输入noRows struct {} var _ Result = noRows {}

Question

type noRows struct{}

var _ Result = noRows{}

My question is why initialize a variable but discard it immediately？

Answer 1

Some people use a line like as an interface check. This line ensures that the type noRows implements the Result interface. If it doesn't you will get a compiler error.

I believe checks like that are unnecessary. Normally any type of test involving that type will tell you when a type does not satisfy and important interface. In very rare cases, you can add a conversion test to your unit tests.