improve keyword suggestions - fixes #24016

pkg/analysis_server/test/services/completion/keyword_contributor_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 test.services.completion.dart.keyword;
 
 import 'package:analysis_server/src/protocol.dart';
 import 'package:analysis_server/src/services/completion/dart_completion_manager.dart';
 import 'package:analysis_server/src/services/completion/keyword_contributor.dart';
 import 'package:analyzer/src/generated/scanner.dart';
@@ skipping 61 matching lines @@
     Keyword.PART,
     Keyword.TYPEDEF,
     Keyword.VAR,
     Keyword.VOID
   ];
 
   static const List<String> NO_PSEUDO_KEYWORDS = const [];
 
   static const List<Keyword> STMT_START_IN_CLASS = const [
     Keyword.ASSERT,
+    Keyword.CONST,
+    Keyword.DO,
+    Keyword.FINAL,
+    Keyword.FOR,
+    Keyword.IF,
+    Keyword.NEW,
+    Keyword.RETHROW,
+    Keyword.RETURN,
+    Keyword.SUPER,
+    Keyword.SWITCH,
+    Keyword.THIS,
+    Keyword.THROW,
+    Keyword.TRY,
+    Keyword.VAR,
+    Keyword.VOID,
+    Keyword.WHILE
+  ];
+
+  static const List<Keyword> STMT_START_IN_LOOP_IN_CLASS = const [
+    Keyword.ASSERT,
+    Keyword.BREAK,
+    Keyword.CONST,
     Keyword.CONTINUE,
     Keyword.DO,
     Keyword.FINAL,
     Keyword.FOR,
     Keyword.IF,
     Keyword.NEW,
     Keyword.RETHROW,
     Keyword.RETURN,
     Keyword.SUPER,
     Keyword.SWITCH,
     Keyword.THIS,
     Keyword.THROW,
     Keyword.TRY,
     Keyword.VAR,
     Keyword.VOID,
     Keyword.WHILE
   ];
 
   static const List<Keyword> STMT_START_IN_SWITCH_IN_CLASS = const [
     Keyword.ASSERT,
+    Keyword.BREAK,
     Keyword.CASE,
-    Keyword.CONTINUE,
+    Keyword.CONST,
     Keyword.DEFAULT,
     Keyword.DO,
     Keyword.FINAL,
     Keyword.FOR,
     Keyword.IF,
     Keyword.NEW,
     Keyword.RETHROW,
     Keyword.RETURN,
     Keyword.SUPER,
     Keyword.SWITCH,
     Keyword.THIS,
     Keyword.THROW,
     Keyword.TRY,
     Keyword.VAR,
     Keyword.VOID,
     Keyword.WHILE
   ];
 
   static const List<Keyword> STMT_START_IN_SWITCH_OUTSIDE_CLASS = const [
     Keyword.ASSERT,
+    Keyword.BREAK,
     Keyword.CASE,
-    Keyword.CONTINUE,
+    Keyword.CONST,
     Keyword.DEFAULT,
     Keyword.DO,
     Keyword.FINAL,
     Keyword.FOR,
     Keyword.IF,
     Keyword.NEW,
     Keyword.RETHROW,
     Keyword.RETURN,
     Keyword.SWITCH,
     Keyword.THROW,
     Keyword.TRY,
     Keyword.VAR,
     Keyword.VOID,
     Keyword.WHILE
   ];
 
   static const List<Keyword> STMT_START_OUTSIDE_CLASS = const [
     Keyword.ASSERT,
+    Keyword.CONST,
+    Keyword.DO,
+    Keyword.FINAL,
+    Keyword.FOR,
+    Keyword.IF,
+    Keyword.NEW,
+    Keyword.RETHROW,
+    Keyword.RETURN,
+    Keyword.SWITCH,
+    Keyword.THROW,
+    Keyword.TRY,
+    Keyword.VAR,
+    Keyword.VOID,
+    Keyword.WHILE
+  ];
+
+  static const List<Keyword> STMT_START_IN_LOOP_OUTSIDE_CLASS = const [
+    Keyword.ASSERT,
+    Keyword.BREAK,
+    Keyword.CONST,
     Keyword.CONTINUE,
     Keyword.DO,
     Keyword.FINAL,
     Keyword.FOR,
     Keyword.IF,
     Keyword.NEW,
     Keyword.RETHROW,
     Keyword.RETURN,
     Keyword.SWITCH,
     Keyword.THROW,
     Keyword.TRY,
     Keyword.VAR,
     Keyword.VOID,
     Keyword.WHILE
   ];
 
   static const List<Keyword> EXPRESSION_START_INSTANCE = const [
+    Keyword.CONST,
     Keyword.FALSE,
     Keyword.NEW,
     Keyword.NULL,
     Keyword.SUPER,
     Keyword.THIS,
     Keyword.TRUE,
   ];
 
   static const List<Keyword> EXPRESSION_START_NO_INSTANCE = const [
+    Keyword.CONST,
     Keyword.FALSE,
     Keyword.NEW,
     Keyword.NULL,
     Keyword.TRUE,
   ];
 
   void assertSuggestKeywords(Iterable<Keyword> expectedKeywords,
       {List<String> pseudoKeywords: NO_PSEUDO_KEYWORDS,
       int relevance: DART_RELEVANCE_KEYWORD}) {
     Set<String> expectedCompletions = new Set<String>();
@@ skipping 352 matching lines @@
     expect(computeFast(), isTrue);
     assertSuggestKeywords([Keyword.THIS]);
   }
 
   test_constructor_param2() {
     addTestSource('class A { A(t^) {});}');
     expect(computeFast(), isTrue);
     assertSuggestKeywords([Keyword.THIS]);
   }
 
+  test_do_break_continue() {
+    addTestSource('main() {do {^} while (true);}');
+    expect(computeFast(), isTrue);
+    assertSuggestKeywords(STMT_START_IN_LOOP_OUTSIDE_CLASS,
+        relevance: DART_RELEVANCE_KEYWORD);
+  }
+
+  test_do_break_continue2() {
+    addTestSource('class A {foo() {do {^} while (true);}}');
+    expect(computeFast(), isTrue);
+    assertSuggestKeywords(STMT_START_IN_LOOP_IN_CLASS,
+        relevance: DART_RELEVANCE_KEYWORD);
+  }
+
   test_empty() {
     addTestSource('^');
     expect(computeFast(), isTrue);
     assertSuggestKeywords(DIRECTIVE_DECLARATION_AND_LIBRARY_KEYWORDS,
         relevance: DART_RELEVANCE_HIGH);
   }
 
+  test_for_break_continue() {
+    addTestSource('main() {for (int x in myList) {^}}');
+    expect(computeFast(), isTrue);
+    assertSuggestKeywords(STMT_START_IN_LOOP_OUTSIDE_CLASS,
+        relevance: DART_RELEVANCE_KEYWORD);
+  }
+
+  test_for_break_continue2() {
+    addTestSource('class A {foo() {for (int x in myList) {^}}}');
+    expect(computeFast(), isTrue);
+    assertSuggestKeywords(STMT_START_IN_LOOP_IN_CLASS,
+        relevance: DART_RELEVANCE_KEYWORD);
+  }
+
   test_for_expression_in() {
     addTestSource('main() {for (int x i^)}');
     expect(computeFast(), isTrue);
     assertSuggestKeywords([Keyword.IN], relevance: DART_RELEVANCE_HIGH);
   }
 
   test_for_expression_in2() {
     addTestSource('main() {for (int x in^)}');
     expect(computeFast(), isTrue);
     assertSuggestKeywords([Keyword.IN], relevance: DART_RELEVANCE_HIGH);
   }
 
   test_for_expression_init() {
     addTestSource('main() {for (int x = i^)}');
     expect(computeFast(), isTrue);
-    assertSuggestKeywords(
-        [Keyword.FALSE, Keyword.NEW, Keyword.NULL, Keyword.TRUE]);
+    assertSuggestKeywords(EXPRESSION_START_NO_INSTANCE);
   }
 
   test_for_expression_init2() {
     addTestSource('main() {for (int x = in^)}');
     expect(computeFast(), isTrue);
-    assertSuggestKeywords(
-        [Keyword.FALSE, Keyword.NEW, Keyword.NULL, Keyword.TRUE]);
+    assertSuggestKeywords(EXPRESSION_START_NO_INSTANCE);
   }
 
   test_function_async() {
     addTestSource('main()^');
     expect(computeFast(), isTrue);
     assertSuggestKeywords(DECLARATION_KEYWORDS,
         pseudoKeywords: ['async'], relevance: DART_RELEVANCE_HIGH);
   }
 
   test_function_async2() {
@@ skipping 370 matching lines @@
     addTestSource(
         'library bar; import "zoo.dart"; imp^ import "package:foo/foo.dart";');
     expect(computeFast(), isTrue);
     // TODO(danrubel) should not suggest declaration keywords
     assertSuggestKeywords(DIRECTIVE_AND_DECLARATION_KEYWORDS,
         relevance: DART_RELEVANCE_HIGH);
     expect(request.replacementOffset, 32);
     expect(request.replacementLength, 3);
   }
 
+  test_is_expression() {
+    addTestSource('main() {if (x is^)}');
+    expect(computeFast(), isTrue);
+    assertSuggestKeywords([Keyword.IS], relevance: DART_RELEVANCE_HIGH);
+  }
+
   test_library() {
     addTestSource('library foo;^');
     expect(computeFast(), isTrue);
     assertSuggestKeywords(DIRECTIVE_AND_DECLARATION_KEYWORDS,
         relevance: DART_RELEVANCE_HIGH);
   }
 
   test_library_declaration() {
     addTestSource('library ^');
     expect(computeFast(), isTrue);
@@ skipping 311 matching lines @@
     expect(computeFast(), isTrue);
     assertSuggestKeywords(STMT_START_IN_SWITCH_OUTSIDE_CLASS);
   }
 
   test_switch_statement2() {
     addTestSource('class A{foo() {switch(1) {case 1:^}}}');
     expect(computeFast(), isTrue);
     assertSuggestKeywords(STMT_START_IN_SWITCH_IN_CLASS);
   }
 
+  test_while_break_continue() {
+    addTestSource('main() {while (true) {^}}');
+    expect(computeFast(), isTrue);
+    assertSuggestKeywords(STMT_START_IN_LOOP_OUTSIDE_CLASS,
+        relevance: DART_RELEVANCE_KEYWORD);
+  }
+
+  test_while_break_continue2() {
+    addTestSource('class A {foo() {while (true) {^}}}');
+    expect(computeFast(), isTrue);
+    assertSuggestKeywords(STMT_START_IN_LOOP_IN_CLASS,
+        relevance: DART_RELEVANCE_KEYWORD);
+  }
+
   void _appendCompletions(
       StringBuffer msg, Iterable<String> completions, Iterable<String> other) {
     List<String> sorted = completions.toList();
     sorted.sort((c1, c2) => c1.compareTo(c2));
     sorted.forEach(
         (c) => msg.writeln('  $c, ${other.contains(c) ? '' : '<<<<<<<<<<<'}'));
   }
 
   bool _equalSets(Iterable<String> iter1, Iterable<String> iter2) {
     if (iter1.length != iter2.length) return false;
     if (iter1.any((c) => !iter2.contains(c))) return false;
     if (iter2.any((c) => !iter1.contains(c))) return false;
     return true;
   }
 }