[libc++][ranges] Fix incorrect integer type in `view_interface` tests.

`ForwardIter() - ForwardIter()` returns `ptrdiff_t`, and converting it
to an unsigned type isn't guaranteed to produce the same type as
`size_t`.

Reviewed By: #libc, ldionne

Differential Revision: https://reviews.llvm.org/D141456

diff --git a/libcxx/test/std/ranges/range.utility/view.interface/view.interface.pass.cpp b/libcxx/test/std/ranges/range.utility/view.interface/view.interface.pass.cpp
index 830f3f77c29ec3f32a6ee689daa6d78c382762c3..b1ed28f80e9148247c27b83b48a82dacfe8618cb 100644 (file)
--- a/libcxx/test/std/ranges/range.utility/view.interface/view.interface.pass.cpp
+++ b/libcxx/test/std/ranges/range.utility/view.interface/view.interface.pass.cpp
@@ -15,6 +15,7 @@
 #include <ranges>
 
 #include <cassert>
+#include <utility>
 #include "test_macros.h"
 #include "test_iterators.h"
 
@@ -233,17 +234,20 @@ constexpr bool testSize() {
   static_assert(!SizeInvocable<NotSizedSentinel>);
   static_assert( SizeInvocable<ForwardRange>);
 
-  using SignedSize = std::common_type_t<std::ptrdiff_t, std::make_signed_t<std::size_t>>;
+  // Test the test.
+  static_assert(std::same_as<decltype(std::declval<ForwardIter>() - std::declval<ForwardIter>()), std::ptrdiff_t>);
+  using UnsignedSize = std::make_unsigned_t<std::ptrdiff_t>;
+  using SignedSize = std::common_type_t<std::ptrdiff_t, std::make_signed_t<UnsignedSize>>;
   ForwardRange forwardRange;
   assert(forwardRange.size() == 8);
   assert(static_cast<ForwardRange const&>(forwardRange).size() == 8);
 
   assert(std::ranges::size(forwardRange) == 8);
-  static_assert(std::same_as<decltype(std::ranges::size(std::declval<ForwardRange>())), std::size_t>);
+  static_assert(std::same_as<decltype(std::ranges::size(std::declval<ForwardRange>())), UnsignedSize>);
   static_assert(std::same_as<decltype(std::ranges::ssize(std::declval<ForwardRange>())), SignedSize>);
 
   assert(std::ranges::size(static_cast<ForwardRange const&>(forwardRange)) == 8);
-  static_assert(std::same_as<decltype(std::ranges::size(std::declval<ForwardRange const>())), std::size_t>);
+  static_assert(std::same_as<decltype(std::ranges::size(std::declval<ForwardRange const>())), UnsignedSize>);
   static_assert(std::same_as<decltype(std::ranges::ssize(std::declval<ForwardRange const>())), SignedSize>);
 
   SizeIsTen sizeTen;