[ADT][NFC] Remove some redundant code

[yuntaopan]

Summary

Some typetraits are defined twice, delete this part of the code.

[MaskRay]

is_one_of is used by llvm/include/llvm/Support/FormatProviders.h
are_base_of is used by llvm/include/llvm/IR/DerivedTypes.h and llvm/include/llvm/IR/Constants.h

[yuntaopan]

@MaskRay is_one_of and are_base_of have been defined in llvm/include/llvm/ADT/STLExtras.h lines 210 to 218, so delete the duplicate code starting at line 1487

[MaskRay]

In D159331#4633453, @yuntaopan wrote:

@MaskRay is_one_of and are_base_of have been defined in llvm/include/llvm/ADT/STLExtras.h lines 210 to 218, so delete the duplicate code starting at line 1487

So we have llvm::detail::are_base_of and llvm::are_base_of. The use in llvm/include/llvm/IR/DerivedTypes.h is llvm::are_base_of which you are removing?

[yuntaopan]

In D159331#4633457, @MaskRay wrote:

In D159331#4633453, @yuntaopan wrote:

@MaskRay is_one_of and are_base_of have been defined in llvm/include/llvm/ADT/STLExtras.h lines 210 to 218, so delete the duplicate code starting at line 1487

So we have llvm::detail::are_base_of and llvm::are_base_of. The use in llvm/include/llvm/IR/DerivedTypes.h is llvm::are_base_of which you are removing?

I didn’t find llvm::detail::are_base_of. These two parts of code are both defined in the namespace of llvm.

[MaskRay]

Looks great! You're right. Sorry for misreading..

llvm/include/llvm/ADT/STLExtras.h

struct on_first {
   }
 };
 
 /// Utility type to build an inheritance chain that makes it easy to rank
 /// overload candidates.
 template <int N> struct rank : rank<N - 1> {};
 template <> struct rank<0> {};
 
-/// traits class for checking whether type T is one of any of the given
-/// types in the variadic list.
-template <typename T, typename... Ts>
-using is_one_of = std::disjunction<std::is_same<T, Ts>...>;
-
-/// traits class for checking whether type T is a base class for all
-///  the given types in the variadic list.
-template <typename T, typename... Ts>
-using are_base_of = std::conjunction<std::is_base_of<T, Ts>...>;
-
 namespace detail {
 template <typename... Ts> struct Visitor;
 
 template <typename HeadT, typename... TailTs>
 struct Visitor<HeadT, TailTs...> : remove_cvref_t<HeadT>, Visitor<TailTs...> {
   explicit constexpr Visitor(HeadT &&Head, TailTs &&...Tail)
       : remove_cvref_t<HeadT>(std::forward<HeadT>(Head)),
         Visitor<TailTs...>(std::forward<TailTs>(Tail)...) {}