2003-05-14 Ravi Pratap <ravi@ximian.com>

2003-05-14  Ravi Pratap  <ravi@ximian.com>

	* enum.cs (ImplicitConversionExists) : Rename to
	ImplicitEnumConversionExists to remove ambiguity.

	* ecore.cs (NullCast): New type of cast expression class which
	basically is very similar to EmptyCast with the difference being
	it still is a constant since it is used only to cast a null to
	something else
	(eg. (string) null)

	* convert.cs (ImplicitReferenceConversion): When casting a null
	literal, we return a NullCast.

	* literal.cs (NullLiteralTyped): Remove - I don't see why this
	should be around anymore.

	The renaming (reported was slightly wrong). Corrections:

	ConvertImplicitStandard -> ImplicitConversionStandard
	ConvertExplicitStandard -> ExplicitConversionStandard

	* expression.cs (StaticCallExpr.MakeSimpleCall): Resolve arguments
	before passing them in !

	* convert.cs (ImplicitConversionStandard): When comparing for
	equal expr and target types, ensure that expr is not a
	NullLiteral.

	In general, we must not be checking (expr_type ==
	target_type) in the top level conversion methods
	(ImplicitConversion, ExplicitConversion etc). This checking is
	done in the methods that they delegate to.

svn path=/trunk/mcs/; revision=14773