318,7 +318,7 @@ TemplateNameKind Sema::isTemplateName(Scope *S,
     }
   }
 
-  if (isPackProducingBuiltinTemplateName(Template) &&
+  if (isPackProducingBuiltinTemplateName(Template) && S &&
       S->getTemplateParamParent() == nullptr)
     Diag(Name.getBeginLoc(), diag::err_builtin_pack_outside_template) << TName;
   // Recover by returning the template, even though we would never be able to

Original file line number	Diff line number	Diff line change
`@@ -318,7 +318,7 @@ TemplateNameKind Sema::isTemplateName(Scope *S,`
`318`	`318`	`}`
`319`	`319`	`}`
`320`	`320`
`321`		`- if (isPackProducingBuiltinTemplateName(Template) &&`
	`321`	`+ if (isPackProducingBuiltinTemplateName(Template) && S &&`
`322`	`322`	`S->getTemplateParamParent() == nullptr)`
`323`	`323`	`Diag(Name.getBeginLoc(), diag::err_builtin_pack_outside_template) << TName;`
`324`	`324`	`// Recover by returning the template, even though we would never be able to`