Migrate block 116.

tests/language_2/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 110 matching lines @@
     h.operations.add('$s[$index]=$value');
   }
 
   final finalOne = 1;
   final finalNull = null;
 
   void instanceTest() {
     // v ??= e is equivalent to ((x) => x == null ? v = e : x)(v)
     vGetValue = 1; check(1, () => v ??= bad(), ['$s.v']); //# 01: ok
     yGetValue = 1; check(1, () => v ??= y, ['$s.v', 'y', '$s.v=1']); //# 02: ok
-    check(1, () => finalOne ??= bad(), []); //# 03: static type warning
-    yGetValue = 1; checkThrows(noMethod, () => finalNull ??= y, ['y']); //# 04: static type warning
+    finalOne ??= null; //# 03: compile-time error
+    yGetValue = 1;
   }
 }
 
 class D extends C {
   D(String s) : super(s);
 
   get v => bad();
 
   void set v(value) {
     bad();
@@ skipping 16 matching lines @@
   new C('c').instanceTest();
   new D('d').derivedInstanceTest();
 
   // v ??= e is equivalent to ((x) => x == null ? v = e : x)(v)
   xGetValue = 1; check(1, () => x ??= bad(), ['x']); //# 07: ok
   yGetValue = 1; check(1, () => x ??= y, ['x', 'y', 'x=1']); //# 08: ok
   h.xGetValue = 1; check(1, () => h.x ??= bad(), ['h.x']); //# 09: ok
   yGetValue = 1; check(1, () => h.x ??= y, ['h.x', 'y', 'h.x=1']); //# 10: ok
   { var l = 1; check(1, () => l ??= bad(), []); } //# 11: ok
   { var l; yGetValue = 1; check(1, () => l ??= y, ['y']); Expect.equals(1, l); } //# 12: ok
-  { final l = 1; check(1, () => l ??= bad(), []); } //# 13: static type warning
-  { final l = null; yGetValue = 1; checkThrows(noMethod, () => l ??= y, ['y']); } //# 14: static type warning
-  check(C, () => C ??= bad(), []); //# 15: static type warning
+  { final l = 1; l ??= null; } //# 13: compile-time error
+  C ??= null; //# 15: compile-time error
   h ??= null; //# 29: compile-time error
   h[0] ??= null; //# 30: compile-time error
 
   // C.v ??= e is equivalent to ((x) => x == null ? C.v = e : x)(C.v)
   C.xGetValue = 1; check(1, () => C.x ??= bad(), ['C.x']); //# 16: ok
   yGetValue = 1; check(1, () => C.x ??= y, ['C.x', 'y', 'C.x=1']); //# 17: ok
   h.C.xGetValue = 1; check(1, () => h.C.x ??= bad(), ['h.C.x']); //# 18: ok
   yGetValue = 1; check(1, () => h.C.x ??= y, ['h.C.x', 'y', 'h.C.x=1']); //# 19: ok
 
   // e1.v ??= e2 is equivalent to
@@ skipping 24 matching lines @@
   // 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
 }