How line and column of SourceNode instance related to the contained chunk(s)?

[Mingun]

Working on the PR that enables support of source-maps for peggyjs parsers I found that high-level SourceNode API is not documented enough. In particular, it is non-obvious would SourceNode constructor automatically recalculate lines if chunk parameter is a multi-line string?

I have the following simplified code for generating source-map:

let userSourceCodeInGrammar = `potentially
   multi
   line
   string`;
// Actual SourceNode used for mapping is behind a hierarchy of SourceNodes
let node = new SourceNode(
  null, null, grammarSource,
  [
    "some code before",
    // actual mapping
    new SourceNode(
      line, column, grammarSource,
      userSourceCodeInGrammar
    ),
    "some code after",
  ]
);

let { code, map } = node.toStringWithSourceMap();

In the result, the code contains content of the userSourceCodeInGrammar as-is, but map maps all strings in it to the (line, column) supplied to the SourceNode constructor.

How to correctly work with multi-line code chunks?