Conditions, case, and unintended latches

Write complete choices, make priorities visible, and avoid storage created by omission.

What an if statement describes

Inside a combinational block, an if followed by else if branches describes a priority. The first true condition selects the result.

module request_priority (
  input  wire [2:0] i_request,
  output reg  [2:0] o_grant,
  output reg        o_valid
);
 
  always @* begin
    o_grant = 3'b000;
    o_valid = 1'b1;
 
    if (i_request[2])
      o_grant = 3'b100;
    else if (i_request[1