无效的操作：currency.Name（）==货币（字符串和* config.Currency类型不匹配）

Question

I have a function that takes in a string, and checks to see if that string is present in a list of other strings. Simple enough.

func (s *Foo) validateCurrency(currency string) error {
    for _, currency := range s.Config.Currencies {
        if currency.Name() == currency {
            return nil
        }
    }
    return ErrCurrencyNotFound
}

This is the Currency struct:

type Currency struct {
    name    string
    // ...
}

func (c *Currency) Name() string {
    return c.name
}

Yet I seem to be getting this error:

invalid operation: currency.Name() == currency (mismatched types string and *config.Currency)

Why on earth is the Go compiler yelling at me? I don't get it... both are strings. currency.Name() returns a string. Why does the error say it returns a *config.Currency?

Answer 1

You're shadowing currency in the for loop. Look at this code for a simpler example: https://play.golang.org/p/UFmwqQ4JZtG

First assignment to currency -> func (s *Foo) validateCurrency(currency string) error {

Second assignment which shadows the first: -> for _, currency := range s.Config.Currencies {

Change one of those variable names for a fix.