Why mockgen generates all interfaces in file?

I have a package with interfaces

package worker

import "context"

//go:generate mockgen -source interfaces.go -destination mock-interfaces.go -package worker Doer

type (
    Doer interface {
        Do(ctx context.Context) error
    }

    LazyThing interface {
        Rest(ctx context.Context) error
    }
)

I assumed that mock class will be generated for Doer interface only. But I always get mocks for both.

How can I limit the list of processed interfaces?