Support optional new/const. (#669)

In almost all cases, an elided "new"/"const" is parsed as a normal
method call by analyzer, so the existing formatting behavior for those
does the right thing. The only edge case is a named constructor on a
generic class. That syntax can *only* be a constructor call, so it's
parsed as an instance creation expression.

When we get to that code path, we need to not add an extra space before
the class name if there is no preceding "new" or "const" keyword.

Fix #652.

Author: munificent

CHANGELOG.md

@@ -1,3 +1,7 @@
+# 1.0.10
+
+* Support optional `new`/`const` (#652).
+
 # 1.0.9
 
 * Updated tests. No user-facing changes.

bin/format.dart

@@ -14,7 +14,7 @@ import 'package:dart_style/src/io.dart';
 import 'package:dart_style/src/source_code.dart';
 
 // Note: The following line of code is modified by tool/grind.dart.
-const version = "1.0.9";
+const version = "1.0.10";
 
 void main(List<String> args) {
   var parser = new ArgParser(allowTrailingOptions: true);

lib/src/dart_formatter.dart

@@ -103,7 +103,7 @@ class DartFormatter {
 
     // Parse it.
     var parser = new Parser(stringSource, errorListener);
-    parser.enableAssertInitializer = true;
+    parser.enableOptionalNewAndConst = true;
 
     AstNode node;
     if (source.isCompilationUnit) {

lib/src/source_visitor.dart

@@ -1341,8 +1341,7 @@ class SourceVisitor extends ThrowingAstVisitor {
 
   visitInstanceCreationExpression(InstanceCreationExpression node) {
     builder.startSpan();
-    token(node.keyword);
-    space();
+    token(node.keyword, after: space);
     builder.startSpan(Cost.constructorName);
 
     // Start the expression nesting for the argument list here, in case this

pubspec.lock

@@ -7,7 +7,7 @@ packages:
       name: analyzer
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "0.31.1"
+    version: "0.31.2-alpha.0"
   args:
     dependency: "direct main"
     description:
@@ -91,7 +91,7 @@ packages:
       name: front_end
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "0.1.0-alpha.9"
+    version: "0.1.0-alpha.10"
   glob:
     dependency: transitive
     description:
@@ -161,7 +161,7 @@ packages:
       name: kernel
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "0.3.0-alpha.9"
+    version: "0.3.0-alpha.10"
   logging:
     dependency: transitive
     description:

pubspec.yaml

@@ -1,27 +1,27 @@
 name: dart_style
 # Note: See tool/grind.dart for how to bump the version.
-version: 1.0.9+1
+version: 1.0.10
 author: Dart Team <[email protected]>
 description: Opinionated, automatic Dart source code formatter.
 homepage: https://github.com/dart-lang/dart_style
 environment:
-  sdk: ">=1.8.0 <2.0.0"
+  sdk: '>=1.8.0 <2.0.0'
 dependencies:
-  analyzer: '>=0.30.0 <0.32.0'
+  analyzer: ^0.31.2-alpha.0
   args: '>=0.12.1 <2.0.0'
-  path: '>=1.0.0 <2.0.0'
-  source_span: '>=1.4.0 <2.0.0'
+  path: ^1.0.0
+  source_span: ^1.4.0
 dev_dependencies:
   async: '>=1.0.0 <=3.0.0'
-  browser: '>=0.10.0 <0.11.0'
-  grinder: '^0.8.0'
+  browser: ^0.10.0
+  grinder: ^0.8.0
   js: ^0.6.0
   node_preamble: ^1.0.0
-  pub_semver: '^1.2.3'
-  test: '>=0.12.0 <0.13.0'
-  test_descriptor: "^1.0.0"
-  test_process: "^1.0.0"
-  yaml: '^2.0.0'
+  pub_semver: ^1.2.3
+  test: ^0.12.0
+  test_descriptor: ^1.0.0
+  test_process: ^1.0.0
+  yaml: ^2.0.0
 executables:
   dartfmt: format
   dartformat: format # Allow the old name for compatibility.

test/whitespace/type_arguments.stmt

@@ -14,4 +14,8 @@ new Foo<void, void Function()>();
 >>> void as a generic method type argument
 list.map<   void,void    Function()>();
 <<<
-list.map<void, void Function()>();
+list.map<void, void Function()>();
+>>> named constructor with implicit "new"
+C <  int  ,float>  .named(42);
+<<<
+C<int, float>.named(42);