Bug 342007

Comment 1 Robert von Massow 2011-04-06 08:22:36 EDT

(In reply to comment #0)
> Build Identifier: N201104060452
> 
> The following expression is a valid Xtend snippet (according to the validation
> and specification):
> 
> testBug0() {
>     val it0 = newArrayList() as List<List<String>>;
> }
> 
> The compiled result:
> public void testBug0() {
>   ArrayList<Object> _newArrayList = CollectionLiterals.<Object>newArrayList();
>   final List<String> it0 = ((java.util.List<java.lang.String>) _newArrayList);
> }
> 
> has the following error:
> Cannot cast from ArrayList<Object> to List<String>
> 
> Reproducible: Always

Sorry, wrong Xtend snippet, I actually used the following:
testBug0() {
	val it0 = newArrayList() as List<String>;
}

Comment 2 Sven Efftinge 2011-04-08 03:36:42 EDT

We need to fully implement what is defined in the Java Language Specification §5.5:

http://java.sun.com/docs/books/jls/third_edition/html/conversions.html#5.5

Some of the conversions are already supported by the ConformanceComputer, but we still need to have 
- the narrowing primitive  conversion http://java.sun.com/docs/books/jls/third_edition/html/conversions.html#25363
- the narrowing reference conversion
http://java.sun.com/docs/books/jls/third_edition/html/conversions.html#25379
- unchecked conversion
http://java.sun.com/docs/books/jls/third_edition/html/conversions.html#190772

Comment 3 Sebastian Zarnekow 2011-05-04 06:11:33 EDT

Preliminary scheduled for 2.0RC1

Comment 4 Sven Efftinge 2011-05-04 09:59:06 EDT

postponed to SR1

Comment 5 Sven Efftinge 2011-09-26 05:52:59 EDT

later

Comment 6 Sebastian Zarnekow 2011-11-28 05:05:41 EST

see also bug 364931

Comment 7 Sven Efftinge 2012-01-31 06:12:30 EST

*** Bug 362239 has been marked as a duplicate of this bug. ***

Comment 8 Sven Efftinge 2012-04-26 11:46:33 EDT

*** Bug 377771 has been marked as a duplicate of this bug. ***

Comment 9 Sven Efftinge 2012-11-08 08:12:59 EST

*** Bug 381152 has been marked as a duplicate of this bug. ***

Comment 10 Dennis Huebner 2013-02-13 02:47:54 EST

Still valid with new TS

Comment 11 Sebastian Zarnekow 2013-02-13 03:15:38 EST

We'll have to introduce the notion of 'proofable distinct types' to support full cast validation.

Comment 12 Sven Efftinge 2013-03-06 04:15:37 EST

*** Bug 364931 has been marked as a duplicate of this bug. ***

Comment 13 Sven Efftinge 2013-03-06 04:15:47 EST

*** Bug 389872 has been marked as a duplicate of this bug. ***

Comment 14 Sven Efftinge 2013-09-13 04:26:17 EDT

*** Bug 409238 has been marked as a duplicate of this bug. ***

Comment 15 Karsten Becker 2013-09-17 11:16:10 EDT

Probably the same as comment #0:
import java.util.List

class B extends A{}
class A {}
class Testcase {
	def main() {
		val List<A> a={}
		print(a as List<B>)
	}
	def print(List<B> bs){}
}

Comment 16 Joerg Reichert 2014-05-04 02:38:08 EDT

Invalid cast of CharSequence to String isn't discovered as well:

class StringCastBug {
	
   def test() {
       '''Test''' as String
   }
}

Comment 17 Jan Koehnlein 2015-09-09 09:58:33 EDT

Another example

  interface IBar<C extends IBar<C>> {}
	
  class Bar implements IBar<Bar> {}
	
  class Foo<T extends IBar<T>> {}
	
  class SubFoo<T extends IBar<T>> extends Foo<T> {}
	
  class Baz {
    def baz(Foo<Bar> keyRange) {
      keyRange as SubFoo<?>  
                     // Error: Cannot cast from Foo<Bar> to SubFoo<?>
    }
  }