logger -expect error "unique keyword cannot be used for 'else if' branch" 1
read_verilog -sv <<EOF
module top( input[2:0] a );
always_comb begin
    // invalid example from 1800-2012 12.4.2
    unique if ((a==0) || (a==1)) $display("0 or 1");
    else unique if (a == 2) $display("2");
    else if (a == 4) $display("4");
end
endmodule
EOF