Go - Cannot use as type in assignment

I'm new in Go Lang.

I confused why this error message still coming.
> cannot use cmd.Args() (type cli.Args) as type CmdArgs in assignment

The error message explain that cmd.Args() (type cli.Args) cannot assignment to type CmdArgs which is type CmdArgs is cli.Args.

I have read https://stackoverflow.com/questions/43900806/cannot-use-as-type-in-assignment-in-go, but it does not make me understand where's my wrong is. I think that's a different matter with me.

Any solution please?

Here's my code.

package main

import (
	"fmt"
	"os"

	"github.com/urfave/cli"
)

// CmdArgs is command arguments
type CmdArgs cli.Args

func main() {
	program := cli.NewApp()
	program.Action = func(cmd *cli.Context) error {
		var args CmdArgs
		args = cmd.Args()
               ▼▼▼▼▼▼▼▼▼
               cannot use cmd.Args() (type cli.Args) as type CmdArgs in assignment

		return nil
	}

	program.Run(os.Args)
}

Thanks for your attention.

The error means exactly what it says: you're trying to assign the return value of a function to a variable that's of a different type than the return value, which is invalid. When you define a new type, it's a new type, and not directly assignable. You can cast between them, but there is no implicit casting in Go - the cast must be done explicitly:

    var args CmdArgs
    normalArgs := cmd.Args()
    args = CmdArgs(normalArgs)

Though I have to wonder why you're creating a new type CmdArgs to begin with, but I assume there's some reason that's not indicated in the code example. You might have an easier time embedding rather than aliasing, however.

args is a variable of type CmdArgs which has a vairable of type cli.Args

Change your function to

package main

import (
    "fmt"
    "os"

    "github.com/urfave/cli"
)

func main() {
    program := cli.NewApp()
    program.Action = func(cmd *cli.Context) error {
        args := cmd.Args()
        return nil
    }

    program.Run(os.Args)
}

and it should run.