2006-11-30 Marek Safar <marek.safar@gmail.com>

2006-11-30  Marek Safar  <marek.safar@gmail.com>

	Correct unary operators implementation (part I)
	Also fixes #80026

	* cfold.cs (Error_CompileTimeOverflow): Made internal

	* const.cs (IConstant): Changed to use reference to constant and
	not constant itself.
	Updated IConstant implementations.

	* constant.cs (CreateConstant): New factory method.
	Updated IConstant implementation.

	* convert.cs (ImplicitStandardConversionExists): Uses compiler Equals.

	* ecore.cs: Updated to use CreateConstantReference.

	* enum.cs: Reflects IConstant changes.

	* expression.cs (Unary): Reimplemented +,-,~ to conform C# standard.

	* literal.cs (NullConstant): Change to be independently usable.

Second try :-(

svn path=/trunk/mcs/; revision=68785