Migrate the renderers to NNBD (#2816)

* Migrate renderers

* dartfmt

Author: jcollins-g

lib/src/model/language_feature.dart

@@ -2,8 +2,6 @@
 // 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.
 
-// @dart=2.9
-
 import 'package:dartdoc/src/render/language_feature_renderer.dart';
 
 const Map<String, String> _featureDescriptions = {
@@ -18,11 +16,11 @@ const Map<String, String> _featureUrls = {
 /// the user that the documentation should be specially interpreted.
 class LanguageFeature {
   /// The description of this language feature.
-  String get featureDescription => _featureDescriptions[name];
+  String? get featureDescription => _featureDescriptions[name];
 
   /// A URL containing more information about this feature or `null` if there
   /// is none.
-  String /*?*/ get featureUrl => _featureUrls[name];
+  String? get featureUrl => _featureUrls[name];
 
   /// The rendered label for this language feature.
   String get featureLabel => _featureRenderer.renderLanguageFeatureLabel(this);

lib/src/render/category_renderer.dart

@@ -2,8 +2,6 @@
 // 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.
 
-// @dart=2.9
-
 import 'package:dartdoc/src/model/category.dart';
 
 /// A renderer for a [Category].

lib/src/render/documentation_renderer.dart

@@ -2,16 +2,13 @@
 // 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.
 
-// @dart=2.9
-
 import 'package:html/parser.dart' show parse;
 import 'package:markdown/markdown.dart' as md;
-import 'package:meta/meta.dart';
 
 abstract class DocumentationRenderer {
   DocumentationRenderResult render(
     List<md.Node> nodes, {
-    @required bool processFullDocs,
+    required bool processFullDocs,
   });
 }
 
@@ -21,7 +18,7 @@ class DocumentationRendererHtml implements DocumentationRenderer {
   @override
   DocumentationRenderResult render(
     List<md.Node> nodes, {
-    @required bool processFullDocs,
+    required bool processFullDocs,
   }) {
     if (nodes.isEmpty) {
       return DocumentationRenderResult.empty;
@@ -51,11 +48,10 @@ class DocumentationRendererHtml implements DocumentationRenderer {
     if (processFullDocs) {
       // `trim` fixes an issue with line ending differences between Mac and
       // Windows.
-      asHtml = asHtmlDocument.body.innerHtml?.trim();
+      asHtml = (asHtmlDocument.body?.innerHtml ?? '').trim();
     }
-    var asOneLiner = asHtmlDocument.body.children.isEmpty
-        ? ''
-        : asHtmlDocument.body.children.first.innerHtml;
+    var children = asHtmlDocument.body?.children ?? [];
+    var asOneLiner = children.isEmpty ? '' : children.first.innerHtml;
 
     return DocumentationRenderResult(asHtml: asHtml, asOneLiner: asOneLiner);
   }
@@ -68,5 +64,5 @@ class DocumentationRenderResult {
   final String asOneLiner;
 
   const DocumentationRenderResult(
-      {@required this.asHtml, @required this.asOneLiner});
+      {required this.asHtml, required this.asOneLiner});
 }

lib/src/render/enum_field_renderer.dart

@@ -2,8 +2,6 @@
 // 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.
 
-// @dart=2.9
-
 import 'package:dartdoc/src/model/enum.dart';
 
 abstract class EnumFieldRenderer {

lib/src/render/feature_renderer.dart

@@ -2,8 +2,6 @@
 // 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.
 
-// @dart=2.9
-
 import 'dart:convert';
 
 import 'package:dartdoc/src/model/annotation.dart';

lib/src/render/language_feature_renderer.dart

@@ -2,8 +2,6 @@
 // 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.
 
-// @dart=2.9
-
 import 'package:dartdoc/src/model/language_feature.dart';
 
 /// A renderer for a [LanguageFeature].

lib/src/render/model_element_renderer.dart

@@ -2,8 +2,6 @@
 // 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.
 
-// @dart=2.9
-
 import 'package:dartdoc/src/model/feature.dart';
 import 'package:dartdoc/src/model/model_element.dart';
 

lib/src/render/parameter_renderer.dart

@@ -2,14 +2,10 @@
 // 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.
 
-// @dart=2.9
-
 import 'dart:convert';
 
-import 'package:analyzer/dart/element/type.dart';
 import 'package:dartdoc/src/element_type.dart';
 import 'package:dartdoc/src/model/parameter.dart';
-import 'package:meta/meta.dart' as meta;
 
 /// Render HTML in an extended vertical format using <ol> tag.
 class ParameterRendererHtmlList extends ParameterRendererHtml {
@@ -136,7 +132,7 @@ abstract class ParameterRenderer {
 
   void _renderLinkedParameterSublist(
       List<Parameter> parameters, StringBuffer output,
-      {@meta.required bool trailingComma,
+      {required bool trailingComma,
       String openBracket = '',
       String closeBracket = '',
       bool showMetadata = true,
@@ -164,8 +160,8 @@ abstract class ParameterRenderer {
 
   String _renderParam(
     Parameter param, {
-    @meta.required String prefix,
-    @meta.required String suffix,
+    required String prefix,
+    required String suffix,
     bool showMetadata = true,
     bool showNames = true,
   }) {
@@ -195,8 +191,7 @@ abstract class ParameterRenderer {
       buf.write(typeName(returnTypeName));
       if (showNames) {
         buf.write(' ${parameterName(param.name)}');
-      } else if (paramModelType.isTypedef ||
-          paramModelType.type is FunctionType) {
+      } else {
         buf.write(' ${parameterName(paramModelType.name)}');
       }
       if (!paramModelType.isTypedef && paramModelType is DefinedElementType) {
@@ -208,7 +203,7 @@ abstract class ParameterRenderer {
         buf.write(')');
         buf.write(paramModelType.nullabilitySuffix);
       }
-      if (!paramModelType.isTypedef && paramModelType.type is FunctionType) {
+      if (!paramModelType.isTypedef) {
         buf.write('(');
         buf.write(renderLinkedParams(paramModelType.parameters,
             showMetadata: showMetadata, showNames: showNames));

lib/src/render/source_code_renderer.dart

@@ -2,8 +2,6 @@
 // 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.
 
-// @dart=2.9
-
 import 'dart:convert';
 
 /// Renderer for source code snippets extracted from source files.

lib/src/render/template_renderer.dart

@@ -2,8 +2,6 @@
 // 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.
 
-// @dart=2.9
-
 abstract class LayoutRenderer {
   String composeLayoutTitle(String name, String kind, bool isDeprecated);
 }

lib/src/render/type_parameters_renderer.dart

@@ -2,8 +2,6 @@
 // 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.
 
-// @dart=2.9
-
 import 'package:dartdoc/src/model/type_parameter.dart';
 
 abstract class TypeParametersRenderer {

lib/src/render/typedef_renderer.dart

@@ -2,8 +2,6 @@
 // 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.
 
-// @dart=2.9
-
 import 'package:dartdoc/src/model/type_parameter.dart';
 import 'package:dartdoc/src/model/typedef.dart';