Lines are calculated wrong when relying on ASI

[eslint]

Lines are calculated wrong when relying on ASI

[lo1tuma]

Related esprima issue

[nzakas]

Ah yes, I've run into this as well. I'll need to dig into the spec a bit to figure out the right thing to do (I'm not sure if ASI means the semicolon is inserted at the end of input in this case or immediately after the paren).

[btmills]

This annoyed me as I was working on the token API, but I looked at the spec's rules for ASI, which seem to indicate that this is the correct behavior.

a semicolon is automatically inserted before the offending token

Then in an example,

{ 1
2 } 3

gets transformed into

{ 1
;2 ;} 3;

[btmills]

And more relevant to this case in particular:

When, as the program is parsed from left to right, the end of the input stream of tokens is encountered and the parser is unable to parse the input token stream as a single complete ECMAScript Program, then a semicolon is automatically inserted at the end of the input stream.

(Emphasis mine)

[nzakas]

Thanks for the research, that matched up with my expectation. So it seems like we are doing the right thing in this case.

[lo1tuma]

Thanks for the clarification 🍻.

[aaronabramov]

is this still considered the right behavior?
https://github.com/jquery/esprima seems to not have this issue any more

a()

{
    "loc": {
        "start": {
            "line": 1,
            "column": 0
        },
        "end": {
            "line": 1,
            "column": 3
        }
    },
    "type": "Program",
    "body": [
        {
            "loc": {
                "start": {
                    "line": 1,
                    "column": 0
                },
                "end": {
                    "line": 1,
                    "column": 3
                }
            },
            "type": "ExpressionStatement",
            "expression": {
                "loc": {
                    "start": {
                        "line": 1,
                        "column": 0
                    },
                    "end": {
                        "line": 1,
                        "column": 3
                    }
                },
                "type": "CallExpression",
                "callee": {
                    "loc": {
                        "start": {
                            "line": 1,
                            "column": 0
                        },
                        "end": {
                            "line": 1,
                            "column": 1
                        }
                    },
                    "type": "Identifier",
                    "name": "a"
                },
                "arguments": []
            }
        }
    ],
    "sourceType": "script"
}

[aaronabramov]

the problem that i found is that when comment option is set to true, the comment range overlaps with node ranges and it's very hard to identify where the comment belongs to
e.g.

// nodes
{
  type: 'Identifier',
  range: [20, 36]
}
/// comments
{
  type: 'Line',
  range: [25, 36]