Given this Magefile at site.go/project:

// +build mage

package main

import (
	// mage:import
	"site.com/project/subfolder"
)

var Aliases = map[string]interface{}{
	"fizz": subfolder.Foo.Bar,
}

And this single go file being imported from site.go/project/subfolder:

// +build mage

package subfolder

import (
	"github.com/magefile/mage/mg"
)

type Foo mg.Namespace

func (Foo) Bar() error {
	return nil
}

The following warning is received on running mage: warning: alias declaration (fizz) does not reference a mage target

Following this, mage exits with status 1.

mage -version outputs:

Mage Build Tool v1.7.1
Build Date: 2018-10-31T09:48:07-05:00
Commit: 11d1591
built with: go1.11

This was built on windows/amd64

The behavior expected would be for fizz to be a valid alias to the target in the subfolder.