A const that kept its initializer's layout records the initializer's
checker type by declaration symbol. A function body lowers once per
instance, and only an instance for a wider argument keeps the layout, so
the record from that instance made the function's own lowering bind the
wider layout for `grow(alias)`: the argument converted into a copy and the
callee's writes did not reach the caller. The recorded type now applies
only while it maps to the layout of the binding the current lowering
resolves.
Chris Tate
e9977107fe