(v3) Creating an expression that simplifies to a certain dimension before including the dimension's header causes explicit specialization errors

[Gold856]

MRE:

#include <units/velocity.h>
#include <units/length.h>
auto x = 0_mps / 0_m;
#include <units/frequency.h>

This is particularly problematic when going between linear and angular velocities, since you'll briefly cancel out the distance unit before applying a new distance unit, so one of the expressions will result in Hz, effectively, which then conflicts with the frequency definitions.

[nholthaus]

Fixed in v3.4.0 (PR #358): strong-type resolution is now an ADL customization point rather than an explicit template specialization, so an expression that reduces to a not-yet-included dimension (e.g. velocity/length) no longer triggers 'explicit specialization after instantiation'. Verified on GCC 13/15, Clang 19, and MSVC.