add 3 lints for always specify types

example/all.yaml

@@ -6,6 +6,9 @@ linter:
     - always_put_control_body_on_new_line
     - always_put_required_named_parameters_first
     - always_require_non_null_named_parameters
+    - always_specify_type_annotations
+    - always_specify_type_arguments_for_classes
+    - always_specify_type_arguments_for_methods
     - always_specify_types
     - annotate_overrides
     - avoid_annotating_with_dynamic

lib/src/rules.dart

@@ -7,6 +7,9 @@ import 'package:linter/src/rules/always_declare_return_types.dart';
 import 'package:linter/src/rules/always_put_control_body_on_new_line.dart';
 import 'package:linter/src/rules/always_put_required_named_parameters_first.dart';
 import 'package:linter/src/rules/always_require_non_null_named_parameters.dart';
+import 'package:linter/src/rules/always_specify_type_annotations.dart';
+import 'package:linter/src/rules/always_specify_type_arguments_for_classes.dart';
+import 'package:linter/src/rules/always_specify_type_arguments_for_methods.dart';
 import 'package:linter/src/rules/always_specify_types.dart';
 import 'package:linter/src/rules/annotate_overrides.dart';
 import 'package:linter/src/rules/avoid_annotating_with_dynamic.dart';
@@ -138,6 +141,9 @@ void registerLintRules() {
     ..register(new AlwaysPutControlBodyOnNewLine())
     ..register(new AlwaysPutRequiredNamedParametersFirst())
     ..register(new AlwaysRequireNonNullNamedParameters())
+    ..register(new AlwaysSpecifyTypeAnnotations())
+    ..register(new AlwaysSpecifyTypeArgumentsForClasses())
+    ..register(new AlwaysSpecifyTypeArgumentsForMethods())
     ..register(new AlwaysSpecifyTypes())
     ..register(new AnnotateOverrides())
     ..register(new AvoidAnnotatingWithDynamic())

lib/src/rules/always_specify_type_annotations.dart

@@ -0,0 +1,80 @@
+// Copyright (c) 2018, 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.
+
+import 'package:analyzer/dart/ast/ast.dart';
+import 'package:analyzer/dart/ast/visitor.dart';
+import 'package:linter/src/analyzer.dart';
+import 'package:linter/src/utils.dart';
+
+const _desc = r'Specify type annotations.';
+
+const _details = r'''
+
+**DO** specify type annotations.
+
+**GOOD:**
+```
+int foo = 10;
+final Bar bar = new Bar();
+String baz = 'hello';
+const int quux = 20;
+```
+
+**BAD:**
+```
+var foo = 10;
+final bar = new Bar();
+const quux = 20;
+```
+''';
+
+class AlwaysSpecifyTypeAnnotations extends LintRule implements NodeLintRule {
+  AlwaysSpecifyTypeAnnotations()
+      : super(
+            name: 'always_specify_type_annotations',
+            description: _desc,
+            details: _details,
+            group: Group.style);
+
+  @override
+  void registerNodeProcessors(NodeLintRegistry registry) {
+    final visitor = new _Visitor(this);
+    registry.addDeclaredIdentifier(this, visitor);
+    registry.addSimpleFormalParameter(this, visitor);
+    registry.addVariableDeclarationList(this, visitor);
+  }
+}
+
+class _Visitor extends SimpleAstVisitor<void> {
+  final LintRule rule;
+
+  _Visitor(this.rule);
+
+  @override
+  void visitDeclaredIdentifier(DeclaredIdentifier node) {
+    if (node.type == null) {
+      rule.reportLintForToken(node.keyword);
+    }
+  }
+
+  @override
+  void visitSimpleFormalParameter(SimpleFormalParameter param) {
+    if (param.type == null &&
+        param.identifier != null &&
+        !isJustUnderscores(param.identifier.name)) {
+      if (param.keyword != null) {
+        rule.reportLintForToken(param.keyword);
+      } else {
+        rule.reportLint(param);
+      }
+    }
+  }
+
+  @override
+  void visitVariableDeclarationList(VariableDeclarationList list) {
+    if (list.type == null) {
+      rule.reportLintForToken(list.keyword);
+    }
+  }
+}

lib/src/rules/always_specify_type_arguments_for_classes.dart

@@ -0,0 +1,131 @@
+// Copyright (c) 2018, 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.
+
+import 'package:analyzer/dart/ast/ast.dart';
+import 'package:analyzer/dart/ast/visitor.dart';
+import 'package:analyzer/dart/element/element.dart';
+import 'package:analyzer/dart/element/type.dart';
+import 'package:linter/src/analyzer.dart';
+
+const _desc = r'Specify type arguments for classes.';
+
+const _details = r'''
+
+**DO** specify type arguments for classes.
+
+**GOOD:**
+```
+final a = <int>[];
+final b = new List<int>();
+final c = <int, String>{};
+final d = new Map<int, String>();
+```
+
+**BAD:**
+```
+final a = [];
+final b = new List();
+final c = {};
+final d = new Map();
+```
+
+NOTE: Using the the `@optionalTypeArgs` annotation in the `meta` package, API
+authors can special-case type variables whose type needs to by dynamic but whose
+declaration should be treated as optional. For example, suppose you have a
+`Key` object whose type parameter you'd like to treat as optional. Using the
+`@optionalTypeArgs` would look like this:
+
+```
+import 'package:meta/meta.dart';
+
+@optionalTypeArgs
+class Key<T> {
+ ...
+}
+
+main() {
+  Key s = new Key(); // OK!
+}
+```
+
+''';
+
+/// The name of `meta` library, used to define analysis annotations.
+String _META_LIB_NAME = 'meta';
+
+/// The name of the top-level variable used to mark a Class as having optional
+/// type args.
+String _OPTIONAL_TYPE_ARGS_VAR_NAME = 'optionalTypeArgs';
+
+bool _isOptionallyParameterized(ParameterizedType type) {
+  List<ElementAnnotation> metadata = type.element?.metadata;
+  if (metadata != null) {
+    return metadata
+        .any((ElementAnnotation a) => _isOptionalTypeArgs(a.element));
+  }
+  return false;
+}
+
+bool _isOptionalTypeArgs(Element element) =>
+    element is PropertyAccessorElement &&
+    element.name == _OPTIONAL_TYPE_ARGS_VAR_NAME &&
+    element.library?.name == _META_LIB_NAME;
+
+class AlwaysSpecifyTypeArgumentsForClasses extends LintRule
+    implements NodeLintRule {
+  AlwaysSpecifyTypeArgumentsForClasses()
+      : super(
+            name: 'always_specify_type_arguments_for_classes',
+            description: _desc,
+            details: _details,
+            group: Group.style);
+
+  @override
+  void registerNodeProcessors(NodeLintRegistry registry) {
+    final visitor = new _Visitor(this);
+    registry.addListLiteral(this, visitor);
+    registry.addMapLiteral(this, visitor);
+    registry.addTypeName(this, visitor);
+  }
+}
+
+class _Visitor extends SimpleAstVisitor<void> {
+  final LintRule rule;
+
+  _Visitor(this.rule);
+
+  @override
+  void visitListLiteral(ListLiteral literal) {
+    _checkLiteral(literal);
+  }
+
+  @override
+  void visitMapLiteral(MapLiteral literal) {
+    _checkLiteral(literal);
+  }
+
+  void _checkLiteral(TypedLiteral literal) {
+    if (literal.typeArguments == null) {
+      rule.reportLintForToken(literal.beginToken);
+    }
+  }
+
+  // Future kernel API.
+  void visitNamedType(NamedType namedType) {
+    DartType type = namedType.type;
+    if (type is ParameterizedType) {
+      if (type.typeParameters.isNotEmpty &&
+          namedType.typeArguments == null &&
+          namedType.parent is! IsExpression &&
+          !_isOptionallyParameterized(type)) {
+        rule.reportLint(namedType);
+      }
+    }
+  }
+
+  @override
+  void visitTypeName(NamedType typeName) {
+    visitNamedType(typeName);
+  }
+}

lib/src/rules/always_specify_type_arguments_for_methods.dart

@@ -0,0 +1,91 @@
+// Copyright (c) 2015, 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.
+
+import 'package:analyzer/dart/ast/ast.dart';
+import 'package:analyzer/dart/ast/visitor.dart';
+import 'package:analyzer/dart/element/element.dart';
+import 'package:linter/src/analyzer.dart';
+
+const _desc = r'Specify type arguments for methods.';
+
+const _details = r'''
+
+**DO** specify type arguments for methods.
+
+**GOOD:**
+```
+void m<T>(T t1, T t2) {}
+m<int>(1, 2);
+```
+
+**BAD:**
+```
+void m<T>(T t1, T t2) {}
+m(1, 2);
+```
+
+NOTE: Using the the `@optionalTypeArgs` annotation in the `meta` package, API
+authors can special-case type variables whose type needs to by dynamic but whose
+declaration should be treated as optional. For example, suppose you have a
+`m` function whose type parameter you'd like to treat as optional. Using the
+`@optionalTypeArgs` would look like this:
+
+```
+import 'package:meta/meta.dart';
+
+@optionalTypeArgs
+void m<T>(T t1, T t2) {}
+
+main() {
+  m(1, 2); // OK!
+}
+```
+
+''';
+
+/// The name of `meta` library, used to define analysis annotations.
+String _META_LIB_NAME = 'meta';
+
+/// The name of the top-level variable used to mark a Class as having optional
+/// type args.
+String _OPTIONAL_TYPE_ARGS_VAR_NAME = 'optionalTypeArgs';
+
+bool _isOptionalTypeArgs(Element element) =>
+    element is PropertyAccessorElement &&
+    element.name == _OPTIONAL_TYPE_ARGS_VAR_NAME &&
+    element.library?.name == _META_LIB_NAME;
+
+class AlwaysSpecifyTypeArgumentsForMethods extends LintRule
+    implements NodeLintRule {
+  AlwaysSpecifyTypeArgumentsForMethods()
+      : super(
+            name: 'always_specify_type_arguments_for_methods',
+            description: _desc,
+            details: _details,
+            group: Group.style);
+
+  @override
+  void registerNodeProcessors(NodeLintRegistry registry) {
+    final visitor = new _Visitor(this);
+    registry.addMethodInvocation(this, visitor);
+  }
+}
+
+class _Visitor extends SimpleAstVisitor<void> {
+  final LintRule rule;
+
+  _Visitor(this.rule);
+
+  @override
+  void visitMethodInvocation(MethodInvocation node) {
+    if (node.typeArguments == null) {
+      final element = node.methodName.bestElement;
+      if (element is FunctionTypedElement &&
+          element.typeParameters.isNotEmpty &&
+          !element.metadata.any((a) => _isOptionalTypeArgs(a.element))) {
+        rule.reportLint(node.methodName);
+      }
+    }
+  }
+}

test/rules/always_specify_type_annotations.dart

@@ -0,0 +1,55 @@
+// Copyright (c) 2018, 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.
+
+// test w/ `pub run test -N always_specify_type_annotations`
+
+final x = 1; //LINT [1:5]
+final int xx = 3;
+const y = 2; //LINT
+const int yy = 3;
+
+a(var x) {} //LINT
+b(s) {} //LINT [3:1]
+c(int x) {}
+d(final x) {} //LINT
+e(final int x) {}
+
+main() {
+  var x = ''; //LINT [3:3]
+  for (var i = 0; i < 10; ++i) {  //LINT [8:3]
+    print(i);
+  }
+  List<String> ls = <String>[];
+  ls.forEach((s) => print(s)); //LINT [15:1]
+  for (var l in ls) { //LINT [8:3]
+    print(l);
+  }
+  try {
+    for (final l in ls) { // LINT [10:5]
+      print(l);
+    }
+  } on Exception catch (ex) {
+    print(ex);
+  } catch (e) { // NO warning (https://codereview.chromium.org/1427223002/)
+    print(e);
+  }
+
+  var __; // LINT
+
+  listen((_) { // OK!
+    // ...
+  });
+}
+
+listen(void onData(Object event)) {}
+
+var z; //LINT
+
+class Foo {
+  static var bar; //LINT
+  static final baz  = 1; //LINT
+  static final int bazz = 42;
+  var foo; //LINT
+  Foo(var bar); //LINT [7:3]
+}