Assertion of parseJsImport fails

[Sehun0819]

Assertion in parseJsImport function can fail, so I guess it should be properly treated instead of assertion.

• Representative example:

  import@

The problem is, parseJsFfiDeclaration happens to return None which violates assertion.
I patched it by handling None case with an empty declaration, but I'm not sure it is a right way.

[cristianoc]

See how other errors are handled.
E.g. just a few lines above here:

Parser.err ~startPos:attrLoc.loc_start ~endPos:attrLoc.loc_end p
        (Diagnostics.message (ErrorMessages.attributeWithoutNode attr));

Currently it goes all the way to the end of the file silently (e.g. in the provided test).

[cristianoc]

Also see this example for where to define the default value to use (inside Recover:

    Parser.err p (Diagnostics.unexpected token p.breadcrumbs);
    Recover.defaultModuleExpr ()

[Sehun0819]

@cristianoc Please check what I added for error handling.
And, do you mean it's better to define the default value(JsFfi.emptyDecl, I made) inside Recover module?
It seems that all default values in Recover are Ast of Ocaml compiler, while Js ffi decls are not.

[IwanKaramazow]

FWIW import was a leftover from an experiment that we were never able to ship. Seems like the community found it a very bad thing (#217). Maybe the code path in the parser should just be removed?

[Sehun0819]

@IwanKaramazow Thank you for informing of what was going on.
I had been curious because the source code seemed to accept more grammar than documentation, finally got an answer :)

[cristianoc]

Let's remove it.

[cristianoc]

I guess it means starting over with this PR

[Sehun0819]

Then, should I close this PR? 🤔

[cristianoc]

Or just undo the changes. Don't think anything will stay.

[cristianoc]

The idea is to literally remove parsing "import".

[cristianoc]

The same goes for "export".

[cristianoc]

Here's what it would look like: #597

after removing all the resulting dead code reported from the analysis which runs on make test.

The same goes for export.