xref: /aosp_15_r20/external/clang/test/SemaTemplate/alias-church-numerals.cpp (revision 67e74705e28f6214e480b399dd47ea732279e315)
1*67e74705SXin Li // RUN: %clang_cc1 -std=c++11 -fsyntax-only -verify %s
2*67e74705SXin Li // expected-no-diagnostics
3*67e74705SXin Li 
4*67e74705SXin Li template<template<template<typename> class, typename> class T, template<typename> class V> struct PartialApply {
5*67e74705SXin Li   template<typename W> using R = T<V, W>;
6*67e74705SXin Li };
7*67e74705SXin Li 
8*67e74705SXin Li template<typename T> using Id = T;
9*67e74705SXin Li template<template<typename> class, typename X> using Zero = X;
10*67e74705SXin Li template<template<template<typename> class, typename> class N, template<typename> class F, typename X> using Succ = F<N<F,X>>;
11*67e74705SXin Li 
12*67e74705SXin Li template<template<typename> class F, typename X> using One = Succ<Zero, F, X>;
13*67e74705SXin Li template<template<typename> class F, typename X> using Two = Succ<One, F, X>;
14*67e74705SXin Li 
15*67e74705SXin Li template<template<template<typename> class, typename> class A,
16*67e74705SXin Li          template<template<typename> class, typename> class B,
17*67e74705SXin Li          template<typename> class F,
18*67e74705SXin Li          typename X> using Add = A<F, B<F, X>>;
19*67e74705SXin Li 
20*67e74705SXin Li template<template<template<typename> class, typename> class A,
21*67e74705SXin Li          template<template<typename> class, typename> class B,
22*67e74705SXin Li          template<typename> class F,
23*67e74705SXin Li          typename X> using Mul = A<PartialApply<B,F>::template R, X>;
24*67e74705SXin Li 
25*67e74705SXin Li template<template<typename> class F, typename X> using Four = Add<Two, Two, F, X>;
26*67e74705SXin Li template<template<typename> class F, typename X> using Sixteen = Mul<Four, Four, F, X>;
27*67e74705SXin Li template<template<typename> class F, typename X> using TwoHundredAndFiftySix = Mul<Sixteen, Sixteen, F, X>;
28*67e74705SXin Li 
29*67e74705SXin Li template<typename T, T N> struct Const { static const T value = N; };
30*67e74705SXin Li template<typename A> struct IncrementHelper;
31*67e74705SXin Li template<typename T, T N> struct IncrementHelper<Const<T, N>> { using Result = Const<T, N+1>; };
32*67e74705SXin Li template<typename A> using Increment = typename IncrementHelper<A>::Result;
33*67e74705SXin Li 
34*67e74705SXin Li using Arr = int[TwoHundredAndFiftySix<Increment, Const<int, 0>>::value];
35*67e74705SXin Li using Arr = int[256];
36