using StringHash = System.Collections.Generic.Dictionary<string, string>;

public class Stuff
{
    static void Foo(StringHash.Enumerator she)
    {
    }
}

Put the caret onto 'Enumerator' and apply 'Use base type where possible'.
Select generic interface 'IEnumerator<T>'.
Unresolved symbols are intoduced into the code.

using System.Collections.Generic;
using StringHash = System.Collections.Generic.Dictionary<string, string>;

public class Stuff
{
    // error CS0246: The type or namespace name 'TKey' could not be found (are you missing a using directive or an assembly reference?)
    // error CS0246: The type or namespace name 'TValue' could not be found (are you missing a using directive or an assembly reference?)
    static void Foo(IEnumerator<KeyValuePair<TKey, TValue>> she)
    {
    }
}

Issue was closed