Don't type promote local functions.

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 256 matching lines @@
     // absolute URI.
     return enclosingLibrary.importUri.toString();
   }
 
   void _setInferredType(DartType inferredType) {
     _isInferred = true;
     super.type = inferredType;
   }
 }
 
+/// Concrete shadow object representing a local function declaration in kernel
+/// form.
+class KernelFunctionDeclaration extends FunctionDeclaration
+    implements KernelStatement {
+  KernelFunctionDeclaration(VariableDeclaration variable, FunctionNode function)
+      : super(variable, function);
+
+  @override
+  void _inferStatement(KernelTypeInferrer inferrer) {
+    inferrer.inferFunctionDeclaration(function.body);
+  }
+}
+
 /// Concrete shadow object representing a function expression in kernel form.
 class KernelFunctionExpression extends FunctionExpression
     implements KernelExpression {
   KernelFunctionExpression(FunctionNode function) : super(function);
 
   @override
   DartType _inferExpression(
       KernelTypeInferrer inferrer, DartType typeContext, bool typeNeeded) {
     var asyncMarker = function.asyncMarker;
     bool isAsync = asyncMarker == AsyncMarker.Async ||
@@ skipping 560 matching lines @@
     } else {
       // Hack to deal with the fact that BodyBuilder still creates raw
       // VariableDeclaration objects sometimes.
       // TODO(paulberry): get rid of this once the type parameter is
       // KernelVariableDeclaration.
       return 0;
     }
   }
 
   @override
+  bool isPromotionCandidate(VariableDeclaration variable) {
+    if (variable is KernelVariableDeclaration) {
+      return !variable._isLocalFunction;
+    } else {
+      // Hack to deal with the fact that BodyBuilder still creates raw
+      // VariableDeclaration objects sometimes.
+      // TODO(paulberry): get rid of this once the type parameter is
+      // KernelVariableDeclaration.
+      return true;
+    }
+  }
+
+  @override
   bool sameExpressions(Expression a, Expression b) {
     return identical(a, b);
   }
 
   @override
   void setVariableMutatedAnywhere(VariableDeclaration variable) {
     if (variable is KernelVariableDeclaration) {
       variable._mutatedAnywhere = true;
     } else {
       // Hack to deal with the fact that BodyBuilder still creates raw
@@ skipping 33 matching lines @@
 class KernelVariableDeclaration extends VariableDeclaration
     implements KernelStatement {
   final bool _implicitlyTyped;
 
   final int _functionNestingLevel;
 
   bool _mutatedInClosure = false;
 
   bool _mutatedAnywhere = false;
 
+  final bool _isLocalFunction;
+
   KernelVariableDeclaration(String name, this._functionNestingLevel,
       {Expression initializer,
       DartType type,
       bool isFinal: false,
-      bool isConst: false})
+      bool isConst: false,
+      bool isLocalFunction: false})
       : _implicitlyTyped = type == null,
+        _isLocalFunction = isLocalFunction,
         super(name,
             initializer: initializer,
             type: type ?? const DynamicType(),
             isFinal: isFinal,
             isConst: isConst);
 
   DartType get _declaredType => _implicitlyTyped ? null : type;
 
   @override
   void _inferStatement(KernelTypeInferrer inferrer) {
@@ skipping 32 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);
   }
 }