Fix a number of lints, disable a couple of lints that cannot be easily fixed (flutter#97)

Author: kevmoo

.travis.yml

@@ -1,7 +1,7 @@
 language: dart
 
 dart:
-  - 2.1.0
+  - 2.2.0
   - dev
 
 dart_task:
@@ -12,7 +12,7 @@ matrix:
   include:
     - dart: dev
       dartanalyzer: --fatal-infos --fatal-warnings .
-    - dart: 2.1.0
+    - dart: 2.2.0
       dartanalyzer: --fatal-warnings .
     - dart: dev
       dart_task: dartfmt

analysis_options.yaml

@@ -1,5 +1,10 @@
 include: package:pedantic/analysis_options.yaml
 
+analyzer:
+  errors:
+    always_declare_return_types: ignore # 318
+    omit_local_variable_types: ignore # 48
+
 linter:
   rules:
   - prefer_equal_for_default_values

example/call_parser.dart

@@ -15,16 +15,15 @@ const _default = css.PreprocessorOptions(
 /// tests (by default) will ensure that the CSS is really valid.
 StyleSheet parseCss(String cssInput,
     {List<css.Message> errors, css.PreprocessorOptions opts}) {
-  return css.parse(cssInput,
-      errors: errors, options: opts == null ? _default : opts);
+  return css.parse(cssInput, errors: errors, options: opts ?? _default);
 }
 
 // Pretty printer for CSS.
 var emitCss = CssPrinter();
 String prettyPrint(StyleSheet ss) =>
     (emitCss..visitTree(ss, pretty: true)).toString();
 
-main() {
+void main() {
   var errors = <css.Message>[];
 
   // Parse a simple stylesheet.
@@ -42,7 +41,7 @@ main() {
       errors: errors);
 
   if (errors.isNotEmpty) {
-    print("Got ${errors.length} errors.\n");
+    print('Got ${errors.length} errors.\n');
     for (var error in errors) {
       print(error);
     }
@@ -60,7 +59,7 @@ main() {
       errors: errors);
 
   if (errors.isNotEmpty) {
-    print("Got ${errors.length} errors.\n");
+    print('Got ${errors.length} errors.\n');
     for (var error in errors) {
       print(error);
     }
@@ -74,7 +73,7 @@ main() {
   stylesheetError = parseCss('# div1 { color: red; }', errors: errors);
 
   if (errors.isNotEmpty) {
-    print("Detected ${errors.length} problem in checked mode.\n");
+    print('Detected ${errors.length} problem in checked mode.\n');
     for (var error in errors) {
       print(error);
     }
@@ -87,7 +86,7 @@ main() {
   print('   ======================');
   var selectorAst = css.selector('#div .foo', errors: errors);
   if (errors.isNotEmpty) {
-    print("Got ${errors.length} errors.\n");
+    print('Got ${errors.length} errors.\n');
     for (var error in errors) {
       print(error);
     }