Fix for issue 5223 : Import 'dart:core' implicitly only if it has not been

Fix for issue 5223 : Import 'dart:core' implicitly only if it has not been
already explicitly imported in the script.
Committed: https://code.google.com/p/dart/source/detail?r=12673

[hausner, 2012-09-20 16:18:16]

LGTM but I think a more elegant solution would have been to add a method bool
Library::ImportsCore(). Then, in the parser, after the import clauses are
processed, you can write 

if (!library_.ImportsCore()) { .... }

[siva, 2012-09-20 21:12:36]

Added an ImportsCoreLibrary function in library as suggested
and also ensure that import with a prefix is also considered
as having imported dart:core. Added a new test case.

PTAL

[hausner, 2012-09-20 22:25:32]

Something is still importing dart:core without a prefix automatically. The test
that imports dart:core with a prefix should actually fail.

https://chromiumcodereview.appspot.com/10949028/diff/4003/tests/language/impo...
File tests/language/import_core_prefix-test.dart (right):

https://chromiumcodereview.appspot.com/10949028/diff/4003/tests/language/impo...
tests/language/import_core_prefix-test.dart:10: var test = new
Map<int,String>();
I don't think new Map() should work in this case. You import core with a prefix,
so you should have to write new mycore.Map().

[siva, 2012-09-21 00:42:35]

https://chromiumcodereview.appspot.com/10949028/diff/4003/tests/language/impo...
File tests/language/import_core_prefix-test.dart (right):

https://chromiumcodereview.appspot.com/10949028/diff/4003/tests/language/impo...
tests/language/import_core_prefix-test.dart:10: var test = new
Map<int,String>();
Good point. I had named the file import_core_prefix-test.dart and hence it was
not getting picked up by the test harness. Fixed the file name verified that
these were flagged as errors and fixed them by adding the prefix.

On 2012/09/20 22:25:32, hausner wrote:
> I don't think new Map() should work in this case. You import core with a
prefix,
> so you should have to write new mycore.Map().