From 3603f7d0b1d311f99a506549b9024f3e790e68e7 Mon Sep 17 00:00:00 2001
From: Marijn Haverbeke <marijnh@gmail.com>
Date: Wed, 8 Oct 2014 11:52:40 +0200
Subject: [PATCH] Adjust start positions of parenthesized expressions to not
 include parentheses

Issue #136
---
 acorn.js              |  88 +++++++++---------
 test/driver.js        |   9 +-
 test/tests-harmony.js | 176 ++++++++++++++++++------------------
 test/tests.js         | 201 ++++++++----------------------------------
 4 files changed, 174 insertions(+), 300 deletions(-)

diff --git a/acorn.js b/acorn.js
index 6ac1979e40..8b5cb15aed 100644
--- a/acorn.js
+++ b/acorn.js
@@ -1236,19 +1236,24 @@
     return node;
   }
 
-  // Start a node whose start offset information should be based on
-  // the start of another node. For example, a binary operator node is
-  // only started after its left-hand side has already been parsed.
+  // Sometimes, a node is only started *after* the token stream passed
+  // its start position. The functions below help storing a position
+  // and creating a node from a previous position.
 
-  function startNodeFrom(other) {
-    var node = new Node();
-    node.start = other.start;
+  function storeCurrentPos() {
+    return options.locations ? [tokStart, tokStartLoc] : tokStart;
+  }
+
+  function startNodeAt(pos) {
+    var node = new Node(), start = pos;
     if (options.locations) {
       node.loc = new SourceLocation();
-      node.loc.start = other.loc.start;
+      node.loc.start = start[1];
+      start = pos[0];
     }
+    node.start = start;
     if (options.ranges)
-      node.range = [other.range[0], 0];
+      node.range = [start, 0];
 
     return node;
   }
@@ -1827,9 +1832,10 @@
   // or the `in` operator (in for loops initalization expressions).
 
   function parseExpression(noComma, noIn) {
+    var start = storeCurrentPos();
     var expr = parseMaybeAssign(noIn);
     if (!noComma && tokType === _comma) {
-      var node = startNodeFrom(expr);
+      var node = startNodeAt(start);
       node.expressions = [expr];
       while (eat(_comma)) node.expressions.push(parseMaybeAssign(noIn));
       return finishNode(node, "SequenceExpression");
@@ -1841,9 +1847,10 @@
   // operators like `+=`.
 
   function parseMaybeAssign(noIn) {
+    var start = storeCurrentPos();
     var left = parseMaybeConditional(noIn);
     if (tokType.isAssign) {
-      var node = startNodeFrom(left);
+      var node = startNodeAt(start);
       node.operator = tokVal;
       node.left = tokType === _eq ? toAssignable(left) : left;
       checkLVal(left);
@@ -1857,9 +1864,10 @@
   // Parse a ternary conditional (`?:`) operator.
 
   function parseMaybeConditional(noIn) {
+    var start = storeCurrentPos();
     var expr = parseExprOps(noIn);
     if (eat(_question)) {
-      var node = startNodeFrom(expr);
+      var node = startNodeAt(start);
       node.test = expr;
       node.consequent = parseExpression(true);
       expect(_colon);
@@ -1872,7 +1880,8 @@
   // Start the precedence parser.
 
   function parseExprOps(noIn) {
-    return parseExprOp(parseMaybeUnary(), -1, noIn);
+    var start = storeCurrentPos();
+    return parseExprOp(parseMaybeUnary(), start, -1, noIn);
   }
 
   // Parse binary operators with the operator precedence parsing
@@ -1881,18 +1890,19 @@
   // defer further parser to one of its callers when it encounters an
   // operator that has a lower precedence than the set it is parsing.
 
-  function parseExprOp(left, minPrec, noIn) {
+  function parseExprOp(left, leftStart, minPrec, noIn) {
     var prec = tokType.binop;
     if (prec != null && (!noIn || tokType !== _in)) {
       if (prec > minPrec) {
-        var node = startNodeFrom(left);
+        var node = startNodeAt(leftStart);
         node.left = left;
         node.operator = tokVal;
         var op = tokType;
         next();
-        node.right = parseExprOp(parseMaybeUnary(), prec, noIn);
-        var exprNode = finishNode(node, (op === _logicalOR || op === _logicalAND) ? "LogicalExpression" : "BinaryExpression");
-        return parseExprOp(exprNode, minPrec, noIn);
+        var start = storeCurrentPos();
+        node.right = parseExprOp(parseMaybeUnary(), start, prec, noIn);
+        finishNode(node, (op === _logicalOR || op === _logicalAND) ? "LogicalExpression" : "BinaryExpression");
+        return parseExprOp(node, leftStart, minPrec, noIn);
       }
     }
     return left;
@@ -1914,9 +1924,10 @@
         raise(node.start, "Deleting local variable in strict mode");
       return finishNode(node, update ? "UpdateExpression" : "UnaryExpression");
     }
+    var start = storeCurrentPos();
     var expr = parseExprSubscripts();
     while (tokType.postfix && !canInsertSemicolon()) {
-      var node = startNodeFrom(expr);
+      var node = startNodeAt(start);
       node.operator = tokVal;
       node.prefix = false;
       node.argument = expr;
@@ -1930,33 +1941,34 @@
   // Parse call, dot, and `[]`-subscript expressions.
 
   function parseExprSubscripts() {
-    return parseSubscripts(parseExprAtom());
+    var start = storeCurrentPos();
+    return parseSubscripts(parseExprAtom(), start);
   }
 
-  function parseSubscripts(base, noCalls) {
+  function parseSubscripts(base, start, noCalls) {
     if (eat(_dot)) {
-      var node = startNodeFrom(base);
+      var node = startNodeAt(start);
       node.object = base;
       node.property = parseIdent(true);
       node.computed = false;
-      return parseSubscripts(finishNode(node, "MemberExpression"), noCalls);
+      return parseSubscripts(finishNode(node, "MemberExpression"), start, noCalls);
     } else if (eat(_bracketL)) {
-      var node = startNodeFrom(base);
+      var node = startNodeAt(start);
       node.object = base;
       node.property = parseExpression();
       node.computed = true;
       expect(_bracketR);
-      return parseSubscripts(finishNode(node, "MemberExpression"), noCalls);
+      return parseSubscripts(finishNode(node, "MemberExpression"), start, noCalls);
     } else if (!noCalls && eat(_parenL)) {
-      var node = startNodeFrom(base);
+      var node = startNodeAt(start);
       node.callee = base;
       node.arguments = parseExprList(_parenR, false);
-      return parseSubscripts(finishNode(node, "CallExpression"), noCalls);
+      return parseSubscripts(finishNode(node, "CallExpression"), start, noCalls);
     } else if (tokType === _bquote) {
-      var node = startNodeFrom(base);
+      var node = startNodeAt(start);
       node.tag = base;
       node.quasi = parseTemplate();
-      return parseSubscripts(finishNode(node, "TaggedTemplateExpression"), noCalls);
+      return parseSubscripts(finishNode(node, "TaggedTemplateExpression"), start, noCalls);
     } return base;
   }
 
@@ -1976,9 +1988,10 @@
       if (inGenerator) return parseYield();
 
     case _name:
+      var start = storeCurrentPos();
       var id = parseIdent(tokType !== _name);
       if (eat(_arrow)) {
-        return parseArrowExpression(startNodeFrom(id), [id]);
+        return parseArrowExpression(startNodeAt(start), [id]);
       }
       return id;
 
@@ -1997,11 +2010,12 @@
       return finishNode(node, "Literal");
 
     case _parenL:
+      var start = storeCurrentPos();
       var tokStartLoc1 = tokStartLoc, tokStart1 = tokStart, val, exprList;
       next();
       // check whether this is generator comprehension or regular expression
       if (options.ecmaVersion >= 6 && tokType === _for) {
-        val = parseComprehension(startNode(), true);
+        val = parseComprehension(startNodeAt(start), true);
       } else {
         var oldParenL = ++metParenL;
         if (tokType !== _parenR) {
@@ -2013,7 +2027,7 @@
         expect(_parenR);
         // if '=>' follows '(...)', convert contents to arguments
         if (metParenL === oldParenL && eat(_arrow)) {
-          val = parseArrowExpression(startNode(), exprList);
+          val = parseArrowExpression(startNodeAt(start), exprList);
         } else {
           // forbid '()' before everything but '=>'
           if (!val) unexpected(lastStart);
@@ -2025,15 +2039,6 @@
           }
         }
       }
-      val.start = tokStart1;
-      val.end = lastEnd;
-      if (options.locations) {
-        val.loc.start = tokStartLoc1;
-        val.loc.end = lastEndLoc;
-      }
-      if (options.ranges) {
-        val.range = [tokStart1, lastEnd];
-      }
       return val;
 
     case _bracketL:
@@ -2078,7 +2083,8 @@
   function parseNew() {
     var node = startNode();
     next();
-    node.callee = parseSubscripts(parseExprAtom(), true);
+    var start = storeCurrentPos();
+    node.callee = parseSubscripts(parseExprAtom(), start, true);
     if (eat(_parenL)) node.arguments = parseExprList(_parenR, false);
     else node.arguments = empty;
     return finishNode(node, "NewExpression");
diff --git a/test/driver.js b/test/driver.js
index 3b1551092a..a08bf6e837 100644
--- a/test/driver.js
+++ b/test/driver.js
@@ -43,10 +43,9 @@
           else callback("ok", test.code);
         } else {
           var mis = misMatch(test.ast, ast);
+          if (!mis && test.comments) mis = misMatch(test.comments, comments);
           if (mis) callback("fail", test.code, mis);
-          if (test.comments) mis = misMatch(test.comments, comments);
-          if (!mis) callback("ok", test.code);
-          else callback("fail", test.code, mis);
+          else callback("ok", test.code);
         }
       } catch(e) {
         if (test.error && e instanceof SyntaxError) {
@@ -67,7 +66,7 @@
     return str + " (" + pt + ")";
   }
 
-  function misMatch(exp, act) {
+  var misMatch = exports.misMatch = function(exp, act) {
     if (!exp || !act || (typeof exp != "object") || (typeof act != "object")) {
       if (exp !== act) return ppJSON(exp) + " !== " + ppJSON(act);
     } else if (exp.splice) {
@@ -83,7 +82,7 @@
         if (mis) return addPath(mis, prop);
       }
     }
-  }
+  };
 
   function mangle(ast) {
     if (typeof ast != "object" || !ast) return;
diff --git a/test/tests-harmony.js b/test/tests-harmony.js
index e0d36665ad..deeb049f65 100644
--- a/test/tests-harmony.js
+++ b/test/tests-harmony.js
@@ -1511,10 +1511,10 @@ test("e => ({ property: 42 })", {
             end: {line: 1, column: 20}
           }
         }],
-        range: [5, 23],
+        range: [6, 22],
         loc: {
-          start: {line: 1, column: 5},
-          end: {line: 1, column: 23}
+          start: {line: 1, column: 6},
+          end: {line: 1, column: 22}
         }
       },
       rest: null,
@@ -2330,10 +2330,10 @@ test("(x => x)", {
       rest: null,
       generator: false,
       expression: true,
-      range: [0, 8],
+      range: [1, 7],
       loc: {
-        start: {line: 1, column: 0},
-        end: {line: 1, column: 8}
+        start: {line: 1, column: 1},
+        end: {line: 1, column: 7}
       }
     },
     range: [0, 8],
@@ -2500,19 +2500,19 @@ test("(x) => ((y, z) => (x, y, z))", {
               }
             }
           ],
-          range: [18, 27],
+          range: [19, 26],
           loc: {
-            start: {line: 1, column: 18},
-            end: {line: 1, column: 27}
+            start: {line: 1, column: 19},
+            end: {line: 1, column: 26}
           }
         },
         rest: null,
         generator: false,
         expression: true,
-        range: [7, 28],
+        range: [8, 27],
         loc: {
-          start: {line: 1, column: 7},
-          end: {line: 1, column: 28}
+          start: {line: 1, column: 8},
+          end: {line: 1, column: 27}
         }
       },
       rest: null,
@@ -4268,10 +4268,10 @@ test("({ responseText: text }) = res", {
             end: {line: 1, column: 21}
           }
         }],
-        range: [0, 24],
+        range: [1, 23],
         loc: {
-          start: {line: 1, column: 0},
-          end: {line: 1, column: 24}
+          start: {line: 1, column: 1},
+          end: {line: 1, column: 23}
         }
       },
       right: {
@@ -6115,10 +6115,10 @@ test("(function* () { yield v })", {
       rest: null,
       generator: true,
       expression: false,
-      range: [0, 26],
+      range: [1, 25],
       loc: {
-        start: {line: 1, column: 0},
-        end: {line: 1, column: 26}
+        start: {line: 1, column: 1},
+        end: {line: 1, column: 25}
       }
     },
     range: [0, 26],
@@ -6195,10 +6195,10 @@ test("(function* () { yield\nv })", {
       rest: null,
       generator: true,
       expression: false,
-      range: [0, 26],
+      range: [1, 25],
       loc: {
-        start: {line: 1, column: 0},
-        end: {line: 2, column: 4}
+        start: {line: 1, column: 1},
+        end: {line: 2, column: 3}
       }
     },
     range: [0, 26],
@@ -6264,10 +6264,10 @@ test("(function* () { yield *v })", {
       rest: null,
       generator: true,
       expression: false,
-      range: [0, 27],
+      range: [1, 26],
       loc: {
-        start: {line: 1, column: 0},
-        end: {line: 1, column: 27}
+        start: {line: 1, column: 1},
+        end: {line: 1, column: 26}
       }
     },
     range: [0, 27],
@@ -6572,10 +6572,10 @@ test("(function* () { yield yield 10 })", {
       rest: null,
       generator: true,
       expression: false,
-      range: [0, 33],
+      range: [1, 32],
       loc: {
-        start: {line: 1, column: 0},
-        end: {line: 1, column: 33}
+        start: {line: 1, column: 1},
+        end: {line: 1, column: 32}
       }
     },
     range: [0, 33],
@@ -8138,10 +8138,10 @@ test("\"use strict\"; (class A {constructor() { super() }})", {
             end: {line: 1, column: 50}
           }
         },
-        range: [14, 51],
+        range: [15, 50],
         loc: {
-          start: {line: 1, column: 14},
-          end: {line: 1, column: 51}
+          start: {line: 1, column: 15},
+          end: {line: 1, column: 50}
         }
       },
       range: [14, 51],
@@ -8482,10 +8482,10 @@ test("\"use strict\"; (class A { static constructor() { super() }})", {
             end: {line: 1, column: 58}
           }
         },
-        range: [14, 59],
+        range: [15, 58],
         loc: {
-          start: {line: 1, column: 14},
-          end: {line: 1, column: 59}
+          start: {line: 1, column: 15},
+          end: {line: 1, column: 58}
         }
       },
       range: [14, 59],
@@ -9437,10 +9437,10 @@ test("({[x]: 10})", {
           end: {line: 1, column: 9}
         }
       }],
-      range: [0, 11],
+      range: [1, 10],
       loc: {
-        start: {line: 1, column: 0},
-        end: {line: 1, column: 11}
+        start: {line: 1, column: 1},
+        end: {line: 1, column: 10}
       }
     },
     range: [0, 11],
@@ -9517,10 +9517,10 @@ test("({[\"x\" + \"y\"]: 10})", {
           end: {line: 1, column: 17}
         }
       }],
-      range: [0, 19],
+      range: [1, 18],
       loc: {
-        start: {line: 1, column: 0},
-        end: {line: 1, column: 19}
+        start: {line: 1, column: 1},
+        end: {line: 1, column: 18}
       }
     },
     range: [0, 19],
@@ -9590,10 +9590,10 @@ test("({[x]: function() {}})", {
           end: {line: 1, column: 20}
         }
       }],
-      range: [0, 22],
+      range: [1, 21],
       loc: {
-        start: {line: 1, column: 0},
-        end: {line: 1, column: 22}
+        start: {line: 1, column: 1},
+        end: {line: 1, column: 21}
       }
     },
     range: [0, 22],
@@ -9683,10 +9683,10 @@ test("({[x]: 10, y: 20})", {
           }
         }
       ],
-      range: [0, 18],
+      range: [1, 17],
       loc: {
-        start: {line: 1, column: 0},
-        end: {line: 1, column: 18}
+        start: {line: 1, column: 1},
+        end: {line: 1, column: 17}
       }
     },
     range: [0, 18],
@@ -9810,10 +9810,10 @@ test("({get [x]() {}, set [x](v) {}})", {
           }
         }
       ],
-      range: [0, 31],
+      range: [1, 30],
       loc: {
-        start: {line: 1, column: 0},
-        end: {line: 1, column: 31}
+        start: {line: 1, column: 1},
+        end: {line: 1, column: 30}
       }
     },
     range: [0, 31],
@@ -9883,10 +9883,10 @@ test("({[x]() {}})", {
           end: {line: 1, column: 10}
         }
       }],
-      range: [0, 12],
+      range: [1, 11],
       loc: {
-        start: {line: 1, column: 0},
-        end: {line: 1, column: 12}
+        start: {line: 1, column: 1},
+        end: {line: 1, column: 11}
       }
     },
     range: [0, 12],
@@ -10769,10 +10769,10 @@ test("({f: function({x} = {x: 10}) {}})", {
           end: {line: 1, column: 31}
         }
       }],
-      range: [0, 33],
+      range: [1, 32],
       loc: {
-        start: {line: 1, column: 0},
-        end: {line: 1, column: 33}
+        start: {line: 1, column: 1},
+        end: {line: 1, column: 32}
       }
     },
     range: [0, 33],
@@ -10917,10 +10917,10 @@ test("({f({x} = {x: 10}) {}})", {
           end: {line: 1, column: 21}
         }
       }],
-      range: [0, 23],
+      range: [1, 22],
       loc: {
-        start: {line: 1, column: 0},
-        end: {line: 1, column: 23}
+        start: {line: 1, column: 1},
+        end: {line: 1, column: 22}
       }
     },
     range: [0, 23],
@@ -11073,10 +11073,10 @@ test("(class {f({x} = {x: 10}) {}})", {
           end: {line: 1, column: 28}
         }
       },
-      range: [0, 29],
+      range: [1, 28],
       loc: {
-        start: {line: 1, column: 0},
-        end: {line: 1, column: 29}
+        start: {line: 1, column: 1},
+        end: {line: 1, column: 28}
       }
     },
     range: [0, 29],
@@ -11192,10 +11192,10 @@ test("(({x} = {x: 10}) => {})", {
       rest: null,
       generator: false,
       expression: false,
-      range: [0, 23],
+      range: [1, 22],
       loc: {
-        start: {line: 1, column: 0},
-        end: {line: 1, column: 23}
+        start: {line: 1, column: 1},
+        end: {line: 1, column: 22}
       }
     },
     range: [0, 23],
@@ -12267,10 +12267,10 @@ test("(function x([ a, b ]){})", {
       rest: null,
       generator: false,
       expression: false,
-      range: [0, 24],
+      range: [1, 23],
       loc: {
-        start: {line: 1, column: 0},
-        end: {line: 1, column: 24}
+        start: {line: 1, column: 1},
+        end: {line: 1, column: 23}
       }
     },
     range: [0, 24],
@@ -12388,10 +12388,10 @@ test("(function x({ a, b }){})", {
       rest: null,
       generator: false,
       expression: false,
-      range: [0, 24],
+      range: [1, 23],
       loc: {
-        start: {line: 1, column: 0},
-        end: {line: 1, column: 24}
+        start: {line: 1, column: 1},
+        end: {line: 1, column: 23}
       }
     },
     range: [0, 24],
@@ -12467,10 +12467,10 @@ test("(function x(...[ a, b ]){})", {
       },
       generator: false,
       expression: false,
-      range: [0, 27],
+      range: [1, 26],
       loc: {
-        start: {line: 1, column: 0},
-        end: {line: 1, column: 27}
+        start: {line: 1, column: 1},
+        end: {line: 1, column: 26}
       }
     },
     range: [0, 27],
@@ -12704,10 +12704,10 @@ test("(function x({ a: { w, x }, b: [y, z] }, ...[a, b, c]){})", {
       },
       generator: false,
       expression: false,
-      range: [0, 56],
+      range: [1, 55],
       loc: {
-        start: {line: 1, column: 0},
-        end: {line: 1, column: 56}
+        start: {line: 1, column: 1},
+        end: {line: 1, column: 55}
       }
     },
     range: [0, 56],
@@ -12804,10 +12804,10 @@ test("({ x([ a, b ]){} })", {
           end: {line: 1, column: 16}
         }
       }],
-      range: [0, 19],
+      range: [1, 18],
       loc: {
-        start: {line: 1, column: 0},
-        end: {line: 1, column: 19}
+        start: {line: 1, column: 1},
+        end: {line: 1, column: 18}
       }
     },
     range: [0, 19],
@@ -12904,10 +12904,10 @@ test("({ x(...[ a, b ]){} })", {
           end: {line: 1, column: 19}
         }
       }],
-      range: [0, 22],
+      range: [1, 21],
       loc: {
-        start: {line: 1, column: 0},
-        end: {line: 1, column: 22}
+        start: {line: 1, column: 1},
+        end: {line: 1, column: 21}
       }
     },
     range: [0, 22],
@@ -13162,10 +13162,10 @@ test("({ x({ a: { w, x }, b: [y, z] }, ...[a, b, c]){} })", {
           end: {line: 1, column: 48}
         }
       }],
-      range: [0, 51],
+      range: [1, 50],
       loc: {
-        start: {line: 1, column: 0},
-        end: {line: 1, column: 51}
+        start: {line: 1, column: 1},
+        end: {line: 1, column: 50}
       }
     },
     range: [0, 51],
@@ -15086,10 +15086,10 @@ test("(function () { yield* 10 })", {
       rest: null,
       generator: false,
       expression: false,
-      range: [0, 27],
+      range: [1, 26],
       loc: {
-        start: {line: 1, column: 0},
-        end: {line: 1, column: 27}
+        start: {line: 1, column: 1},
+        end: {line: 1, column: 26}
       }
     },
     range: [0, 27],
@@ -15388,4 +15388,4 @@ test('function normal(x, y = 10) {}', {
     },
     expression: false
   }]
-}, {ecmaVersion: 6});
\ No newline at end of file
+}, {ecmaVersion: 6});
diff --git a/test/tests.js b/test/tests.js
index c39aa3cde6..5a86572a93 100644
--- a/test/tests.js
+++ b/test/tests.js
@@ -2,9 +2,8 @@
 // (http://esprima.org/test/)
 
 if (typeof exports != "undefined") {
-  var test = require("./driver.js").test;
-  var testFail = require("./driver.js").testFail;
-  var testAssert = require("./driver.js").testAssert;
+  var driver = require("./driver.js");
+  var test = driver.test, testFail = driver.testFail, testAssert = driver.testAssert, misMatch = driver.misMatch;
   var acorn = require("..");
 }
 
@@ -177,11 +176,11 @@ test("(1 + 2 ) * 3", {
           loc: {
             start: {
               line: 1,
-              column: 0
+              column: 1
             },
             end: {
               line: 1,
-              column: 8
+              column: 6
             }
           }
         },
@@ -8202,11 +8201,11 @@ test("( new foo).bar()", {
             loc: {
               start: {
                 line: 1,
-                column: 0
+                column: 2
               },
               end: {
                 line: 1,
-                column: 10
+                column: 9
               }
             }
           },
@@ -8371,11 +8370,11 @@ test("(    foo  )()", {
           loc: {
             start: {
               line: 1,
-              column: 0
+              column: 5
             },
             end: {
               line: 1,
-              column: 11
+              column: 8
             }
           }
         },
@@ -17217,11 +17216,11 @@ test("if (morning) (function(){})", {
           loc: {
             start: {
               line: 1,
-              column: 13
+              column: 14
             },
             end: {
               line: 1,
-              column: 27
+              column: 26
             }
           }
         },
@@ -20508,11 +20507,11 @@ test("(function(){ return })", {
         loc: {
           start: {
             line: 1,
-            column: 0
+            column: 1
           },
           end: {
             line: 1,
-            column: 22
+            column: 21
           }
         }
       },
@@ -20581,11 +20580,11 @@ test("(function(){ return; })", {
         loc: {
           start: {
             line: 1,
-            column: 0
+            column: 1
           },
           end: {
             line: 1,
-            column: 23
+            column: 22
           }
         }
       },
@@ -20667,11 +20666,11 @@ test("(function(){ return x; })", {
         loc: {
           start: {
             line: 1,
-            column: 0
+            column: 1
           },
           end: {
             line: 1,
-            column: 25
+            column: 24
           }
         }
       },
@@ -20781,11 +20780,11 @@ test("(function(){ return x * y })", {
         loc: {
           start: {
             line: 1,
-            column: 0
+            column: 1
           },
           end: {
             line: 1,
-            column: 28
+            column: 27
           }
         }
       },
@@ -23194,11 +23193,11 @@ test("(function test(t, t) { })", {
         loc: {
           start: {
             line: 1,
-            column: 0
+            column: 1
           },
           end: {
             line: 1,
-            column: 25
+            column: 24
           }
         }
       },
@@ -24412,11 +24411,11 @@ test("(function(){})", {
         loc: {
           start: {
             line: 1,
-            column: 0
+            column: 1
           },
           end: {
             line: 1,
-            column: 14
+            column: 13
           }
         }
       },
@@ -25522,11 +25521,11 @@ test("(function(){ return\nx; })", {
         loc: {
           start: {
             line: 1,
-            column: 0
+            column: 1
           },
           end: {
             line: 2,
-            column: 5
+            column: 4
           }
         }
       },
@@ -25622,11 +25621,11 @@ test("(function(){ return // Comment\nx; })", {
         loc: {
           start: {
             line: 1,
-            column: 0
+            column: 1
           },
           end: {
             line: 2,
-            column: 5
+            column: 4
           }
         }
       },
@@ -25722,11 +25721,11 @@ test("(function(){ return/* Multiline\nComment */x; })", {
         loc: {
           start: {
             line: 1,
-            column: 0
+            column: 1
           },
           end: {
             line: 2,
-            column: 15
+            column: 14
           }
         }
       },
@@ -26026,8 +26025,6 @@ test("", {
 
 test("foo: if (true) break foo;", {
   type: "Program",
-  start: 0,
-  end: 25,
   loc: {
     start: {
       line: 1,
@@ -26041,8 +26038,6 @@ test("foo: if (true) break foo;", {
   body: [
     {
       type: "LabeledStatement",
-      start: 0,
-      end: 25,
       loc: {
         start: {
           line: 1,
@@ -26055,8 +26050,6 @@ test("foo: if (true) break foo;", {
       },
       body: {
         type: "IfStatement",
-        start: 5,
-        end: 25,
         loc: {
           start: {
             line: 1,
@@ -26069,8 +26062,6 @@ test("foo: if (true) break foo;", {
         },
         test: {
           type: "Literal",
-          start: 9,
-          end: 13,
           loc: {
             start: {
               line: 1,
@@ -26085,8 +26076,6 @@ test("foo: if (true) break foo;", {
         },
         consequent: {
           type: "BreakStatement",
-          start: 15,
-          end: 25,
           loc: {
             start: {
               line: 1,
@@ -26099,8 +26088,6 @@ test("foo: if (true) break foo;", {
           },
           label: {
             type: "Identifier",
-            start: 21,
-            end: 24,
             loc: {
               start: {
                 line: 1,
@@ -26118,8 +26105,6 @@ test("foo: if (true) break foo;", {
       },
       label: {
         type: "Identifier",
-        start: 0,
-        end: 3,
         loc: {
           start: {
             line: 1,
@@ -26138,8 +26123,6 @@ test("foo: if (true) break foo;", {
 
 test("(function () {\n 'use strict';\n '\0';\n}())", {
   type: "Program",
-  start: 0,
-  end: 40,
   loc: {
     start: {
       line: 1,
@@ -26153,8 +26136,6 @@ test("(function () {\n 'use strict';\n '\0';\n}())", {
   body: [
     {
       type: "ExpressionStatement",
-      start: 0,
-      end: 40,
       loc: {
         start: {
           line: 1,
@@ -26167,21 +26148,18 @@ test("(function () {\n 'use strict';\n '\0';\n}())", {
       },
       expression: {
         type: "CallExpression",
-        start: 0,
         loc: {
           start: {
             line: 1,
-            column: 0
+            column: 1
           },
           end: {
             line: 4,
-            column: 4
+            column: 3
           }
         },
         callee: {
           type: "FunctionExpression",
-          start: 1,
-          end: 37,
           loc: {
             start: {
               line: 1,
@@ -26196,8 +26174,6 @@ test("(function () {\n 'use strict';\n '\0';\n}())", {
           params: [],
           body: {
             type: "BlockStatement",
-            start: 13,
-            end: 37,
             loc: {
               start: {
                 line: 1,
@@ -26211,8 +26187,6 @@ test("(function () {\n 'use strict';\n '\0';\n}())", {
             body: [
               {
                 type: "ExpressionStatement",
-                start: 16,
-                end: 29,
                 loc: {
                   start: {
                     line: 2,
@@ -26225,8 +26199,6 @@ test("(function () {\n 'use strict';\n '\0';\n}())", {
                 },
                 expression: {
                   type: "Literal",
-                  start: 16,
-                  end: 28,
                   loc: {
                     start: {
                       line: 2,
@@ -26242,8 +26214,6 @@ test("(function () {\n 'use strict';\n '\0';\n}())", {
               },
               {
                 type: "ExpressionStatement",
-                start: 31,
-                end: 35,
                 loc: {
                   start: {
                     line: 3,
@@ -26256,8 +26226,6 @@ test("(function () {\n 'use strict';\n '\0';\n}())", {
                 },
                 expression: {
                   type: "Literal",
-                  start: 31,
-                  end: 34,
                   loc: {
                     start: {
                       line: 3,
@@ -26275,7 +26243,6 @@ test("(function () {\n 'use strict';\n '\0';\n}())", {
           }
         },
         arguments: [],
-        end: 40
       }
     }
   ]
@@ -26283,43 +26250,29 @@ test("(function () {\n 'use strict';\n '\0';\n}())", {
 
 test("123..toString(10)", {
   type: "Program",
-  start: 0,
-  end: 17,
   body: [
     {
       type: "ExpressionStatement",
-      start: 0,
-      end: 17,
       expression: {
         type: "CallExpression",
-        start: 0,
         callee: {
           type: "MemberExpression",
-          start: 0,
           object: {
             type: "Literal",
-            start: 0,
-            end: 4,
             value: 123
           },
           property: {
             type: "Identifier",
-            start: 5,
-            end: 13,
             name: "toString"
           },
           computed: false,
-          end: 13
         },
         arguments: [
           {
             type: "Literal",
-            start: 14,
-            end: 16,
             value: 10
           }
         ],
-        end: 17
       }
     }
   ]
@@ -26327,30 +26280,20 @@ test("123..toString(10)", {
 
 test("123.+2", {
   type: "Program",
-  start: 0,
-  end: 6,
   body: [
     {
       type: "ExpressionStatement",
-      start: 0,
-      end: 6,
       expression: {
         type: "BinaryExpression",
-        start: 0,
         left: {
           type: "Literal",
-          start: 0,
-          end: 4,
           value: 123
         },
         operator: "+",
         right: {
           type: "Literal",
-          start: 5,
-          end: 6,
           value: 2
         },
-        end: 6
       }
     }
   ]
@@ -26358,28 +26301,18 @@ test("123.+2", {
 
 test("a\u2028b", {
   type: "Program",
-  start: 0,
-  end: 3,
   body: [
     {
       type: "ExpressionStatement",
-      start: 0,
-      end: 1,
       expression: {
         type: "Identifier",
-        start: 0,
-        end: 1,
         name: "a"
       }
     },
     {
       type: "ExpressionStatement",
-      start: 2,
-      end: 3,
       expression: {
         type: "Identifier",
-        start: 2,
-        end: 3,
         name: "b"
       }
     }
@@ -26437,28 +26370,18 @@ test("foo: 10; foo: 20;", {
 
 test("if(1)/  foo/", {
   type: "Program",
-  start: 0,
-  end: 12,
   body: [
     {
       type: "IfStatement",
-      start: 0,
-      end: 12,
       test: {
         type: "Literal",
-        start: 3,
-        end: 4,
         value: 1,
         raw: "1"
       },
       consequent: {
         type: "ExpressionStatement",
-        start: 5,
-        end: 12,
         expression: {
           type: "Literal",
-          start: 5,
-          end: 12,
           raw: "/  foo/"
         }
       },
@@ -26475,8 +26398,6 @@ test("price_9̶9̶_89", {
       expression: {
         type: "Identifier",
         name: "price_9̶9̶_89",
-        start: 0,
-        end: 13
       }
     }
   ]
@@ -26486,8 +26407,6 @@ test("price_9̶9̶_89", {
 
 test("var a = 1;", {
   type: "Program",
-  start: 0,
-  end: 10,
   loc: {
     start: {
       line: 1,
@@ -26502,8 +26421,6 @@ test("var a = 1;", {
   body: [
     {
       type: "VariableDeclaration",
-      start: 0,
-      end: 10,
       loc: {
         start: {
           line: 1,
@@ -26518,8 +26435,6 @@ test("var a = 1;", {
       declarations: [
         {
           type: "VariableDeclarator",
-          start: 4,
-          end: 9,
           loc: {
             start: {
               line: 1,
@@ -26533,8 +26448,6 @@ test("var a = 1;", {
           },
           id: {
             type: "Identifier",
-            start: 4,
-            end: 5,
             loc: {
               start: {
                 line: 1,
@@ -26550,8 +26463,6 @@ test("var a = 1;", {
           },
           init: {
             type: "Literal",
-            start: 8,
-            end: 9,
             loc: {
               start: {
                 line: 1,
@@ -26624,28 +26535,18 @@ test("{}/=/", {
 
 test("foo <!--bar\n+baz", {
   type: "Program",
-  start: 0,
-  end: 16,
   body: [
     {
       type: "ExpressionStatement",
-      start: 0,
-      end: 16,
       expression: {
         type: "BinaryExpression",
-        start: 0,
-        end: 16,
         left: {
           type: "Identifier",
-          start: 0,
-          end: 3,
           name: "foo"
         },
         operator: "+",
         right: {
           type: "Identifier",
-          start: 13,
-          end: 16,
           name: "baz"
         }
       }
@@ -26795,7 +26696,7 @@ testFail("func() = 4",
          "Assigning to rvalue (1:0)");
 
 testFail("(1 + 1) = 10",
-         "Assigning to rvalue (1:0)");
+         "Assigning to rvalue (1:1)");
 
 testFail("1++",
          "Assigning to rvalue (1:0)");
@@ -26810,7 +26711,7 @@ testFail("--1",
          "Assigning to rvalue (1:2)");
 
 testFail("for((1 + 1) in list) process(x);",
-         "Assigning to rvalue (1:4)");
+         "Assigning to rvalue (1:5)");
 
 testFail("[",
          "Unexpected token (1:1)");
@@ -27309,8 +27210,6 @@ testFail("for(let x = 0;;);", "Unexpected token (1:8)");
 
 test("let++", {
   type: "Program",
-  start: 0,
-  end: 5,
   loc: {
     start: {
       line: 1,
@@ -27324,8 +27223,6 @@ test("let++", {
   body: [
     {
       type: "ExpressionStatement",
-      start: 0,
-      end: 5,
       loc: {
         start: {
           line: 1,
@@ -27338,8 +27235,6 @@ test("let++", {
       },
       expression: {
         type: "UpdateExpression",
-        start: 0,
-        end: 5,
         loc: {
           start: {
             line: 1,
@@ -27354,8 +27249,6 @@ test("let++", {
         prefix: false,
         argument: {
           type: "Identifier",
-          start: 0,
-          end: 3,
           loc: {
             start: {
               line: 1,
@@ -28704,8 +28597,6 @@ test("<!--\n;", {
         {
           type: tokTypes._var,
           value: "var",
-          start: 0,
-          end: 3,
           loc: {
             start: {line: 1, column: 0},
             end: {line: 1, column: 3}
@@ -28714,8 +28605,6 @@ test("<!--\n;", {
         {
           type: tokTypes.name,
           value: "x",
-          start: 4,
-          end: 5,
           loc: {
             start: {line: 1, column: 4},
             end: {line: 1, column: 5}
@@ -28724,8 +28613,6 @@ test("<!--\n;", {
         {
           type: tokTypes.eq,
           value: "=",
-          start: 6,
-          end: 7,
           loc: {
             start: {line: 1, column: 6},
             end: {line: 1, column: 7}
@@ -28734,8 +28621,6 @@ test("<!--\n;", {
         {
           type: tokTypes.parenL,
           value: undefined,
-          start: 8,
-          end: 9,
           loc: {
             start: {line: 1, column: 8},
             end: {line: 1, column: 9}
@@ -28744,8 +28629,6 @@ test("<!--\n;", {
         {
           type: tokTypes.num,
           value: 1,
-          start: 9,
-          end: 10,
           loc: {
             start: {line: 1, column: 9},
             end: {line: 1, column: 10}
@@ -28754,8 +28637,6 @@ test("<!--\n;", {
         {
           type: {binop: 9, prefix: true, beforeExpr: true},
           value: "+",
-          start: 11,
-          end: 12,
           loc: {
             start: {line: 1, column: 11},
             end: {line: 1, column: 12}
@@ -28764,8 +28645,6 @@ test("<!--\n;", {
         {
           type: tokTypes.num,
           value: 2,
-          start: 13,
-          end: 14,
           loc: {
             start: {line: 1, column: 13},
             end: {line: 1, column: 14}
@@ -28774,8 +28653,6 @@ test("<!--\n;", {
         {
           type: tokTypes.parenR,
           value: undefined,
-          start: 14,
-          end: 15,
           loc: {
             start: {line: 1, column: 14},
             end: {line: 1, column: 15}
@@ -28784,8 +28661,6 @@ test("<!--\n;", {
         {
           type: tokTypes.eof,
           value: undefined,
-          start: 15,
-          end: 15,
           loc: {
             start: {line: 1, column: 15},
             end: {line: 1, column: 15}
@@ -28794,17 +28669,11 @@ test("<!--\n;", {
       ];
   testAssert('var x = (1 + 2)', function assert(ast) {
     if (actualTokens.length !== expectedTokens.length) {
-      return JSON.stringify(actualTokens) + " !== " + JSON.stringify(expectedTokens);
+      return "Bad token stream length: expected " + expectedTokens.length + ", got " + actualTokens.length;
     } else {
       for (var i=0, n=actualTokens.length; i < n; i++) {
-        var actualToken = JSON.stringify(
-          actualTokens[i],
-          // just remove this when startLoc/endLoc support is dropped
-          function (key, value) { if (key !== 'startLoc' && key !== 'endLoc') return value; }
-        );
-        var expectedToken = JSON.stringify(expectedTokens[i]);
-        if (actualToken !== expectedToken)
-          return actualToken + ' !== ' + expectedToken;
+        var mis = misMatch(expectedTokens[i], actualTokens[i]);
+        if (mis) return mis;
       }
     }
   }, {