Typecheck constructor initializers properly

test/codegen/expect/collection/collection.js

 var collection;
 (function(collection) {
   'use strict';
   let _HashMap$ = dart.generic(function(K, V) {
     class _HashMap extends dart.Object {
       _HashMap() {
         this._length = 0;
         this._strings = null;
         this._nums = null;
         this._rest = null;
@@ skipping 269 matching lines @@
       }
     }
     return _IdentityHashMap;
   });
   let _IdentityHashMap = _IdentityHashMap$(dynamic, dynamic);
   let _CustomHashMap$ = dart.generic(function(K, V) {
     class _CustomHashMap extends _HashMap$(K, V) {
       _CustomHashMap(_equals, _hashCode, validKey) {
         this._equals = _equals;
         this._hashCode = _hashCode;
-        this._validKey = validKey !== null ? validKey : (v) => dart.is(v, K);
+        this._validKey = dart.as(validKey !== null ? validKey : (v) => dart.is(v, K), _Predicate);
         super._HashMap();
       }
       get(key) {
         if (!dart.notNull(this._validKey(key)))
           return dart.as(null, V);
         return super._get(key);
       }
       set(key, value) {
         super._set(key, value);
       }
@@ skipping 33 matching lines @@
         this._map = _map;
         super.IterableBase();
       }
       get length() {
         return dart.as(dart.dload(this._map, '_length'), core.int);
       }
       get isEmpty() {
         return dart.equals(dart.dload(this._map, '_length'), 0);
       }
       get iterator() {
-        return new HashMapKeyIterator(this._map, dart.dinvoke(this._map, '_computeKeys'));
+        return new HashMapKeyIterator(this._map, dart.as(dart.dinvoke(this._map, '_computeKeys'), core.List));
       }
       contains(element) {
         return dart.as(dart.dinvoke(this._map, 'containsKey', element), core.bool);
       }
       forEach(f) {
         let keys = dart.as(dart.dinvoke(this._map, '_computeKeys'), core.List);
         for (let i = 0, length = dart.as(dart.dinvokef(/* Unimplemented unknown name */JS, 'int', '#.length', keys), core.int); i < length; i++) {
           f(dart.as(dart.dinvokef(/* Unimplemented unknown name */JS, 'var', '#[#]', keys, i), E));
           if (dart.dinvokef(/* Unimplemented unknown name */JS, 'bool', '# !== #', keys, dart.dload(this._map, '_keys'))) {
             throw new core.ConcurrentModificationError(this._map);
@@ skipping 318 matching lines @@
       }
     }
     return _LinkedIdentityHashMap;
   });
   let _LinkedIdentityHashMap = _LinkedIdentityHashMap$(dynamic, dynamic);
   let _LinkedCustomHashMap$ = dart.generic(function(K, V) {
     class _LinkedCustomHashMap extends _LinkedHashMap$(K, V) {
       _LinkedCustomHashMap(_equals, _hashCode, validKey) {
         this._equals = _equals;
         this._hashCode = _hashCode;
-        this._validKey = validKey !== null ? validKey : (v) => dart.is(v, K);
+        this._validKey = dart.as(validKey !== null ? validKey : (v) => dart.is(v, K), _Predicate);
         super._LinkedHashMap();
       }
       get(key) {
         if (!dart.notNull(this._validKey(key)))
           return dart.as(null, V);
         return super._get(key);
       }
       set(key, value) {
         super._set(key, value);
       }
@@ skipping 39 matching lines @@
         this._map = _map;
         super.IterableBase();
       }
       get length() {
         return dart.as(dart.dload(this._map, '_length'), core.int);
       }
       get isEmpty() {
         return dart.equals(dart.dload(this._map, '_length'), 0);
       }
       get iterator() {
-        return new LinkedHashMapKeyIterator(this._map, dart.dload(this._map, '_modifications'));
+        return new LinkedHashMapKeyIterator(this._map, dart.as(dart.dload(this._map, '_modifications'), core.int));
       }
       contains(element) {
         return dart.as(dart.dinvoke(this._map, 'containsKey', element), core.bool);
       }
       forEach(f) {
         let cell = dart.as(dart.dload(this._map, '_first'), LinkedHashMapCell);
         let modifications = dart.as(dart.dload(this._map, '_modifications'), core.int);
         while (cell !== null) {
           f(dart.as(cell._key, E));
           if (modifications !== dart.dload(this._map, '_modifications')) {
@@ skipping 284 matching lines @@
       }
     }
     return _IdentityHashSet;
   });
   let _IdentityHashSet = _IdentityHashSet$(dynamic);
   let _CustomHashSet$ = dart.generic(function(E) {
     class _CustomHashSet extends _HashSet$(E) {
       _CustomHashSet(_equality, _hasher, validKey) {
         this._equality = _equality;
         this._hasher = _hasher;
-        this._validKey = validKey !== null ? validKey : (x) => dart.is(x, E);
+        this._validKey = dart.as(validKey !== null ? validKey : (x) => dart.is(x, E), _Predicate);
         super._HashSet();
       }
       _newSet() {
         return new _CustomHashSet(this._equality, this._hasher, this._validKey);
       }
       _findBucketIndex(bucket, element) {
         if (bucket === null)
           return -1;
         let length = dart.as(dart.dinvokef(/* Unimplemented unknown name */JS, 'int', '#.length', bucket), core.int);
         for (let i = 0; i < length; i++) {
@@ skipping 347 matching lines @@
       }
     }
     return _LinkedIdentityHashSet;
   });
   let _LinkedIdentityHashSet = _LinkedIdentityHashSet$(dynamic);
   let _LinkedCustomHashSet$ = dart.generic(function(E) {
     class _LinkedCustomHashSet extends _LinkedHashSet$(E) {
       _LinkedCustomHashSet(_equality, _hasher, validKey) {
         this._equality = _equality;
         this._hasher = _hasher;
-        this._validKey = validKey !== null ? validKey : (x) => dart.is(x, E);
+        this._validKey = dart.as(validKey !== null ? validKey : (x) => dart.is(x, E), _Predicate);
         super._LinkedHashSet();
       }
       _newSet() {
         return new _LinkedCustomHashSet(this._equality, this._hasher, this._validKey);
       }
       _findBucketIndex(bucket, element) {
         if (bucket === null)
           return -1;
         let length = dart.as(dart.dinvokef(/* Unimplemented unknown name */JS, 'int', '#.length', bucket), core.int);
         for (let i = 0; i < length; i++) {
@@ skipping 1215 matching lines @@
         if (this.length === 0)
           return "";
         let buffer = new core.StringBuffer();
         buffer.writeAll(this, separator);
         return buffer.toString();
       }
       where(test) {
         return new _internal.WhereIterable(this, test);
       }
       map(f) {
-        return new _internal.MappedListIterable(this, f);
+        return new _internal.MappedListIterable(this, dart.as(f, dart.throw_("Unimplemented type (dynamic) → dynamic")));
       }
       expand(f) {
         return new _internal.ExpandIterable(this, f);
       }
       reduce(combine) {
         let length = this.length;
         if (length === 0)
           throw _internal.IterableElementError.noElement();
         let value = this.get(0);
         for (let i = 1; i < length; i++) {
           value = combine(value, this.get(i));
           if (length !== this.length) {
             throw new core.ConcurrentModificationError(this);
           }
         }
         return value;
       }
       fold(initialValue, combine) {
         let value = initialValue;
         let length = this.length;
         for (let i = 0; i < length; i++) {
           value = combine(value, this.get(i));
           if (length !== this.length) {
             throw new core.ConcurrentModificationError(this);
           }
         }
         return value;
       }
       skip(count) {
-        return new _internal.SubListIterable(this, count, null);
+        return new _internal.SubListIterable(this, count, dart.as(null, core.int));
       }
       skipWhile(test) {
         return new _internal.SkipWhileIterable(this, test);
       }
       take(count) {
         return new _internal.SubListIterable(this, 0, count);
       }
       takeWhile(test) {
         return new _internal.TakeWhileIterable(this, test);
       }
@@ skipping 1364 matching lines @@
         this.value = value;
         super._SplayTreeNode(key);
       }
     }
     return _SplayTreeMapNode;
   });
   let _SplayTreeMapNode = _SplayTreeMapNode$(dynamic, dynamic);
   let _SplayTree$ = dart.generic(function(K) {
     class _SplayTree extends dart.Object {
       _SplayTree() {
-        this._dummy = new _SplayTreeNode(null);
+        this._dummy = new _SplayTreeNode(dart.as(null, K));
         this._root = null;
         this._count = 0;
         this._modificationCount = 0;
         this._splayCount = 0;
       }
       _splay(key) {
         if (this._root === null)
           return -1;
         let left = this._dummy;
         let right = this._dummy;
@@ skipping 131 matching lines @@
     return _TypeTest;
   });
   let _TypeTest = _TypeTest$(dynamic);
   let SplayTreeMap$ = dart.generic(function(K, V) {
     class SplayTreeMap extends _SplayTree$(K) {
       SplayTreeMap(compare, isValidKey) {
         if (compare === void 0)
           compare = null;
         if (isValidKey === void 0)
           isValidKey = null;
-        this._comparator = compare === null ? core.Comparable.compare : compare;
-        this._validKey = isValidKey !== null ? isValidKey : (v) => dart.is(v, K);
+        this._comparator = dart.as(compare === null ? core.Comparable.compare : compare, core.Comparator);
+        this._validKey = dart.as(isValidKey !== null ? isValidKey : (v) => dart.is(v, K), _Predicate);
         super._SplayTree();
       }
       SplayTreeMap$from(other, compare, isValidKey) {
         if (compare === void 0)
           compare = null;
         if (isValidKey === void 0)
           isValidKey = null;
         let result = new SplayTreeMap();
         other.forEach((k, v) => {
           result.set(k, dart.as(v, V));
@@ skipping 263 matching lines @@
         return this._tree._count;
       }
       get isEmpty() {
         return this._tree._count === 0;
       }
       get iterator() {
         return new _SplayTreeKeyIterator(this._tree);
       }
       toSet() {
         let setOrMap = this._tree;
-        let set = new SplayTreeSet(setOrMap._comparator, setOrMap._validKey);
+        let set = new SplayTreeSet(dart.as(setOrMap._comparator, dart.throw_("Unimplemented type (K, K) → int")), dart.as(setOrMap._validKey, dart.throw_("Unimplemented type (dynamic) → bool")));
         set._count = this._tree._count;
         set._root = set._copyNode(this._tree._root);
         return set;
       }
     }
     return _SplayTreeKeyIterable;
   });
   let _SplayTreeKeyIterable = _SplayTreeKeyIterable$(dynamic);
   let _SplayTreeValueIterable$ = dart.generic(function(K, V) {
     class _SplayTreeValueIterable extends IterableBase$(V) {
@@ skipping 54 matching lines @@
     return _SplayTreeNodeIterator;
   });
   let _SplayTreeNodeIterator = _SplayTreeNodeIterator$(dynamic);
   let SplayTreeSet$ = dart.generic(function(E) {
     class SplayTreeSet extends dart.mixin(_SplayTree$(E), IterableMixin$(E), SetMixin$(E)) {
       SplayTreeSet(compare, isValidKey) {
         if (compare === void 0)
           compare = null;
         if (isValidKey === void 0)
           isValidKey = null;
-        this._comparator = compare === null ? core.Comparable.compare : compare;
-        this._validKey = isValidKey !== null ? isValidKey : (v) => dart.is(v, E);
+        this._comparator = dart.as(compare === null ? core.Comparable.compare : compare, core.Comparator);
+        this._validKey = dart.as(isValidKey !== null ? isValidKey : (v) => dart.is(v, E), _Predicate);
         super._SplayTree();
       }
       SplayTreeSet$from(elements, compare, isValidKey) {
         if (compare === void 0)
           compare = null;
         if (isValidKey === void 0)
           isValidKey = null;
         let result = new SplayTreeSet(compare, isValidKey);
         for (let element of elements) {
           result.add(element);
@@ skipping 196 matching lines @@
   collection.ListQueue$ = ListQueue$;
   collection.SetMixin = SetMixin;
   collection.SetMixin$ = SetMixin$;
   collection.SetBase = SetBase;
   collection.SetBase$ = SetBase$;
   collection.SplayTreeMap = SplayTreeMap;
   collection.SplayTreeMap$ = SplayTreeMap$;
   collection.SplayTreeSet = SplayTreeSet;
   collection.SplayTreeSet$ = SplayTreeSet$;
 })(collection || (collection = {}));