Duplicate Case in Switch

Why This Happens

Go does not allow duplicate case values in switch statements because it would be ambiguous which case to execute. If you need two values to have the same behavior, list them in the same case clause separated by commas.

The Problem

switch x {
case 1:
    fmt.Println("one")
case 1: // duplicate case
    fmt.Println("also one")
}

The Fix

switch x {
case 1:
    fmt.Println("one")
case 2:
    fmt.Println("two")
}

Step-by-Step Fix

1. 1

   Identify the duplicate

   The compiler tells you the duplicate value and the line of the first occurrence.

2. 2

   Remove or merge

   Remove the duplicate case or combine the two cases into one: case 1, 2:.

3. 3

   Review switch logic

   Ensure the remaining cases correctly handle all expected values.