First steps toward AST-based type inference involving closures.

pkg/analyzer/lib/src/summary/summarize_const_expr.dart

 // Copyright (c) 2016, 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.
 
 library serialization.summarize_const_expr;
 
 import 'package:analyzer/dart/ast/ast.dart';
 import 'package:analyzer/dart/ast/token.dart';
 import 'package:analyzer/dart/element/type.dart' show DartType;
 import 'package:analyzer/src/summary/format.dart';
@@ skipping 125 matching lines @@
    */
   EntityRefBuilder serializeConstructorRef(DartType type, Identifier typeName,
       TypeArgumentList typeArguments, SimpleIdentifier name);
 
   /**
    * Return [EntityRefBuilder] that corresponds to the given [identifier].
    */
   EntityRefBuilder serializeIdentifier(Identifier identifier);
 
   /**
+   * Return a pair of ints showing how the given [functionExpression] is nested
+   * within the constant currently being serialized.  The first int indicates
+   * how many levels of function nesting must be popped in order to reach the
+   * parent of the [functionExpression].  The second int is the index of the
+   * [functionExpression] within its parent element.
+   *
+   * If the constant being summarized is in a context where local function
+   * references are not allowed, return `null`.
+   */
+  List<int> serializeFunctionExpression(FunctionExpression functionExpression);
+
+  /**
    * Return [EntityRefBuilder] that corresponds to the given [expr], which
    * must be a sequence of identifiers.
    */
   EntityRefBuilder serializeIdentifierSequence(Expression expr);
 
   void serializeInstanceCreation(
       EntityRefBuilder constructor, ArgumentList argumentList) {
     _serializeArguments(argumentList);
     references.add(constructor);
     operations.add(UnlinkedConstOperation.invokeConstructor);
@@ skipping 140 matching lines @@
       isValidConst = false;
       _serialize(expr.target);
       _serialize(expr.index);
       operations.add(UnlinkedConstOperation.extractIndex);
     } else if (expr is AssignmentExpression) {
       _serializeAssignment(expr);
     } else if (expr is CascadeExpression) {
       _serializeCascadeExpression(expr);
     } else if (expr is FunctionExpression) {
       isValidConst = false;
-      // TODO(scheglov) implement
-      operations.add(UnlinkedConstOperation.pushNull);
+      List<int> indices = serializeFunctionExpression(expr);
+      if (indices != null) {
+        ints.addAll(serializeFunctionExpression(expr));
+        operations.add(UnlinkedConstOperation.pushLocalFunctionReference);
+      } else {
+        // Invalid expression; just push null.
+        operations.add(UnlinkedConstOperation.pushNull);
+      }
     } else if (expr is FunctionExpressionInvocation) {
       isValidConst = false;
       // TODO(scheglov) implement
       operations.add(UnlinkedConstOperation.pushNull);
     } else if (expr is AsExpression) {
       isValidConst = false;
       _serialize(expr.expression);
       references.add(serializeTypeName(expr.type));
       operations.add(UnlinkedConstOperation.typeCast);
     } else if (expr is IsExpression) {
@@ skipping 279 matching lines @@
         expr = (expr as PrefixedIdentifier).prefix;
       } else if (expr is PropertyAccess) {
         expr = (expr as PropertyAccess).target;
       } else {
         return false;
       }
     }
     return false;
   }
 }