[4 T] is the type syntax and is unchanged; it already works in a defvar, a
parameter, a field and a return. A let binding is the one position with no
type slot, and there the brackets are an array literal of two elements whose
second is a type name — which came back as "unknown name rl/Vector2" and cost
32 hand-written Vector2s in one raylib example.
(array COUNT TYPE) is a parser form rather than a builtin call, because the
second argument is a type and the parser's callers have none. Parse assembles
the Tarray itself, so the count takes a constant's name for free and a value
in the type position is refused by the type reader's own message. The checker
resolves it to Tast.Zero — no new backend node and no new type.
(zeroed [4 T]) was proposed first and rejected: the parser can tell, a person
cannot. zeroed keeps its job of being inferred; array is the one that is told.
Joseph Ferano
9f4a59c56f