Implement full closure inference logic.

pkg/front_end/lib/src/fasta/kernel/kernel_shadow_ast.dart

 // Copyright (c) 2017, 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.
 
 /// This file declares a "shadow hierarchy" of concrete classes which extend
 /// the kernel class hierarchy, adding methods and fields needed by the
 /// BodyBuilder.
 ///
 /// Instances of these classes may be created using the factory methods in
 /// `ast_factory.dart`.
@@ skipping 283 matching lines @@
 
   @override
   DartType _inferExpression(
       KernelTypeInferrer inferrer, DartType typeContext, bool typeNeeded) {
     var asyncMarker = function.asyncMarker;
     bool isAsync = asyncMarker == AsyncMarker.Async ||
         asyncMarker == AsyncMarker.AsyncStar;
     bool isGenerator = asyncMarker == AsyncMarker.SyncStar ||
         asyncMarker == AsyncMarker.AsyncStar;
     return inferrer.inferFunctionExpression(
-        typeContext,
-        typeNeeded,
-        function.body,
-        function.body is ReturnStatement,
-        isAsync,
-        isGenerator,
-        fileOffset, (type) {
+        typeContext, typeNeeded, function, isAsync, isGenerator, fileOffset,
+        (type) {
       function.returnType = type;
     }, () => function.functionType);
   }
 }
 
 /// Concrete shadow object representing an if statement in kernel form.
 class KernelIfStatement extends IfStatement implements KernelStatement {
   KernelIfStatement(Expression condition, Statement then, Statement otherwise)
       : super(condition, then, otherwise);
 
@@ skipping 630 matching lines @@
 
   DartType get _declaredType => _implicitlyTyped ? null : type;
 
   @override
   void _inferStatement(KernelTypeInferrer inferrer) {
     inferrer.inferVariableDeclaration(
         _implicitlyTyped ? null : type, initializer, fileOffset, (type) {
       this.type = type;
     });
   }
+
+  /// Determine whether the given [KernelVariableDeclaration] had an implicit
+  /// type.
+  ///
+  /// This is static to avoid introducing a method that would be visible to
+  /// the kernel.
+  static bool isImplicitlyTyped(KernelVariableDeclaration variable) =>
+      variable._implicitlyTyped;
 }
 
 /// Concrete shadow object representing a read from a variable in kernel form.
 class KernelVariableGet extends VariableGet implements KernelExpression {
   final TypePromotionFact<VariableDeclaration> _fact;
 
   final TypePromotionScope _scope;
 
   KernelVariableGet(VariableDeclaration variable, this._fact, this._scope)
       : super(variable);
@@ skipping 17 matching lines @@
       : super(variable, value);
 
   @override
   DartType _inferExpression(
       KernelTypeInferrer inferrer, DartType typeContext, bool typeNeeded) {
     var variable = this.variable as KernelVariableDeclaration;
     return inferrer.inferVariableSet(
         typeContext, typeNeeded, variable._declaredType, value);
   }
 }