Fix an exception caused by incomplete input (issue 29687)

pkg/analyzer/test/src/summary/resynthesize_common.dart

Index: pkg/analyzer/test/src/summary/resynthesize_common.dart
diff --git a/pkg/analyzer/test/src/summary/resynthesize_common.dart b/pkg/analyzer/test/src/summary/resynthesize_common.dart
index 879fbe8297d9943b931bb94206001cb5d83c9027..4173ca9db2d2ece7063c020bc0674c80a32d966c 100644
--- a/pkg/analyzer/test/src/summary/resynthesize_common.dart
+++ b/pkg/analyzer/test/src/summary/resynthesize_common.dart
@@ -473,7 +473,7 @@ abstract class AbstractResynthesizeTest extends AbstractSingleUnitTest {
       } else if (o is BooleanLiteral && r is BooleanLiteral) {
         expect(r.value, o.value, reason: desc);
       } else if (o is IntegerLiteral && r is IntegerLiteral) {
-        expect(r.value, o.value, reason: desc);
+        expect(r.value ?? 0, o.value ?? 0, reason: desc);
       } else if (o is DoubleLiteral && r is DoubleLiteral) {
         if (r.value != null &&
             r.value.isNaN &&
@@ -3293,6 +3293,27 @@ int foo() {}
     }
   }
 
+  test_const_invalid_intLiteral() {
+    var library = checkLibrary(
+        r'''
+const int x = 0x;
+''',
+        allowErrors: true);
+    if (isStrongMode) {
+      checkElementText(
+          library,
+          r'''
+const int x = 0;
+''');
+    } else {
+      checkElementText(
+          library,
+          r'''
+const int x = 0;

[scheglov, 2017/05/30 17:25:18]

I don't think we do this for all the tests, but in this case strong mode and
spec mode expectations are the same, so we could remove "if" and just do the
same check.

[Brian Wilkerson, 2017/05/30 17:38:45]

Done

+''');
+    }
+  }
+
   test_const_invalid_topLevel() {
     variablesWithNotConstInitializers.add('v');
     var library = checkLibrary(