Add type inference for assignments to properties.

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

Index: pkg/front_end/lib/src/fasta/kernel/fasta_accessors.dart
diff --git a/pkg/front_end/lib/src/fasta/kernel/fasta_accessors.dart b/pkg/front_end/lib/src/fasta/kernel/fasta_accessors.dart
index 324352bb0207898f798338710c5ff07999484737..78420049dd2423fb4dca874cf50e60568dbb7fb0 100644
--- a/pkg/front_end/lib/src/fasta/kernel/fasta_accessors.dart
+++ b/pkg/front_end/lib/src/fasta/kernel/fasta_accessors.dart
@@ -9,6 +9,7 @@ import 'package:front_end/src/fasta/kernel/kernel_shadow_ast.dart'
         KernelArguments,
         KernelComplexAssignment,
         KernelIndexAssign,
+        KernelPropertyAssign,
         KernelStaticAssignment,
         KernelThisExpression,
         KernelVariableAssignment;
@@ -675,6 +676,10 @@ class PropertyAccessor extends kernel.PropertyAccessor with FastaAccessor {
               helper, token, receiver, name, getter, setter);
     }
   }
+
+  @override
+  KernelComplexAssignment startComplexAssignment(Expression rhs) =>
+      new KernelPropertyAssign(receiver, rhs);
 }
 
 class StaticAccessor extends kernel.StaticAccessor with FastaAccessor {
@@ -772,6 +777,10 @@ class SuperPropertyAccessor extends kernel.SuperPropertyAccessor
   }
 
   toString() => "SuperPropertyAccessor()";
+
+  @override
+  KernelComplexAssignment startComplexAssignment(Expression rhs) =>
+      new KernelPropertyAssign(null, rhs, isSuper: true);
 }
 
 class ThisIndexAccessor extends kernel.ThisIndexAccessor with FastaAccessor {
@@ -834,6 +843,10 @@ class ThisPropertyAccessor extends kernel.ThisPropertyAccessor
   }
 
   toString() => "ThisPropertyAccessor()";
+
+  @override
+  KernelComplexAssignment startComplexAssignment(Expression rhs) =>
+      new KernelPropertyAssign(null, rhs);
 }
 
 class NullAwarePropertyAccessor extends kernel.NullAwarePropertyAccessor
@@ -851,6 +864,10 @@ class NullAwarePropertyAccessor extends kernel.NullAwarePropertyAccessor
   }
 
   toString() => "NullAwarePropertyAccessor()";
+
+  @override
+  KernelComplexAssignment startComplexAssignment(Expression rhs) =>
+      new KernelPropertyAssign(receiverExpression, rhs);
 }
 
 int adjustForImplicitCall(String name, int offset) {