Some comments not emitted - upgrade 1.0.1 to 1.3.0

[jbondc]

more file.ts

// test
var f = ''
// test #2
module foo {
        function bar() { }
}
// test #3
module empty {
}
// test #4

more file.js

// test
var f = '';
// test #2
var foo;
(function (foo) {
    function bar() {
    }
})(foo || (foo = {}));

Looks like comments after a 'block' aren't emitted. Could it be a missing emitTrailingComments(node) ?

[DanielRosenwasser]

Just to be clear, when you say 1.0.3, do you mean 1.3.0?

[jbondc]

Yip, corrected the title. I attempted a patch here:
https://github.com/jbondc/TypeScript/compare/debug

Tried to get rid of the trailingSeparator logic, still a few fixes needed.

[DanielRosenwasser]

Not to deflect from your current work, but it may be worth seeing what @sheetalkamat has to say about this issue and what the most appropriate fix is in general

[jbondc]

Thanks @DanielRosenwasser, I'll wait for feedback.

Updated the patch with a couple of fixes. 2729 tests failing though most are because newlines are preserved for single line comments.

[jbondc]

So I think I found the right idea to fix & improve, mainly simplify scanner & parser using:

    export interface CommentRange extends TextRange {
        leadingWhitespace?: string;
        trailingWhitespace?: string;
        isAttached?: boolean; /* attached to a Node (trailingWhitespace has at most 1 newline) */
        isFollowed?: boolean; /* followed *//* by another comment */
    }

The other bit is not emitting comments attached to !isDeclarationVisible(node)

As a heads up, only working on compiler scanner.ts emitter.ts, parser.ts

[CyrusNajmabadi]

Hey @jbondc I'm going to be doing a little bit of work related to this. Namely, the introduction of an EndOfFile node to the ast. This should address the case where // test #4 is not in the final tree.

Note: it is by design that test #3 is not in the final tree.

[jbondc]

Super @CyrusNajmabadi, EndOfFile node sounds great. Pushed latest experiment and test case I'm using:
https://github.com/jbondc/TypeScript/blob/debug/tests/cases/compiler/commentsWhitespace.ts

Thought: when scanning can determine 'isAttached', 'isFollowed' & keep whitespace?
https://github.com/jbondc/TypeScript/blob/debug/src/compiler/scanner.ts#L872

Would avoid re-scanning (though don't know about services.ts / keeping in memory):
https://github.com/jbondc/TypeScript/blob/debug/src/compiler/scanner.ts#L373

[synaesthesia]

The bug still exists in 1.5.3. And it's not all blocks:

function hello(ok: boolean) {
        if (ok) {
                console.log("ok1");
                // will be removed
        }
        // will be removed too
        else {
                console.log("ok2");
        }
        // will stay
}

hello(true);

compiles to

function hello(ok) {
    if (ok) {
        console.log("ok1");
    }
    else {
        console.log("ok2");
    }
    // will stay
}
hello(true);

[alvarorahul]

So, this reproduces in TypeScript 1.6 as well

Here's another case where it gets stripped out

export = Main;
module Main {
    // stays

    class Foo {
        // stays
        public bar = 5;
        // gets removed
        }

    // gets removed
}

[DickvdBrink]

The last example is solved and it looks likes the first post is now correct to; only test is removed but as @CyrusNajmabadi mentioned #1311 (comment) that is by design.
So maybe close this one?

[timocov]

Another cases (moved from #26079 (comment)):

index.ts

// comment 1

import * as Module from './module';

// comment 2

import { SomeInterface } from './module';

export type A = typeof Module & SomeInterface;

module.ts

export interface SomeInterface {}

After compiling we get the next content in index.js (for es2015 module):

// comment 1

(it seems that new line after/before comment does not help - #26079 (comment))

function foo() {
  return {
    foo: 5,
    // this comment will be emitted
    bar: 10,
    // but this one wouldn't
  };
}