Handle compile-time constness for conditionals and type literal calls.

tests/language/const_conditional_test.dart

+// Copyright (c) 2013, 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.
+
+// Test for conditionals as compile-time constants.
+
+import 'package:expect/expect.dart';
+
+class Marker {
+  final field;
+  const Marker(this.field);
+}
+
+var var0 = const Marker(0);
+var var1 = const Marker(1);
+const const0 = const Marker(0);
+const const1 = const Marker(1);
+
+const trueConst = true;
+const falseConst = false;
+var nonConst = true;
+const zeroConst = 0;
+
+const cond1 = trueConst ? const0 : const1;
+const cond1a = trueConst ? nonConst : const1; /// 01: compile-time error
+const cond1b = trueConst ? const0 : nonConst; /// 02: compile-time error
+
+const cond2 = falseConst ? const0 : const1;
+const cond2a = falseConst ? nonConst : const1; /// 03: compile-time error
+const cond2b = falseConst ? const0 : nonConst; /// 04: compile-time error
+
+const cond3 = nonConst ? const0 : const1; /// 05: compile-time error
+const cond3a = nonConst ? nonConst : const1; /// 06: compile-time error
+const cond3b = nonConst ? const0 : nonConst; /// 07: compile-time error
+
+const cond4 = zeroConst ? const0 : const1; /// 08: compile-time error
+const cond4a = zeroConst ? nonConst : const1; /// 09: compile-time error
+const cond4b = zeroConst ? const0 : nonConst; /// 10: compile-time error
+
+void main() {
+  Expect.identical(var0, cond1);
+  Expect.identical(nonConst, cond1a); /// 01: continued
+  Expect.identical(var0, cond1b); /// 02: continued
+
+  Expect.identical(var1, cond2);
+  Expect.identical(var1, cond2a); /// 03: continued
+  Expect.identical(nonConst, cond2b); /// 04: continued
+
+  Expect.identical(var0, cond3);  /// 05: continued
+  Expect.identical(nonConst, cond3a); /// 06: continued
+  Expect.identical(var0, cond3b); /// 07: continued
+
+  Expect.identical(var1, cond4);  /// 08: continued
+  Expect.identical(var1, cond4a); /// 09: continued
+  Expect.identical(nonConst, cond4b); /// 10: continued
+}