Error when class implements implicit interface

[DartBot]

This issue was originally filed by karl.k...@gmail.com

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In bleeding_edge as of today (Oct. 27), I get an error running this:

class A {}
class B implements A {}
main () {
  new B();
}

krukow:~$ dart_bin scratchpad/1.dart
Class name 'A' used where interface expected

I would expect B implements A to mean "B implements the implicit interface of A".

[DartBot]

This comment was originally written by zundel@google.com

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from Section 7: Classes

The interface of class C is an implicit interface that declares instance mem-
bers that correspond to the instance members declared by C, and whose direct
superinterfaces are the direct superinterfaces of C (7.9). When a class name
appears as a type or interface, that name denotes the interface of the class.

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Added Area-Compiler, Triaged labels.

[jtmcdole]

Added Fixed label.