gistfile1.v

module foo #(
	parameter BAR = 16,
	parameter BAZ = 8,
) (
	input [BAR - 1:0] bar,
	output [BAZ - 1:0] baz,
);
	/* ... */
endmodule

module top;
	wire [15:0] bar;
	wire [7:0] baz;

	foo fooi (
		.bar (bar),
		.baz (baz),
	);

	wire [fooi.BAR - 1:0] qux;
endmodule