Cannot use symbols defined by internal packages

[nekketsuuu]

If an internal packages is imported on gore, an error "use of internal package not allowed" occurs after evaluating an expression which uses symbols defined in the internal package.

Steps to reproduce

$ echo $GOPATH
/Users/nekketsuuu/dev
$ pwd
/Users/nekketsuuu/dev/src/github.com/nekketsuuu/gore-internal
$ tree .
.
├── cmd
│   └── main.go
├── go.mod
├── internal
│   └── foo
│       └── foo.go
└── pkg
    └── bar
        └── bar.go

5 directories, 4 files
$ cat ./internal/foo/foo.go 
package foo

import "fmt"

func Hello() {
    fmt.Println("Hello!")
}
$ cat ./pkg/bar/bar.go 
package bar

import "fmt"

func World() {
    fmt.Println("World!")
}
$ cat ./cmd/main.go 
package main

import (
    "github.com/nekketsuuu/gore-internal/internal/foo"
    "github.com/nekketsuuu/gore-internal/pkg/bar"
)

func main() {
    foo.Hello()
    bar.World()
}
$ cat go.mod
module github.com/nekketsuuu/gore-internal

go 1.13
$ go run cmd/main.go  # The internal package can be imported normally from `go run`.
Hello!
World!
$ gore
gore version 0.5.0  :help for help
gore> :import github.com/nekketsuuu/gore-internal/internal/foo
gore> :import github.com/nekketsuuu/gore-internal/pkg/bar
gore> foo.Hello()
use of internal package github.com/nekketsuuu/gore-internal/internal/foo not allowed
gore> bar.World()
use of internal package github.com/nekketsuuu/gore-internal/internal/foo not allowed
gore> 
$ gore
gore version 0.5.0  :help for help
gore> :import github.com/nekketsuuu/gore-internal/pkg/bar
gore> bar.World()
World!
gore> 

Environment

• gore 0.5.0 (rev: HEAD/go1.13.6)
• go version go1.13.6 darwin/amd64
• macOS Mojave

[itchyny]

I don't think we can fix this. Maybe print error quickly on :import command?