--- a/devtools/client/sourceeditor/codemirror/README
+++ b/devtools/client/sourceeditor/codemirror/README
@@ -1,16 +1,16 @@
 This is the CodeMirror editor packaged for the Mozilla Project. CodeMirror
 is a JavaScript component that provides a code editor in the browser. When
 a mode is available for the language you are coding in, it will color your
 code, and optionally help with indentation.
 
 # Upgrade
 
-Currently used version is 5.14.2. To upgrade, download a new version of
+Currently used version is 5.15.2. To upgrade, download a new version of
 CodeMirror from the project's page [1] and replace all JavaScript and
 CSS files inside the codemirror directory [2].
 
 To confirm the functionality run mochitests for the following components:
 
  * sourceeditor
  * scratchpad
  * debugger

--- a/devtools/client/sourceeditor/codemirror/addon/edit/closebrackets.js
+++ b/devtools/client/sourceeditor/codemirror/addon/edit/closebrackets.js
@@ -104,17 +104,17 @@
     var pos = pairs.indexOf(ch);
     if (pos == -1) return CodeMirror.Pass;
     var triples = getOption(conf, "triples");
 
     var identical = pairs.charAt(pos + 1) == ch;
     var ranges = cm.listSelections();
     var opening = pos % 2 == 0;
 
-    var type, next;
+    var type;
     for (var i = 0; i < ranges.length; i++) {
       var range = ranges[i], cur = range.head, curType;
       var next = cm.getRange(cur, Pos(cur.line, cur.ch + 1));
       if (opening && !range.empty()) {
         curType = "surround";
       } else if ((identical || !opening) && next == ch) {
         if (triples.indexOf(ch) >= 0 && cm.getRange(cur, Pos(cur.line, cur.ch + 3)) == ch + ch + ch)
           curType = "skipThree";

--- a/devtools/client/sourceeditor/codemirror/addon/fold/brace-fold.js
+++ b/devtools/client/sourceeditor/codemirror/addon/fold/brace-fold.js
@@ -8,17 +8,17 @@
     define(["../../lib/codemirror"], mod);
   else // Plain browser env
     mod(CodeMirror);
 })(function(CodeMirror) {
 "use strict";
 
 CodeMirror.registerHelper("fold", "brace", function(cm, start) {
   var line = start.line, lineText = cm.getLine(line);
-  var startCh, tokenType;
+  var tokenType;
 
   function findOpening(openCh) {
     for (var at = start.ch, pass = 0;;) {
       var found = at <= 0 ? -1 : lineText.lastIndexOf(openCh, at - 1);
       if (found == -1) {
         if (pass == 1) break;
         pass = 1;
         at = lineText.length;
@@ -67,39 +67,39 @@ CodeMirror.registerHelper("fold", "impor
     if (start.type != "keyword" || start.string != "import") return null;
     // Now find closing semicolon, return its position
     for (var i = line, e = Math.min(cm.lastLine(), line + 10); i <= e; ++i) {
       var text = cm.getLine(i), semi = text.indexOf(";");
       if (semi != -1) return {startCh: start.end, end: CodeMirror.Pos(i, semi)};
     }
   }
 
-  var start = start.line, has = hasImport(start), prev;
-  if (!has || hasImport(start - 1) || ((prev = hasImport(start - 2)) && prev.end.line == start - 1))
+  var startLine = start.line, has = hasImport(startLine), prev;
+  if (!has || hasImport(startLine - 1) || ((prev = hasImport(startLine - 2)) && prev.end.line == startLine - 1))
     return null;
   for (var end = has.end;;) {
     var next = hasImport(end.line + 1);
     if (next == null) break;
     end = next.end;
   }
-  return {from: cm.clipPos(CodeMirror.Pos(start, has.startCh + 1)), to: end};
+  return {from: cm.clipPos(CodeMirror.Pos(startLine, has.startCh + 1)), to: end};
 });
 
 CodeMirror.registerHelper("fold", "include", function(cm, start) {
   function hasInclude(line) {
     if (line < cm.firstLine() || line > cm.lastLine()) return null;
     var start = cm.getTokenAt(CodeMirror.Pos(line, 1));
     if (!/\S/.test(start.string)) start = cm.getTokenAt(CodeMirror.Pos(line, start.end + 1));
     if (start.type == "meta" && start.string.slice(0, 8) == "#include") return start.start + 8;
   }
 
-  var start = start.line, has = hasInclude(start);
-  if (has == null || hasInclude(start - 1) != null) return null;
-  for (var end = start;;) {
+  var startLine = start.line, has = hasInclude(startLine);
+  if (has == null || hasInclude(startLine - 1) != null) return null;
+  for (var end = startLine;;) {
     var next = hasInclude(end + 1);
     if (next == null) break;
     ++end;
   }
-  return {from: CodeMirror.Pos(start, has + 1),
+  return {from: CodeMirror.Pos(startLine, has + 1),
           to: cm.clipPos(CodeMirror.Pos(end))};
 });
 
 });

--- a/devtools/client/sourceeditor/codemirror/addon/fold/xml-fold.js
+++ b/devtools/client/sourceeditor/codemirror/addon/fold/xml-fold.js
@@ -135,19 +135,19 @@
   }
 
   CodeMirror.registerHelper("fold", "xml", function(cm, start) {
     var iter = new Iter(cm, start.line, 0);
     for (;;) {
       var openTag = toNextTag(iter), end;
       if (!openTag || iter.line != start.line || !(end = toTagEnd(iter))) return;
       if (!openTag[1] && end != "selfClose") {
-        var start = Pos(iter.line, iter.ch);
-        var close = findMatchingClose(iter, openTag[2]);
-        return close && {from: start, to: close.from};
+        var startPos = Pos(iter.line, iter.ch);
+        var endPos = findMatchingClose(iter, openTag[2]);
+        return endPos && {from: startPos, to: endPos.from};
       }
     }
   });
   CodeMirror.findMatchingTag = function(cm, pos, range) {
     var iter = new Iter(cm, pos.line, pos.ch, range);
     if (iter.text.indexOf(">") == -1 && iter.text.indexOf("<") == -1) return;
     var end = toTagEnd(iter), to = end && Pos(iter.line, iter.ch);
     var start = end && toTagStart(iter);

--- a/devtools/client/sourceeditor/codemirror/keymap/sublime.js
+++ b/devtools/client/sourceeditor/codemirror/keymap/sublime.js
@@ -119,16 +119,17 @@
         var at = Pos(head.line + (above ? 0 : 1), 0);
         cm.replaceRange("\n", at, null, "+insertLine");
         cm.indentLine(at.line, null, true);
         newSelection.push({head: at, anchor: at});
         last = head.line + 1;
       }
       cm.setSelections(newSelection);
     });
+    cm.execCommand("indentAuto");
   }
 
   cmds[map[ctrl + "Enter"] = "insertLineAfter"] = function(cm) { return insertLine(cm, false); };
 
   cmds[map["Shift-" + ctrl + "Enter"] = "insertLineBefore"] = function(cm) { return insertLine(cm, true); };
 
   function wordAt(cm, pos) {
     var start = pos.ch, end = start, line = cm.getLine(pos.line);
@@ -414,37 +415,16 @@
         at = word.from;
         cm.replaceRange(mod(word.word), word.from, word.to);
       }
     });
   }
 
   map[cK + ctrl + "Backspace"] = "delLineLeft";
 
-  cmds[map["Backspace"] = "smartBackspace"] = function(cm) {
-    if (cm.somethingSelected()) return CodeMirror.Pass;
-
-    var cursor = cm.getCursor();
-    var toStartOfLine = cm.getRange({line: cursor.line, ch: 0}, cursor);
-    var column = CodeMirror.countColumn(toStartOfLine, null, cm.getOption("tabSize"));
-    var indentUnit = cm.getOption("indentUnit");
-
-    if (toStartOfLine && !/\S/.test(toStartOfLine) && column % indentUnit == 0) {
-      var prevIndent = new Pos(cursor.line,
-        CodeMirror.findColumn(toStartOfLine, column - indentUnit, indentUnit));
-
-      // If no smart delete is happening (due to tab sizing) just do a regular delete
-      if (prevIndent.ch == cursor.ch) return CodeMirror.Pass;
-
-      return cm.replaceRange("", prevIndent, cursor, "+delete");
-    } else {
-      return CodeMirror.Pass;
-    }
-  };
-
   cmds[map[cK + ctrl + "K"] = "delLineRight"] = function(cm) {
     cm.operation(function() {
       var ranges = cm.listSelections();
       for (var i = ranges.length - 1; i >= 0; i--)
         cm.replaceRange("", ranges[i].anchor, Pos(ranges[i].to().line), "+delete");
       cm.scrollIntoView();
     });
   };

--- a/devtools/client/sourceeditor/codemirror/keymap/vim.js
+++ b/devtools/client/sourceeditor/codemirror/keymap/vim.js
@@ -3777,27 +3777,20 @@
       if (cm.openNotification) {
         cm.openNotification('<span style="color: red">' + text + '</span>',
                             {bottom: true, duration: 5000});
       } else {
         alert(text);
       }
     }
     function makePrompt(prefix, desc) {
-      var raw = '';
-      if (prefix) {
-        raw += '<span style="font-family: monospace">' + prefix + '</span>';
-      }
-      raw += '<input type="text"/> ' +
-          '<span style="color: #888">';
-      if (desc) {
-        raw += '<span style="color: #888">';
-        raw += desc;
-        raw += '</span>';
-      }
+      var raw = '<span style="font-family: monospace; white-space: pre">' +
+          (prefix || "") + '<input type="text"></span>';
+      if (desc)
+        raw += ' <span style="color: #888">' + desc + '</span>';
       return raw;
     }
     var searchPromptDesc = '(Javascript regexp)';
     function showPrompt(cm, options) {
       var shortText = (options.prefix || '') + ' ' + (options.desc || '');
       var prompt = makePrompt(options.prefix, options.desc);
       dialog(cm, prompt, shortText, options.onClose, options);
     }

--- a/devtools/client/sourceeditor/codemirror/lib/codemirror.css
+++ b/devtools/client/sourceeditor/codemirror/lib/codemirror.css
@@ -47,17 +47,17 @@
   width: 0;
 }
 /* Shown when moving in bi-directional text */
 .CodeMirror div.CodeMirror-secondarycursor {
   border-left: 1px solid silver;
 }
 .cm-fat-cursor .CodeMirror-cursor {
   width: auto;
-  border: 0;
+  border: 0 !important;
   background: #7e7;
 }
 .cm-fat-cursor div.CodeMirror-cursors {
   z-index: 1;
 }
 
 .cm-animate-fat-cursor {
   width: auto;

--- a/devtools/client/sourceeditor/codemirror/lib/codemirror.js
+++ b/devtools/client/sourceeditor/codemirror/lib/codemirror.js
@@ -1091,50 +1091,52 @@
   function minPos(a, b) { return cmp(a, b) < 0 ? a : b; }
 
   // INPUT HANDLING
 
   function ensureFocus(cm) {
     if (!cm.state.focused) { cm.display.input.focus(); onFocus(cm); }
   }
 
-  // This will be set to an array of strings when copying, so that,
-  // when pasting, we know what kind of selections the copied text
-  // was made out of.
+  // This will be set to a {lineWise: bool, text: [string]} object, so
+  // that, when pasting, we know what kind of selections the copied
+  // text was made out of.
   var lastCopied = null;
 
   function applyTextInput(cm, inserted, deleted, sel, origin) {
     var doc = cm.doc;
     cm.display.shift = false;
     if (!sel) sel = doc.sel;
 
     var paste = cm.state.pasteIncoming || origin == "paste";
-    var textLines = doc.splitLines(inserted), multiPaste = null;
+    var textLines = doc.splitLines(inserted), multiPaste = null
     // When pasing N lines into N selections, insert one line per selection
     if (paste && sel.ranges.length > 1) {
-      if (lastCopied && lastCopied.join("\n") == inserted) {
-        if (sel.ranges.length % lastCopied.length == 0) {
+      if (lastCopied && lastCopied.text.join("\n") == inserted) {
+        if (sel.ranges.length % lastCopied.text.length == 0) {
           multiPaste = [];
-          for (var i = 0; i < lastCopied.length; i++)
-            multiPaste.push(doc.splitLines(lastCopied[i]));
+          for (var i = 0; i < lastCopied.text.length; i++)
+            multiPaste.push(doc.splitLines(lastCopied.text[i]));
         }
       } else if (textLines.length == sel.ranges.length) {
         multiPaste = map(textLines, function(l) { return [l]; });
       }
     }
 
     // Normal behavior is to insert the new text into every selection
     for (var i = sel.ranges.length - 1; i >= 0; i--) {
       var range = sel.ranges[i];
       var from = range.from(), to = range.to();
       if (range.empty()) {
         if (deleted && deleted > 0) // Handle deletion
           from = Pos(from.line, from.ch - deleted);
         else if (cm.state.overwrite && !paste) // Handle overwrite
           to = Pos(to.line, Math.min(getLine(doc, to.line).text.length, to.ch + lst(textLines).length));
+        else if (lastCopied && lastCopied.lineWise && lastCopied.text.join("\n") == inserted)
+          from = to = Pos(from.line, 0)
       }
       var updateInput = cm.curOp.updateInput;
       var changeEvent = {from: from, to: to, text: multiPaste ? multiPaste[i % multiPaste.length] : textLines,
                          origin: origin || (paste ? "paste" : cm.state.cutIncoming ? "cut" : "+input")};
       makeChange(cm.doc, changeEvent);
       signalLater(cm, "inputRead", cm, changeEvent);
     }
     if (inserted && !paste)
@@ -1257,28 +1259,28 @@
 
         cm.state.pasteIncoming = true;
         input.fastPoll();
       });
 
       function prepareCopyCut(e) {
         if (signalDOMEvent(cm, e)) return
         if (cm.somethingSelected()) {
-          lastCopied = cm.getSelections();
+          lastCopied = {lineWise: false, text: cm.getSelections()};
           if (input.inaccurateSelection) {
             input.prevInput = "";
             input.inaccurateSelection = false;
-            te.value = lastCopied.join("\n");
+            te.value = lastCopied.text.join("\n");
             selectInput(te);
           }
         } else if (!cm.options.lineWiseCopyCut) {
           return;
         } else {
           var ranges = copyableRanges(cm);
-          lastCopied = ranges.text;
+          lastCopied = {lineWise: true, text: ranges.text};
           if (e.type == "cut") {
             cm.setSelections(ranges.ranges, null, sel_dontScroll);
           } else {
             input.prevInput = "";
             te.value = ranges.text.join("\n");
             selectInput(te);
           }
         }
@@ -1616,40 +1618,40 @@
         if (input.composing) return;
         if (cm.isReadOnly() || !input.pollContent())
           runInOp(input.cm, function() {regChange(cm);});
       });
 
       function onCopyCut(e) {
         if (signalDOMEvent(cm, e)) return
         if (cm.somethingSelected()) {
-          lastCopied = cm.getSelections();
+          lastCopied = {lineWise: false, text: cm.getSelections()};
           if (e.type == "cut") cm.replaceSelection("", null, "cut");
         } else if (!cm.options.lineWiseCopyCut) {
           return;
         } else {
           var ranges = copyableRanges(cm);
-          lastCopied = ranges.text;
+          lastCopied = {lineWise: true, text: ranges.text};
           if (e.type == "cut") {
             cm.operation(function() {
               cm.setSelections(ranges.ranges, 0, sel_dontScroll);
               cm.replaceSelection("", null, "cut");
             });
           }
         }
         // iOS exposes the clipboard API, but seems to discard content inserted into it
         if (e.clipboardData && !ios) {
           e.preventDefault();
           e.clipboardData.clearData();
-          e.clipboardData.setData("text/plain", lastCopied.join("\n"));
+          e.clipboardData.setData("text/plain", lastCopied.text.join("\n"));
         } else {
           // Old-fashioned briefly-focus-a-textarea hack
           var kludge = hiddenTextarea(), te = kludge.firstChild;
           cm.display.lineSpace.insertBefore(kludge, cm.display.lineSpace.firstChild);
-          te.value = lastCopied.join("\n");
+          te.value = lastCopied.text.join("\n");
           var hadFocus = document.activeElement;
           selectInput(te);
           setTimeout(function() {
             cm.display.lineSpace.removeChild(kludge);
             hadFocus.focus();
           }, 50);
         }
       }
@@ -1658,19 +1660,19 @@
     },
 
     prepareSelection: function() {
       var result = prepareSelection(this.cm, false);
       result.focus = this.cm.state.focused;
       return result;
     },
 
-    showSelection: function(info) {
+    showSelection: function(info, takeFocus) {
       if (!info || !this.cm.display.view.length) return;
-      if (info.focus) this.showPrimarySelection();
+      if (info.focus || takeFocus) this.showPrimarySelection();
       this.showMultipleSelections(info);
     },
 
     showPrimarySelection: function() {
       var sel = window.getSelection(), prim = this.cm.doc.sel.primary();
       var curAnchor = domToPos(this.cm, sel.anchorNode, sel.anchorOffset);
       var curFocus = domToPos(this.cm, sel.focusNode, sel.focusOffset);
       if (curAnchor && !curAnchor.bad && curFocus && !curFocus.bad &&
@@ -3096,42 +3098,42 @@
       op.adjustWidthTo = measureChar(cm, display.maxLine, display.maxLine.text.length).left + 3;
       cm.display.sizerWidth = op.adjustWidthTo;
       op.barMeasure.scrollWidth =
         Math.max(display.scroller.clientWidth, display.sizer.offsetLeft + op.adjustWidthTo + scrollGap(cm) + cm.display.barWidth);
       op.maxScrollLeft = Math.max(0, display.sizer.offsetLeft + op.adjustWidthTo - displayWidth(cm));
     }
 
     if (op.updatedDisplay || op.selectionChanged)
-      op.preparedSelection = display.input.prepareSelection();
+      op.preparedSelection = display.input.prepareSelection(op.focus);
   }
 
   function endOperation_W2(op) {
     var cm = op.cm;
 
     if (op.adjustWidthTo != null) {
       cm.display.sizer.style.minWidth = op.adjustWidthTo + "px";
       if (op.maxScrollLeft < cm.doc.scrollLeft)
         setScrollLeft(cm, Math.min(cm.display.scroller.scrollLeft, op.maxScrollLeft), true);
       cm.display.maxLineChanged = false;
     }
 
+    var takeFocus = op.focus && op.focus == activeElt() && (!document.hasFocus || document.hasFocus())
     if (op.preparedSelection)
-      cm.display.input.showSelection(op.preparedSelection);
+      cm.display.input.showSelection(op.preparedSelection, takeFocus);
     if (op.updatedDisplay || op.startHeight != cm.doc.height)
       updateScrollbars(cm, op.barMeasure);
     if (op.updatedDisplay)
       setDocumentHeight(cm, op.barMeasure);
 
     if (op.selectionChanged) restartBlink(cm);
 
     if (cm.state.focused && op.updateInput)
       cm.display.input.reset(op.typing);
-    if (op.focus && op.focus == activeElt() && (!document.hasFocus || document.hasFocus()))
-      ensureFocus(op.cm);
+    if (takeFocus) ensureFocus(op.cm);
   }
 
   function endOperation_finish(op) {
     var cm = op.cm, display = cm.display, doc = cm.doc;
 
     if (op.updatedDisplay) postUpdateDisplay(cm, op.update);
 
     // Abort mouse wheel delta measurement, when scrolling explicitly
@@ -5387,17 +5389,17 @@
         pos = found + val.length;
         newBreaks.push(Pos(lineNo, found));
       }
       lineNo++;
     });
     for (var i = newBreaks.length - 1; i >= 0; i--)
       replaceRange(cm.doc, val, newBreaks[i], Pos(newBreaks[i].line, newBreaks[i].ch + val.length))
   });
-  option("specialChars", /[\t\u0000-\u0019\u00ad\u200b-\u200f\u2028\u2029\ufeff]/g, function(cm, val, old) {
+  option("specialChars", /[\u0000-\u001f\u007f\u00ad\u200b-\u200f\u2028\u2029\ufeff]/g, function(cm, val, old) {
     cm.state.specialChars = new RegExp(val.source + (val.test("\t") ? "" : "|\t"), "g");
     if (old != CodeMirror.Init) cm.refresh();
   });
   option("specialCharPlaceholder", defaultSpecialCharPlaceholder, function(cm) {cm.refresh();}, true);
   option("electricChars", true);
   option("inputStyle", mobile ? "contenteditable" : "textarea", function() {
     throw new Error("inputStyle can not (yet) be changed in a running editor"); // FIXME
   }, true);
@@ -5716,17 +5718,17 @@
     indentMore: function(cm) {cm.indentSelection("add");},
     indentLess: function(cm) {cm.indentSelection("subtract");},
     insertTab: function(cm) {cm.replaceSelection("\t");},
     insertSoftTab: function(cm) {
       var spaces = [], ranges = cm.listSelections(), tabSize = cm.options.tabSize;
       for (var i = 0; i < ranges.length; i++) {
         var pos = ranges[i].from();
         var col = countColumn(cm.getLine(pos.line), pos.ch, tabSize);
-        spaces.push(new Array(tabSize - col % tabSize + 1).join(" "));
+        spaces.push(spaceStr(tabSize - col % tabSize));
       }
       cm.replaceSelections(spaces);
     },
     defaultTab: function(cm) {
       if (cm.somethingSelected()) cm.indentSelection("add");
       else cm.execCommand("insertTab");
     },
     transposeChars: function(cm) {
@@ -5759,16 +5761,17 @@
         for (var i = 0; i < len; i++) {
           var range = cm.listSelections()[i];
           cm.replaceRange(cm.doc.lineSeparator(), range.anchor, range.head, "+input");
           cm.indentLine(range.from().line + 1, null, true);
         }
         ensureCursorVisible(cm);
       });
     },
+    openLine: function(cm) {cm.replaceSelection("\n", "start")},
     toggleOverwrite: function(cm) {cm.toggleOverwrite();}
   };
 
 
   // STANDARD KEYMAPS
 
   var keyMap = CodeMirror.keyMap = {};
 
@@ -5793,17 +5796,18 @@
     "Ctrl-U": "undoSelection", "Shift-Ctrl-U": "redoSelection", "Alt-U": "redoSelection",
     fallthrough: "basic"
   };
   // Very basic readline/emacs-style bindings, which are standard on Mac.
   keyMap.emacsy = {
     "Ctrl-F": "goCharRight", "Ctrl-B": "goCharLeft", "Ctrl-P": "goLineUp", "Ctrl-N": "goLineDown",
     "Alt-F": "goWordRight", "Alt-B": "goWordLeft", "Ctrl-A": "goLineStart", "Ctrl-E": "goLineEnd",
     "Ctrl-V": "goPageDown", "Shift-Ctrl-V": "goPageUp", "Ctrl-D": "delCharAfter", "Ctrl-H": "delCharBefore",
-    "Alt-D": "delWordAfter", "Alt-Backspace": "delWordBefore", "Ctrl-K": "killLine", "Ctrl-T": "transposeChars"
+    "Alt-D": "delWordAfter", "Alt-Backspace": "delWordBefore", "Ctrl-K": "killLine", "Ctrl-T": "transposeChars",
+    "Ctrl-O": "openLine"
   };
   keyMap.macDefault = {
     "Cmd-A": "selectAll", "Cmd-D": "deleteLine", "Cmd-Z": "undo", "Shift-Cmd-Z": "redo", "Cmd-Y": "redo",
     "Cmd-Home": "goDocStart", "Cmd-Up": "goDocStart", "Cmd-End": "goDocEnd", "Cmd-Down": "goDocEnd", "Alt-Left": "goGroupLeft",
     "Alt-Right": "goGroupRight", "Cmd-Left": "goLineLeft", "Cmd-Right": "goLineRight", "Alt-Backspace": "delGroupBefore",
     "Ctrl-Alt-Backspace": "delGroupAfter", "Alt-Delete": "delGroupAfter", "Cmd-S": "save", "Cmd-F": "find",
     "Cmd-G": "findNext", "Shift-Cmd-G": "findPrev", "Cmd-Alt-F": "replace", "Shift-Cmd-Alt-F": "replaceAll",
     "Cmd-[": "indentLess", "Cmd-]": "indentMore", "Cmd-Backspace": "delWrappedLineLeft", "Cmd-Delete": "delWrappedLineRight",
@@ -6555,18 +6559,18 @@
     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 && (cmp(found.to, from) > 0 || (sp.marker.inclusiveRight && marker.inclusiveLeft)) ||
-          fromCmp >= 0 && (cmp(found.from, to) < 0 || (sp.marker.inclusiveLeft && marker.inclusiveRight)))
+      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
   // visual line. This finds the start of the visual line that the
   // given line is part of (usually that is the line itself).
@@ -6958,18 +6962,21 @@
         lineView.measure.cache = {};
       } else {
         (lineView.measure.maps || (lineView.measure.maps = [])).push(builder.map);
         (lineView.measure.caches || (lineView.measure.caches = [])).push({});
       }
     }
 
     // See issue #2901
-    if (webkit && /\bcm-tab\b/.test(builder.content.lastChild.className))
-      builder.content.className = "cm-tab-wrap-hack";
+    if (webkit) {
+      var last = builder.content.lastChild
+      if (/\bcm-tab\b/.test(last.className) || (last.querySelector && last.querySelector(".cm-tab")))
+        builder.content.className = "cm-tab-wrap-hack";
+    }
 
     signal(cm, "renderLine", cm, lineView.line, builder.pre);
     if (builder.pre.className)
       builder.textClass = joinClasses(builder.pre.className, builder.textClass || "");
 
     return builder;
   }
 
@@ -7311,23 +7318,26 @@
     insertInner: function(at, lines, height) {
       this.size += lines.length;
       this.height += height;
       for (var i = 0; i < this.children.length; ++i) {
         var child = this.children[i], sz = child.chunkSize();
         if (at <= sz) {
           child.insertInner(at, lines, height);
           if (child.lines && child.lines.length > 50) {
-            while (child.lines.length > 50) {
-              var spilled = child.lines.splice(child.lines.length - 25, 25);
-              var newleaf = new LeafChunk(spilled);
-              child.height -= newleaf.height;
-              this.children.splice(i + 1, 0, newleaf);
-              newleaf.parent = this;
+            // To avoid memory thrashing when child.lines is huge (e.g. first view of a large file), it's never spliced.
+            // Instead, small slices are taken. They're taken in order because sequential memory accesses are fastest.
+            var remaining = child.lines.length % 25 + 25
+            for (var pos = remaining; pos < child.lines.length;) {
+              var leaf = new LeafChunk(child.lines.slice(pos, pos += 25));
+              child.height -= leaf.height;
+              this.children.splice(++i, 0, leaf);
+              leaf.parent = this;
             }
+            child.lines = child.lines.slice(0, remaining);
             this.maybeSpill();
           }
           break;
         }
         at -= sz;
       }
     },
     // When a node has grown, check whether it should be split.
@@ -7337,17 +7347,17 @@
       do {
         var spilled = me.children.splice(me.children.length - 5, 5);
         var sibling = new BranchChunk(spilled);
         if (!me.parent) { // Become the parent node
           var copy = new BranchChunk(me.children);
           copy.parent = me;
           me.children = [copy, sibling];
           me = copy;
-        } else {
+       } else {
           me.size -= sibling.size;
           me.height -= sibling.height;
           var myIndex = indexOf(me.parent.children, me);
           me.parent.children.splice(myIndex + 1, 0, sibling);
         }
         sibling.parent = me.parent;
       } while (me.children.length > 10);
       me.parent.maybeSpill();
@@ -8887,12 +8897,12 @@
         order.push(new BidiSpan(order[0].level, len, len));
 
       return order;
     };
   })();
 
   // THE END
 
-  CodeMirror.version = "5.14.2";
+  CodeMirror.version = "5.15.2";
 
   return CodeMirror;
 });

--- a/devtools/client/sourceeditor/codemirror/mode/clike.js
+++ b/devtools/client/sourceeditor/codemirror/mode/clike.js
@@ -6,48 +6,47 @@
     mod(require("../../lib/codemirror"));
   else if (typeof define == "function" && define.amd) // AMD
     define(["../../lib/codemirror"], mod);
   else // Plain browser env
     mod(CodeMirror);
 })(function(CodeMirror) {
 "use strict";
 
-function Context(indented, column, type, align, prev) {
+function Context(indented, column, type, info, align, prev) {
   this.indented = indented;
   this.column = column;
   this.type = type;
+  this.info = info;
   this.align = align;
   this.prev = prev;
 }
-function isStatement(type) {
-  return type == "statement" || type == "switchstatement" || type == "namespace";
-}
-function pushContext(state, col, type) {
+function pushContext(state, col, type, info) {
   var indent = state.indented;
-  if (state.context && isStatement(state.context.type) && !isStatement(type))
+  if (state.context && state.context.type != "statement" && type != "statement")
     indent = state.context.indented;
-  return state.context = new Context(indent, col, type, null, state.context);
+  return state.context = new Context(indent, col, type, info, null, state.context);
 }
 function popContext(state) {
   var t = state.context.type;
   if (t == ")" || t == "]" || t == "}")
     state.indented = state.context.indented;
   return state.context = state.context.prev;
 }
 
-function typeBefore(stream, state) {
+function typeBefore(stream, state, pos) {
   if (state.prevToken == "variable" || state.prevToken == "variable-3") return true;
-  if (/\S(?:[^- ]>|[*\]])\s*$|\*$/.test(stream.string.slice(0, stream.start))) return true;
+  if (/\S(?:[^- ]>|[*\]])\s*$|\*$/.test(stream.string.slice(0, pos))) return true;
+  if (state.typeAtEndOfLine && stream.column() == stream.indentation()) return true;
 }
 
 function isTopScope(context) {
   for (;;) {
     if (!context || context.type == "top") return true;
-    if (context.type == "}" && context.prev.type != "namespace") return false;
+    if (context.type == "}" && context.prev.info != "namespace") return false;
     context = context.prev;
   }
 }
 
 CodeMirror.defineMode("clike", function(config, parserConfig) {
   var indentUnit = config.indentUnit,
       statementIndentUnit = parserConfig.statementIndentUnit || indentUnit,
       dontAlignCalls = parserConfig.dontAlignCalls,
@@ -142,96 +141,100 @@ CodeMirror.defineMode("clike", function(
         state.tokenize = null;
         break;
       }
       maybeEnd = (ch == "*");
     }
     return "comment";
   }
 
+  function maybeEOL(stream, state) {
+    if (parserConfig.typeFirstDefinitions && stream.eol() && isTopScope(state.context))
+      state.typeAtEndOfLine = typeBefore(stream, state, stream.pos)
+  }
+
   // Interface
 
   return {
     startState: function(basecolumn) {
       return {
         tokenize: null,
-        context: new Context((basecolumn || 0) - indentUnit, 0, "top", false),
+        context: new Context((basecolumn || 0) - indentUnit, 0, "top", null, false),
         indented: 0,
         startOfLine: true,
         prevToken: null
       };
     },
 
     token: function(stream, state) {
       var ctx = state.context;
       if (stream.sol()) {
         if (ctx.align == null) ctx.align = false;
         state.indented = stream.indentation();
         state.startOfLine = true;
       }
-      if (stream.eatSpace()) return null;
+      if (stream.eatSpace()) { maybeEOL(stream, state); return null; }
       curPunc = isDefKeyword = null;
       var style = (state.tokenize || tokenBase)(stream, state);
       if (style == "comment" || style == "meta") return style;
       if (ctx.align == null) ctx.align = true;
 
-      if (endStatement.test(curPunc)) while (isStatement(state.context.type)) popContext(state);
+      if (endStatement.test(curPunc)) while (state.context.type == "statement") popContext(state);
       else if (curPunc == "{") pushContext(state, stream.column(), "}");
       else if (curPunc == "[") pushContext(state, stream.column(), "]");
       else if (curPunc == "(") pushContext(state, stream.column(), ")");
       else if (curPunc == "}") {
-        while (isStatement(ctx.type)) ctx = popContext(state);
+        while (ctx.type == "statement") ctx = popContext(state);
         if (ctx.type == "}") ctx = popContext(state);
-        while (isStatement(ctx.type)) ctx = popContext(state);
+        while (ctx.type == "statement") ctx = popContext(state);
       }
       else if (curPunc == ctx.type) popContext(state);
       else if (indentStatements &&
                (((ctx.type == "}" || ctx.type == "top") && curPunc != ";") ||
-                (isStatement(ctx.type) && curPunc == "newstatement"))) {
-        var type = "statement";
-        if (curPunc == "newstatement" && indentSwitch && stream.current() == "switch")
-          type = "switchstatement";
-        else if (style == "keyword" && stream.current() == "namespace")
-          type = "namespace";
-        pushContext(state, stream.column(), type);
+                (ctx.type == "statement" && curPunc == "newstatement"))) {
+        pushContext(state, stream.column(), "statement", stream.current());
       }
 
       if (style == "variable" &&
           ((state.prevToken == "def" ||
-            (parserConfig.typeFirstDefinitions && typeBefore(stream, state) &&
+            (parserConfig.typeFirstDefinitions && typeBefore(stream, state, stream.start) &&
              isTopScope(state.context) && stream.match(/^\s*\(/, false)))))
         style = "def";
 
       if (hooks.token) {
         var result = hooks.token(stream, state, style);
         if (result !== undefined) style = result;
       }
 
       if (style == "def" && parserConfig.styleDefs === false) style = "variable";
 
       state.startOfLine = false;
       state.prevToken = isDefKeyword ? "def" : style || curPunc;
+      maybeEOL(stream, state);
       return style;
     },
 
     indent: function(state, textAfter) {
-      if (state.tokenize != tokenBase && state.tokenize != null) return CodeMirror.Pass;
+      if (state.tokenize != tokenBase && state.tokenize != null || state.typeAtEndOfLine) return CodeMirror.Pass;
       var ctx = state.context, firstChar = textAfter && textAfter.charAt(0);
-      if (isStatement(ctx.type) && firstChar == "}") ctx = ctx.prev;
+      if (ctx.type == "statement" && firstChar == "}") ctx = ctx.prev;
+      if (parserConfig.dontIndentStatements)
+        while (ctx.type == "statement" && parserConfig.dontIndentStatements.test(ctx.info))
+          ctx = ctx.prev
       if (hooks.indent) {
         var hook = hooks.indent(state, ctx, textAfter);
         if (typeof hook == "number") return hook
       }
       var closing = firstChar == ctx.type;
-      var switchBlock = ctx.prev && ctx.prev.type == "switchstatement";
+      var switchBlock = ctx.prev && ctx.prev.info == "switch";
       if (parserConfig.allmanIndentation && /[{(]/.test(firstChar)) {
         while (ctx.type != "top" && ctx.type != "}") ctx = ctx.prev
         return ctx.indented
       }
-      if (isStatement(ctx.type))
+      if (ctx.type == "statement")
         return ctx.indented + (firstChar == "{" ? 0 : statementIndentUnit);
       if (ctx.align && (!dontAlignCalls || ctx.type != ")"))
         return ctx.column + (closing ? 0 : 1);
       if (ctx.type == ")" && !closing)
         return ctx.indented + statementIndentUnit;
 
       return ctx.indented + (closing ? 0 : indentUnit) +
         (!closing && switchBlock && !/^(?:case|default)\b/.test(textAfter) ? indentUnit : 0);
@@ -381,16 +384,17 @@ CodeMirror.defineMode("clike", function(
                     "this using const_cast inline public throw virtual delete mutable protected " +
                     "alignas alignof constexpr decltype nullptr noexcept thread_local final " +
                     "static_assert override"),
     types: words(cTypes + " bool wchar_t"),
     blockKeywords: words("catch class do else finally for if struct switch try while"),
     defKeywords: words("class namespace struct enum union"),
     typeFirstDefinitions: true,
     atoms: words("true false null"),
+    dontIndentStatements: /^template$/,
     hooks: {
       "#": cppHook,
       "*": pointerHook,
       "u": cpp11StringHook,
       "U": cpp11StringHook,
       "L": cpp11StringHook,
       "R": cpp11StringHook,
       "0": cpp14Literal,
@@ -424,16 +428,17 @@ CodeMirror.defineMode("clike", function(
                     "try volatile while"),
     types: words("byte short int long float double boolean char void Boolean Byte Character Double Float " +
                  "Integer Long Number Object Short String StringBuffer StringBuilder Void"),
     blockKeywords: words("catch class do else finally for if switch try while"),
     defKeywords: words("class interface package enum"),
     typeFirstDefinitions: true,
     atoms: words("true false null"),
     endStatement: /^[;:]$/,
+    number: /^(?:0x[a-f\d_]+|0b[01_]+|(?:[\d_]+\.?\d*|\.\d+)(?:e[-+]?[\d_]+)?)(u|ll?|l|f)?/i,
     hooks: {
       "@": function(stream) {
         stream.eatWhile(/[\w\$_]/);
         return "meta";
       }
     },
     modeProps: {fold: ["brace", "import"]}
   });
@@ -526,17 +531,17 @@ CodeMirror.defineMode("clike", function(
       },
       "'": function(stream) {
         stream.eatWhile(/[\w\$_\xa1-\uffff]/);
         return "atom";
       },
       "=": function(stream, state) {
         var cx = state.context
         if (cx.type == "}" && cx.align && stream.eat(">")) {
-          state.context = new Context(cx.indented, cx.column, cx.type, null, cx.prev)
+          state.context = new Context(cx.indented, cx.column, cx.type, cx.info, null, cx.prev)
           return "operator"
         } else {
           return false
         }
       }
     },
     modeProps: {closeBrackets: {triples: '"'}}
   });

--- a/devtools/client/sourceeditor/codemirror/mode/css.js
+++ b/devtools/client/sourceeditor/codemirror/mode/css.js
@@ -479,19 +479,19 @@ CodeMirror.defineMode("css", function(co
     "elevation", "empty-cells", "fit", "fit-position", "flex", "flex-basis",
     "flex-direction", "flex-flow", "flex-grow", "flex-shrink", "flex-wrap",
     "float", "float-offset", "flow-from", "flow-into", "font", "font-feature-settings",
     "font-family", "font-kerning", "font-language-override", "font-size", "font-size-adjust",
     "font-stretch", "font-style", "font-synthesis", "font-variant",
     "font-variant-alternates", "font-variant-caps", "font-variant-east-asian",
     "font-variant-ligatures", "font-variant-numeric", "font-variant-position",
     "font-weight", "grid", "grid-area", "grid-auto-columns", "grid-auto-flow",
-    "grid-auto-position", "grid-auto-rows", "grid-column", "grid-column-end",
-    "grid-column-start", "grid-row", "grid-row-end", "grid-row-start",
-    "grid-template", "grid-template-areas", "grid-template-columns",
+    "grid-auto-rows", "grid-column", "grid-column-end", "grid-column-gap",
+    "grid-column-start", "grid-gap", "grid-row", "grid-row-end", "grid-row-gap",
+    "grid-row-start", "grid-template", "grid-template-areas", "grid-template-columns",
     "grid-template-rows", "hanging-punctuation", "height", "hyphens",
     "icon", "image-orientation", "image-rendering", "image-resolution",
     "inline-box-align", "justify-content", "left", "letter-spacing",
     "line-break", "line-height", "line-stacking", "line-stacking-ruby",
     "line-stacking-shift", "line-stacking-strategy", "list-style",
     "list-style-image", "list-style-position", "list-style-type", "margin",
     "margin-bottom", "margin-left", "margin-right", "margin-top",
     "marker-offset", "marks", "marquee-direction", "marquee-loop",
@@ -596,37 +596,37 @@ CodeMirror.defineMode("css", function(co
     "buttonface", "buttonhighlight", "buttonshadow", "buttontext", "calc", "cambodian",
     "capitalize", "caps-lock-indicator", "caption", "captiontext", "caret",
     "cell", "center", "checkbox", "circle", "cjk-decimal", "cjk-earthly-branch",
     "cjk-heavenly-stem", "cjk-ideographic", "clear", "clip", "close-quote",
     "col-resize", "collapse", "color", "color-burn", "color-dodge", "column", "column-reverse",
     "compact", "condensed", "contain", "content",
     "content-box", "context-menu", "continuous", "copy", "counter", "counters", "cover", "crop",
     "cross", "crosshair", "currentcolor", "cursive", "cyclic", "darken", "dashed", "decimal",
-    "decimal-leading-zero", "default", "default-button", "destination-atop",
+    "decimal-leading-zero", "default", "default-button", "dense", "destination-atop",
     "destination-in", "destination-out", "destination-over", "devanagari", "difference",
     "disc", "discard", "disclosure-closed", "disclosure-open", "document",
     "dot-dash", "dot-dot-dash",
     "dotted", "double", "down", "e-resize", "ease", "ease-in", "ease-in-out", "ease-out",
     "element", "ellipse", "ellipsis", "embed", "end", "ethiopic", "ethiopic-abegede",
     "ethiopic-abegede-am-et", "ethiopic-abegede-gez", "ethiopic-abegede-ti-er",
     "ethiopic-abegede-ti-et", "ethiopic-halehame-aa-er",
     "ethiopic-halehame-aa-et", "ethiopic-halehame-am-et",
     "ethiopic-halehame-gez", "ethiopic-halehame-om-et",
     "ethiopic-halehame-sid-et", "ethiopic-halehame-so-et",
     "ethiopic-halehame-ti-er", "ethiopic-halehame-ti-et", "ethiopic-halehame-tig",
     "ethiopic-numeric", "ew-resize", "exclusion", "expanded", "extends", "extra-condensed",
     "extra-expanded", "fantasy", "fast", "fill", "fixed", "flat", "flex", "flex-end", "flex-start", "footnotes",
-    "forwards", "from", "geometricPrecision", "georgian", "graytext", "groove",
+    "forwards", "from", "geometricPrecision", "georgian", "graytext", "grid", "groove",
     "gujarati", "gurmukhi", "hand", "hangul", "hangul-consonant", "hard-light", "hebrew",
     "help", "hidden", "hide", "higher", "highlight", "highlighttext",
     "hiragana", "hiragana-iroha", "horizontal", "hsl", "hsla", "hue", "icon", "ignore",
     "inactiveborder", "inactivecaption", "inactivecaptiontext", "infinite",
     "infobackground", "infotext", "inherit", "initial", "inline", "inline-axis",
-    "inline-block", "inline-flex", "inline-table", "inset", "inside", "intrinsic", "invert",
+    "inline-block", "inline-flex", "inline-grid", "inline-table", "inset", "inside", "intrinsic", "invert",
     "italic", "japanese-formal", "japanese-informal", "justify", "kannada",
     "katakana", "katakana-iroha", "keep-all", "khmer",
     "korean-hangul-formal", "korean-hanja-formal", "korean-hanja-informal",
     "landscape", "lao", "large", "larger", "left", "level", "lighter", "lighten",
     "line-through", "linear", "linear-gradient", "lines", "list-item", "listbox", "listitem",
     "local", "logical", "loud", "lower", "lower-alpha", "lower-armenian",
     "lower-greek", "lower-hexadecimal", "lower-latin", "lower-norwegian",
     "lower-roman", "lowercase", "ltr", "luminosity", "malayalam", "match", "matrix", "matrix3d",

--- a/devtools/client/sourceeditor/codemirror/mode/htmlmixed.js
+++ b/devtools/client/sourceeditor/codemirror/mode/htmlmixed.js
@@ -110,17 +110,17 @@
         state.inTag += stream.current()
         if (stream.eol()) state.inTag += " "
       }
       return style;
     };
 
     return {
       startState: function () {
-        var state = htmlMode.startState();
+        var state = CodeMirror.startState(htmlMode);
         return {token: html, inTag: null, localMode: null, localState: null, htmlState: state};
       },
 
       copyState: function (state) {
         var local;
         if (state.localState) {
           local = CodeMirror.copyState(state.localMode, state.localState);
         }

--- a/devtools/client/sourceeditor/codemirror/mode/javascript.js
+++ b/devtools/client/sourceeditor/codemirror/mode/javascript.js
@@ -37,17 +37,18 @@ CodeMirror.defineMode("javascript", func
       "if": kw("if"), "while": A, "with": A, "else": B, "do": B, "try": B, "finally": B,
       "return": C, "break": C, "continue": C, "new": kw("new"), "delete": C, "throw": C, "debugger": C,
       "var": kw("var"), "const": kw("var"), "let": kw("var"),
       "function": kw("function"), "catch": kw("catch"),
       "for": kw("for"), "switch": kw("switch"), "case": kw("case"), "default": kw("default"),
       "in": operator, "typeof": operator, "instanceof": operator,
       "true": atom, "false": atom, "null": atom, "undefined": atom, "NaN": atom, "Infinity": atom,
       "this": kw("this"), "class": kw("class"), "super": kw("atom"),
-      "yield": C, "export": kw("export"), "import": kw("import"), "extends": C
+      "yield": C, "export": kw("export"), "import": kw("import"), "extends": C,
+      "await": C, "async": kw("async")
     };
 
     // Extend the 'normal' keywords with the TypeScript language extensions
     if (isTS) {
       var type = {type: "variable", style: "variable-3"};
       var tsKeywords = {
         // object-like things
         "interface": kw("class"),
@@ -361,16 +362,17 @@ CodeMirror.defineMode("javascript", func
     if (type == "case") return cont(expression, expect(":"));
     if (type == "default") return cont(expect(":"));
     if (type == "catch") return cont(pushlex("form"), pushcontext, expect("("), funarg, expect(")"),
                                      statement, poplex, popcontext);
     if (type == "class") return cont(pushlex("form"), className, poplex);
     if (type == "export") return cont(pushlex("stat"), afterExport, poplex);
     if (type == "import") return cont(pushlex("stat"), afterImport, poplex);
     if (type == "module") return cont(pushlex("form"), pattern, pushlex("}"), expect("{"), block, poplex, poplex)
+    if (type == "async") return cont(statement)
     return pass(pushlex("stat"), expression, expect(";"), poplex);
   }
   function expression(type) {
     return expressionInner(type, false);
   }
   function expressionNoComma(type) {
     return expressionInner(type, true);
   }
@@ -483,47 +485,51 @@ CodeMirror.defineMode("javascript", func
     cx.marked = "property";
     return cont(functiondef);
   }
   function afterprop(type) {
     if (type == ":") return cont(expressionNoComma);
     if (type == "(") return pass(functiondef);
   }
   function commasep(what, end) {
-    function proceed(type) {
+    function proceed(type, value) {
       if (type == ",") {
         var lex = cx.state.lexical;
         if (lex.info == "call") lex.pos = (lex.pos || 0) + 1;
         return cont(what, proceed);
       }
-      if (type == end) return cont();
+      if (type == end || value == end) return cont();
       return cont(expect(end));
     }
-    return function(type) {
-      if (type == end) return cont();
+    return function(type, value) {
+      if (type == end || value == end) return cont();
       return pass(what, proceed);
     };
   }
   function contCommasep(what, end, info) {
     for (var i = 3; i < arguments.length; i++)
       cx.cc.push(arguments[i]);
     return cont(pushlex(end, info), commasep(what, end), poplex);
   }
   function block(type) {
     if (type == "}") return cont();
     return pass(statement, block);
   }
   function maybetype(type) {
-    if (isTS && type == ":") return cont(typedef);
+    if (isTS && type == ":") return cont(typeexpr);
   }
   function maybedefault(_, value) {
     if (value == "=") return cont(expressionNoComma);
   }
-  function typedef(type) {
-    if (type == "variable") {cx.marked = "variable-3"; return cont();}
+  function typeexpr(type) {
+    if (type == "variable") {cx.marked = "variable-3"; return cont(afterType);}
+  }
+  function afterType(type, value) {
+    if (value == "<") return cont(commasep(typeexpr, ">"), afterType)
+    if (type == "[") return cont(expect("]"), afterType)
   }
   function vardef() {
     return pass(pattern, maybetype, maybeAssign, vardefCont);
   }
   function pattern(type, value) {
     if (type == "modifier") return cont(pattern)
     if (type == "variable") { register(value); return cont(); }
     if (type == "spread") return cont(pattern);
@@ -568,17 +574,17 @@ CodeMirror.defineMode("javascript", func
     return pass(expression, expect(";"), forspec3);
   }
   function forspec3(type) {
     if (type != ")") cont(expression);
   }
   function functiondef(type, value) {
     if (value == "*") {cx.marked = "keyword"; return cont(functiondef);}
     if (type == "variable") {register(value); return cont(functiondef);}
-    if (type == "(") return cont(pushcontext, pushlex(")"), commasep(funarg, ")"), poplex, statement, popcontext);
+    if (type == "(") return cont(pushcontext, pushlex(")"), commasep(funarg, ")"), poplex, maybetype, statement, popcontext);
   }
   function funarg(type) {
     if (type == "spread") return cont(funarg);
     return pass(pattern, maybetype, maybedefault);
   }
   function className(type, value) {
     if (type == "variable") {register(value); return cont(classNameAfter);}
   }