go - cannot use address (type string) as type AccountAddress in assignment

Question

I'm facing an issue while assignment of a string with a type of type AccountAddress [16]uint8.

type AccountAddress [16]uint8

address := c.Param("adress")
var account AccountAddress
account = address

Error cannot use address (type string) as type AccountAddress in assignment

Tried:

 var account diemtypes.AccountAddress
 account = []uint8(address)

Error cannot use ([]uint8)(address) (type []uint8) as type diemtypes.AccountAddress in assignment

Can anyone please help me in this.

question from:https://stackoverflow.com/questions/65840381/cannot-use-address-type-string-as-type-accountaddress-in-assignment

Answer 1

Here you are confusing many basic things thing. Let me clear them on by one

1. In golang custom types are treated as separate types even both are defined with the same built-in type

For example

    type StringType1 string 
    type StringType2 string
    
    var name1 StringType1="Umar"
    var name2 StringType2="Hayat"
    
    fmt.Println("StringType1 : ", name1)
    fmt.Println("StringType2 : ", name2)

The output of the above code is https://play.golang.org/p/QDcaM1IolbJ

StringType1 :  Umar
StringType2 :  Hayat

Here we have two custom types StringType1 and StringType2 both are defined by string`. But we can not assign a variable of these two types to each other directly until we convert them to the required type e.g

    name1=name2

Output

cannot use name2 (type StringType2) as type StringType1 in assignment

Similar is the case with your code. You are converting a string to a custom type without applying conversion.

2. Second you are trying to convert a string to a byte array of fixed length 15 and type uint8. This can be done as mentioned by @Cerise Limon

copy(account[:], c.Param("adress"))

But keep one thing here in mind you are copying string to unit8 type so you should not expect characters in account instead it will be ASCI values of that string character. I hope it will clear all your miss conceptions.