Implement smart addition of use statements

[temporaryhamper]

Found with:

• IntelliJ IDEA 2017.2.6 Build #IU-172.4574.11
• Perl5 plugin 2017.3.2
• Perl 5.18.4
• Java 1.8.0_152-b16
• macOS Sierra 10.12.6

Steps to reproduce:

1. File -> New -> Project...
2. Select Perl5 module
3. Click Next
4. Enter a project location
5. Click Finish
6. Click OK to create the project directory
7. Select the sources root in the Project tools window
8. File -> New -> Package
9. Enter lib as the package name
10. Click OK to create the package
11. Select the sources root in the Project tools window
12. File -> New -> Package
13. Enter src as the package name
14. Click OK to create the package
15. IntelliJ IDEA -> Preferences...
16. Languages & Frameworks -> Perl5
17. Select Project
18. Select a Perl5 Interpreter
19. Select your project's name
20. Right-click lib and select Perl5 libraries
21. Click OK to save your preferences
22. Select lib in the Project tools window
23. File -> New -> Perl5 File
24. Enter MyModule as the file name
25. Select Package kind
26. Click OK to create the Perl module
27. Select src in the Project tools window
28. File -> New -> Perl5 File
29. Enter myscript as the file name
30. Select Script kind
31. Click OK to create the Perl script

Add the following contents to MyModule.pm and save:

package MyModule;

use strict;
use warnings FATAL => 'all';

require Exporter;
use vars qw(@ISA @EXPORT);
@ISA = qw(Exporter);
@EXPORT = qw(
    hello_world
);

sub hello_world()
{
    print "Hello, world\n";
}

1;

Add the following contents to myscript.pl:

#!/usr/bin/perl
use strict;
use warnings FATAL => 'all';

hello_world();

Expected results:

• When you enter hello_world, use MyModule; or use MyModule qw(hello_world); is automatically added to the top of the file, or a pop-up appears suggesting the name of a module to import

Actual results:

• No imports automatically appear
• When you hover over hello_world, a tooltip says:

  
  Unable to find sub definition, declaration, constant definition or typeglob aliasing

Check if sub has been defined, declared or aliased with a typeglob.

- The tooltip links to https://github.com/Camelcade/Perl5-IDEA/wiki/Subs-resolution-status for more information
- Whether you save `myscript.pl` or not doesn't make a difference

The following also doesn't help:
1. File -> Project Structure...
1. Select `Project`
1. Select a Java version for the Project SDK
1. Select `Modules`
1. Right-click `lib` and select `Sources`

It also doesn't help if you unmark the project root as `Sources`

If I'm doing something wrong, then I think this is at least a doc bug, as I couldn't find anything in the wiki documenting how to properly set up auto imports.

[hurricup]

And where is use MyModule in the myscript.pl ? :)

[temporaryhamper]

That's what I expect auto import to add. Much like what IDEs do for Java. I expect to type the name of a subroutine in a file and to see the module it's defined in to automatically be imported.

Type hello_world and that should trigger use MyModule qw(hello_world); (or at least use MyModule) to be added to the top of the file.

Additional detail, in case it's relevant:

• I'm using IdeaVim plugin 0.48

[hurricup]

Oh now I see. I thought it's about not resovled imported sub. No, there is no such feature yet. But if You'll add use manually, it should work.