```go
for param := range fn.Signature().Params().Variables() {
   use(param)
}
```

The methods are:
[`Interface.EmbeddedTypes`](/pkg/go/types#Interface.EmbeddedTypes),
[`Interface.ExplicitMethods`](/pkg/go/types#Interface.ExplicitMethods),
[`Interface.Methods`](/pkg/go/types#Interface.Methods),
[`MethodSet.Methods`](/pkg/go/types#MethodSet.Methods),
[`Named.Methods`](/pkg/go/types#Named.Methods),

pkg go/types, method (*Interface) EmbeddedTypes() iter.Seq[Type] #66626
pkg go/types, method (*Interface) ExplicitMethods() iter.Seq[*Func] #66626
pkg go/types, method (*Interface) Methods() iter.Seq[*Func] #66626
pkg go/types, method (*MethodSet) Methods() iter.Seq[*Selection] #66626
pkg go/types, method (*Named) Methods() iter.Seq[*Func] #66626
pkg go/types, method (*Scope) Children() iter.Seq[*Scope] #66626
pkg go/types, method (*Struct) Fields() iter.Seq[*Var] #66626