subtype: Teach obvious_subtype about Intersect (#61950)

Fixes regression noted in
https://github.com/JuliaLang/julia/pull/61940#issuecomment-4579764722.
Bug analyzed by GPT 5.5 Pro. Fix implemented by GPT 5.5.

Keno Fischer committed 3mo ago

6765a54061494888e5c6aa2a4ab938965b4bf714

Parent: e092315

Committed by GitHub <noreply@github.com> on 5/30/2026, 3:46:41 AM