Roll Observatory deps (charted -> ^0.3.0)

packages/analyzer/lib/src/task/strong/rules.dart

Index: packages/analyzer/lib/src/task/strong/rules.dart
diff --git a/packages/analyzer/lib/src/task/strong/rules.dart b/packages/analyzer/lib/src/task/strong/rules.dart
new file mode 100644
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+++ b/packages/analyzer/lib/src/task/strong/rules.dart
@@ -0,0 +1,770 @@
+// Copyright (c) 2015, the Dart project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
+// TODO(jmesserly): this was ported from package:dev_compiler, and needs to be
+// refactored to fit into analyzer.
+library analyzer.src.task.strong.rules;
+
+import 'package:analyzer/src/generated/ast.dart';
+import 'package:analyzer/src/generated/element.dart';
+import 'package:analyzer/src/generated/resolver.dart';
+
+import 'info.dart';
+
+// TODO(jmesserly): this entire file needs to be removed in favor of TypeSystem.
+
+final _objectMap = new Expando('providerToObjectMap');
+Map<String, DartType> getObjectMemberMap(TypeProvider typeProvider) {
+  var map = _objectMap[typeProvider] as Map<String, DartType>;
+  if (map == null) {
+    map = <String, DartType>{};
+    _objectMap[typeProvider] = map;
+    var objectType = typeProvider.objectType;
+    var element = objectType.element;
+    // Only record methods (including getters) with no parameters.  As parameters are contravariant wrt
+    // type, using Object's version may be too strict.
+    // Add instance methods.
+    element.methods.where((method) => !method.isStatic).forEach((method) {
+      map[method.name] = method.type;
+    });
+    // Add getters.
+    element.accessors
+        .where((member) => !member.isStatic && member.isGetter)
+        .forEach((member) {
+      map[member.name] = member.type.returnType;
+    });
+  }
+  return map;
+}
+
+class TypeRules {
+  final TypeProvider provider;
+
+  /// Map of fields / properties / methods on Object.
+  final Map<String, DartType> objectMembers;
+
+  DownwardsInference inferrer;
+
+  TypeRules(TypeProvider provider)
+      : provider = provider,
+        objectMembers = getObjectMemberMap(provider) {
+    inferrer = new DownwardsInference(this);
+  }
+
+  /// Given a type t, if t is an interface type with a call method
+  /// defined, return the function type for the call method, otherwise
+  /// return null.
+  FunctionType getCallMethodType(DartType t) {
+    if (t is InterfaceType) {
+      ClassElement element = t.element;
+      InheritanceManager manager = new InheritanceManager(element.library);
+      FunctionType callType = manager.lookupMemberType(t, "call");
+      return callType;
+    }
+    return null;
+  }
+
+  /// Given an expression, return its type assuming it is
+  /// in the caller position of a call (that is, accounting
+  /// for the possibility of a call method).  Returns null
+  /// if expression is not statically callable.
+  FunctionType getTypeAsCaller(Expression applicand) {
+    var t = getStaticType(applicand);
+    if (t is InterfaceType) {
+      return getCallMethodType(t);
+    }
+    if (t is FunctionType) return t;
+    return null;
+  }
+
+  /// Gets the expected return type of the given function [body], either from
+  /// a normal return/yield, or from a yield*.
+  DartType getExpectedReturnType(FunctionBody body, {bool yieldStar: false}) {
+    FunctionType functionType;
+    var parent = body.parent;
+    if (parent is Declaration) {
+      functionType = elementType(parent.element);
+    } else {
+      assert(parent is FunctionExpression);
+      functionType = getStaticType(parent);
+    }
+
+    var type = functionType.returnType;
+
+    InterfaceType expectedType = null;
+    if (body.isAsynchronous) {
+      if (body.isGenerator) {
+        // Stream<T> -> T
+        expectedType = provider.streamType;
+      } else {
+        // Future<T> -> T
+        // TODO(vsm): Revisit with issue #228.
+        expectedType = provider.futureType;
+      }
+    } else {
+      if (body.isGenerator) {
+        // Iterable<T> -> T
+        expectedType = provider.iterableType;
+      } else {
+        // T -> T
+        return type;
+      }
+    }
+    if (yieldStar) {
+      if (type.isDynamic) {
+        // Ensure it's at least a Stream / Iterable.
+        return expectedType.substitute4([provider.dynamicType]);
+      } else {
+        // Analyzer will provide a separate error if expected type
+        // is not compatible with type.
+        return type;
+      }
+    }
+    if (type.isDynamic) {
+      return type;
+    } else if (type is InterfaceType && type.element == expectedType.element) {
+      return type.typeArguments[0];
+    } else {
+      // Malformed type - fallback on analyzer error.
+      return null;
+    }
+  }
+
+  DartType getStaticType(Expression expr) {
+    return expr.staticType ?? provider.dynamicType;
+  }
+
+  bool _isBottom(DartType t, {bool dynamicIsBottom: false}) {
+    if (t.isDynamic && dynamicIsBottom) return true;
+    // TODO(vsm): We need direct support for non-nullability in DartType.
+    // This should check on "true/nonnullable" Bottom
+    if (t.isBottom) return true;
+    return false;
+  }
+
+  bool _isTop(DartType t, {bool dynamicIsBottom: false}) {
+    if (t.isDynamic && !dynamicIsBottom) return true;
+    if (t.isObject) return true;
+    return false;
+  }
+
+  bool _anyParameterType(FunctionType ft, bool predicate(DartType t)) {
+    return ft.normalParameterTypes.any(predicate) ||
+        ft.optionalParameterTypes.any(predicate) ||
+        ft.namedParameterTypes.values.any(predicate);
+  }
+
+  // TODO(leafp): Revisit this.
+  bool isGroundType(DartType t) {
+    if (t is TypeParameterType) return false;
+    if (_isTop(t)) return true;
+
+    if (t is FunctionType) {
+      if (!_isTop(t.returnType) ||
+          _anyParameterType(t, (pt) => !_isBottom(pt, dynamicIsBottom: true))) {
+        return false;
+      } else {
+        return true;
+      }
+    }
+
+    if (t is InterfaceType) {
+      var typeArguments = t.typeArguments;
+      for (var typeArgument in typeArguments) {
+        if (!_isTop(typeArgument)) return false;
+      }
+      return true;
+    }
+
+    // We should not see any other type aside from malformed code.
+    return false;
+  }
+
+  /// Check that f1 is a subtype of f2. [ignoreReturn] is used in the DDC
+  /// checker to determine whether f1 would be a subtype of f2 if the return
+  /// type of f1 is set to match f2's return type.
+  // [fuzzyArrows] indicates whether or not the f1 and f2 should be
+  // treated as fuzzy arrow types (and hence dynamic parameters to f2 treated as
+  // bottom).
+  bool isFunctionSubTypeOf(FunctionType f1, FunctionType f2,
+      {bool fuzzyArrows: true, bool ignoreReturn: false}) {
+    final r1s = f1.normalParameterTypes;
+    final o1s = f1.optionalParameterTypes;
+    final n1s = f1.namedParameterTypes;
+    final r2s = f2.normalParameterTypes;
+    final o2s = f2.optionalParameterTypes;
+    final n2s = f2.namedParameterTypes;
+    final ret1 = ignoreReturn ? f2.returnType : f1.returnType;
+    final ret2 = f2.returnType;
+
+    // A -> B <: C -> D if C <: A and
+    // either D is void or B <: D
+    if (!ret2.isVoid && !isSubTypeOf(ret1, ret2)) return false;
+
+    // Reject if one has named and the other has optional
+    if (n1s.length > 0 && o2s.length > 0) return false;
+    if (n2s.length > 0 && o1s.length > 0) return false;
+
+    // f2 has named parameters
+    if (n2s.length > 0) {
+      // Check that every named parameter in f2 has a match in f1
+      for (String k2 in n2s.keys) {
+        if (!n1s.containsKey(k2)) return false;
+        if (!isSubTypeOf(n2s[k2], n1s[k2],
+            dynamicIsBottom: fuzzyArrows)) return false;
+      }
+    }
+    // If we get here, we either have no named parameters,
+    // or else the named parameters match and we have no optional
+    // parameters
+
+    // If f1 has more required parameters, reject
+    if (r1s.length > r2s.length) return false;
+
+    // If f2 has more required + optional parameters, reject
+    if (r2s.length + o2s.length > r1s.length + o1s.length) return false;
+
+    // The parameter lists must look like the following at this point
+    // where rrr is a region of required, and ooo is a region of optionals.
+    // f1: rrr ooo ooo ooo
+    // f2: rrr rrr ooo
+    int rr = r1s.length; // required in both
+    int or = r2s.length - r1s.length; // optional in f1, required in f2
+    int oo = o2s.length; // optional in both
+
+    for (int i = 0; i < rr; ++i) {
+      if (!isSubTypeOf(r2s[i], r1s[i],
+          dynamicIsBottom: fuzzyArrows)) return false;
+    }
+    for (int i = 0, j = rr; i < or; ++i, ++j) {
+      if (!isSubTypeOf(r2s[j], o1s[i],
+          dynamicIsBottom: fuzzyArrows)) return false;
+    }
+    for (int i = or, j = 0; i < oo; ++i, ++j) {
+      if (!isSubTypeOf(o2s[j], o1s[i],
+          dynamicIsBottom: fuzzyArrows)) return false;
+    }
+    return true;
+  }
+
+  bool _isInterfaceSubTypeOf(InterfaceType i1, InterfaceType i2) {
+    if (i1 == i2) return true;
+
+    if (i1.element == i2.element) {
+      List<DartType> tArgs1 = i1.typeArguments;
+      List<DartType> tArgs2 = i2.typeArguments;
+
+      // TODO(leafp): Verify that this is always true
+      // Do raw types get filled in?
+      assert(tArgs1.length == tArgs2.length);
+
+      for (int i = 0; i < tArgs1.length; i++) {
+        DartType t1 = tArgs1[i];
+        DartType t2 = tArgs2[i];
+        if (!isSubTypeOf(t1, t2)) return false;
+      }
+      return true;
+    }
+
+    if (i2.isDartCoreFunction) {
+      if (i1.element.getMethod("call") != null) return true;
+    }
+
+    if (i1 == provider.objectType) return false;
+
+    if (_isInterfaceSubTypeOf(i1.superclass, i2)) return true;
+
+    for (final parent in i1.interfaces) {
+      if (_isInterfaceSubTypeOf(parent, i2)) return true;
+    }
+
+    for (final parent in i1.mixins) {
+      if (_isInterfaceSubTypeOf(parent, i2)) return true;
+    }
+
+    return false;
+  }
+
+  bool isSubTypeOf(DartType t1, DartType t2, {bool dynamicIsBottom: false}) {
+    if (t1 == t2) return true;
+
+    // Trivially true.
+    if (_isTop(t2, dynamicIsBottom: dynamicIsBottom) ||
+        _isBottom(t1, dynamicIsBottom: dynamicIsBottom)) {
+      return true;
+    }
+
+    // Trivially false.
+    if (_isTop(t1, dynamicIsBottom: dynamicIsBottom) ||
+        _isBottom(t2, dynamicIsBottom: dynamicIsBottom)) {
+      return false;
+    }
+
+    // The null type is a subtype of any nullable type, which is all Dart types.
+    // TODO(vsm): Note, t1.isBottom still allows for null confusingly.
+    // _isBottom(t1) does not necessarily imply t1.isBottom if there are
+    // nonnullable types in the system.
+    if (t1.isBottom) {
+      return true;
+    }
+
+    // S <: T where S is a type variable
+    //  T is not dynamic or object (handled above)
+    //  S != T (handled above)
+    //  So only true if bound of S is S' and
+    //  S' <: T
+    if (t1 is TypeParameterType) {
+      DartType bound = t1.element.bound;
+      if (bound == null) return false;
+      return isSubTypeOf(bound, t2);
+    }
+
+    if (t2 is TypeParameterType) {
+      return false;
+    }
+
+    if (t2.isDartCoreFunction) {
+      if (t1 is FunctionType) return true;
+      if (t1.element is ClassElement) {
+        if ((t1.element as ClassElement).getMethod("call") != null) return true;
+      }
+    }
+
+    // "Traditional" name-based subtype check.
+    if (t1 is InterfaceType && t2 is InterfaceType) {
+      return _isInterfaceSubTypeOf(t1, t2);
+    }
+
+    if (t1 is! FunctionType && t2 is! FunctionType) return false;
+
+    if (t1 is InterfaceType && t2 is FunctionType) {
+      var callType = getCallMethodType(t1);
+      if (callType == null) return false;
+      return isFunctionSubTypeOf(callType, t2);
+    }
+
+    if (t1 is FunctionType && t2 is InterfaceType) {
+      return false;
+    }
+
+    // Functions
+    // Note: it appears under the hood all Dart functions map to a class /
+    // hidden type that:
+    //  (a) subtypes Object (an internal _FunctionImpl in the VM)
+    //  (b) implements Function
+    //  (c) provides standard Object members (hashCode, toString)
+    //  (d) contains private members (corresponding to _FunctionImpl?)
+    //  (e) provides a call method to handle the actual function invocation
+    //
+    // The standard Dart subtyping rules are structural in nature.  I.e.,
+    // bivariant on arguments and return type.
+    //
+    // The below tries for a more traditional subtyping rule:
+    // - covariant on return type
+    // - contravariant on parameters
+    // - 'sensible' (?) rules on optional and/or named params
+    // but doesn't properly mix with class subtyping.  I suspect Java 8 lambdas
+    // essentially map to dynamic (and rely on invokedynamic) due to similar
+    // issues.
+    return isFunctionSubTypeOf(t1 as FunctionType, t2 as FunctionType);
+  }
+
+  bool isAssignable(DartType t1, DartType t2) {
+    return isSubTypeOf(t1, t2);
+  }
+
+  // Produce a coercion which coerces something of type fromT
+  // to something of type toT.
+  // If wrap is true and both are function types, a closure
+  // wrapper coercion is produced using _wrapTo (see above)
+  // Returns the error coercion if the types cannot be coerced
+  // according to our current criteria.
+  Coercion _coerceTo(DartType fromT, DartType toT) {
+    // We can use anything as void
+    if (toT.isVoid) return Coercion.identity(toT);
+
+    // fromT <: toT, no coercion needed
+    if (isSubTypeOf(fromT, toT)) return Coercion.identity(toT);
+
+    // For now, reject conversions between function types and
+    // call method objects.  We could choose to allow casts here.
+    // Wrapping a function type to assign it to a call method
+    // object will never succeed.  Wrapping the other way could
+    // be allowed.
+    if ((fromT is FunctionType && getCallMethodType(toT) != null) ||
+        (toT is FunctionType && getCallMethodType(fromT) != null)) {
+      return Coercion.error();
+    }
+
+    // Downcast if toT <: fromT
+    if (isSubTypeOf(toT, fromT)) return Coercion.cast(fromT, toT);
+
+    // Downcast if toT <===> fromT
+    // The intention here is to allow casts that are sideways in the restricted
+    // type system, but allowed in the regular dart type system, since these
+    // are likely to succeed.  The canonical example is List<dynamic> and
+    // Iterable<T> for some concrete T (e.g. Object).  These are unrelated
+    // in the restricted system, but List<dynamic> <: Iterable<T> in dart.
+    if (fromT.isAssignableTo(toT)) {
+      return Coercion.cast(fromT, toT);
+    }
+    return Coercion.error();
+  }
+
+  StaticInfo checkAssignment(Expression expr, DartType toT) {
+    final fromT = getStaticType(expr);
+    final Coercion c = _coerceTo(fromT, toT);
+    if (c is Identity) return null;
+    if (c is CoercionError) return new StaticTypeError(this, expr, toT);
+    var reason = null;
+
+    var errors = <String>[];
+    var ok = inferrer.inferExpression(expr, toT, errors);
+    if (ok) return InferredType.create(this, expr, toT);
+    reason = (errors.isNotEmpty) ? errors.first : null;
+
+    if (c is Cast) return DownCast.create(this, expr, c, reason: reason);
+    assert(false);
+    return null;
+  }
+
+  DartType elementType(Element e) {
+    if (e == null) {
+      // Malformed code - just return dynamic.
+      return provider.dynamicType;
+    }
+    return (e as dynamic).type;
+  }
+
+  bool _isLibraryPrefix(Expression node) =>
+      node is SimpleIdentifier && node.staticElement is PrefixElement;
+
+  /// Returns `true` if the target expression is dynamic.
+  bool isDynamicTarget(Expression node) {
+    if (node == null) return false;
+
+    if (_isLibraryPrefix(node)) return false;
+
+    // Null type happens when we have unknown identifiers, like a dart: import
+    // that doesn't resolve.
+    var type = node.staticType;
+    return type == null || type.isDynamic;
+  }
+
+  /// Returns `true` if the expression is a dynamic function call or method
+  /// invocation.
+  bool isDynamicCall(Expression call) {
+    var ft = getTypeAsCaller(call);
+    // TODO(leafp): This will currently return true if t is Function
+    // This is probably the most correct thing to do for now, since
+    // this code is also used by the back end.  Maybe revisit at some
+    // point?
+    if (ft == null) return true;
+    // Dynamic as the parameter type is treated as bottom.  A function with
+    // a dynamic parameter type requires a dynamic call in general.
+    // However, as an optimization, if we have an original definition, we know
+    // dynamic is reified as Object - in this case a regular call is fine.
+    if (call is SimpleIdentifier) {
+      var element = call.staticElement;
+      if (element is FunctionElement || element is MethodElement) {
+        // An original declaration.
+        return false;
+      }
+    }
+
+    return _anyParameterType(ft, (pt) => pt.isDynamic);
+  }
+}
+
+class DownwardsInference {
+  final TypeRules rules;
+
+  DownwardsInference(this.rules);
+
+  /// Called for each list literal which gets inferred
+  void annotateListLiteral(ListLiteral e, List<DartType> targs) {}
+
+  /// Called for each map literal which gets inferred
+  void annotateMapLiteral(MapLiteral e, List<DartType> targs) {}
+
+  /// Called for each new/const which gets inferred
+  void annotateInstanceCreationExpression(
+      InstanceCreationExpression e, List<DartType> targs) {}
+
+  /// Called for cast from dynamic required for inference to succeed
+  void annotateCastFromDynamic(Expression e, DartType t) {}
+
+  /// Called for each function expression return type inferred
+  void annotateFunctionExpression(FunctionExpression e, DartType returnType) {}
+
+  /// Downward inference
+  bool inferExpression(Expression e, DartType t, List<String> errors) {
+    // Don't cast top level expressions, only sub-expressions
+    return _inferExpression(e, t, errors, cast: false);
+  }
+
+  /// Downward inference
+  bool _inferExpression(Expression e, DartType t, List<String> errors,
+      {cast: true}) {
+    if (e is ConditionalExpression) {
+      return _inferConditionalExpression(e, t, errors);
+    }
+    if (e is ParenthesizedExpression) {
+      return _inferParenthesizedExpression(e, t, errors);
+    }
+    if (rules.isSubTypeOf(rules.getStaticType(e), t)) return true;
+    if (cast && rules.getStaticType(e).isDynamic) {
+      annotateCastFromDynamic(e, t);
+      return true;
+    }
+    if (e is FunctionExpression) return _inferFunctionExpression(e, t, errors);
+    if (e is ListLiteral) return _inferListLiteral(e, t, errors);
+    if (e is MapLiteral) return _inferMapLiteral(e, t, errors);
+    if (e is NamedExpression) return _inferNamedExpression(e, t, errors);
+    if (e is InstanceCreationExpression) {
+      return _inferInstanceCreationExpression(e, t, errors);
+    }
+    errors.add("$e cannot be typed as $t");
+    return false;
+  }
+
+  /// If t1 = I<dynamic, ..., dynamic>, then look for a supertype
+  /// of t1 of the form K<S0, ..., Sm> where t2 = K<S0', ..., Sm'>
+  /// If the supertype exists, use the constraints S0 <: S0', ... Sm <: Sm'
+  /// to derive a concrete instantation for I of the form <T0, ..., Tn>,
+  /// such that I<T0, .., Tn> <: t2
+  List<DartType> _matchTypes(InterfaceType t1, InterfaceType t2) {
+    if (t1 == t2) return t2.typeArguments;
+    var tArgs1 = t1.typeArguments;
+    var tArgs2 = t2.typeArguments;
+    // If t1 isn't a raw type, bail out
+    if (tArgs1 != null && tArgs1.any((t) => !t.isDynamic)) return null;
+
+    // This is our inferred type argument list.  We start at all dynamic,
+    // and fill in with inferred types when we reach a match.
+    var actuals =
+        new List<DartType>.filled(tArgs1.length, rules.provider.dynamicType);
+
+    // When we find the supertype of t1 with the same
+    // classname as t2 (see below), we have the following:
+    // If t1 is an instantiation of a class T1<X0, ..., Xn>
+    // and t2 is an instantiation of a class T2<Y0, ...., Ym>
+    // of the form t2 = T2<S0, ..., Sm>
+    // then we want to choose instantiations for the Xi
+    // T0, ..., Tn such that T1<T0, ..., Tn> <: t2 .
+    // To find this, we simply instantate T1 with
+    // X0, ..., Xn, and then find its superclass
+    // T2<T0', ..., Tn'>.  We then solve the constraint
+    // set T0' <: S0, ..., Tn' <: Sn for the Xi.
+    // Currently, we only handle constraints where
+    // the Ti' is one of the Xi'.  If there are multiple
+    // constraints on some Xi, we choose the lower of the
+    // two (if it exists).
+    bool permute(List<DartType> permutedArgs) {
+      if (permutedArgs == null) return false;
+      var ps = t1.typeParameters;
+      var ts = ps.map((p) => p.type).toList();
+      for (int i = 0; i < permutedArgs.length; i++) {
+        var tVar = permutedArgs[i];
+        var tActual = tArgs2[i];
+        var index = ts.indexOf(tVar);
+        if (index >= 0 && rules.isSubTypeOf(tActual, actuals[index])) {
+          actuals[index] = tActual;
+        }
+      }
+      return actuals.any((x) => !x.isDynamic);
+    }
+
+    // Look for the first supertype of t1 with the same class name as t2.
+    bool match(InterfaceType t1) {
+      if (t1.element == t2.element) {
+        return permute(t1.typeArguments);
+      }
+
+      if (t1 == rules.provider.objectType) return false;
+
+      if (match(t1.superclass)) return true;
+
+      for (final parent in t1.interfaces) {
+        if (match(parent)) return true;
+      }
+
+      for (final parent in t1.mixins) {
+        if (match(parent)) return true;
+      }
+      return false;
+    }
+
+    // We have that t1 = T1<dynamic, ..., dynamic>.
+    // To match t1 against t2, we use the uninstantiated version
+    // of t1, essentially treating it as an instantiation with
+    // fresh variables, and solve for the variables.
+    // t1.element.type will be of the form T1<X0, ..., Xn>
+    if (!match(t1.element.type)) return null;
+    var newT1 = t1.element.type.substitute4(actuals);
+    // If we found a solution, return it.
+    if (rules.isSubTypeOf(newT1, t2)) return actuals;
+    return null;
+  }
+
+  /// These assume that e is not already a subtype of t
+
+  bool _inferConditionalExpression(
+      ConditionalExpression e, DartType t, errors) {
+    return _inferExpression(e.thenExpression, t, errors) &&
+        _inferExpression(e.elseExpression, t, errors);
+  }
+
+  bool _inferParenthesizedExpression(
+      ParenthesizedExpression e, DartType t, errors) {
+    return _inferExpression(e.expression, t, errors);
+  }
+
+  bool _inferInstanceCreationExpression(
+      InstanceCreationExpression e, DartType t, errors) {
+    var arguments = e.argumentList.arguments;
+    var rawType = rules.getStaticType(e);
+    // rawType is the instantiated type of the instance
+    if (rawType is! InterfaceType) return false;
+    var type = (rawType as InterfaceType);
+    if (type.typeParameters == null ||
+        type.typeParameters.length == 0) return false;
+    if (e.constructorName.type == null) return false;
+    // classTypeName is the type name of the class being instantiated
+    var classTypeName = e.constructorName.type;
+    // Check that we were not passed any type arguments
+    if (classTypeName.typeArguments != null) return false;
+    // Infer type arguments
+    if (t is! InterfaceType) return false;
+    var targs = _matchTypes(type, t);
+    if (targs == null) return false;
+    if (e.staticElement == null) return false;
+    var constructorElement = e.staticElement;
+    // From the constructor element get:
+    //  the instantiated type of the constructor, then
+    //     the uninstantiated element for the constructor, then
+    //        the uninstantiated type for the constructor
+    var rawConstructorElement =
+        constructorElement.type.element as ConstructorElement;
+    var baseType = rawConstructorElement.type;
+    if (baseType == null) return false;
+    // From the interface type (instantiated), get:
+    //  the uninstantiated element, then
+    //    the uninstantiated type, then
+    //      the type arguments (aka the type parameters)
+    var tparams = type.element.type.typeArguments;
+    // Take the uninstantiated constructor type, and replace the type
+    // parameters with the inferred arguments.
+    var fType = baseType.substitute2(targs, tparams);
+    {
+      var rTypes = fType.normalParameterTypes;
+      var oTypes = fType.optionalParameterTypes;
+      var pTypes = new List.from(rTypes)..addAll(oTypes);
+      var pArgs = arguments.where((x) => x is! NamedExpression);
+      var pi = 0;
+      for (var arg in pArgs) {
+        if (pi >= pTypes.length) return false;
+        var argType = pTypes[pi];
+        if (!_inferExpression(arg, argType, errors)) return false;
+        pi++;
+      }
+      var nTypes = fType.namedParameterTypes;
+      for (var arg0 in arguments) {
+        if (arg0 is! NamedExpression) continue;
+        var arg = arg0 as NamedExpression;
+        SimpleIdentifier nameNode = arg.name.label;
+        String name = nameNode.name;
+        var argType = nTypes[name];
+        if (argType == null) return false;
+        if (!_inferExpression(arg, argType, errors)) return false;
+      }
+    }
+    annotateInstanceCreationExpression(e, targs);
+    return true;
+  }
+
+  bool _inferNamedExpression(NamedExpression e, DartType t, errors) {
+    return _inferExpression(e.expression, t, errors);
+  }
+
+  bool _inferFunctionExpression(FunctionExpression e, DartType t, errors) {
+    if (t is! FunctionType) return false;
+    var fType = t as FunctionType;
+    var eType = e.staticType as FunctionType;
+    if (eType is! FunctionType) return false;
+
+    // We have a function literal, so we can treat the arrow type
+    // as non-fuzzy.  Since we're not improving on parameter types
+    // currently, if this check fails then we cannot succeed, so
+    // bail out.  Otherwise, we never need to check the parameter types
+    // again.
+    if (!rules.isFunctionSubTypeOf(eType, fType,
+        fuzzyArrows: false, ignoreReturn: true)) return false;
+
+    // This only entered inference because of fuzzy typing.
+    // The function type is already specific enough, we can just
+    // succeed and treat it as a successful inference
+    if (rules.isSubTypeOf(eType.returnType, fType.returnType)) return true;
+
+    // Fuzzy typing again, handle the void case (not caught by the previous)
+    if (fType.returnType.isVoid) return true;
+
+    if (e.body is! ExpressionFunctionBody) return false;
+    var body = (e.body as ExpressionFunctionBody).expression;
+    if (!_inferExpression(body, fType.returnType, errors)) return false;
+
+    // TODO(leafp): Try narrowing the argument types if possible
+    // to get better code in the function body.  This requires checking
+    // that the body is well-typed at the more specific type.
+
+    // At this point, we know that the parameter types are in the appropriate subtype
+    // relation, and we have checked that we can type the body at the appropriate return
+    // type, so we can are done.
+    annotateFunctionExpression(e, fType.returnType);
+    return true;
+  }
+
+  bool _inferListLiteral(ListLiteral e, DartType t, errors) {
+    var dyn = rules.provider.dynamicType;
+    var listT = rules.provider.listType.substitute4([dyn]);
+    // List <: t (using dart rules) must be true
+    if (!listT.isSubtypeOf(t)) return false;
+    // The list literal must have no type arguments
+    if (e.typeArguments != null) return false;
+    if (t is! InterfaceType) return false;
+    var targs = _matchTypes(listT, t);
+    if (targs == null) return false;
+    assert(targs.length == 1);
+    var etype = targs[0];
+    assert(!etype.isDynamic);
+    var elements = e.elements;
+    var b = elements.every((e) => _inferExpression(e, etype, errors));
+    if (b) annotateListLiteral(e, targs);
+    return b;
+  }
+
+  bool _inferMapLiteral(MapLiteral e, DartType t, errors) {
+    var dyn = rules.provider.dynamicType;
+    var mapT = rules.provider.mapType.substitute4([dyn, dyn]);
+    // Map <: t (using dart rules) must be true
+    if (!mapT.isSubtypeOf(t)) return false;
+    // The map literal must have no type arguments
+    if (e.typeArguments != null) return false;
+    if (t is! InterfaceType) return false;
+    var targs = _matchTypes(mapT, t);
+    if (targs == null) return false;
+    assert(targs.length == 2);
+    var kType = targs[0];
+    var vType = targs[1];
+    assert(!(kType.isDynamic && vType.isDynamic));
+    var entries = e.entries;
+    bool inferEntry(MapLiteralEntry entry) {
+      return _inferExpression(entry.key, kType, errors) &&
+          _inferExpression(entry.value, vType, errors);
+    }
+    var b = entries.every(inferEntry);
+    if (b) annotateMapLiteral(e, targs);
+    return b;
+  }
+}