Code completion improvement. Recommend all 'E.x' where E is an enum, also, filter out only the correct enum types in named arguments.

BUG=#24759

Review URL: https://codereview.chromium.org/1989393002 .

Author: jwren

pkg/analysis_server/lib/src/provisional/completion/dart/completion_dart.dart

@@ -20,7 +20,7 @@ export 'package:analysis_server/src/provisional/completion/completion_core.dart'
 const int DART_RELEVANCE_COMMON_USAGE = 1200;
 const int DART_RELEVANCE_DEFAULT = 1000;
 const int DART_RELEVANCE_HIGH = 2000;
-const int DART_RELEVANCE_INCREMENT = 20;
+const int DART_RELEVANCE_INCREMENT = 100;
 const int DART_RELEVANCE_INHERITED_ACCESSOR = 1057;
 const int DART_RELEVANCE_INHERITED_FIELD = 1058;
 const int DART_RELEVANCE_INHERITED_METHOD = 1057;

pkg/analysis_server/lib/src/services/completion/dart/local_reference_contributor.dart

@@ -256,6 +256,13 @@ class _LocalVisitor extends LocalDeclarationVisitor {
       _addLocalSuggestion_includeTypeNameSuggestions(
           declaration.name, NO_RETURN_TYPE, protocol.ElementKind.ENUM,
           isDeprecated: _isDeprecated(declaration));
+      for (EnumConstantDeclaration enumConstant in declaration.constants) {
+        if (!enumConstant.isSynthetic) {
+          _addLocalSuggestion_includeReturnValueSuggestions_enumConstant(
+              enumConstant, declaration,
+              isDeprecated: _isDeprecated(declaration));
+        }
+      }
     }
   }
 
@@ -419,6 +426,42 @@ class _LocalVisitor extends LocalDeclarationVisitor {
     }
   }
 
+  void _addLocalSuggestion_enumConstant(
+      EnumConstantDeclaration constantDeclaration,
+      EnumDeclaration enumDeclaration,
+      {bool isAbstract: false,
+      bool isDeprecated: false,
+      ClassDeclaration classDecl,
+      int relevance: DART_RELEVANCE_DEFAULT}) {
+    String completion =
+        '${enumDeclaration.name.name}.${constantDeclaration.name.name}';
+    CompletionSuggestion suggestion = new CompletionSuggestion(
+        CompletionSuggestionKind.INVOCATION,
+        isDeprecated ? DART_RELEVANCE_LOW : relevance,
+        completion,
+        completion.length,
+        0,
+        isDeprecated,
+        false,
+        returnType: enumDeclaration.name.name);
+
+    suggestionMap.putIfAbsent(suggestion.completion, () => suggestion);
+    int flags = protocol.Element.makeFlags(
+        isAbstract: isAbstract,
+        isDeprecated: isDeprecated,
+        isPrivate: Identifier.isPrivateName(constantDeclaration.name.name));
+    suggestion.element = new protocol.Element(
+        protocol.ElementKind.ENUM_CONSTANT,
+        constantDeclaration.name.name,
+        flags,
+        location: new Location(
+            request.source.fullName,
+            constantDeclaration.name.offset,
+            constantDeclaration.name.length,
+            0,
+            0));
+  }
+
   void _addLocalSuggestion_includeReturnValueSuggestions(
       SimpleIdentifier id, TypeName typeName, protocol.ElementKind elemKind,
       {bool isAbstract: false,
@@ -438,6 +481,22 @@ class _LocalVisitor extends LocalDeclarationVisitor {
     }
   }
 
+  void _addLocalSuggestion_includeReturnValueSuggestions_enumConstant(
+      EnumConstantDeclaration constantDeclaration,
+      EnumDeclaration enumDeclaration,
+      {bool isAbstract: false,
+      bool isDeprecated: false,
+      int relevance: DART_RELEVANCE_DEFAULT}) {
+    relevance = optype.returnValueSuggestionsFilter(
+        enumDeclaration.element.type, relevance);
+    if (relevance != null) {
+      _addLocalSuggestion_enumConstant(constantDeclaration, enumDeclaration,
+          isAbstract: isAbstract,
+          isDeprecated: isDeprecated,
+          relevance: relevance);
+    }
+  }
+
   void _addLocalSuggestion_includeTypeNameSuggestions(
       SimpleIdentifier id, TypeName typeName, protocol.ElementKind elemKind,
       {bool isAbstract: false,

pkg/analysis_server/lib/src/services/completion/dart/optype.dart

@@ -641,6 +641,16 @@ class _OpTypeAstVisitor extends GeneralizingAstVisitor {
       optype.includeReturnValueSuggestions = true;
       optype.returnValueSuggestionsFilter = (DartType dartType, int relevance) {
         DartType type = node.element?.type;
+        bool isEnum = type != null &&
+            type.element is ClassElement &&
+            (type.element as ClassElement).isEnum;
+        if (isEnum) {
+          if (type == dartType) {
+            return relevance + DART_RELEVANCE_INCREMENT;
+          } else {
+            return null;
+          }
+        }
         if (type != null &&
             dartType != null &&
             !type.isDynamic &&

pkg/analysis_server/test/services/completion/dart/completion_contributor_util.dart

@@ -216,9 +216,10 @@ abstract class DartCompletionContributorTest extends AbstractContextTest {
   }
 
   CompletionSuggestion assertSuggestEnumConst(String completion,
-      {bool isDeprecated: false}) {
+      {int relevance: DART_RELEVANCE_DEFAULT, bool isDeprecated: false}) {
     CompletionSuggestion suggestion =
-        assertSuggest(completion, isDeprecated: isDeprecated);
+        assertSuggest(completion, relevance: relevance, isDeprecated: isDeprecated);
+    expect(suggestion.completion, completion);
     expect(suggestion.isDeprecated, isDeprecated);
     expect(suggestion.element.kind, protocol.ElementKind.ENUM_CONSTANT);
     return suggestion;

pkg/analysis_server/test/services/completion/dart/local_reference_contributor_test.dart

@@ -355,21 +355,19 @@ void main() {expect(foo: ^)}''');
     expect(replacementLength, 0);
     assertSuggestTopLevelVar('a', 'A',
         relevance:
-        DART_RELEVANCE_LOCAL_TOP_LEVEL_VARIABLE + DART_RELEVANCE_INCREMENT);
+            DART_RELEVANCE_LOCAL_TOP_LEVEL_VARIABLE + DART_RELEVANCE_INCREMENT);
     assertSuggestTopLevelVar('b', 'B',
         relevance:
-        DART_RELEVANCE_LOCAL_TOP_LEVEL_VARIABLE + DART_RELEVANCE_INCREMENT);
+            DART_RELEVANCE_LOCAL_TOP_LEVEL_VARIABLE + DART_RELEVANCE_INCREMENT);
     assertSuggestTopLevelVar('c', 'C',
         relevance:
-        DART_RELEVANCE_LOCAL_TOP_LEVEL_VARIABLE + DART_RELEVANCE_INCREMENT);
+            DART_RELEVANCE_LOCAL_TOP_LEVEL_VARIABLE + DART_RELEVANCE_INCREMENT);
     assertSuggestTopLevelVar('d', 'D',
         relevance: DART_RELEVANCE_LOCAL_TOP_LEVEL_VARIABLE);
     assertSuggestTopLevelVar('e', 'E',
         relevance: DART_RELEVANCE_LOCAL_TOP_LEVEL_VARIABLE);
   }
 
-
-
   test_AsExpression_type() async {
     // SimpleIdentifier  TypeName  AsExpression
     addTestSource('''
@@ -1929,6 +1927,8 @@ class A {a(blat: ^) { }}''');
     addTestSource('enum E { one, two } main() {^}');
     await computeSuggestions();
     assertSuggestEnum('E');
+    assertSuggestEnumConst('E.one');
+    assertSuggestEnumConst('E.two');
     assertNotSuggested('one');
     assertNotSuggested('two');
   }
@@ -1937,10 +1937,38 @@ class A {a(blat: ^) { }}''');
     addTestSource('@deprecated enum E { one, two } main() {^}');
     await computeSuggestions();
     assertSuggestEnum('E', isDeprecated: true);
+    assertSuggestEnumConst('E.one', isDeprecated: true);
+    assertSuggestEnumConst('E.two', isDeprecated: true);
     assertNotSuggested('one');
     assertNotSuggested('two');
   }
 
+  test_enum_filter() async {
+    // SimpleIdentifier  NamedExpression  ArgumentList
+    // InstanceCreationExpression
+    addTestSource('''
+        enum E { one, two }
+        enum F { three, four }
+        class A {}
+        class B {
+          B({E someE});
+        }
+        A a = new A();
+        B b = new B(someE: ^);
+  ''');
+    await computeSuggestions();
+
+    expect(replacementOffset, completionOffset);
+    expect(replacementLength, 0);
+    assertSuggestEnumConst('E.one',
+        relevance: DART_RELEVANCE_DEFAULT + DART_RELEVANCE_INCREMENT);
+    assertSuggestEnumConst('E.two',
+        relevance: DART_RELEVANCE_DEFAULT + DART_RELEVANCE_INCREMENT);
+    assertNotSuggested('a');
+    assertNotSuggested('F.three');
+    assertNotSuggested('F.four');
+  }
+
   test_ExpressionStatement_identifier() async {
     // SimpleIdentifier  ExpressionStatement  Block
     addSource(