Unqualified std type trait use?

https://github.com/boostorg/type_traits/blob/efc0be6b55672720da464a923f97bc77b48117c8/include/boost/type_traits/intrinsics.hpp#L228-L235

When I compile this with clang-cl on Windows, I get the following error (in Boost 1.68, but the code appears unchanged here):

T:\boost\boost_1_68_0\include\boost/type_traits/has_trivial_move_assign.hpp(49): error : no template named 'is_assignable'; did you mean 'std::is_assignable'?
T:\boost\boost_1_68_0\include\boost/type_traits/intrinsics.hpp(233): note: expanded from macro 'BOOST_HAS_TRIVIAL_MOVE_ASSIGN'

It does seem peculiar that this is being called unqualified here.

Start by inspecting include/boost/type_traits/intrinsics.hpp around lines 228-235 and the related has_trivial_move_assign.hpp diagnostic. Reproduce the reported clang-cl build on Windows, then verify that the type-trait reference is resolved appropriately without breaking other supported compilers.

Written by the indexing model from the issue text.