A float-default parameter handed None through a variable raised TypeError

Found 2026-10-20 in Vloot's GUI: Graph(parent, height, colours, top=100.0) is built from a metrics table where top is None for the auto-scaled graphs, and draw() asks if top is None:. The native build raised TypeError: expected a number, got NoneType from the first timer tick.

Cause: PyParamTypeFromSites lets the default anchor a scalar claim (float here) when a call site cannot be typed. That is deliberate (lekkerzeilen's Vec3 fields are typed this way). It is a bet that the untypeable site passes the default's type. Here the site passed a variable that is sometimes None. A literal None at a site already vetoed the claim; None through a variable could not.

Fix: before a scalar claim stands, look for a None test of the name (x is None, is not None, == None, != None, with or without a receiver) in the class body, or in the def body for a plain function. If there is one, make no claim, so the parameter stays a variant. The check matches on the token name only, so it can veto more often than needed but never less. A veto costs speed, never a wrong value. The n.psites debug channel reports it.

Test: test_nilpy_float_default_handed_none_through_a_variable (the pin raises on it).