// produced in build.(*Context).Import; modload.AmbiguousImportError,
	// and modload.PackageNotInModuleError; and the malformed module path errors
	// produced in golang.org/x/mod/module.CheckMod) implement an interface
	// to make it easier to check for them? That would save us from having to
	// move the modload errors into this package to avoid a package import cycle,