Plumb TypeInferrer through KernelExpression._inferExpression.

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 19 matching lines @@
   void _inferStatement(KernelTypeInferrer inferrer) {
     // TODO(paulberry): implement.
   }
 }
 
 /// Common base class for shadow objects representing expressions in kernel
 /// form.
 abstract class KernelExpression implements Expression {
   /// Calls back to [inferrer] to perform type inference for whatever concrete
   /// type of [KernelExpression] this is.
-  DartType _inferExpression(DartType typeContext, bool typeNeeded);
+  DartType _inferExpression(
+      KernelTypeInferrer inferrer, DartType typeContext, bool typeNeeded);
 }
 
 /// Concrete shadow object representing a function expression in kernel form.
 class KernelFunctionExpression extends FunctionExpression
     implements KernelExpression {
   KernelFunctionExpression(FunctionNode function) : super(function);
 
   @override
-  DartType _inferExpression(DartType typeContext, bool typeNeeded) {
+  DartType _inferExpression(
+      KernelTypeInferrer inferrer, DartType typeContext, bool typeNeeded) {
     // TODO(paulberry): implement.
     return typeNeeded ? const DynamicType() : null;
   }
 }
 
 /// Concrete shadow object representing an integer literal in kernel form.
 class KernelIntLiteral extends IntLiteral implements KernelExpression {
   KernelIntLiteral(int value) : super(value);
 
   @override
-  DartType _inferExpression(DartType typeContext, bool typeNeeded) {
+  DartType _inferExpression(
+      KernelTypeInferrer inferrer, DartType typeContext, bool typeNeeded) {
     // TODO(paulberry): implement.
     return typeNeeded ? const DynamicType() : null;
   }
 }
 
 /// Concrete shadow object representing a list literal in kernel form.
 class KernelListLiteral extends ListLiteral implements KernelExpression {
   KernelListLiteral(List<KernelExpression> expressions,
       {DartType typeArgument, bool isConst: false})
       : super(expressions, typeArgument: typeArgument, isConst: isConst);
 
   @override
-  DartType _inferExpression(DartType typeContext, bool typeNeeded) {
+  DartType _inferExpression(
+      KernelTypeInferrer inferrer, DartType typeContext, bool typeNeeded) {
     // TODO(paulberry): implement.
     return typeNeeded ? const DynamicType() : null;
   }
 }
 
 /// Concrete shadow object representing a null literal in kernel form.
 class KernelNullLiteral extends NullLiteral implements KernelExpression {
   @override
-  DartType _inferExpression(DartType typeContext, bool typeNeeded) {
+  DartType _inferExpression(
+      KernelTypeInferrer inferrer, DartType typeContext, bool typeNeeded) {
     // TODO(paulberry): implement.
     return typeNeeded ? const DynamicType() : null;
   }
 }
 
 /// Concrete shadow object representing a return statement in kernel form.
 class KernelReturnStatement extends ReturnStatement implements KernelStatement {
   KernelReturnStatement([KernelExpression expression]) : super(expression);
 
   @override
@@ skipping 19 matching lines @@
 
   @override
   DartType inferExpression(
       Expression expression, DartType typeContext, bool typeNeeded) {
     if (expression is KernelExpression) {
       // Use polymorphic dispatch on [KernelExpression] to perform whatever kind
       // of type inference is correct for this kind of statement.
       // TODO(paulberry): experiment to see if dynamic dispatch would be better,
       // so that the type hierarchy will be simpler (which may speed up "is"
       // checks).
-      return expression._inferExpression(typeContext, typeNeeded);
+      return expression._inferExpression(this, typeContext, typeNeeded);
     } else {
       // Encountered an expression type for which type inference is not yet
       // implemented, so just infer dynamic for now.
       // TODO(paulberry): once the BodyBuilder uses shadow classes for
       // everything, this case should no longer be needed.
       return typeNeeded ? const DynamicType() : null;
     }
   }
 
   @override
@@ skipping 33 matching lines @@
     // TODO(paulberry): implement.
   }
 }
 
 /// Concrete shadow object representing a read from a variable in kernel form.
 class KernelVariableGet extends VariableGet implements KernelExpression {
   KernelVariableGet(VariableDeclaration variable, [DartType promotedType])
       : super(variable, promotedType);
 
   @override
-  DartType _inferExpression(DartType typeContext, bool typeNeeded) {
+  DartType _inferExpression(
+      KernelTypeInferrer inferrer, DartType typeContext, bool typeNeeded) {
     // TODO(paulberry): implement.
     return typeNeeded ? const DynamicType() : null;
   }
 }