Add label support to ExitDetector

pkg/analyzer/test/generated/all_the_rest_test.dart

 // Copyright (c) 2014, 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.generated.all_the_rest_test;
 
 import 'package:analyzer/dart/ast/ast.dart';
 import 'package:analyzer/dart/ast/token.dart';
 import 'package:analyzer/dart/element/element.dart';
 import 'package:analyzer/dart/element/type.dart';
@@ skipping 3838 matching lines @@
   }
 }
 
 /**
  * Tests for the [ExitDetector] that require that the AST be resolved.
  *
  * See [ExitDetectorTest] for tests that do not require the AST to be resolved.
  */
 @reflectiveTest
 class ExitDetectorTest2 extends ResolverTestCase {
+  void test_forStatement_implicitTrue_breakWithLabel() {
+    Source source = addSource(r'''
+void f() {
+  x: for (;;) {
+    if (1 < 2) {
+      break x;
+    }
+    return;
+  }
+}
+''');
+    _assertNthStatementDoesNotExit(source, 0);
+  }
+
   void test_switch_withEnum_false_noDefault() {
     Source source = addSource(r'''
 enum E { A, B }
 String f(E e) {
   var x;
   switch (e) {
     case A:
       x = 'A';
     case B:
       x = 'B';
   }
   return x;
 }
 ''');
-    LibraryElement element = resolve2(source);
-    CompilationUnit unit = resolveCompilationUnit(source, element);
-    FunctionDeclaration function = unit.declarations.last;
-    BlockFunctionBody body = function.functionExpression.body;
-    Statement statement = body.block.statements[1];
-    expect(ExitDetector.exits(statement), false);
+    _assertNthStatementDoesNotExit(source, 1);
   }
 
   void test_switch_withEnum_false_withDefault() {
     Source source = addSource(r'''
 enum E { A, B }
 String f(E e) {
   var x;
   switch (e) {
     case A:
       x = 'A';
     default:
       x = '?';
   }
   return x;
 }
 ''');
-    LibraryElement element = resolve2(source);
-    CompilationUnit unit = resolveCompilationUnit(source, element);
-    FunctionDeclaration function = unit.declarations.last;
-    BlockFunctionBody body = function.functionExpression.body;
-    Statement statement = body.block.statements[1];
-    expect(ExitDetector.exits(statement), false);
+    _assertNthStatementDoesNotExit(source, 1);
   }
 
   void test_switch_withEnum_true_noDefault() {
     Source source = addSource(r'''
 enum E { A, B }
 String f(E e) {
   switch (e) {
     case A:
       return 'A';
     case B:
       return 'B';
   }
 }
 ''');
-    LibraryElement element = resolve2(source);
-    CompilationUnit unit = resolveCompilationUnit(source, element);
-    FunctionDeclaration function = unit.declarations.last;
-    BlockFunctionBody body = function.functionExpression.body;
-    Statement statement = body.block.statements[0];
-    expect(ExitDetector.exits(statement), true);
+    _assertNthStatementExits(source, 0);
   }
 
   void test_switch_withEnum_true_withDefault() {
     Source source = addSource(r'''
 enum E { A, B }
 String f(E e) {
   switch (e) {
     case A:
       return 'A';
     default:
       return '?';
   }
 }
 ''');
+    _assertNthStatementExits(source, 0);
+  }
+
+  void test_whileStatement_breakWithLabel() {
+    Source source = addSource(r'''
+void f() {
+  x: while (true) {
+    if (1 < 2) {
+      break x;
+    }
+    return;
+  }
+}
+''');
+    _assertNthStatementDoesNotExit(source, 0);
+  }
+
+  void test_whileStatement_breakWithLabel_afterExting() {
+    Source source = addSource(r'''
+void f() {
+  x: while (true) {
+    return;
+    if (1 < 2) {
+      break x;
+    }
+  }
+}
+''');
+    _assertNthStatementExits(source, 0);
+  }
+
+  void _assertHasReturn(bool expectedResult, String source, int n) {
     LibraryElement element = resolve2(source);
     CompilationUnit unit = resolveCompilationUnit(source, element);
     FunctionDeclaration function = unit.declarations.last;
     BlockFunctionBody body = function.functionExpression.body;
-    Statement statement = body.block.statements[0];
-    expect(ExitDetector.exits(statement), true);
+    Statement statement = body.block.statements[n];
+    expect(ExitDetector.exits(statement), expectedResult);
+  }
+
+  // Assert that the [n]th statement in the last function declaration of
+  // [source] exits.
+  void _assertNthStatementExits(String source, int n) {
+    _assertHasReturn(true, source, n);
+  }
+
+  // Assert that the [n]th statement in the last function declaration of
+  // [source] does not exit.
+  void _assertNthStatementDoesNotExit(String source, int n) {
+    _assertHasReturn(false, source, n);
   }
 }
 
 @reflectiveTest
 class FileBasedSourceTest {
   void test_equals_false_differentFiles() {
     JavaFile file1 = FileUtilities2.createFile("/does/not/exist1.dart");
     JavaFile file2 = FileUtilities2.createFile("/does/not/exist2.dart");
     FileBasedSource source1 = new FileBasedSource(file1);
     FileBasedSource source2 = new FileBasedSource(file2);
@@ skipping 361 matching lines @@
     expect(UriKind.fromEncoding(0x70), same(UriKind.PACKAGE_URI));
     expect(UriKind.fromEncoding(0x58), same(null));
   }
 
   void test_getEncoding() {
     expect(UriKind.DART_URI.encoding, 0x64);
     expect(UriKind.FILE_URI.encoding, 0x66);
     expect(UriKind.PACKAGE_URI.encoding, 0x70);
   }
 }