In reply to a72:
That gets interpreted as
bins ar1 = (1'b0 => (1'b1 || 1'b1) => 1'b0);
// resolves to
bins ar1 = (8'h00 => 8'h01 => 8'h00);
Which is probably not what you are expecting. See Bitwise toggle coverage for a bitvector | Verification Academy