Index: src/Virtual/ExpandCasts.cc
===================================================================
--- src/Virtual/ExpandCasts.cc	(revision a5f0529a63fd135c870940242904abe5132d58e6)
+++ src/Virtual/ExpandCasts.cc	(revision a5f0529a63fd135c870940242904abe5132d58e6)
@@ -0,0 +1,150 @@
+//
+// Cforall Version 1.0.0 Copyright (C) 2015 University of Waterloo
+//
+// The contents of this file are covered under the licence agreement in the
+// file "LICENCE" distributed with Cforall.
+//
+// ExpandCasts.cc --
+//
+// Author           : Andrew Beach
+// Created On       : Mon Jul 24 13:59:00 2017
+// Last Modified By : Andrew Beach
+// Last Modified On : Wed Jul 26 14:16:00 2017
+// Update Count     : 0
+//
+
+#include "ExpandCasts.h"
+#include "Common/PassVisitor.h"
+
+namespace Virtual {
+
+	/* Currently virtual depends on the rather brittle name matching between
+	 * a (strict/explicate) virtual type, its vtable type and the vtable
+	 * instance.
+	 * A stronger implementation, would probably keep track of those triads
+	 * and use that information to create better error messages.
+	 */
+
+	std::string get_vtable_name( std::string const & name ) {
+		return name + "_vtable";
+	}
+
+	std::string get_vtable_inst_name( std::string const & name ) {
+		return std::string("_") + get_vtable_name( name ) + "_instance";
+	}
+
+	std::string get_vtable_name_root( std::string const & name ) {
+		return name.substr(0, name.size() - 7 );
+	}
+
+	std::string get_vtable_inst_name_root( std::string const & name ) {
+		return get_vtable_name_root( name.substr(1, name.size() - 10 ) );
+	}
+
+	bool is_vtable_name( std::string const & name ) {
+		return (name.substr( name.size() - 7 ) == "_vtable" );
+	}
+
+	bool is_vtable_inst_name( std::string const & name ) {
+		return 17 < name.size() &&
+			name == get_vtable_inst_name( get_vtable_inst_name_root( name ) );
+	}
+
+	class VirtualCastCore {
+        std::map<std::string, ObjectDecl *> vtable_instances;
+        FunctionDecl *vcast_decl;
+        StructDecl *pvt_decl;
+
+		Type * pointer_to_pvt(int level_of_indirection) {
+			Type * type = new StructInstType(
+				Type::Qualifiers( Type::Const ), pvt_decl );
+			for (int i = 0 ; i < level_of_indirection ; ++i) {
+				type = new PointerType( noQualifiers, type );
+			}
+			return type;
+		}
+
+	public:
+		VirtualCastCore() :
+			vtable_instances(), vcast_decl( nullptr ), pvt_decl( nullptr )
+		{}
+
+		void premutate( FunctionDecl * functionDecl );
+		void premutate( StructDecl * structDecl );
+		void premutate( ObjectDecl * objectDecl );
+
+		Expression * postmutate( VirtualCastExpr * castExpr );
+	};
+
+	void VirtualCastCore::premutate( FunctionDecl * functionDecl ) {
+		if ( (! vcast_decl) && functionDecl->get_statements() &&
+		     functionDecl->get_name() == "__cfa__virtual_cast" ) {
+			vcast_decl = functionDecl;
+		}
+	}
+
+	void VirtualCastCore::premutate( StructDecl * structDecl ) {
+		if ( pvt_decl || ! structDecl->has_body() ) {
+			return;
+		} else if ( structDecl->get_name() == "__cfa__parent_vtable" ) {
+			pvt_decl = structDecl;
+		}
+	}
+
+	void VirtualCastCore::premutate( ObjectDecl * objectDecl ) {
+		if ( is_vtable_inst_name( objectDecl->get_name() ) ) {
+			vtable_instances[objectDecl->get_name()] = objectDecl;
+		}
+	}
+
+	Expression * VirtualCastCore::postmutate( VirtualCastExpr * castExpr ) {
+		assertf( castExpr->get_result(), "Virtual Cast target not found before expansion." );
+
+		//assert( vcast_decl );
+		assert( pvt_decl );
+
+		// May only cast to a pointer or reference type.
+		// A earlier validation should give a syntax error, this is
+		// just to make sure errors don't creep in.
+		PointerType * target_type =
+			dynamic_cast<PointerType *>( castExpr->get_result() );
+        assert( target_type );
+
+		StructInstType * target_struct =
+			dynamic_cast<StructInstType *>( target_type->get_base() );
+		StructDecl * target_decl = target_struct->get_baseStruct();
+
+		std::map<std::string, ObjectDecl *>::iterator found =
+			vtable_instances.find(
+				get_vtable_inst_name( target_decl->get_name() ) );
+		if ( vtable_instances.end() == found ) {
+			assertf( false, "virtual table instance not found." );
+		}
+		ObjectDecl * table = found->second;
+
+		Expression * result = new CastExpr(
+			//new ApplicationExpr( new VariableExpr( vcast_decl ), {
+			new UntypedExpr( new NameExpr( "__cfa__virtual_cast" ), {
+				new CastExpr(
+					new AddressExpr( new VariableExpr( table ) ),
+					pointer_to_pvt(1)
+					),
+				new CastExpr(
+					castExpr->get_arg(),
+					pointer_to_pvt(2)
+					) }
+				),
+			castExpr->get_result()
+			);
+
+		castExpr->set_arg( nullptr );
+		castExpr->set_result( nullptr );
+		delete castExpr;
+		return result;
+	}
+
+	void expandCasts( std::list< Declaration * > & translationUnit ) {
+		PassVisitor<VirtualCastCore> translator;
+		mutateAll( translationUnit, translator );
+	}
+}
Index: src/Virtual/ExpandCasts.h
===================================================================
--- src/Virtual/ExpandCasts.h	(revision a5f0529a63fd135c870940242904abe5132d58e6)
+++ src/Virtual/ExpandCasts.h	(revision a5f0529a63fd135c870940242904abe5132d58e6)
@@ -0,0 +1,27 @@
+//
+// Cforall Version 1.0.0 Copyright (C) 2015 University of Waterloo
+//
+// The contents of this file are covered under the licence agreement in the
+// file "LICENCE" distributed with Cforall.
+//
+// ExpandCasts.h --
+//
+// Author           : Andrew Beach
+// Created On       : Mon Jul 24 13:54:00 2017
+// Last Modified By : Andrew Beach
+// Last Modified On : Tus Jul 25 14:51:00 2017
+// Update Count     : 0
+//
+
+#pragma once
+
+#include <list>
+#include "SynTree/SynTree.h"
+
+namespace Virtual {
+	void expandCasts( std::list< Declaration * > & translationUnit );
+	// Breaks all virtual cast nodes up into translatable nodes.
+
+	// Later this might just set some information so it can happen at CodeGen.
+
+}
Index: src/Virtual/module.mk
===================================================================
--- src/Virtual/module.mk	(revision a5f0529a63fd135c870940242904abe5132d58e6)
+++ src/Virtual/module.mk	(revision a5f0529a63fd135c870940242904abe5132d58e6)
@@ -0,0 +1,17 @@
+######################### -*- Mode: Makefile-Gmake -*- ########################
+##
+## Cforall Version 1.0.0 Copyright (C) 2015 University of Waterloo
+##
+## The contents of this file are covered under the licence agreement in the
+## file "LICENCE" distributed with Cforall.
+##
+## module.mk --
+##
+## Author           : Andrew Beach
+## Created On       : Tus Jul 25 10:18:00 2017
+## Last Modified By : Andrew Beach
+## Last Modified On : Tus Jul 25 10:18:00 2017
+## Update Count     : 0
+###############################################################################
+
+SRC += Virtual/ExpandCasts.cc