One should actually not do one-line printing of nested aggregates even if they are not the base class
This check was overly strict. Relax it.
While one could conceivably want nested one-lining:
(Foo) aFoo = (x = 1, y = (t = 3, q = “Hello), z = 3.14)
the spirit of this feature is mostly to make *SMALL LINEAR* structs come out more compact.
Aggregates with children and no summary for now just disable the one-lining. Define a one-liner summary to override :)