class RSpec::Support::Source::ExpressionSequenceNode
@private Basically ‘Ripper.sexp` generates arrays whose first element is a symbol (type of sexp), but it exceptionally generates typeless arrays for expression sequence:
Ripper.sexp(‘foo; bar’)
> [¶ ↑
:program, [ # Typeless array [:vcall, [:@ident, "foo", [1, 0]]], [:vcall, [:@ident, "bar", [1, 5]]] ] ]
We wrap typeless arrays in this pseudo type node so that it can be handled in the same way as other type node.