Comment Attachment is confused by comment within condintion

[lo1tuma]

Given the following code:

/* foo */
if (/* bar */  a) {}

produces the following partial AST when attachComment is enabled:

{
  "type": "IfStatement",
  "test": {
    "type": "Identifier",
    "name": "a",
    "leadingComments": [
      {
        "type": "Block",
        "value": " foo "
      },
      {
        "type": "Block",
        "value": " bar "
      }
    ]
  },
  "consequent": {
    "type": "BlockStatement",
    "body": []
  },
  "alternate": null
}

As you can see both comments are attached to the Identifier node of the IfStatement test.

If the comment in the test condition is not present, the first comment foo is directly attached to the IfStatement node.

/* foo */
if (a) {}

{
  "type": "IfStatement",
  "test": {
    "type": "Identifier",
    "name": "a"
  },
  "consequent": {
    "type": "BlockStatement",
    "body": []
  },
  "alternate": null,
  "leadingComments": [
    {
      "type": "Block",
      "value": " foo "
    }
  ]
}

I would expect a more reliable behavior of the comment attachment algorithm, so that the first comment foo is always attached to the same node (preferable the IfStatement node).

Same problem exists for WhileStatement and I would guess ForStatement, ForInStatement, and ForOfStatement.

[nzakas]

Agreed, seems like a bug. Comment attachment is hard.