Add type inference for assignments to properties.

pkg/front_end/testcases/inference/infer_assign_to_property_super_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 Base {
+  int intProp;
+  num numProp;
+  double doubleProp;
+}
+
+class Test1 extends Base {
+  void test() {
+    var /*@type=int*/ v1 = super. /*@target=Base::intProp*/ intProp = getInt();
+    var /*@type=num*/ v2 = super. /*@target=Base::intProp*/ intProp = getNum();
+    var /*@type=int*/ v4 =
+        super. /*@target=Base::intProp*/ intProp ??= getInt();
+    var /*@type=num*/ v5 =
+        super. /*@target=Base::intProp*/ intProp ??= getNum();
+    var /*@type=int*/ v7 = super. /*@target=Base::intProp*/ intProp += getInt();
+    var /*@type=num*/ v8 = super. /*@target=Base::intProp*/ intProp += getNum();
+    var /*@type=int*/ v10 = ++super. /*@target=Base::intProp*/ intProp;
+    var /*@type=int*/ v11 = super. /*@target=Base::intProp*/ intProp++;
+  }
+}
+
+class Test2 extends Base {
+  void test() {
+    var /*@type=int*/ v1 = super. /*@target=Base::numProp*/ numProp = getInt();
+    var /*@type=num*/ v2 = super. /*@target=Base::numProp*/ numProp = getNum();
+    var /*@type=double*/ v3 =
+        super. /*@target=Base::numProp*/ numProp = getDouble();
+    var /*@type=num*/ v4 =
+        super. /*@target=Base::numProp*/ numProp ??= getInt();
+    var /*@type=num*/ v5 =
+        super. /*@target=Base::numProp*/ numProp ??= getNum();
+    var /*@type=num*/ v6 =
+        super. /*@target=Base::numProp*/ numProp ??= getDouble();
+    var /*@type=num*/ v7 = super. /*@target=Base::numProp*/ numProp += getInt();
+    var /*@type=num*/ v8 = super. /*@target=Base::numProp*/ numProp += getNum();
+    var /*@type=num*/ v9 =
+        super. /*@target=Base::numProp*/ numProp += getDouble();
+    var /*@type=num*/ v10 = ++super. /*@target=Base::numProp*/ numProp;
+    var /*@type=num*/ v11 = super. /*@target=Base::numProp*/ numProp++;
+  }
+}
+
+class Test3 extends Base {
+  void test3() {
+    var /*@type=num*/ v2 =
+        super. /*@target=Base::doubleProp*/ doubleProp = getNum();
+    var /*@type=double*/ v3 =
+        super. /*@target=Base::doubleProp*/ doubleProp = getDouble();
+    var /*@type=num*/ v5 =
+        super. /*@target=Base::doubleProp*/ doubleProp ??= getNum();
+    var /*@type=double*/ v6 =
+        super. /*@target=Base::doubleProp*/ doubleProp ??= getDouble();
+    var /*@type=double*/ v7 =
+        super. /*@target=Base::doubleProp*/ doubleProp += getInt();
+    var /*@type=double*/ v8 =
+        super. /*@target=Base::doubleProp*/ doubleProp += getNum();
+    var /*@type=double*/ v9 =
+        super. /*@target=Base::doubleProp*/ doubleProp += getDouble();
+    var /*@type=double*/ v10 = ++super. /*@target=Base::doubleProp*/ doubleProp;
+    var /*@type=double*/ v11 = super. /*@target=Base::doubleProp*/ doubleProp++;
+  }
+}
+
+main() {}