When a file is removed from the driver, reschedule full analysis.

pkg/analyzer/test/src/dart/analysis/driver_test.dart

 // Copyright (c) 2016, 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.
 
 library analyzer.test.driver;
 
 import 'dart:async';
 import 'dart:convert';
 
 import 'package:analyzer/dart/ast/ast.dart';
@@ skipping 949 matching lines @@
     expect(driver.hasFilesToAnalyze, isFalse);
 
     // Request of referenced names is not analysis of a file.
     driver.getFilesReferencingName('X');
     expect(driver.hasFilesToAnalyze, isFalse);
   }
 
   test_knownFiles() async {
     var a = _p('/test/lib/a.dart');
     var b = _p('/test/lib/b.dart');
+    var c = _p('/test/lib/c.dart');
 
     provider.newFile(
         a,
         r'''
 import 'b.dart';
 ''');
+    provider.newFile(b, '');
+    provider.newFile(c, '');
 
     driver.addFile(a);
+    driver.addFile(c);
     await _waitForIdle();
 
-    expect(driver.knownFiles, contains(a));
-    expect(driver.knownFiles, contains(b));
+    expect(driver.knownFiles, unorderedEquals([a, b, c]));
 
+    // Remove a.dart and analyze.
+    // Both a.dart and b.dart are not known now.
     driver.removeFile(a);
-
-    // a.dart was removed, but we don't clean up the file state state yet.
-    expect(driver.knownFiles, contains(a));
-    expect(driver.knownFiles, contains(b));
+    await _waitForIdle();
+    expect(driver.knownFiles, unorderedEquals([c]));
   }
 
   test_knownFiles_beforeAnalysis() async {
     var a = _p('/test/lib/a.dart');
     var b = _p('/test/lib/b.dart');
 
     provider.newFile(a, '');
 
     // 'a.dart' is added, but not processed yet.
     // So, the set of known files is empty yet.
@@ skipping 332 matching lines @@
     // Remove the file and send the change notification.
     // The change notification does nothing, because the file is explicitly
     // or implicitly analyzed.
     driver.removeFile(testFile);
     driver.changeFile(testFile);
 
     await _waitForIdle();
     expect(allResults, isEmpty);
   }
 
+  test_removeFile_invalidate_importers() async {
+    var a = _p('/test/lib/a.dart');
+    var b = _p('/test/lib/b.dart');
+
+    provider.newFile(a, 'class A {}');
+    provider.newFile(b, "import 'a.dart';  var a = new A();");
+
+    driver.addFile(a);
+    driver.addFile(b);
+    await _waitForIdle();
+
+    // b.dart s clean.
+    expect(allResults.singleWhere((r) => r.path == b).errors, isEmpty);
+    allResults.clear();
+
+    // Remove a.dart, now b.dart should be reanalyzed and has an error.
+    provider.deleteFile(a);
+    driver.removeFile(a);
+    await _waitForIdle();
+    expect(allResults.singleWhere((r) => r.path == b).errors, hasLength(2));
+    allResults.clear();
+  }
+
   test_results_priority() async {
     String content = 'int f() => 42;';
     addTestFile(content, priority: true);
 
     await _waitForIdle();
 
     expect(allResults, hasLength(1));
     AnalysisResult result = allResults.single;
     expect(result.path, testFile);
     expect(result.uri.toString(), 'package:test/test.dart');
@@ skipping 151 matching lines @@
   String _p(String path) => provider.convertPath(path);
 
   Future<Null> _waitForIdle() async {
     await idleStatusMonitor.signal;
   }
 
   static String _md5(String content) {
     return hex.encode(md5.convert(UTF8.encode(content)).bytes);
   }
 }