Never compare the address of a variable to nil (e.g., `&x == nil`). To check if a pointer is nil, compare the pointer itself to nil. The address of a variable (`&x`) will always be non-nil if `x` exists.
Comparing `&x` to nil is a logical mistake; the condition will never be true (unless x is a nil pointer itself and you're taking the address of a pointer variable incorrectly). This bug can lead to code that never runs or always runs unexpectedly, since the condition is based on a false premise.
Side-by-side examples engineers can pattern-match during review.
var ptr *int
if &ptr != nil {
// This block will always execute, even if ptr is nil
fmt.Println("ptr is not nil")
}var ptr *int
if ptr != nil {
// This will execute only if ptr points to a value
fmt.Println("ptr is not nil")
}var ptr *int
if &ptr != nil {
// This block will always execute, even if ptr is nil
fmt.Println("ptr is not nil")
}var ptr *int
if ptr != nil {
// This will execute only if ptr points to a value
fmt.Println("ptr is not nil")
}From the same buckets as this rule.
Check if loops use equality operators (== or !=) in termination conditions. These can lead to infinite loops if the condition is never met exactly. Instead, use relational operators like < or > for safer loop termination.