Index: src/ResolvExpr/CurrentObject.cc
===================================================================
--- src/ResolvExpr/CurrentObject.cc	(revision c6b4432f5c6c6679b981f5a6bded51ad30ac00d9)
+++ src/ResolvExpr/CurrentObject.cc	(revision 8c13ca8142cd08bd07508ef52c311b80b56b6d46)
@@ -41,567 +41,573 @@
 
 namespace ast {
-	/// Iterates members of a type by initializer.
-	class MemberIterator {
-	public:
-		virtual ~MemberIterator() {}
-
-		/// Internal set position based on iterator ranges.
-		virtual void setPosition(
-			std::deque< ptr< Expr > >::const_iterator it,
-			std::deque< ptr< Expr > >::const_iterator end ) = 0;
-
-		/// Walks the current object using the given designators as a guide.
-		void setPosition( const std::deque< ptr< Expr > > & designators ) {
-			setPosition( designators.begin(), designators.end() );
-		}
-
-		/// Retrieve the list of possible (Type,Designation) pairs for the
-		/// current position in the current object.
-		virtual std::deque< InitAlternative > operator* () const = 0;
-
-		/// True if the iterator is not currently at the end.
-		virtual operator bool() const = 0;
-
-		/// Moves the iterator by one member in the current object.
-		virtual MemberIterator & bigStep() = 0;
-
-		/// Moves the iterator by one member in the current subobject.
-		virtual MemberIterator & smallStep() = 0;
-
-		/// The type of the current object.
-		virtual const Type * getType() = 0;
-
-		/// The type of the current subobject.
-		virtual const Type * getNext() = 0;
-
-		/// Helper for operator*; aggregates must add designator to each init
-		/// alternative, but adding designators in operator* creates duplicates.
-		virtual std::deque< InitAlternative > first() const = 0;
-	};
-
-	/// create a new MemberIterator that traverses a type correctly
-	MemberIterator * createMemberIterator( const CodeLocation & loc, const Type * type );
-
-	/// Iterates "other" types (e.g. basic, pointer) which do not change at list initializer entry
-	class SimpleIterator final : public MemberIterator {
-		CodeLocation location;
-		const Type * type = nullptr;
-	public:
-		SimpleIterator( const CodeLocation & loc, const Type * t ) : location( loc ), type( t ) {}
-
-		void setPosition(
-			std::deque< ptr< Expr > >::const_iterator begin,
-			std::deque< ptr< Expr > >::const_iterator end
-		) override {
-			if ( begin != end ) {
-				SemanticError( location, "Un-designated initializer given non-empty designator" );
-			}
-		}
-
-		std::deque< InitAlternative > operator* () const override { return first(); }
-
-		operator bool() const override { return type; }
-
-		SimpleIterator & bigStep() override { return smallStep(); }
-		SimpleIterator & smallStep() override {
-			type = nullptr;  // empty on increment because no members
-			return *this;
-		}
-
-		const Type * getType() override { return type; }
-
-		const Type * getNext() override { return type; }
-
-		std::deque< InitAlternative > first() const override {
-			if ( type ) return { InitAlternative{ type, new Designation{ location } } };
-			return {};
-		}
-	};
-
-	/// Iterates over an indexed type:
-	class IndexIterator : public MemberIterator {
-	protected:
-		CodeLocation location;
-		size_t index = 0;
-		size_t size = 0;
-		std::unique_ptr<MemberIterator> memberIter;
-	public:
-		IndexIterator( const CodeLocation & loc, size_t size ) :
-			location( loc ), size( size )
-		{}
-
-		void setPosition( const Expr * expr ) {
-			// need to permit integer-constant-expressions, including: integer constants,
-			// enumeration constants, character constants, sizeof expressions, alignof expressions,
-			// cast expressions
-
-			auto arg = eval( expr );
-			assertf( arg.hasKnownValue, "Non-evaluable expression made it to IndexIterator" );
-			index = arg.knownValue;
-
-			// if ( auto constExpr = dynamic_cast< const ConstantExpr * >( expr ) ) {
-			// 	try {
-			// 		index = constExpr->intValue();
-			// 	} catch ( SemanticErrorException & ) {
-			// 		SemanticError( expr, "Constant expression of non-integral type in array designator: " );
-			// 	}
-			// } else if ( auto castExpr = dynamic_cast< const CastExpr * >( expr ) ) {
-			// 	setPosition( castExpr->arg );
-			// } else if ( dynamic_cast< const SizeofExpr * >( expr ) || dynamic_cast< const AlignofExpr * >( expr ) ) {
-			// 	index = 0;
-			// } else {
-			// 	assertf( false,	"2 bad designator given to ArrayIterator: %s", toString( expr ).c_str() );
-			// }
-		}
-
-		void setPosition(
-			std::deque<ast::ptr<ast::Expr>>::const_iterator begin,
-			std::deque<ast::ptr<ast::Expr>>::const_iterator end
-		) override {
-			if ( begin == end ) return;
-
-			setPosition( *begin );
-			memberIter->setPosition( ++begin, end );
-		}
-
-		std::deque< InitAlternative > operator* () const override { return first(); }
-
-		operator bool() const override { return index < size; }
-	};
-
-	/// Iterates over the members of array types:
-	class ArrayIterator final : public IndexIterator {
-		const ArrayType * array = nullptr;
-		const Type * base = nullptr;
-
-		size_t getSize( const Expr * expr ) {
-			auto res = eval( expr );
-			if ( !res.hasKnownValue ) {
-				SemanticError( location, toString( "Array designator must be a constant expression: ", expr ) );
-			}
-			return res.knownValue;
-		}
-
-	public:
-		ArrayIterator( const CodeLocation & loc, const ArrayType * at ) :
-				IndexIterator( loc, getSize( at->dimension) ),
-				array( at ), base( at->base ) {
-			PRINT( std::cerr << "Creating array iterator: " << at << std::endl; )
-			memberIter.reset( createMemberIterator( loc, base ) );
-			if ( at->isVarLen ) {
-				SemanticError( location, at, "VLA initialization does not support @=: " );
-			}
-		}
-
-		ArrayIterator & bigStep() override {
-			PRINT( std::cerr << "bigStep in ArrayIterator (" << index << "/" << size << ")" << std::endl; )
-			++index;
-			memberIter.reset( index < size ? createMemberIterator( location, base ) : nullptr );
-			return *this;
-		}
-
-		ArrayIterator & smallStep() override {
-			PRINT( std::cerr << "smallStep in ArrayIterator (" << index << "/" << size << ")" << std::endl; )
-			if ( memberIter ) {
-				PRINT( std::cerr << "has member iter: " << *memberIter << std::endl; )
-				memberIter->smallStep();
-				if ( *memberIter ) {
-					PRINT( std::cerr << "has valid member iter" << std::endl; )
-					return *this;
-				}
-			}
-			return bigStep();
-		}
-
-		const Type * getType() override { return array; }
-
-		const Type * getNext() override { return base; }
-
-		std::deque< InitAlternative > first() const override {
-			PRINT( std::cerr << "first in ArrayIterator (" << index << "/" << size << ")" << std::endl; )
-			if ( memberIter && *memberIter ) {
-				std::deque< InitAlternative > ret = memberIter->first();
-				for ( InitAlternative & alt : ret ) {
-					alt.designation.get_and_mutate()->designators.emplace_front( ConstantExpr::from_ulong( location, index ) );
-				}
-				return ret;
-			}
-			return {};
-		}
-	};
-
-	class AggregateIterator : public MemberIterator {
-	protected:
-		using MemberList = std::vector< ptr< Decl > >;
-
-		CodeLocation location;
-		std::string kind;  // for debug
-		std::string name;
-		const Type * inst;
-		const MemberList & members;
-		MemberList::const_iterator curMember;
-		bool atbegin = true;  // false at first {small,big}Step
-		const Type * curType = nullptr;
-		std::unique_ptr< MemberIterator > memberIter = nullptr;
-		TypeSubstitution sub;
-
-		bool init() {
-			PRINT( std::cerr << "--init()--" << members.size() << std::endl; )
-			if ( curMember != members.end() ) {
-				if ( auto field = curMember->as< ObjectDecl >() ) {
-					PRINT( std::cerr << "incremented to field: " << field << std::endl; )
-					curType = field->get_type();
-					memberIter.reset( createMemberIterator( location, curType ) );
-					return true;
-				}
-			}
-			return false;
-		}
-
-		AggregateIterator(
-			const CodeLocation & loc, const std::string k, const std::string & n, const Type * i,
-			const MemberList & ms )
-		: location( loc ), kind( k ), name( n ), inst( i ), members( ms ), curMember( ms.begin() ),
-		  sub( genericSubstitution( i ) ) {
-			PRINT( std::cerr << "Creating " << kind << "(" << name << ")"; )
-			init();
-		}
-
-	public:
-		void setPosition(
-			std::deque< ptr< Expr > >::const_iterator begin,
-			std::deque< ptr< Expr > >::const_iterator end
-		) final {
-			if ( begin == end ) return;
-
-			if ( auto varExpr = begin->as< VariableExpr >() ) {
-				for ( curMember = members.begin(); curMember != members.end(); ++curMember ) {
-					if ( *curMember != varExpr->var ) continue;
-
-					++begin;
-
-					memberIter.reset( createMemberIterator( location, varExpr->result ) );
-					curType = varExpr->result;
-					atbegin = curMember == members.begin() && begin == end;
-					memberIter->setPosition( begin, end );
-					return;
-				}
-				assertf( false, "could not find member in %s: %s", kind.c_str(), toString( varExpr ).c_str() );
-			} else {
-				assertf( false, "1 bad designator given to %s: %s", kind.c_str(), toString( *begin ).c_str() );
-			}
-		}
-
-		std::deque< InitAlternative > operator* () const final {
-			if ( memberIter && *memberIter ) {
-				std::deque< InitAlternative > ret = memberIter->first();
-				PRINT( std::cerr << "sub: " << sub << std::endl; )
-				for ( InitAlternative & alt : ret ) {
-					PRINT( std::cerr << "iterating and adding designators" << std::endl; )
-					alt.designation.get_and_mutate()->designators.emplace_front(
-						new VariableExpr{ location, curMember->strict_as< ObjectDecl >() } );
-					// need to substitute for generic types so that casts are to concrete types
-					alt.type = shallowCopy(alt.type.get());
-					PRINT( std::cerr << "  type is: " << alt.type; )
-					sub.apply( alt.type ); // also apply to designation??
-					PRINT( std::cerr << " ==> " << alt.type << std::endl; )
-				}
-				return ret;
-			}
-			return {};
-		}
-
-		AggregateIterator & smallStep() final {
-			PRINT( std::cerr << "smallStep in " << kind << std::endl; )
-			atbegin = false;
-			if ( memberIter ) {
-				PRINT( std::cerr << "has member iter, incrementing..." << std::endl; )
-				memberIter->smallStep();
-				if ( *memberIter ) {
-					PRINT( std::cerr << "success!" << std::endl; )
-					return *this;
-				}
-			}
-			return bigStep();
-		}
-
-		AggregateIterator & bigStep() override = 0;
-
-		const Type * getType() final { return inst; }
-
-		const Type * getNext() final {
-			bool hasMember = memberIter && *memberIter;
-			return hasMember ? memberIter->getType() : nullptr;
-		}
-
-		std::deque< InitAlternative > first() const final {
-			std::deque< InitAlternative > ret;
-			PRINT( std::cerr << "first " << kind << std::endl; )
-			if ( memberIter && *memberIter ) {
-				PRINT( std::cerr << "adding children" << std::endl; )
-				ret = memberIter->first();
-				for ( InitAlternative & alt : ret ) {
-					PRINT( std::cerr << "iterating and adding designators" << std::endl; )
-					alt.designation.get_and_mutate()->designators.emplace_front(
-						new VariableExpr{ location, curMember->strict_as< ObjectDecl >() } );
-				}
-			}
-			if ( atbegin ) {
-				// only add self if at the very beginning of the structure
-				PRINT( std::cerr << "adding self" << std::endl; )
-				ret.emplace_front( inst, new Designation{ location } );
+
+/// Iterates members of a type by initializer.
+class MemberIterator {
+public:
+	virtual ~MemberIterator() {}
+
+	/// Internal set position based on iterator ranges.
+	virtual void setPosition(
+		std::deque< ptr< Expr > >::const_iterator it,
+		std::deque< ptr< Expr > >::const_iterator end ) = 0;
+
+	/// Walks the current object using the given designators as a guide.
+	void setPosition( const std::deque< ptr< Expr > > & designators ) {
+		setPosition( designators.begin(), designators.end() );
+	}
+
+	/// Retrieve the list of possible (Type,Designation) pairs for the
+	/// current position in the current object.
+	virtual std::deque< InitAlternative > operator* () const = 0;
+
+	/// True if the iterator is not currently at the end.
+	virtual operator bool() const = 0;
+
+	/// Moves the iterator by one member in the current object.
+	virtual MemberIterator & bigStep() = 0;
+
+	/// Moves the iterator by one member in the current subobject.
+	virtual MemberIterator & smallStep() = 0;
+
+	/// The type of the current object.
+	virtual const Type * getType() = 0;
+
+	/// The type of the current subobject.
+	virtual const Type * getNext() = 0;
+
+	/// Helper for operator*; aggregates must add designator to each init
+	/// alternative, but adding designators in operator* creates duplicates.
+	virtual std::deque< InitAlternative > first() const = 0;
+};
+
+namespace {
+
+/// create a new MemberIterator that traverses a type correctly
+MemberIterator * createMemberIterator( const CodeLocation & loc, const Type * type );
+
+/// Iterates "other" types (e.g. basic, pointer) which do not change at list initializer entry
+class SimpleIterator final : public MemberIterator {
+	CodeLocation location;
+	const Type * type = nullptr;
+public:
+	SimpleIterator( const CodeLocation & loc, const Type * t ) : location( loc ), type( t ) {}
+
+	void setPosition(
+		std::deque< ptr< Expr > >::const_iterator begin,
+		std::deque< ptr< Expr > >::const_iterator end
+	) override {
+		if ( begin != end ) {
+			SemanticError( location, "Un-designated initializer given non-empty designator" );
+		}
+	}
+
+	std::deque< InitAlternative > operator* () const override { return first(); }
+
+	operator bool() const override { return type; }
+
+	SimpleIterator & bigStep() override { return smallStep(); }
+	SimpleIterator & smallStep() override {
+		type = nullptr;  // empty on increment because no members
+		return *this;
+	}
+
+	const Type * getType() override { return type; }
+
+	const Type * getNext() override { return type; }
+
+	std::deque< InitAlternative > first() const override {
+		if ( type ) return { InitAlternative{ type, new Designation{ location } } };
+		return {};
+	}
+};
+
+/// Iterates over an indexed type:
+class IndexIterator : public MemberIterator {
+protected:
+	CodeLocation location;
+	size_t index = 0;
+	size_t size = 0;
+	std::unique_ptr<MemberIterator> memberIter;
+public:
+	IndexIterator( const CodeLocation & loc, size_t size ) :
+		location( loc ), size( size )
+	{}
+
+	void setPosition( const Expr * expr ) {
+		// need to permit integer-constant-expressions, including: integer constants,
+		// enumeration constants, character constants, sizeof expressions, alignof expressions,
+		// cast expressions
+
+		auto arg = eval( expr );
+		assertf( arg.hasKnownValue, "Non-evaluable expression made it to IndexIterator" );
+		index = arg.knownValue;
+
+		// if ( auto constExpr = dynamic_cast< const ConstantExpr * >( expr ) ) {
+		// 	try {
+		// 		index = constExpr->intValue();
+		// 	} catch ( SemanticErrorException & ) {
+		// 		SemanticError( expr, "Constant expression of non-integral type in array designator: " );
+		// 	}
+		// } else if ( auto castExpr = dynamic_cast< const CastExpr * >( expr ) ) {
+		// 	setPosition( castExpr->arg );
+		// } else if ( dynamic_cast< const SizeofExpr * >( expr ) || dynamic_cast< const AlignofExpr * >( expr ) ) {
+		// 	index = 0;
+		// } else {
+		// 	assertf( false,	"2 bad designator given to ArrayIterator: %s", toString( expr ).c_str() );
+		// }
+	}
+
+	void setPosition(
+		std::deque<ast::ptr<ast::Expr>>::const_iterator begin,
+		std::deque<ast::ptr<ast::Expr>>::const_iterator end
+	) override {
+		if ( begin == end ) return;
+
+		setPosition( *begin );
+		memberIter->setPosition( ++begin, end );
+	}
+
+	std::deque< InitAlternative > operator* () const override { return first(); }
+
+	operator bool() const override { return index < size; }
+};
+
+/// Iterates over the members of array types:
+class ArrayIterator final : public IndexIterator {
+	const ArrayType * array = nullptr;
+	const Type * base = nullptr;
+
+	size_t getSize( const Expr * expr ) {
+		auto res = eval( expr );
+		if ( !res.hasKnownValue ) {
+			SemanticError( location, toString( "Array designator must be a constant expression: ", expr ) );
+		}
+		return res.knownValue;
+	}
+
+public:
+	ArrayIterator( const CodeLocation & loc, const ArrayType * at ) :
+			IndexIterator( loc, getSize( at->dimension) ),
+			array( at ), base( at->base ) {
+		PRINT( std::cerr << "Creating array iterator: " << at << std::endl; )
+		memberIter.reset( createMemberIterator( loc, base ) );
+		if ( at->isVarLen ) {
+			SemanticError( location, at, "VLA initialization does not support @=: " );
+		}
+	}
+
+	ArrayIterator & bigStep() override {
+		PRINT( std::cerr << "bigStep in ArrayIterator (" << index << "/" << size << ")" << std::endl; )
+		++index;
+		memberIter.reset( index < size ? createMemberIterator( location, base ) : nullptr );
+		return *this;
+	}
+
+	ArrayIterator & smallStep() override {
+		PRINT( std::cerr << "smallStep in ArrayIterator (" << index << "/" << size << ")" << std::endl; )
+		if ( memberIter ) {
+			PRINT( std::cerr << "has member iter: " << *memberIter << std::endl; )
+			memberIter->smallStep();
+			if ( *memberIter ) {
+				PRINT( std::cerr << "has valid member iter" << std::endl; )
+				return *this;
+			}
+		}
+		return bigStep();
+	}
+
+	const Type * getType() override { return array; }
+
+	const Type * getNext() override { return base; }
+
+	std::deque< InitAlternative > first() const override {
+		PRINT( std::cerr << "first in ArrayIterator (" << index << "/" << size << ")" << std::endl; )
+		if ( memberIter && *memberIter ) {
+			std::deque< InitAlternative > ret = memberIter->first();
+			for ( InitAlternative & alt : ret ) {
+				alt.designation.get_and_mutate()->designators.emplace_front( ConstantExpr::from_ulong( location, index ) );
 			}
 			return ret;
 		}
-	};
-
-	class StructIterator final : public AggregateIterator {
-	public:
-		StructIterator( const CodeLocation & loc, const StructInstType * inst )
-		: AggregateIterator( loc, "StructIterator", inst->name, inst, inst->base->members ) {}
-
-		operator bool() const override {
-			return curMember != members.end() || (memberIter && *memberIter);
-		}
-
-		StructIterator & bigStep() override {
-			PRINT( std::cerr << "bigStep in " << kind << std::endl; )
-			atbegin = false;
-			memberIter = nullptr;
-			curType = nullptr;
-			while ( curMember != members.end() ) {
-				++curMember;
-				if ( init() ) return *this;
-			}
-			return *this;
-		}
-	};
-
-	class UnionIterator final : public AggregateIterator {
-	public:
-		UnionIterator( const CodeLocation & loc, const UnionInstType * inst )
-		: AggregateIterator( loc, "UnionIterator", inst->name, inst, inst->base->members ) {}
-
-		operator bool() const override { return memberIter && *memberIter; }
-
-		UnionIterator & bigStep() override {
-			// unions only initialize one member
-			PRINT( std::cerr << "bigStep in " << kind << std::endl; )
-			atbegin = false;
-			memberIter = nullptr;
-			curType = nullptr;
-			curMember = members.end();
-			return *this;
-		}
-	};
-
-	/// Iterates across the positions in a tuple:
-	class TupleIterator final : public IndexIterator {
-		ast::TupleType const * const tuple;
-
-		const ast::Type * typeAtIndex() const {
-			assert( index < size );
-			return tuple->types[ index ].get();
-		}
-
-	public:
-		TupleIterator( const CodeLocation & loc, const TupleType * type )
-		: IndexIterator( loc, type->size() ), tuple( type ) {
-			PRINT( std::cerr << "Creating tuple iterator: " << type << std::endl; )
-			memberIter.reset( createMemberIterator( loc, typeAtIndex() ) );
-		}
-
-		TupleIterator & bigStep() override {
-			++index;
-			memberIter.reset( index < size ?
-				createMemberIterator( location, typeAtIndex() ) : nullptr );
-			return *this;
-		}
-
-		TupleIterator & smallStep() override {
-			if ( memberIter ) {
-				PRINT( std::cerr << "has member iter: " << *memberIter << std::endl; )
-				memberIter->smallStep();
-				if ( !memberIter ) {
-					PRINT( std::cerr << "has valid member iter" << std::endl; )
-					return *this;
-				}
-			}
-			return bigStep();
-		}
-
-		const ast::Type * getType() override {
-			return tuple;
-		}
-
-		const ast::Type * getNext() override {
-			bool hasMember = memberIter && *memberIter;
-			return hasMember ? memberIter->getType() : nullptr;
-		}
-
-		std::deque< InitAlternative > first() const override {
-			PRINT( std::cerr << "first in TupleIterator (" << index << "/" << size << ")" << std::endl; )
-			if ( memberIter && *memberIter ) {
-				std::deque< InitAlternative > ret = memberIter->first();
-				for ( InitAlternative & alt : ret ) {
-					alt.designation.get_and_mutate()->designators.emplace_front(
-						ConstantExpr::from_ulong( location, index ) );
-				}
-				return ret;
-			}
-			return {};
-		}
-	};
-
-	MemberIterator * createMemberIterator( const CodeLocation & loc, const Type * type ) {
-		if ( auto aggr = dynamic_cast< const BaseInstType * >( type ) ) {
-			if ( auto sit = dynamic_cast< const StructInstType * >( aggr ) ) {
-				assert( sit->base );
-				return new StructIterator{ loc, sit };
-			} else if ( auto uit = dynamic_cast< const UnionInstType * >( aggr ) ) {
-				assert( uit->base );
-				return new UnionIterator{ loc, uit };
-			} else {
-				assertf(
-					dynamic_cast< const EnumInstType * >( type )
-						|| dynamic_cast< const TypeInstType * >( type ),
-					"Encountered unhandled BaseInstType in createMemberIterator: %s",
-						toString( type ).c_str() );
-				return new SimpleIterator{ loc, type };
-			}
-		} else if ( auto at = dynamic_cast< const ArrayType * >( type ) ) {
-			return new ArrayIterator{ loc, at };
-		} else if ( auto tt = dynamic_cast< const TupleType * >( type ) ) {
-			return new TupleIterator{ loc, tt };
+		return {};
+	}
+};
+
+class AggregateIterator : public MemberIterator {
+protected:
+	using MemberList = std::vector< ptr< Decl > >;
+
+	CodeLocation location;
+	std::string kind;  // for debug
+	std::string name;
+	const Type * inst;
+	const MemberList & members;
+	MemberList::const_iterator curMember;
+	bool atbegin = true;  // false at first {small,big}Step
+	const Type * curType = nullptr;
+	std::unique_ptr< MemberIterator > memberIter = nullptr;
+	TypeSubstitution sub;
+
+	bool init() {
+		PRINT( std::cerr << "--init()--" << members.size() << std::endl; )
+		if ( curMember != members.end() ) {
+			if ( auto field = curMember->as< ObjectDecl >() ) {
+				PRINT( std::cerr << "incremented to field: " << field << std::endl; )
+				curType = field->get_type();
+				memberIter.reset( createMemberIterator( location, curType ) );
+				return true;
+			}
+		}
+		return false;
+	}
+
+	AggregateIterator(
+		const CodeLocation & loc, const std::string k, const std::string & n, const Type * i,
+		const MemberList & ms )
+	: location( loc ), kind( k ), name( n ), inst( i ), members( ms ), curMember( ms.begin() ),
+	  sub( genericSubstitution( i ) ) {
+		PRINT( std::cerr << "Creating " << kind << "(" << name << ")"; )
+		init();
+	}
+
+public:
+	void setPosition(
+		std::deque< ptr< Expr > >::const_iterator begin,
+		std::deque< ptr< Expr > >::const_iterator end
+	) final {
+		if ( begin == end ) return;
+
+		if ( auto varExpr = begin->as< VariableExpr >() ) {
+			for ( curMember = members.begin(); curMember != members.end(); ++curMember ) {
+				if ( *curMember != varExpr->var ) continue;
+
+				++begin;
+
+				memberIter.reset( createMemberIterator( location, varExpr->result ) );
+				curType = varExpr->result;
+				atbegin = curMember == members.begin() && begin == end;
+				memberIter->setPosition( begin, end );
+				return;
+			}
+			assertf( false, "could not find member in %s: %s", kind.c_str(), toString( varExpr ).c_str() );
 		} else {
+			assertf( false, "1 bad designator given to %s: %s", kind.c_str(), toString( *begin ).c_str() );
+		}
+	}
+
+	std::deque< InitAlternative > operator* () const final {
+		if ( memberIter && *memberIter ) {
+			std::deque< InitAlternative > ret = memberIter->first();
+			PRINT( std::cerr << "sub: " << sub << std::endl; )
+			for ( InitAlternative & alt : ret ) {
+				PRINT( std::cerr << "iterating and adding designators" << std::endl; )
+				alt.designation.get_and_mutate()->designators.emplace_front(
+					new VariableExpr{ location, curMember->strict_as< ObjectDecl >() } );
+				// need to substitute for generic types so that casts are to concrete types
+				alt.type = shallowCopy(alt.type.get());
+				PRINT( std::cerr << "  type is: " << alt.type; )
+				sub.apply( alt.type ); // also apply to designation??
+				PRINT( std::cerr << " ==> " << alt.type << std::endl; )
+			}
+			return ret;
+		}
+		return {};
+	}
+
+	AggregateIterator & smallStep() final {
+		PRINT( std::cerr << "smallStep in " << kind << std::endl; )
+		atbegin = false;
+		if ( memberIter ) {
+			PRINT( std::cerr << "has member iter, incrementing..." << std::endl; )
+			memberIter->smallStep();
+			if ( *memberIter ) {
+				PRINT( std::cerr << "success!" << std::endl; )
+				return *this;
+			}
+		}
+		return bigStep();
+	}
+
+	AggregateIterator & bigStep() override = 0;
+
+	const Type * getType() final { return inst; }
+
+	const Type * getNext() final {
+		bool hasMember = memberIter && *memberIter;
+		return hasMember ? memberIter->getType() : nullptr;
+	}
+
+	std::deque< InitAlternative > first() const final {
+		std::deque< InitAlternative > ret;
+		PRINT( std::cerr << "first " << kind << std::endl; )
+		if ( memberIter && *memberIter ) {
+			PRINT( std::cerr << "adding children" << std::endl; )
+			ret = memberIter->first();
+			for ( InitAlternative & alt : ret ) {
+				PRINT( std::cerr << "iterating and adding designators" << std::endl; )
+				alt.designation.get_and_mutate()->designators.emplace_front(
+					new VariableExpr{ location, curMember->strict_as< ObjectDecl >() } );
+			}
+		}
+		if ( atbegin ) {
+			// only add self if at the very beginning of the structure
+			PRINT( std::cerr << "adding self" << std::endl; )
+			ret.emplace_front( inst, new Designation{ location } );
+		}
+		return ret;
+	}
+};
+
+class StructIterator final : public AggregateIterator {
+public:
+	StructIterator( const CodeLocation & loc, const StructInstType * inst )
+	: AggregateIterator( loc, "StructIterator", inst->name, inst, inst->base->members ) {}
+
+	operator bool() const override {
+		return curMember != members.end() || (memberIter && *memberIter);
+	}
+
+	StructIterator & bigStep() override {
+		PRINT( std::cerr << "bigStep in " << kind << std::endl; )
+		atbegin = false;
+		memberIter = nullptr;
+		curType = nullptr;
+		while ( curMember != members.end() ) {
+			++curMember;
+			if ( init() ) return *this;
+		}
+		return *this;
+	}
+};
+
+class UnionIterator final : public AggregateIterator {
+public:
+	UnionIterator( const CodeLocation & loc, const UnionInstType * inst )
+	: AggregateIterator( loc, "UnionIterator", inst->name, inst, inst->base->members ) {}
+
+	operator bool() const override { return memberIter && *memberIter; }
+
+	UnionIterator & bigStep() override {
+		// unions only initialize one member
+		PRINT( std::cerr << "bigStep in " << kind << std::endl; )
+		atbegin = false;
+		memberIter = nullptr;
+		curType = nullptr;
+		curMember = members.end();
+		return *this;
+	}
+};
+
+/// Iterates across the positions in a tuple:
+class TupleIterator final : public IndexIterator {
+	ast::TupleType const * const tuple;
+
+	const ast::Type * typeAtIndex() const {
+		assert( index < size );
+		return tuple->types[ index ].get();
+	}
+
+public:
+	TupleIterator( const CodeLocation & loc, const TupleType * type )
+	: IndexIterator( loc, type->size() ), tuple( type ) {
+		PRINT( std::cerr << "Creating tuple iterator: " << type << std::endl; )
+		memberIter.reset( createMemberIterator( loc, typeAtIndex() ) );
+	}
+
+	TupleIterator & bigStep() override {
+		++index;
+		memberIter.reset( index < size ?
+			createMemberIterator( location, typeAtIndex() ) : nullptr );
+		return *this;
+	}
+
+	TupleIterator & smallStep() override {
+		if ( memberIter ) {
+			PRINT( std::cerr << "has member iter: " << *memberIter << std::endl; )
+			memberIter->smallStep();
+			if ( !memberIter ) {
+				PRINT( std::cerr << "has valid member iter" << std::endl; )
+				return *this;
+			}
+		}
+		return bigStep();
+	}
+
+	const ast::Type * getType() override {
+		return tuple;
+	}
+
+	const ast::Type * getNext() override {
+		bool hasMember = memberIter && *memberIter;
+		return hasMember ? memberIter->getType() : nullptr;
+	}
+
+	std::deque< InitAlternative > first() const override {
+		PRINT( std::cerr << "first in TupleIterator (" << index << "/" << size << ")" << std::endl; )
+		if ( memberIter && *memberIter ) {
+			std::deque< InitAlternative > ret = memberIter->first();
+			for ( InitAlternative & alt : ret ) {
+				alt.designation.get_and_mutate()->designators.emplace_front(
+					ConstantExpr::from_ulong( location, index ) );
+			}
+			return ret;
+		}
+		return {};
+	}
+};
+
+MemberIterator * createMemberIterator( const CodeLocation & loc, const Type * type ) {
+	if ( auto aggr = dynamic_cast< const BaseInstType * >( type ) ) {
+		if ( auto sit = dynamic_cast< const StructInstType * >( aggr ) ) {
+			assert( sit->base );
+			return new StructIterator{ loc, sit };
+		} else if ( auto uit = dynamic_cast< const UnionInstType * >( aggr ) ) {
+			assert( uit->base );
+			return new UnionIterator{ loc, uit };
+		} else {
+			assertf(
+				dynamic_cast< const EnumInstType * >( type )
+					|| dynamic_cast< const TypeInstType * >( type ),
+				"Encountered unhandled BaseInstType in createMemberIterator: %s",
+					toString( type ).c_str() );
 			return new SimpleIterator{ loc, type };
 		}
-	}
-
-	CurrentObject::CurrentObject( const CodeLocation & loc, const Type * type ) : objStack() {
-		objStack.emplace_back( new SimpleIterator{ loc, type } );
-	}
-
-	const Designation * CurrentObject::findNext( const Designation * designation ) {
-		using DesignatorChain = std::deque< ptr< Expr > >;
-		PRINT( std::cerr << "___findNext" << std::endl; )
-
-		// find all the d's
-		std::vector< DesignatorChain > desigAlts{ {} }, newDesigAlts;
-		std::deque< const Type * > curTypes{ objStack.back()->getType() }, newTypes;
-		for ( const Expr * expr : designation->designators ) {
-			PRINT( std::cerr << "____untyped: " << expr << std::endl; )
-			auto dit = desigAlts.begin();
-
-			for ( const Type * t : curTypes ) {
-				assert( dit != desigAlts.end() );
-				DesignatorChain & d = *dit;
-				if ( auto nexpr = dynamic_cast< const NameExpr *>( expr ) ) {
-					PRINT( std::cerr << "____actual: " << t << std::endl; )
-					if ( auto refType = dynamic_cast< const BaseInstType * >( t ) ) {
-						// concatenate identical field names
-						for ( const Decl * mem : refType->lookup( nexpr->name ) ) {
-							if ( auto field = dynamic_cast< const ObjectDecl * >( mem ) ) {
-								PRINT( std::cerr << "____alt: " << field->type << std::endl; )
-								DesignatorChain d2 = d;
-								d2.emplace_back( new VariableExpr{ expr->location, field } );
-								newDesigAlts.emplace_back( std::move( d2 ) );
-								newTypes.emplace_back( field->type );
-							}
-						}
-					} else if ( auto at = dynamic_cast< const ArrayType * >( t ) ) {
-						auto nexpr = dynamic_cast< const NameExpr *>( expr );
-						for ( const Decl * mem : refType->lookup( nexpr->name ) ) {
-							if ( auto field = dynamic_cast< const ObjectDecl * >( mem ) ) {
-								DesignatorChain d2 = d;
-								d2.emplace_back( new VariableExpr{ expr->location, field } );
-								newDesigAlts.emplace_back( std::move( d2 ) );
-								newTypes.emplace_back( at->base );
-							}
+	} else if ( auto at = dynamic_cast< const ArrayType * >( type ) ) {
+		return new ArrayIterator{ loc, at };
+	} else if ( auto tt = dynamic_cast< const TupleType * >( type ) ) {
+		return new TupleIterator{ loc, tt };
+	} else {
+		return new SimpleIterator{ loc, type };
+	}
+}
+
+} // namespace
+
+CurrentObject::CurrentObject( const CodeLocation & loc, const Type * type ) : objStack() {
+	objStack.emplace_back( new SimpleIterator{ loc, type } );
+}
+
+const Designation * CurrentObject::findNext( const Designation * designation ) {
+	using DesignatorChain = std::deque< ptr< Expr > >;
+	PRINT( std::cerr << "___findNext" << std::endl; )
+
+	// find all the d's
+	std::vector< DesignatorChain > desigAlts{ {} }, newDesigAlts;
+	std::deque< const Type * > curTypes{ objStack.back()->getType() }, newTypes;
+	for ( const Expr * expr : designation->designators ) {
+		PRINT( std::cerr << "____untyped: " << expr << std::endl; )
+		auto dit = desigAlts.begin();
+
+		for ( const Type * t : curTypes ) {
+			assert( dit != desigAlts.end() );
+			DesignatorChain & d = *dit;
+			if ( auto nexpr = dynamic_cast< const NameExpr *>( expr ) ) {
+				PRINT( std::cerr << "____actual: " << t << std::endl; )
+				if ( auto refType = dynamic_cast< const BaseInstType * >( t ) ) {
+					// concatenate identical field names
+					for ( const Decl * mem : refType->lookup( nexpr->name ) ) {
+						if ( auto field = dynamic_cast< const ObjectDecl * >( mem ) ) {
+							PRINT( std::cerr << "____alt: " << field->type << std::endl; )
+							DesignatorChain d2 = d;
+							d2.emplace_back( new VariableExpr{ expr->location, field } );
+							newDesigAlts.emplace_back( std::move( d2 ) );
+							newTypes.emplace_back( field->type );
 						}
 					}
-
-					++dit;
-				} else {
-					if ( auto at = dynamic_cast< const ArrayType * >( t ) ) {
-						PRINT( std::cerr << "____alt: " << at->get_base() << std::endl; )
-						d.emplace_back( expr );
-						newDesigAlts.emplace_back( d );
-						newTypes.emplace_back( at->base );
+				} else if ( auto at = dynamic_cast< const ArrayType * >( t ) ) {
+					auto nexpr = dynamic_cast< const NameExpr *>( expr );
+					for ( const Decl * mem : refType->lookup( nexpr->name ) ) {
+						if ( auto field = dynamic_cast< const ObjectDecl * >( mem ) ) {
+							DesignatorChain d2 = d;
+							d2.emplace_back( new VariableExpr{ expr->location, field } );
+							newDesigAlts.emplace_back( std::move( d2 ) );
+							newTypes.emplace_back( at->base );
+						}
 					}
 				}
-			}
-
-			// reset queue
-			desigAlts = std::move( newDesigAlts );
-			newDesigAlts.clear();
-			curTypes = std::move( newTypes );
-			newTypes.clear();
-			assertf( desigAlts.size() == curTypes.size(), "Designator alternatives (%zu) and current types (%zu) out of sync", desigAlts.size(), curTypes.size() );
-		}
-
-		if ( desigAlts.size() > 1 ) {
-			SemanticError( designation, toString("Too many alternatives (", desigAlts.size(), ") for designation: ") );
-		} else if ( desigAlts.empty() ) {
-			SemanticError( designation, "No reasonable alternatives for designation: " );
-		}
-
-		DesignatorChain & d = desigAlts.back();
-		PRINT( for ( Expression * expr : d ) {
-			std::cerr << "____desig: " << expr << std::endl;
-		} ) // for
-		assertf( ! curTypes.empty(), "empty designator chosen");
-
-		// set new designators
-		assertf( ! objStack.empty(), "empty object stack when setting designation" );
-		Designation * actualDesignation =
-			new Designation{ designation->location, DesignatorChain{d} };
-		objStack.back()->setPosition( d ); // destroys d
-		return actualDesignation;
-	}
-
-	void CurrentObject::setNext( const Designation * designation ) {
-		PRINT( std::cerr << "____setNext" << designation << std::endl; )
-		assertf( ! objStack.empty(), "obj stack empty in setNext" );
-		objStack.back()->setPosition( designation->designators );
-	}
-
-	void CurrentObject::increment() {
-		PRINT( std::cerr << "____increment" << std::endl; )
-		if ( objStack.empty() ) return;
+
+				++dit;
+			} else {
+				if ( auto at = dynamic_cast< const ArrayType * >( t ) ) {
+					PRINT( std::cerr << "____alt: " << at->get_base() << std::endl; )
+					d.emplace_back( expr );
+					newDesigAlts.emplace_back( d );
+					newTypes.emplace_back( at->base );
+				}
+			}
+		}
+
+		// reset queue
+		desigAlts = std::move( newDesigAlts );
+		newDesigAlts.clear();
+		curTypes = std::move( newTypes );
+		newTypes.clear();
+		assertf( desigAlts.size() == curTypes.size(), "Designator alternatives (%zu) and current types (%zu) out of sync", desigAlts.size(), curTypes.size() );
+	}
+
+	if ( desigAlts.size() > 1 ) {
+		SemanticError( designation, toString("Too many alternatives (", desigAlts.size(), ") for designation: ") );
+	} else if ( desigAlts.empty() ) {
+		SemanticError( designation, "No reasonable alternatives for designation: " );
+	}
+
+	DesignatorChain & d = desigAlts.back();
+	PRINT( for ( Expression * expr : d ) {
+		std::cerr << "____desig: " << expr << std::endl;
+	} ) // for
+	assertf( ! curTypes.empty(), "empty designator chosen");
+
+	// set new designators
+	assertf( ! objStack.empty(), "empty object stack when setting designation" );
+	Designation * actualDesignation =
+		new Designation{ designation->location, DesignatorChain{d} };
+	objStack.back()->setPosition( d ); // destroys d
+	return actualDesignation;
+}
+
+void CurrentObject::setNext( const Designation * designation ) {
+	PRINT( std::cerr << "____setNext" << designation << std::endl; )
+	assertf( ! objStack.empty(), "obj stack empty in setNext" );
+	objStack.back()->setPosition( designation->designators );
+}
+
+void CurrentObject::increment() {
+	PRINT( std::cerr << "____increment" << std::endl; )
+	if ( objStack.empty() ) return;
+	PRINT( std::cerr << *objStack.back() << std::endl; )
+	objStack.back()->smallStep();
+}
+
+void CurrentObject::enterListInit( const CodeLocation & loc ) {
+	PRINT( std::cerr << "____entering list init" << std::endl; )
+	assertf( ! objStack.empty(), "empty obj stack entering list init" );
+	const ast::Type * type = objStack.back()->getNext();
+	assert( type );
+	objStack.emplace_back( createMemberIterator( loc, type ) );
+}
+
+void CurrentObject::exitListInit() {
+	PRINT( std::cerr << "____exiting list init" << std::endl; )
+	assertf( ! objStack.empty(), "objstack empty" );
+	objStack.pop_back();
+	if ( ! objStack.empty() ) {
 		PRINT( std::cerr << *objStack.back() << std::endl; )
-		objStack.back()->smallStep();
-	}
-
-	void CurrentObject::enterListInit( const CodeLocation & loc ) {
-		PRINT( std::cerr << "____entering list init" << std::endl; )
-		assertf( ! objStack.empty(), "empty obj stack entering list init" );
-		const ast::Type * type = objStack.back()->getNext();
-		assert( type );
-		objStack.emplace_back( createMemberIterator( loc, type ) );
-	}
-
-	void CurrentObject::exitListInit() {
-		PRINT( std::cerr << "____exiting list init" << std::endl; )
-		assertf( ! objStack.empty(), "objstack empty" );
-		objStack.pop_back();
-		if ( ! objStack.empty() ) {
-			PRINT( std::cerr << *objStack.back() << std::endl; )
-			objStack.back()->bigStep();
-		}
-	}
-
-	std::deque< InitAlternative > CurrentObject::getOptions() {
-		PRINT( std::cerr << "____getting current options" << std::endl; )
-		assertf( ! objStack.empty(), "objstack empty in getOptions" );
-		return **objStack.back();
-	}
-
-	const Type * CurrentObject::getCurrentType() {
-		PRINT( std::cerr << "____getting current type" << std::endl; )
-		assertf( ! objStack.empty(), "objstack empty in getCurrentType" );
-		return objStack.back()->getNext();
-	}
-}
+		objStack.back()->bigStep();
+	}
+}
+
+std::deque< InitAlternative > CurrentObject::getOptions() {
+	PRINT( std::cerr << "____getting current options" << std::endl; )
+	assertf( ! objStack.empty(), "objstack empty in getOptions" );
+	return **objStack.back();
+}
+
+const Type * CurrentObject::getCurrentType() {
+	PRINT( std::cerr << "____getting current type" << std::endl; )
+	assertf( ! objStack.empty(), "objstack empty in getCurrentType" );
+	return objStack.back()->getNext();
+}
+
+} // namespace ast
 
 // Local Variables: //