adjust intersection notes, call for simplfying unions

Author: msullivan

peps/pep-0827.rst

@@ -665,6 +665,10 @@ Union processing
 * ``FromUnion[T]``: Returns a tuple containing all of the union
   elements, or a 1-ary tuple containing T if it is not a union.
 
+  The union should first be simplified by removing elements that are
+  subtypes of other elements, but *not* by replacing ``Literal[True,
+  False]`` with ``bool`` or vice-versa or similar.
+
   The goal here is to make it possible to lift operations over
   unions. Care ought to be taken when using this, since the particular
   order of elements is not specified; typically the result should be
@@ -1856,10 +1860,14 @@ Open Issues
   Arguably, though, we would like ``tuple[Any | None, ...]`` as the result,
   which would require some more careful thought to specify.
 
-* Would adding intersection types conflict with any of this, if they
-  are added? Would it be sufficient to add ``FromIntersection`` to
-  deal with it, in addition to specifying how the existing operators
-  should handle it?
+* Would intersection types conflict with any of this, if they are
+  added? Would it be sufficient to just specify how existing operators
+  should handle it (probably including that intersections should be
+  distributed over unions when doing ``FromUnion``, I'd guess, like TS
+  does for conditional types)? We could potentially add
+  ``FromIntersection``, but intersections simplify aggressively and it
+  is not clear it would be sensical. TypeScript does not have an
+  equivalent.
 
 * Should ``GetMemberType`` follow the descriptor protocol,
   ``__getattr__``, etc? (Currently the behavior is for it to