conv_geometry test fails with PG9.6 and Ruby2.4 on Ubuntu

[koizumistr]

test.out is like this:

set client_min_messages = 'WARNING';
create table pl_box (
data box, barea float, boverlaps bool, boverleft bool, boverright bool,
bleft bool, bright bool
);
create or replace function box_val(box[]) returns setof pl_box as '
b1 = Box.new(2.5,2.5,1.0,1.0)
b2 = Box.new(2.0,2.0,2.5,2.5)
b3 = Box.new(3.0,3.0,5.0,5.0)
args[0].each do |b|
yield [b, b.area, b.overlap?(b1), b.overleft?(b2),
b.overright?(b2), b.left?(b3), b3.right?(b)]
end
' language 'plruby';
select * from
box_val('{(2.0,2.0,0.0,0.0);(1.0,1.0,3.0,3.0);(2.5,2.5,2.5,3.5);(3.0,3.0,3.0,3.0)}'::box[]);
server closed the connection unexpectedly
This probably means the server terminated abnormally
before or while processing the request.
connection to server was lost

[koizumistr]

test succeeds with Ruby 2.3!