Always store the type of a conditional expression on the node.

testcases/input/null_aware.dart

Index: testcases/input/null_aware.dart
diff --git a/testcases/input/null_aware.dart b/testcases/input/null_aware.dart
new file mode 100644
index 0000000000000000000000000000000000000000..45db741e46abb21e1849cf9d9d7cd9a93ed82584
--- /dev/null
+++ b/testcases/input/null_aware.dart
@@ -0,0 +1,17 @@
+class Foo {

[ahe, 2016/11/01 13:45:00]

No copyright.

[asgerf, 2016/11/01 14:34:49]

Done.

+  int field;
+  static int staticField;
+}
+
+main() {
+  Foo foo = new Foo();
+  foo?.field = 5;
+  Foo?.staticField = 5;
+  foo.field ??= 5;
+  Foo.staticField ??= 5;
+  foo?.field ??= 5;
+  Foo?.staticField ??= 5;
+
+  int intValue = foo.field ?? 6;
+  num numValue = foo.field ?? 4.5;
+}