Go Maps Explained: How Key-Value Pairs Are Actually Stored

func changeMap ( m2 map [ string ] int ) { m2 = map [ string ] int { "hello" : 2 } } func main () { m1 := map [ string ] int { "hello" : 1 } changeMap ( m1 ) println ( m1 [ "hello" ]) // 1 } But here’s the deal, while the hash function used for maps in Go is consistent across all maps with the same key type, the seed used by that hash function is different for each map instance. If the old bucket has overflow buckets, the map also moves the elements from these overflow buckets to the new buckets.