Cannot Fallthrough in Type Switch

Why This Happens

Unlike regular switch statements, type switches do not support the fallthrough keyword because the variable has a different type in each case block. If you need to handle multiple types the same way, list them in a single case separated by commas.

The Problem

func process(v interface{}) {
    switch v.(type) {
    case int:
        fallthrough // not allowed in type switch
    case int64:
        fmt.Println("integer type")
    }
}

The Fix

func process(v interface{}) {
    switch v.(type) {
    case int, int64:
        fmt.Println("integer type")
    }
}

Step-by-Step Fix

1. 1

   Identify the fallthrough

   Find the fallthrough keyword inside a type switch.

2. 2

   Combine cases

   List multiple types in a single case clause separated by commas.

3. 3

   Extract shared logic

   If cases need different handling but share some logic, extract the shared part into a function.