clang/test/SemaTemplate/alias-church-numerals.cpp

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