[llvm] 97e544f - [ADT] Use C++17 fold expression in PointerSumType (NFC) (#159560)

[via llvm-commits]

Author: Kazu Hirata
Date: 2025-09-18T08:55:58-07:00
New Revision: 97e544f617a10011a5415b39a892de9d1aa88fd0

URL: https://github.com/llvm/llvm-project/commit/97e544f617a10011a5415b39a892de9d1aa88fd0
DIFF: https://github.com/llvm/llvm-project/commit/97e544f617a10011a5415b39a892de9d1aa88fd0.diff

LOG: [ADT] Use C++17 fold expression in PointerSumType (NFC) (#159560)

This patch simplifes the recursive Checker template with a C++17 fold
expression and "inlines" it right into the `static_assert`.

Added: 
    

Modified: 
    llvm/include/llvm/ADT/PointerSumType.h

Removed: 
    


################################################################################
diff  --git a/llvm/include/llvm/ADT/PointerSumType.h b/llvm/include/llvm/ADT/PointerSumType.h
index 132eab58b112a..c4971bf3af87a 100644
--- a/llvm/include/llvm/ADT/PointerSumType.h
+++ b/llvm/include/llvm/ADT/PointerSumType.h
@@ -239,19 +239,9 @@ struct PointerSumTypeHelper : MemberTs... {
     TagMask = ~PointerMask
   };
 
-  // Finally we need a recursive template to do static checks of each
-  // member.
-  template <typename MemberT, typename... InnerMemberTs>
-  struct Checker : Checker<InnerMemberTs...> {
-    static_assert(MemberT::Tag < (1 << NumTagBits),
-                  "This discriminant value requires too many bits!");
-  };
-  template <typename MemberT> struct Checker<MemberT> : std::true_type {
-    static_assert(MemberT::Tag < (1 << NumTagBits),
-                  "This discriminant value requires too many bits!");
-  };
-  static_assert(Checker<MemberTs...>::value,
-                "Each member must pass the checker.");
+  // Finally, statically check each member.
+  static_assert(((MemberTs::Tag < (1 << NumTagBits)) && ...),
+                "A discriminant value requires too many bits!");
 };
 
 } // end namespace detail