Function conflictingCollapsedRange

src/codemirror.js:6571–6585

(doc, lineNo, from, to, marker)

  // overlaps (covers the start or end, but not both) of a new span.
  // Such overlap is not allowed.
  function conflictingCollapsedRange(doc, lineNo, from, to, marker) {
    var line = getLine(doc, lineNo);
    var sps = sawCollapsedSpans && line.markedSpans;
    if (sps) for (var i = 0; i < sps.length; ++i) {
      var sp = sps[i];
      if (!sp.marker.collapsed) continue;
      var found = sp.marker.find(0);
      var fromCmp = cmp(found.from, from) || extraLeft(sp.marker) - extraLeft(marker);
      var toCmp = cmp(found.to, to) || extraRight(sp.marker) - extraRight(marker);
      if (fromCmp >= 0 && toCmp <= 0 || fromCmp <= 0 && toCmp >= 0) continue;
      if (fromCmp <= 0 && (sp.marker.inclusiveRight && marker.inclusiveLeft ? cmp(found.to, from) >= 0 : cmp(found.to, from) > 0) ||
          fromCmp >= 0 && (sp.marker.inclusiveRight && marker.inclusiveLeft ? cmp(found.from, to) <= 0 : cmp(found.from, to) < 0))
        return true;
    }
  }

  // A visual line is a line as drawn on the screen. Folding, for
  // example, can cause multiple logical lines to appear on the same