In gcc/objc/:
2010-11-29  Nicola Pero  <nicola.pero@meta-innovation.com>

	* objc-act.c (start_class): When a class is reimplemented,
	generate an error and avoid adding the class to the list of
	implemented classes again, but do not return error_mark_node.

In gcc/testsuite/:
2010-11-29  Nicola Pero  <nicola.pero@meta-innovation.com>

	* objc.dg/duplicate-class-1.m: New.
	* obj-c++.dg/duplicate-class-1.mm: New.

From-SVN: r167270