exp_ch4.adb (Expand_N_Type_Conversion): Handle missing interface type conversion.

2006-10-31  Javier Miranda  <miranda@adacore.com>
	    Ed Schonberg  <schonberg@adacore.com>
	    Bob Duff  <duff@adacore.com>
	    Gary Dismukes  <dismukes@adacore.com>
	    Robert Dewar  <dewar@adacore.com>
        
        * exp_ch4.adb (Expand_N_Type_Conversion): Handle missing interface type
	conversion.
        (Expand_N_In): Do validity checks on range
	(Expand_Selected_Component): Use updated for of Denotes_Discriminant.
	(Expand_N_Allocator): For "new T", if the object is constrained by
	discriminant defaults, allocate the right amount of memory, rather than
	the maximum for type T.
	(Expand_Allocator_Expression): Suppress the call to Remove_Side_Effects
	when the allocator is initialized by a build-in-place call, since the
	allocator is already rewritten as a reference to the function result,
	and this prevents an unwanted duplication of the function call.
	Add with and use of Exp_Ch6.
	(Expand_Allocator_Expresssion): Check for an allocator whose expression
	is a call to build-in-place function and apply
	Make_Build_In_Place_Call_In_Allocator to the call (for both tagged and
	untagged designated types).
	(Expand_N_Unchecked_Type_Conversion): Do not do integer literal
	optimization if source or target is biased.
	(Expand_N_Allocator): Add comments for case of an allocator within a
	function that returns an anonymous access type designating tasks.
	(Expand_N_Allocator): apply discriminant checks for access
	discriminants of anonymous access types (AI-402, AI-416)

From-SVN: r118257