implement opassign, fix bugs in pre/postfix, introduce a let* helper

lib/runtime/dart/collection.js

 var collection;
 (function(exports) {
   'use strict';
   let _source = Symbol('_source');
   let UnmodifiableListView$ = dart.generic(function(E) {
     class UnmodifiableListView extends _internal.UnmodifiableListBase$(E) {
       UnmodifiableListView(source) {
         this[_source] = source;
         super.UnmodifiableListBase();
       }
@@ skipping 132 matching lines @@
         this.removeAll(toRemove);
       }
       containsAll(other) {
         for (let o of other) {
           if (!dart.notNull(this.contains(o)))
             return false;
         }
         return true;
       }
       union(other) {
-        return ((_) => {
-          _.addAll(other);
-          return _;
-        })(this.toSet());
+        let _ = this.toSet();
+        _.addAll(other);
+        return _;
       }
       intersection(other) {
         let result = this.toSet();
         for (let element of this) {
           if (!dart.notNull(other[core.$contains](element)))
             result.remove(element);
         }
         return result;
       }
       difference(other) {
         let result = this.toSet();
         for (let element of this) {
           if (other[core.$contains](element))
             result.remove(element);
         }
         return result;
       }
       [core.$toList](opts) {
         let growable = opts && 'growable' in opts ? opts.growable : true;
-        let result = growable ? ((_) => {
-          _[core.$length] = this.length;
-          return _;
-        }).bind(this)(new (core.List$(E))()) : new (core.List$(E))(this.length);
+        let result = growable ? ((_) => (_ = new (core.List$(E))(), _[core.$length] = this.length, _)).bind(this)() : new (core.List$(E))(this.length);
         let i = 0;
         for (let element of this)
-          result[core.$set](((x$) => i = dart.notNull(x$) + 1, x$)(i), element);
+          result[core.$set](((x$) => (x$ = i, i = dart.notNull(x$) + 1, x$))(), element);
         return result;
       }
       [core.$map](f) {
         return new (_internal.EfficientLengthMappedIterable$(E, dynamic))(this, f);
       }
       get [core.$single]() {
         if (dart.notNull(this.length) > 1)
           throw _internal.IterableElementError.tooMany();
         let it = this.iterator;
         if (!dart.notNull(it.moveNext()))
@@ skipping 175 matching lines @@
       }
       intersection(other) {
         let result = this[_newSet]();
         for (let element of this) {
           if (other[core.$contains](element))
             result.add(element);
         }
         return result;
       }
       [core.$toSet]() {
-        return ((_) => {
-          _.addAll(this);
-          return _;
-        }).bind(this)(this[_newSet]());
+        return ((_) => (_ = this[_newSet](), _.addAll(this), _)).bind(this)();
       }
     }
     return _HashSetBase;
   });
   let _HashSetBase = _HashSetBase$();
   let HashSet$ = dart.generic(function(E) {
     class HashSet extends core.Object {
       HashSet(opts) {
         let equals = opts && 'equals' in opts ? opts.equals : null;
         let hashCode = opts && 'hashCode' in opts ? opts.hashCode : null;
@@ skipping 443 matching lines @@
         }
         let parts = new core.List.from([]);
         IterableBase[_toStringVisiting][core.$add](iterable);
         try {
           IterableBase[_iterablePartsToStrings](iterable, parts);
         } finally {
           dart.assert(core.identical(IterableBase[_toStringVisiting][core.$last], iterable));
           IterableBase[_toStringVisiting][core.$removeLast]();
         }
         return ((_) => {
+          _ = new core.StringBuffer(leftDelimiter);
           _.writeAll(parts, ", ");
           _.write(rightDelimiter);
           return _;
-        })(new core.StringBuffer(leftDelimiter)).toString();
+        })().toString();
       }
       static iterableToFullString(iterable, leftDelimiter, rightDelimiter) {
         if (leftDelimiter === void 0)
           leftDelimiter = '(';
         if (rightDelimiter === void 0)
           rightDelimiter = ')';
         if (IterableBase[_isToStringVisiting](iterable)) {
           return `${leftDelimiter}...${rightDelimiter}`;
         }
         let buffer = new core.StringBuffer(leftDelimiter);
@@ skipping 22 matching lines @@
         let OVERHEAD = 2;
         let ELLIPSIS_SIZE = 3;
         let length = 0;
         let count = 0;
         let it = iterable[core.$iterator];
         while (dart.notNull(length) < dart.notNull(LENGTH_LIMIT) || dart.notNull(count) < dart.notNull(HEAD_COUNT)) {
           if (!dart.notNull(it.moveNext()))
             return;
           let next = `${it.current}`;
           parts[core.$add](next);
-          length = dart.notNull(next.length) + dart.notNull(OVERHEAD);
+          length = dart.notNull(length) + (dart.notNull(next.length) + dart.notNull(OVERHEAD));
           count = dart.notNull(count) + 1;
         }
         let penultimateString = null;
         let ultimateString = null;
         let penultimate = null;
         let ultimate = null;
         if (!dart.notNull(it.moveNext())) {
           if (dart.notNull(count) <= dart.notNull(HEAD_COUNT) + dart.notNull(TAIL_COUNT))
             return;
           ultimateString = dart.as(parts[core.$removeLast](), core.String);
           penultimateString = dart.as(parts[core.$removeLast](), core.String);
         } else {
           penultimate = it.current;
           count = dart.notNull(count) + 1;
           if (!dart.notNull(it.moveNext())) {
             if (dart.notNull(count) <= dart.notNull(HEAD_COUNT) + 1) {
               parts[core.$add](`${penultimate}`);
               return;
             }
             ultimateString = `${penultimate}`;
             penultimateString = dart.as(parts[core.$removeLast](), core.String);
-            length = dart.notNull(ultimateString.length) + dart.notNull(OVERHEAD);
+            length = dart.notNull(length) + (dart.notNull(ultimateString.length) + dart.notNull(OVERHEAD));
           } else {
             ultimate = it.current;
             count = dart.notNull(count) + 1;
             dart.assert(dart.notNull(count) < dart.notNull(MAX_COUNT));
             while (it.moveNext()) {
               penultimate = ultimate;
               ultimate = it.current;
               count = dart.notNull(count) + 1;
               if (dart.notNull(count) > dart.notNull(MAX_COUNT)) {
                 while (dart.notNull(length) > dart.notNull(LENGTH_LIMIT) - dart.notNull(ELLIPSIS_SIZE) - dart.notNull(OVERHEAD) && dart.notNull(count) > dart.notNull(HEAD_COUNT)) {
-                  length = dart.as(dart.dbinary(dart.dload(parts[core.$removeLast](), 'length'), '+', OVERHEAD), core.int);
+                  length = dart.notNull(length) - dart.notNull(dart.as(dart.dbinary(dart.dload(parts[core.$removeLast](), 'length'), '+', OVERHEAD), core.int));
                   count = dart.notNull(count) - 1;
                 }
                 parts[core.$add]("...");
                 return;
               }
             }
             penultimateString = `${penultimate}`;
             ultimateString = `${ultimate}`;
-            length = dart.notNull(ultimateString.length) + dart.notNull(penultimateString.length) + 2 * dart.notNull(OVERHEAD);
+            length = dart.notNull(length) + (dart.notNull(ultimateString.length) + dart.notNull(penultimateString.length) + 2 * dart.notNull(OVERHEAD));
           }
         }
         let elision = null;
         if (dart.notNull(count) > dart.notNull(parts[core.$length]) + dart.notNull(TAIL_COUNT)) {
           elision = "...";
-          length = dart.notNull(ELLIPSIS_SIZE) + dart.notNull(OVERHEAD);
+          length = dart.notNull(length) + (dart.notNull(ELLIPSIS_SIZE) + dart.notNull(OVERHEAD));
         }
         while (dart.notNull(length) > dart.notNull(LENGTH_LIMIT) && dart.notNull(parts[core.$length]) > dart.notNull(HEAD_COUNT)) {
-          length = dart.as(dart.dbinary(dart.dload(parts[core.$removeLast](), 'length'), '+', OVERHEAD), core.int);
+          length = dart.notNull(length) - dart.notNull(dart.as(dart.dbinary(dart.dload(parts[core.$removeLast](), 'length'), '+', OVERHEAD), core.int));
           if (elision == null) {
             elision = "...";
-            length = dart.notNull(ELLIPSIS_SIZE) + dart.notNull(OVERHEAD);
+            length = dart.notNull(length) + (dart.notNull(ELLIPSIS_SIZE) + dart.notNull(OVERHEAD));
           }
         }
         if (elision != null) {
           parts[core.$add](elision);
         }
         parts[core.$add](penultimateString);
         parts[core.$add](ultimateString);
       }
     }
     IterableBase[dart.implements] = () => [core.Iterable$(E)];
@@ skipping 518 matching lines @@
       [core.$take](count) {
         return new (_internal.SubListIterable$(E))(this, 0, count);
       }
       [core.$takeWhile](test) {
         return new (_internal.TakeWhileIterable$(E))(this, test);
       }
       [core.$toList](opts) {
         let growable = opts && 'growable' in opts ? opts.growable : true;
         let result = null;
         if (growable) {
-          result = ((_) => {
-            _[core.$length] = this.length;
-            return _;
-          }).bind(this)(new (core.List$(E))());
+          result = new (core.List$(E))();
+          result[core.$length] = this.length;
         } else {
           result = new (core.List$(E))(this.length);
         }
         for (let i = 0; dart.notNull(i) < dart.notNull(this.length); i = dart.notNull(i) + 1) {
           result[core.$set](i, this[core.$get](i));
         }
         return result;
       }
       [core.$toSet]() {
         let result = new (core.Set$(E))();
         for (let i = 0; dart.notNull(i) < dart.notNull(this.length); i = dart.notNull(i) + 1) {
           result.add(this[core.$get](i));
         }
         return result;
       }
       [core.$add](element) {
-        this[core.$set](((x$) => this[core.$length] = dart.notNull(x$) + 1, x$).bind(this)(this[core.$length]), element);
+        this[core.$set](((o$, x$) => {
+          o$ = this;
+          x$ = o$[core.$length];
+          o$[core.$length] = dart.notNull(x$) + 1;
+          return x$;
+        }).bind(this)(), element);
       }
       [core.$addAll](iterable) {
         for (let element of iterable) {
-          this[core.$set](((x$) => this[core.$length] = dart.notNull(x$) + 1, x$).bind(this)(this[core.$length]), element);
+          this[core.$set](((o$, x$) => {
+            o$ = this;
+            x$ = o$[core.$length];
+            o$[core.$length] = dart.notNull(x$) + 1;
+            return x$;
+          }).bind(this)(), element);
         }
       }
       [core.$remove](element) {
         for (let i = 0; dart.notNull(i) < dart.notNull(this[core.$length]); i = dart.notNull(i) + 1) {
           if (dart.equals(this[core.$get](i), element)) {
             this[core.$setRange](i, dart.notNull(this[core.$length]) - 1, this, dart.notNull(i) + 1);
-            this[core.$length] = 1;
+            let o$ = this;
+            o$[core.$length] = dart.notNull(o$[core.$length]) - 1;
             return true;
           }
         }
         return false;
       }
       [core.$removeWhere](test) {
         ListMixin[_filter](this, test, false);
       }
       [core.$retainWhere](test) {
         ListMixin[_filter](this, test, true);
@@ skipping 36 matching lines @@
         _internal.Sort.sort(this, compare);
       }
       [core.$shuffle](random) {
         if (random === void 0)
           random = null;
         if (random == null)
           random = new math.Random();
         let length = this[core.$length];
         while (dart.notNull(length) > 1) {
           let pos = random.nextInt(length);
-          length = 1;
+          length = dart.notNull(length) - 1;
           let tmp = this[core.$get](length);
           this[core.$set](length, this[core.$get](pos));
           this[core.$set](pos, tmp);
         }
       }
       [core.$asMap]() {
         return new (_internal.ListMapView$(E))(this);
       }
       [core.$sublist](start, end) {
         if (end === void 0)
@@ skipping 11 matching lines @@
         return result;
       }
       [core.$getRange](start, end) {
         core.RangeError.checkValidRange(start, end, this[core.$length]);
         return new (_internal.SubListIterable$(E))(this, start, end);
       }
       [core.$removeRange](start, end) {
         core.RangeError.checkValidRange(start, end, this[core.$length]);
         let length = dart.notNull(end) - dart.notNull(start);
         this.setRange(start, dart.notNull(this[core.$length]) - dart.notNull(length), this, end);
-        this[core.$length] = length;
+        let o$ = this;
+        o$[core.$length] = dart.notNull(o$[core.$length]) - dart.notNull(length);
       }
       [core.$fillRange](start, end, fill) {
         if (fill === void 0)
           fill = null;
         core.RangeError.checkValidRange(start, end, this[core.$length]);
         for (let i = start; dart.notNull(i) < dart.notNull(end); i = dart.notNull(i) + 1) {
           this[core.$set](i, fill);
         }
       }
       [core.$setRange](start, end, iterable, skipCount) {
@@ skipping 88 matching lines @@
         return -1;
       }
       [core.$insert](index, element) {
         core.RangeError.checkValueInInterval(index, 0, this.length, "index");
         if (index == this[core.$length]) {
           this.add(element);
           return;
         }
         if (!(typeof index == 'number'))
           throw new core.ArgumentError(index);
-        this[core.$length] = dart.notNull(this[core.$length]) + 1;
+        let o$ = this;
+        o$[core.$length] = dart.notNull(o$[core.$length]) + 1;
         this.setRange(dart.notNull(index) + 1, this[core.$length], this, index);
         this[core.$set](index, element);
       }
       [core.$removeAt](index) {
         let result = this[core.$get](index);
         this.setRange(index, dart.notNull(this[core.$length]) - 1, this, dart.notNull(index) + 1);
         this.length = dart.notNull(this.length) - 1;
         return result;
       }
       [core.$insertAll](index, iterable) {
         core.RangeError.checkValueInInterval(index, 0, this.length, "index");
         if (dart.is(iterable, _internal.EfficientLength)) {
           iterable = iterable[core.$toList]();
         }
         let insertionLength = iterable[core.$length];
-        this[core.$length] = insertionLength;
+        let o$ = this;
+        o$[core.$length] = dart.notNull(o$[core.$length]) + dart.notNull(insertionLength);
         this.setRange(dart.notNull(index) + dart.notNull(insertionLength), this[core.$length], this, index);
         this.setAll(index, iterable);
       }
       [core.$setAll](index, iterable) {
         if (dart.is(iterable, core.List)) {
           this.setRange(index, dart.notNull(index) + dart.notNull(iterable[core.$length]), iterable);
         } else {
           for (let element of iterable) {
-            this[core.$set](((x$) => index = dart.notNull(x$) + 1, x$)(index), element);
+            this[core.$set](((x$) => (x$ = index, index = dart.notNull(x$) + 1, x$))(), element);
           }
         }
       }
       get [core.$reversed]() {
         return new (_internal.ReversedListIterable$(E))(this);
       }
       toString() {
         return IterableBase.iterableToFullString(this, '[', ']');
       }
     }
@@ skipping 626 matching lines @@
         return this[_table][core.$get](this[_head]);
       }
       [core.$elementAt](index) {
         core.RangeError.checkValidIndex(index, this);
         return this[_table][core.$get](dart.notNull(this[_head]) + dart.notNull(index) & dart.notNull(this[_table][core.$length]) - 1);
       }
       [core.$toList](opts) {
         let growable = opts && 'growable' in opts ? opts.growable : true;
         let list = null;
         if (growable) {
-          list = ((_) => {
-            _[core.$length] = this.length;
-            return _;
-          }).bind(this)(new (core.List$(E))());
+          list = new (core.List$(E))();
+          list[core.$length] = this.length;
         } else {
           list = new (core.List$(E))(this.length);
         }
         this[_writeToList](list);
         return list;
       }
       add(element) {
         this[_add](element);
       }
       addAll(elements) {
         if (dart.is(elements, core.List)) {
           let list = dart.as(elements, core.List);
           let addCount = list[core.$length];
           let length = this[core.$length];
           if (dart.notNull(length) + dart.notNull(addCount) >= dart.notNull(this[_table][core.$length])) {
             this[_preGrow](dart.notNull(length) + dart.notNull(addCount));
             this[_table][core.$setRange](length, dart.notNull(length) + dart.notNull(addCount), dart.as(list, core.Iterable$(E)), 0);
-            this[_tail] = addCount;
+            this[_tail] = dart.notNull(this[_tail]) + dart.notNull(addCount);
           } else {
             let endSpace = dart.notNull(this[_table][core.$length]) - dart.notNull(this[_tail]);
             if (dart.notNull(addCount) < dart.notNull(endSpace)) {
               this[_table][core.$setRange](this[_tail], dart.notNull(this[_tail]) + dart.notNull(addCount), dart.as(list, core.Iterable$(E)), 0);
-              this[_tail] = addCount;
+              this[_tail] = dart.notNull(this[_tail]) + dart.notNull(addCount);
             } else {
               let preSpace = dart.notNull(addCount) - dart.notNull(endSpace);
               this[_table][core.$setRange](this[_tail], dart.notNull(this[_tail]) + dart.notNull(endSpace), dart.as(list, core.Iterable$(E)), 0);
               this[_table][core.$setRange](0, preSpace, dart.as(list, core.Iterable$(E)), endSpace);
               this[_tail] = preSpace;
             }
           }
           this[_modificationCount] = dart.notNull(this[_modificationCount]) + 1;
         } else {
           for (let element of elements)
@@ skipping 141 matching lines @@
           return length;
         } else {
           let firstPartSize = dart.notNull(this[_table][core.$length]) - dart.notNull(this[_head]);
           target[core.$setRange](0, firstPartSize, this[_table], this[_head]);
           target[core.$setRange](firstPartSize, dart.notNull(firstPartSize) + dart.notNull(this[_tail]), this[_table], 0);
           return dart.notNull(this[_tail]) + dart.notNull(firstPartSize);
         }
       }
       [_preGrow](newElementCount) {
         dart.assert(dart.notNull(newElementCount) >= dart.notNull(this.length));
-        newElementCount = dart.notNull(newElementCount) >> 1;
+        newElementCount = dart.notNull(newElementCount) + (dart.notNull(newElementCount) >> 1);
         let newCapacity = ListQueue[_nextPowerOf2](newElementCount);
         let newTable = new (core.List$(E))(newCapacity);
         this[_tail] = this[_writeToList](newTable);
         this[_table] = newTable;
         this[_head] = 0;
       }
     }
     ListQueue[dart.implements] = () => [Queue$(E)];
     dart.defineNamedConstructor(ListQueue, 'from');
     ListQueue._INITIAL_CAPACITY = 8;
@@ skipping 708 matching lines @@
       }
       difference(other) {
         let result = new (SplayTreeSet$(E))(dart.as(this[_comparator], dart.throw_("Unimplemented type (E, E) → int")), this[_validKey]);
         for (let element of this) {
           if (!dart.notNull(other[core.$contains](element)))
             result.add(element);
         }
         return result;
       }
       union(other) {
-        return ((_) => {
-          _.addAll(other);
-          return _;
-        })(this[_clone]());
+        let _ = this[_clone]();
+        _.addAll(other);
+        return _;
       }
       [_clone]() {
         let set = new (SplayTreeSet$(E))(dart.as(this[_comparator], dart.throw_("Unimplemented type (E, E) → int")), this[_validKey]);
         set[_count] = this[_count];
         set[_root] = this[_copyNode](this[_root]);
         return set;
       }
       [_copyNode](node) {
         if (node == null)
           return null;
-        return ((_) => {
-          _.left = this[_copyNode](node.left);
-          _.right = this[_copyNode](node.right);
-          return _;
-        }).bind(this)(new (_SplayTreeNode$(E))(node.key));
+        let _ = new (_SplayTreeNode$(E))(node.key);
+        _.left = this[_copyNode](node.left);
+        _.right = this[_copyNode](node.right);
+        return _;
       }
       clear() {
         this[_clear]();
       }
       [core.$toSet]() {
         return this[_clone]();
       }
       toString() {
         return IterableBase.iterableToFullString(this, '{', '}');
       }
@@ skipping 196 matching lines @@
           }
         }
         let rest = this[_rest];
         if (rest != null) {
           let names = Object.getOwnPropertyNames(rest);
           let entries = names.length;
           for (let i = 0; dart.notNull(i) < dart.notNull(entries); i = dart.notNull(i) + 1) {
             let key = names[i];
             let bucket = rest[key];
             let length = bucket.length;
-            for (let i = 0; dart.notNull(i) < dart.notNull(length); i = 2) {
+            for (let i = 0; dart.notNull(i) < dart.notNull(length); i = dart.notNull(i) + 2) {
               let key = bucket[i];
               result[index] = key;
               index = dart.notNull(index) + 1;
             }
           }
         }
         dart.assert(index == this[_length]);
         return this[_keys] = result;
       }
       [_addHashTableEntry](table, key, value) {
@@ skipping 42 matching lines @@
         delete table[key];
       }
       [_getBucket](table, key) {
         let hash = this[_computeHashCode](key);
         return dart.as(table[hash], core.List);
       }
       [_findBucketIndex](bucket, key) {
         if (bucket == null)
           return -1;
         let length = bucket.length;
-        for (let i = 0; dart.notNull(i) < dart.notNull(length); i = 2) {
+        for (let i = 0; dart.notNull(i) < dart.notNull(length); i = dart.notNull(i) + 2) {
           if (dart.equals(bucket[i], key))
             return i;
         }
         return -1;
       }
       static [_newHashTable]() {
         let table = Object.create(null);
         let temporaryKey = '<non-identifier-key>';
         _HashMap[_setTableEntry](table, temporaryKey, table);
         _HashMap[_deleteTableEntry](table, temporaryKey);
         return table;
       }
     }
     _HashMap[dart.implements] = () => [HashMap$(K, V)];
     return _HashMap;
   });
   let _HashMap = _HashMap$();
   let _IdentityHashMap$ = dart.generic(function(K, V) {
     class _IdentityHashMap extends _HashMap$(K, V) {
       [_computeHashCode](key) {
         return core.identityHashCode(key) & 0x3ffffff;
       }
       [_findBucketIndex](bucket, key) {
         if (bucket == null)
           return -1;
         let length = bucket.length;
-        for (let i = 0; dart.notNull(i) < dart.notNull(length); i = 2) {
+        for (let i = 0; dart.notNull(i) < dart.notNull(length); i = dart.notNull(i) + 2) {
           if (core.identical(bucket[i], key))
             return i;
         }
         return -1;
       }
     }
     return _IdentityHashMap;
   });
   let _IdentityHashMap = _IdentityHashMap$();
   let _equals = Symbol('_equals');
@@ skipping 24 matching lines @@
           return null;
         return super[_remove](key);
       }
       [_computeHashCode](key) {
         return this[_hashCode](dart.as(key, K)) & 0x3ffffff;
       }
       [_findBucketIndex](bucket, key) {
         if (bucket == null)
           return -1;
         let length = bucket.length;
-        for (let i = 0; dart.notNull(i) < dart.notNull(length); i = 2) {
+        for (let i = 0; dart.notNull(i) < dart.notNull(length); i = dart.notNull(i) + 2) {
           if (this[_equals](dart.as(bucket[i], K), dart.as(key, K)))
             return i;
         }
         return -1;
       }
       toString() {
         return Maps.mapToString(this);
       }
     }
     return _CustomHashMap;
@@ skipping 1260 matching lines @@
   exports.LinkedHashMapKeyIterable$ = LinkedHashMapKeyIterable$;
   exports.LinkedHashMapKeyIterable = LinkedHashMapKeyIterable;
   exports.LinkedHashMapKeyIterator$ = LinkedHashMapKeyIterator$;
   exports.LinkedHashMapKeyIterator = LinkedHashMapKeyIterator;
   exports.HashSetIterator$ = HashSetIterator$;
   exports.HashSetIterator = HashSetIterator;
   exports.LinkedHashSetCell = LinkedHashSetCell;
   exports.LinkedHashSetIterator$ = LinkedHashSetIterator$;
   exports.LinkedHashSetIterator = LinkedHashSetIterator;
 })(collection || (collection = {}));