Add type inference for assignments to properties.

pkg/front_end/testcases/inference/infer_assign_to_property_upwards.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.
+
+/*@testedFeatures=inference*/
+library test;
+
+int getInt() => 0;
+num getNum() => 0;
+double getDouble() => 0.0;
+
+class Test1 {
+  int prop;
+
+  static void test(Test1 t) {
+    var /*@type=int*/ v1 = t. /*@target=Test1::prop*/ prop = getInt();
+    var /*@type=num*/ v2 = t. /*@target=Test1::prop*/ prop = getNum();
+    var /*@type=int*/ v4 = t. /*@target=Test1::prop*/ prop ??= getInt();
+    var /*@type=num*/ v5 = t. /*@target=Test1::prop*/ prop ??= getNum();
+    var /*@type=int*/ v7 = t. /*@target=Test1::prop*/ prop += getInt();
+    var /*@type=num*/ v8 = t. /*@target=Test1::prop*/ prop += getNum();
+    var /*@type=int*/ v10 = ++t. /*@target=Test1::prop*/ prop;
+    var /*@type=int*/ v11 = t. /*@target=Test1::prop*/ prop++;
+  }
+}
+
+class Test2 {
+  num prop;
+
+  static void test(Test2 t) {
+    var /*@type=int*/ v1 = t. /*@target=Test2::prop*/ prop = getInt();
+    var /*@type=num*/ v2 = t. /*@target=Test2::prop*/ prop = getNum();
+    var /*@type=double*/ v3 = t. /*@target=Test2::prop*/ prop = getDouble();
+    var /*@type=num*/ v4 = t. /*@target=Test2::prop*/ prop ??= getInt();
+    var /*@type=num*/ v5 = t. /*@target=Test2::prop*/ prop ??= getNum();
+    var /*@type=num*/ v6 = t. /*@target=Test2::prop*/ prop ??= getDouble();
+    var /*@type=num*/ v7 = t. /*@target=Test2::prop*/ prop += getInt();
+    var /*@type=num*/ v8 = t. /*@target=Test2::prop*/ prop += getNum();
+    var /*@type=num*/ v9 = t. /*@target=Test2::prop*/ prop += getDouble();
+    var /*@type=num*/ v10 = ++t. /*@target=Test2::prop*/ prop;
+    var /*@type=num*/ v11 = t. /*@target=Test2::prop*/ prop++;
+  }
+}
+
+class Test3 {
+  double prop;
+
+  static void test3(Test3 t) {
+    var /*@type=num*/ v2 = t. /*@target=Test3::prop*/ prop = getNum();
+    var /*@type=double*/ v3 = t. /*@target=Test3::prop*/ prop = getDouble();
+    var /*@type=num*/ v5 = t. /*@target=Test3::prop*/ prop ??= getNum();
+    var /*@type=double*/ v6 = t. /*@target=Test3::prop*/ prop ??= getDouble();
+    var /*@type=double*/ v7 = t. /*@target=Test3::prop*/ prop += getInt();
+    var /*@type=double*/ v8 = t. /*@target=Test3::prop*/ prop += getNum();
+    var /*@type=double*/ v9 = t. /*@target=Test3::prop*/ prop += getDouble();
+    var /*@type=double*/ v10 = ++t. /*@target=Test3::prop*/ prop;
+    var /*@type=double*/ v11 = t. /*@target=Test3::prop*/ prop++;
+  }
+}
+
+main() {}