VERILOG2146: Overlapping items in case statement should be avoided

Summary

Reliability	Security	Maintainability	Code attribute	Effort to fix	Tags

HIGH	-	-	Intentionality \| Logical	10min	synthesis, vscode, linter, simulation

Description

A wildcard case statement contains overlapping items, which can be confusing since the overlapping value(s) will only ever match the first item in the list.

Noncompliant code example

module fly;
  logic [3:0] a;
  initial begin
    casez (a)
      4'b1011:;
      4'b101?:;
      default;
    endcase
  end
endmodule

Compliant solution

module fly;
  logic [3:0] a;
  initial begin
    casez (a)
      4'b1011:;
      4'b111?:;
      default;
    endcase
  end
endmodule

Parameters

No parameters.