Remove unneeded generation of default constructors from the dart backend.

tests/compiler/dart2js/backend_dart/dart_backend_test.dart

Index: tests/compiler/dart2js/backend_dart/dart_backend_test.dart
diff --git a/tests/compiler/dart2js/backend_dart/dart_backend_test.dart b/tests/compiler/dart2js/backend_dart/dart_backend_test.dart
index b92152f9ed10acc7270ebd9e2bd04ec5dfcde805..6746b917ecd0affb4433eb50c01cfc5046002e07 100644
--- a/tests/compiler/dart2js/backend_dart/dart_backend_test.dart
+++ b/tests/compiler/dart2js/backend_dart/dart_backend_test.dart
@@ -878,7 +878,24 @@ main() {
   testDart2Dart(src, expectedResult: expectedResult);
 }
 
-testUnresolvedNamedConstructor() {
+testUnresolvedNamedConstructor1() {

[sigurdm, 2014/09/02 09:14:06]

Maybe it is nicer to keep the class alive with a static:

class A {
  A() {}
  static foo() {}
}

main() {
  A.foo();
  new A.named()
}

==>

class A {
  static foo() {}
}

main() {
  A.foo();
  new unresolved();
}

+  var src = '''
+class A {
+}
+
+main() {
+  new A.named();
+}
+''';
+  var expectedResult = """
+main() {
+  new Unresolved();
+}
+""";
+  testDart2Dart(src, expectedResult: expectedResult);
+}
+
+testUnresolvedNamedConstructor2() {
   var src = '''
 class A {
   A() {}
@@ -895,7 +912,7 @@ class A {
 }
 main() {
   new A();
-  new Unresolved_A();
+  new Unresolved();
 }
 """;
   testDart2Dart(src, expectedResult: expectedResult);
@@ -929,5 +946,6 @@ main() {
   testDeclarationTypePlaceholders();
   testPlatformLibraryMemberNamesAreFixed();
   testConflictsWithCoreLib();
-  testUnresolvedNamedConstructor();
+  testUnresolvedNamedConstructor1();
+  testUnresolvedNamedConstructor2();
 }

[sigurdm, 2014/09/02 09:14:06]

Could also make a language-test (might already exist):

class A {
  A.named();
  static foo() {}
}

main() {
  A.foo();
  Expect.throws(() => new A());
}