Fix analyzer interpretation of 'ClassName?.staticMember'.

tests/language/if_null_assignment_behavior_test.dart

 // Copyright (c) 2015, 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.
 
 // Verify semantics of the ??= operator, including order of operations, by
 // keeping track of the operations performed.
 
 import "package:expect/expect.dart";
 import "if_null_assignment_helper.dart" as h;
 
@@ skipping 183 matching lines @@
   check(2, () => x[y] ??= bad(), ['x', 'y', 'x[1]']);                 /// 24: continued
   xGetValue = new C('x'); yGetValue = 1; zGetValue = 2;          /// 25: ok
   check(2, () => x[y] ??= z, ['x', 'y', 'x[1]', 'z', 'x[1]=2']); /// 25: continued
 
   // e1?.v ??= e2 is equivalent to ((x) => x == null ? null : x.v ??= e2)(e1).
   check(null, () => x?.v ??= bad(), ['x']); /// 26: ok
   xGetValue = new C('x'); xGetValue.vGetValue = 1; /// 27: ok
   check(1, () => x?.v ??= bad(), ['x', 'x.v']);     /// 27: continued
   xGetValue = new C('x'); yGetValue = 1;                 /// 28: ok
   check(1, () => x?.v ??= y, ['x', 'x.v', 'y', 'x.v=1']); /// 28: continued
+
+  // C?.v ??= e2 is equivalent to C.v ??= e2.
+  C.xGetValue = 1;                         /// 29: ok
+  check(1, () => C?.x ??= bad(), ['C.x']); /// 29: continued
+  h.C.xgetValue = 1;                           /// 30: ok
+  check(1, () => h.c?.x ??= bad(), ['h.C.x']); /// 30: continued
+  yGetValue = 1;                                     /// 31: ok
+  check(1, () => C?.x ??= y, ['C.x', 'y', 'C.x=1']); /// 31: continued
+  yGetValue = 1;                                           /// 32: ok
+  check(1, () => h.C?.x ??= y, ['h.C.x', 'y', 'h.C.x=1']); /// 32: continued
 }