diff --git a/NEWS b/NEWS
index 4f23388cea..ff7b02f657 100644
--- a/NEWS
+++ b/NEWS
@@ -151,6 +151,8 @@ Deprecated Functionality
 - ``BroType::HasField()`` and ``BroType::FieldType()`` are deprecated, use
   the methods of ``RecordType`` directly.
 
+- ``BroType::YieldType()`` is deprecated, use ``BroType::Yield()``.
+
 Zeek 3.1.0
 ==========
 
diff --git a/src/Attr.cc b/src/Attr.cc
index 6480f19ce6..747994a396 100644
--- a/src/Attr.cc
+++ b/src/Attr.cc
@@ -273,7 +273,7 @@ void Attributes::CheckAttr(Attr* a)
 			}
 
 		FuncType* aft = at->AsFuncType();
-		if ( ! same_type(aft->YieldType(), type.get()) )
+		if ( ! same_type(aft->Yield().get(), type.get()) )
 			{
 			a->AttrExpr()->Error(
 				is_add ?
@@ -328,7 +328,7 @@ void Attributes::CheckAttr(Attr* a)
 			}
 
 		TableType* tt = type->AsTableType();
-		BroType* ytype = tt->YieldType();
+		BroType* ytype = tt->Yield().get();
 
 		if ( ! in_record )
 			{
@@ -340,7 +340,7 @@ void Attributes::CheckAttr(Attr* a)
 					{
 					FuncType* f = atype->AsFuncType();
 					if ( ! f->CheckArgs(tt->IndexTypes()) ||
-					     ! same_type(f->YieldType(), ytype) )
+					     ! same_type(f->Yield().get(), ytype) )
 						Error("&default function type clash");
 
 					// Ok.
@@ -453,7 +453,7 @@ void Attributes::CheckAttr(Attr* a)
 
 		const FuncType* e_ft = expire_func->Type()->AsFuncType();
 
-		if ( e_ft->YieldType()->Tag() != TYPE_INTERVAL )
+		if ( e_ft->Yield()->Tag() != TYPE_INTERVAL )
 			{
 			Error("&expire_func must yield a value of type interval");
 			break;
@@ -500,7 +500,7 @@ void Attributes::CheckAttr(Attr* a)
 
 		const FuncType* c_ft = change_func->Type()->AsFuncType();
 
-		if ( c_ft->YieldType()->Tag() != TYPE_VOID )
+		if ( c_ft->Yield()->Tag() != TYPE_VOID )
 			{
 			Error("&on_change must not return a value");
 			break;
@@ -542,7 +542,7 @@ void Attributes::CheckAttr(Attr* a)
 			}
 
 		if ( ! type->IsSet() )
-			if ( ! same_type(args[2+t_indexes.size()].get(), the_table->YieldType()) )
+			if ( ! same_type(args[2+t_indexes.size()].get(), the_table->Yield().get()) )
 				{
 				Error("&on_change: value type does not match table");
 				break;
diff --git a/src/CompHash.cc b/src/CompHash.cc
index 416ae38208..ea98690e69 100644
--- a/src/CompHash.cc
+++ b/src/CompHash.cc
@@ -277,7 +277,7 @@ char* CompositeHash::SingleValHash(bool type_check, char* kp0,
 				if ( val )
 					{
 					if ( ! (kp1 = SingleValHash(type_check, kp1,
-					                            vt->YieldType(), val, false)) )
+					                            vt->Yield().get(), val, false)) )
 						return nullptr;
 					}
 				}
@@ -570,7 +570,7 @@ int CompositeHash::SingleTypeKeySize(BroType* bt, const Val* v,
 				sz = SizeAlign(sz, sizeof(unsigned int));
 				sz = SizeAlign(sz, sizeof(unsigned int));
 				if ( val )
-					sz = SingleTypeKeySize(bt->AsVectorType()->YieldType(),
+					sz = SingleTypeKeySize(bt->AsVectorType()->Yield().get(),
 					                       val, type_check, sz, false,
 					                       calc_static_size);
 				if ( ! sz ) return 0;
@@ -956,7 +956,7 @@ const char* CompositeHash::RecoverOneVal(const HashKey* k, const char* kp0,
 				else
 					{
 					IntrusivePtr<Val> value;
-					kp1 = RecoverOneVal(k, kp1, k_end, tt->YieldType(), &value,
+					kp1 = RecoverOneVal(k, kp1, k_end, tt->Yield().get(), &value,
 					                    false);
 					tv->Assign(key.get(), std::move(value));
 					}
@@ -986,7 +986,7 @@ const char* CompositeHash::RecoverOneVal(const HashKey* k, const char* kp0,
 				IntrusivePtr<Val> value;
 
 				if ( have_val )
-					kp1 = RecoverOneVal(k, kp1, k_end, vt->YieldType(), &value,
+					kp1 = RecoverOneVal(k, kp1, k_end, vt->Yield().get(), &value,
 					                    false);
 
 				vv->Assign(index, std::move(value));
diff --git a/src/Expr.cc b/src/Expr.cc
index 0929de3888..cff9cd0d08 100644
--- a/src/Expr.cc
+++ b/src/Expr.cc
@@ -676,7 +676,7 @@ IntrusivePtr<Val> BinaryExpr::Fold(Val* v1, Val* v2) const
 	BroType* ret_type = Type();
 
 	if ( IsVector(ret_type->Tag()) )
-	     ret_type = ret_type->YieldType();
+	     ret_type = ret_type->Yield().get();
 
 	if ( ret_type->Tag() == TYPE_INTERVAL )
 		return make_intrusive<IntervalVal>(d3, 1.0);
@@ -863,9 +863,9 @@ void BinaryExpr::PromoteOps(TypeTag t)
 	bool is_vec2 = IsVector(bt2);
 
 	if ( is_vec1 )
-		bt1 = op1->Type()->AsVectorType()->YieldType()->Tag();
+		bt1 = op1->Type()->AsVectorType()->Yield()->Tag();
 	if ( is_vec2 )
-		bt2 = op2->Type()->AsVectorType()->YieldType()->Tag();
+		bt2 = op2->Type()->AsVectorType()->Yield()->Tag();
 
 	if ( (is_vec1 || is_vec2) && ! (is_vec1 && is_vec2) )
 		reporter->Warning("mixing vector and scalar operands is deprecated");
@@ -922,7 +922,7 @@ IncrExpr::IncrExpr(BroExprTag arg_tag, IntrusivePtr<Expr> arg_op)
 
 	if ( IsVector(t->Tag()) )
 		{
-		if ( ! IsIntegral(t->AsVectorType()->YieldType()->Tag()) )
+		if ( ! IsIntegral(t->AsVectorType()->Yield()->Tag()) )
 			ExprError("vector elements must be integral for increment operator");
 		else
 			{
@@ -956,7 +956,7 @@ IntrusivePtr<Val> IncrExpr::DoSingleEval(Frame* f, Val* v) const
 
 	BroType* ret_type = Type();
 	if ( IsVector(ret_type->Tag()) )
-		ret_type = Type()->YieldType();
+		ret_type = Type()->Yield().get();
 
 	if ( ret_type->Tag() == TYPE_INT )
 		return val_mgr->Int(k);
@@ -1050,7 +1050,7 @@ PosExpr::PosExpr(IntrusivePtr<Expr> arg_op)
 	BroType* t = op->Type();
 
 	if ( IsVector(t->Tag()) )
-		t = t->AsVectorType()->YieldType();
+		t = t->AsVectorType()->Yield().get();
 
 	TypeTag bt = t->Tag();
 	IntrusivePtr<BroType> base_result_type;
@@ -1088,7 +1088,7 @@ NegExpr::NegExpr(IntrusivePtr<Expr> arg_op)
 	BroType* t = op->Type();
 
 	if ( IsVector(t->Tag()) )
-		t = t->AsVectorType()->YieldType();
+		t = t->AsVectorType()->Yield().get();
 
 	TypeTag bt = t->Tag();
 	IntrusivePtr<BroType> base_result_type;
@@ -1153,12 +1153,12 @@ AddExpr::AddExpr(IntrusivePtr<Expr> arg_op1, IntrusivePtr<Expr> arg_op2)
 	TypeTag bt1 = op1->Type()->Tag();
 
 	if ( IsVector(bt1) )
-		bt1 = op1->Type()->AsVectorType()->YieldType()->Tag();
+		bt1 = op1->Type()->AsVectorType()->Yield()->Tag();
 
 	TypeTag bt2 = op2->Type()->Tag();
 
 	if ( IsVector(bt2) )
-		bt2 = op2->Type()->AsVectorType()->YieldType()->Tag();
+		bt2 = op2->Type()->AsVectorType()->Yield()->Tag();
 
 	IntrusivePtr<BroType> base_result_type;
 
@@ -1209,7 +1209,7 @@ AddToExpr::AddToExpr(IntrusivePtr<Expr> arg_op1, IntrusivePtr<Expr> arg_op2)
 
 	else if ( IsVector(bt1) )
 		{
-		bt1 = op1->Type()->AsVectorType()->YieldType()->Tag();
+		bt1 = op1->Type()->AsVectorType()->Yield()->Tag();
 
 		if ( IsArithmetic(bt1) )
 			{
@@ -1279,11 +1279,11 @@ SubExpr::SubExpr(IntrusivePtr<Expr> arg_op1, IntrusivePtr<Expr> arg_op2)
 
 	TypeTag bt1 = t1->Tag();
 	if ( IsVector(bt1) )
-		bt1 = t1->AsVectorType()->YieldType()->Tag();
+		bt1 = t1->AsVectorType()->Yield()->Tag();
 
 	TypeTag bt2 = t2->Tag();
 	if ( IsVector(bt2) )
-		bt2 = t2->AsVectorType()->YieldType()->Tag();
+		bt2 = t2->AsVectorType()->Yield()->Tag();
 
 	IntrusivePtr<BroType> base_result_type;
 
@@ -1366,12 +1366,12 @@ TimesExpr::TimesExpr(IntrusivePtr<Expr> arg_op1, IntrusivePtr<Expr> arg_op2)
 	TypeTag bt1 = op1->Type()->Tag();
 
 	if ( IsVector(bt1) )
-		bt1 = op1->Type()->AsVectorType()->YieldType()->Tag();
+		bt1 = op1->Type()->AsVectorType()->Yield()->Tag();
 
 	TypeTag bt2 = op2->Type()->Tag();
 
 	if ( IsVector(bt2) )
-		bt2 = op2->Type()->AsVectorType()->YieldType()->Tag();
+		bt2 = op2->Type()->AsVectorType()->Yield()->Tag();
 
 	if ( bt1 == TYPE_INTERVAL || bt2 == TYPE_INTERVAL )
 		{
@@ -1403,12 +1403,12 @@ DivideExpr::DivideExpr(IntrusivePtr<Expr> arg_op1,
 	TypeTag bt1 = op1->Type()->Tag();
 
 	if ( IsVector(bt1) )
-		bt1 = op1->Type()->AsVectorType()->YieldType()->Tag();
+		bt1 = op1->Type()->AsVectorType()->Yield()->Tag();
 
 	TypeTag bt2 = op2->Type()->Tag();
 
 	if ( IsVector(bt2) )
-		bt2 = op2->Type()->AsVectorType()->YieldType()->Tag();
+		bt2 = op2->Type()->AsVectorType()->Yield()->Tag();
 
 	if ( bt1 == TYPE_INTERVAL || bt2 == TYPE_INTERVAL )
 		{
@@ -1470,12 +1470,12 @@ ModExpr::ModExpr(IntrusivePtr<Expr> arg_op1, IntrusivePtr<Expr> arg_op2)
 	TypeTag bt1 = op1->Type()->Tag();
 
 	if ( IsVector(bt1) )
-		bt1 = op1->Type()->AsVectorType()->YieldType()->Tag();
+		bt1 = op1->Type()->AsVectorType()->Yield()->Tag();
 
 	TypeTag bt2 = op2->Type()->Tag();
 
 	if ( IsVector(bt2) )
-		bt2 = op2->Type()->AsVectorType()->YieldType()->Tag();
+		bt2 = op2->Type()->AsVectorType()->Yield()->Tag();
 
 	if ( BothIntegral(bt1, bt2) )
 		PromoteType(max_type(bt1, bt2), is_vector(op1.get()) || is_vector(op2.get()));
@@ -1493,12 +1493,12 @@ BoolExpr::BoolExpr(BroExprTag arg_tag,
 	TypeTag bt1 = op1->Type()->Tag();
 
 	if ( IsVector(bt1) )
-		bt1 = op1->Type()->AsVectorType()->YieldType()->Tag();
+		bt1 = op1->Type()->AsVectorType()->Yield()->Tag();
 
 	TypeTag bt2 = op2->Type()->Tag();
 
 	if ( IsVector(bt2) )
-		bt2 = op2->Type()->AsVectorType()->YieldType()->Tag();
+		bt2 = op2->Type()->AsVectorType()->Yield()->Tag();
 
 	if ( BothBool(bt1, bt2) )
 		{
@@ -1643,12 +1643,12 @@ BitExpr::BitExpr(BroExprTag arg_tag,
 	TypeTag bt1 = t1->Tag();
 
 	if ( IsVector(bt1) )
-		bt1 = t1->AsVectorType()->YieldType()->Tag();
+		bt1 = t1->AsVectorType()->Yield()->Tag();
 
 	TypeTag bt2 = t2->Tag();
 
 	if ( IsVector(bt2) )
-		bt2 = t2->AsVectorType()->YieldType()->Tag();
+		bt2 = t2->AsVectorType()->Yield()->Tag();
 
 	if ( (bt1 == TYPE_COUNT || bt1 == TYPE_COUNTER) &&
 	     (bt2 == TYPE_COUNT || bt2 == TYPE_COUNTER) )
@@ -1697,11 +1697,11 @@ EqExpr::EqExpr(BroExprTag arg_tag,
 
 	TypeTag bt1 = t1->Tag();
 	if ( IsVector(bt1) )
-		bt1 = t1->AsVectorType()->YieldType()->Tag();
+		bt1 = t1->AsVectorType()->Yield()->Tag();
 
 	TypeTag bt2 = t2->Tag();
 	if ( IsVector(bt2) )
-		bt2 = t2->AsVectorType()->YieldType()->Tag();
+		bt2 = t2->AsVectorType()->Yield()->Tag();
 
 	if ( is_vector(op1.get()) || is_vector(op2.get()) )
 		SetType(make_intrusive<VectorType>(base_type(TYPE_BOOL)));
@@ -1799,11 +1799,11 @@ RelExpr::RelExpr(BroExprTag arg_tag,
 
 	TypeTag bt1 = t1->Tag();
 	if ( IsVector(bt1) )
-		bt1 = t1->AsVectorType()->YieldType()->Tag();
+		bt1 = t1->AsVectorType()->Yield()->Tag();
 
 	TypeTag bt2 = t2->Tag();
 	if ( IsVector(bt2) )
-		bt2 = t2->AsVectorType()->YieldType()->Tag();
+		bt2 = t2->AsVectorType()->Yield()->Tag();
 
 	if ( is_vector(op1.get()) || is_vector(op2.get()) )
 		SetType(make_intrusive<VectorType>(base_type(TYPE_BOOL)));
@@ -1851,7 +1851,7 @@ CondExpr::CondExpr(IntrusivePtr<Expr> arg_op1, IntrusivePtr<Expr> arg_op2,
 	TypeTag bt1 = op1->Type()->Tag();
 
 	if ( IsVector(bt1) )
-		bt1 = op1->Type()->AsVectorType()->YieldType()->Tag();
+		bt1 = op1->Type()->AsVectorType()->Yield()->Tag();
 
 	if ( op1->IsError() || op2->IsError() || op3->IsError() )
 		SetError();
@@ -1864,12 +1864,12 @@ CondExpr::CondExpr(IntrusivePtr<Expr> arg_op1, IntrusivePtr<Expr> arg_op2,
 		TypeTag bt2 = op2->Type()->Tag();
 
 		if ( is_vector(op2.get()) )
-			bt2 = op2->Type()->AsVectorType()->YieldType()->Tag();
+			bt2 = op2->Type()->AsVectorType()->Yield()->Tag();
 
 		TypeTag bt3 = op3->Type()->Tag();
 
 		if ( IsVector(bt3) )
-			bt3 = op3->Type()->AsVectorType()->YieldType()->Tag();
+			bt3 = op3->Type()->AsVectorType()->Yield()->Tag();
 
 		if ( is_vector(op1.get()) && ! (is_vector(op2.get()) && is_vector(op3.get())) )
 			{
@@ -2329,7 +2329,7 @@ void AssignExpr::EvalIntoAggregate(const BroType* t, Val* aggr, Frame* f) const
 	TableVal* tv = aggr->AsTableVal();
 
 	auto index = op1->Eval(f);
-	auto v = check_and_promote(op2->Eval(f), t->YieldType(), true);
+	auto v = check_and_promote(op2->Eval(f), t->Yield().get(), true);
 
 	if ( ! index || ! v )
 		return;
@@ -2395,10 +2395,10 @@ IntrusivePtr<Val> AssignExpr::InitVal(const BroType* t, IntrusivePtr<Val> aggr)
 
 		auto tv = cast_intrusive<TableVal>(std::move(aggr));
 		const TableType* tt = tv->Type()->AsTableType();
-		const BroType* yt = tv->Type()->YieldType();
+		const auto& yt = tv->Type()->Yield();
 
 		auto index = op1->InitVal(tt->Indices(), nullptr);
-		auto v = op2->InitVal(yt, nullptr);
+		auto v = op2->InitVal(yt.get(), nullptr);
 
 		if ( ! index || ! v )
 			return nullptr;
@@ -2491,7 +2491,7 @@ IndexExpr::IndexExpr(IntrusivePtr<Expr> arg_op1,
 		SetError(error_msg.data());
 		}
 
-	else if ( ! op1->Type()->YieldType() )
+	else if ( ! op1->Type()->Yield() )
 		{
 		if ( IsString(op1->Type()->Tag()) && match_type == MATCHES_INDEX_SCALAR )
 			SetType(base_type(TYPE_STRING));
@@ -2504,10 +2504,10 @@ IndexExpr::IndexExpr(IntrusivePtr<Expr> arg_op1,
 		}
 
 	else if ( match_type == MATCHES_INDEX_SCALAR )
-		SetType({NewRef{}, op1->Type()->YieldType()});
+		SetType(op1->Type()->Yield());
 
 	else if ( match_type == MATCHES_INDEX_VECTOR )
-		SetType(make_intrusive<VectorType>(IntrusivePtr{NewRef{}, op1->Type()->YieldType()}));
+		SetType(make_intrusive<VectorType>(op1->Type()->Yield()));
 
 	else
 		ExprError("Unknown MatchesIndex() return value");
@@ -2595,7 +2595,7 @@ IntrusivePtr<Val> IndexExpr::Eval(Frame* f) const
 		auto v_result = make_intrusive<VectorVal>(Type()->AsVectorType());
 
 		// Booleans select each element (or not).
-		if ( IsBool(v_v2->Type()->YieldType()->Tag()) )
+		if ( IsBool(v_v2->Type()->Yield()->Tag()) )
 			{
 			if ( v_v1->Size() != v_v2->Size() )
 				{
@@ -3343,7 +3343,7 @@ VectorConstructorExpr::VectorConstructorExpr(IntrusivePtr<ListExpr> constructor_
 		}
 
 	if ( ! check_and_promote_exprs_to_type(op->AsListExpr(),
-					       type->AsVectorType()->YieldType()) )
+					       type->AsVectorType()->Yield().get()) )
 		ExprError("inconsistent types in vector constructor");
 	}
 
@@ -3383,7 +3383,7 @@ IntrusivePtr<Val> VectorConstructorExpr::InitVal(const BroType* t, IntrusivePtr<
 	loop_over_list(exprs, i)
 		{
 		Expr* e = exprs[i];
-		auto v = check_and_promote(e->Eval(nullptr), t->YieldType(), true);
+		auto v = check_and_promote(e->Eval(nullptr), t->Yield().get(), true);
 
 		if ( ! v || ! vec->Assign(i, std::move(v)) )
 			{
@@ -3461,7 +3461,7 @@ ArithCoerceExpr::ArithCoerceExpr(IntrusivePtr<Expr> arg_op, TypeTag t)
 	if ( IsVector(bt) )
 		{
 		SetType(make_intrusive<VectorType>(base_type(t)));
-		vbt = op->Type()->AsVectorType()->YieldType()->Tag();
+		vbt = op->Type()->AsVectorType()->Yield()->Tag();
 		}
 	else
 		SetType(base_type(t));
@@ -3506,12 +3506,12 @@ IntrusivePtr<Val> ArithCoerceExpr::Fold(Val* v) const
 		// invocation is being done per-element rather than on
 		// the whole vector.  Correct the type tag if necessary.
 		if ( type->Tag() == TYPE_VECTOR )
-			t = Type()->AsVectorType()->YieldType()->InternalType();
+			t = Type()->AsVectorType()->Yield()->InternalType();
 
 		return FoldSingleVal(v, t);
 		}
 
-	t = Type()->AsVectorType()->YieldType()->InternalType();
+	t = Type()->AsVectorType()->Yield()->InternalType();
 
 	VectorVal* vv = v->AsVectorVal();
 	auto result = make_intrusive<VectorVal>(Type()->AsVectorType());
@@ -4082,7 +4082,7 @@ CallExpr::CallExpr(IntrusivePtr<Expr> arg_func,
 		SetError("argument type mismatch in function call");
 	else
 		{
-		BroType* yield = func_type->YieldType();
+		const auto& yield = func_type->Yield();
 
 		if ( ! yield )
 			{
@@ -4110,7 +4110,7 @@ CallExpr::CallExpr(IntrusivePtr<Expr> arg_func,
 			}
 			}
 		else
-			SetType({NewRef{}, yield});
+			SetType(yield);
 
 		// Check for call to built-ins that can be statically analyzed.
 		IntrusivePtr<Val> func_val;
@@ -4385,7 +4385,7 @@ EventExpr::EventExpr(const char* arg_name, IntrusivePtr<ListExpr> arg_args)
 		SetError("argument type mismatch in event invocation");
 	else
 		{
-		if ( func_type->YieldType() )
+		if ( func_type->Yield() )
 			{
 			Error("function invoked as an event");
 			SetError();
@@ -4633,7 +4633,7 @@ IntrusivePtr<Val> ListExpr::InitVal(const BroType* t, IntrusivePtr<Val> aggr) co
 		loop_over_list(exprs, i)
 			{
 			Expr* e = exprs[i];
-			auto promoted_e = check_and_promote_expr(e, vec->Type()->AsVectorType()->YieldType());
+			auto promoted_e = check_and_promote_expr(e, vec->Type()->AsVectorType()->Yield().get());
 
 			if ( promoted_e )
 				e = promoted_e.get();
diff --git a/src/Func.cc b/src/Func.cc
index cc8e0b92f3..984e7991ce 100644
--- a/src/Func.cc
+++ b/src/Func.cc
@@ -245,7 +245,7 @@ std::pair<bool, Val*> Func::HandlePluginResult(std::pair<bool, Val*> plugin_resu
 
 	case FUNC_FLAVOR_FUNCTION:
 		{
-		BroType* yt = FType()->YieldType();
+		const auto& yt = FType()->Yield();
 
 		if ( (! yt) || yt->Tag() == TYPE_VOID )
 			{
@@ -423,7 +423,7 @@ IntrusivePtr<Val> BroFunc::Call(const zeek::Args& args, Frame* parent) const
 
 	// Warn if the function returns something, but we returned from
 	// the function without an explicit return, or without a value.
-	else if ( FType()->YieldType() && FType()->YieldType()->Tag() != TYPE_VOID &&
+	else if ( FType()->Yield() && FType()->Yield()->Tag() != TYPE_VOID &&
 		 (flow != FLOW_RETURN /* we fell off the end */ ||
 		  ! result /* explicit return with no result */) &&
 		 ! f->HasDelayed() )
diff --git a/src/RuleCondition.cc b/src/RuleCondition.cc
index e561d28e0f..00b673253a 100644
--- a/src/RuleCondition.cc
+++ b/src/RuleCondition.cc
@@ -141,7 +141,7 @@ RuleConditionEval::RuleConditionEval(const char* func)
 		// Validate argument quantity and type.
 		FuncType* f = id->Type()->AsFuncType();
 
-		if ( f->YieldType()->Tag() != TYPE_BOOL )
+		if ( f->Yield()->Tag() != TYPE_BOOL )
 			rules_error("eval function type must yield a 'bool'", func);
 
 		TypeList tl;
diff --git a/src/Scope.cc b/src/Scope.cc
index f8a6f6d8bf..be702afedd 100644
--- a/src/Scope.cc
+++ b/src/Scope.cc
@@ -34,7 +34,7 @@ Scope::Scope(IntrusivePtr<ID> id, attr_list* al)
 			reporter->InternalError("bad scope id");
 
 		FuncType* ft = id->Type()->AsFuncType();
-		return_type = {NewRef{}, ft->YieldType()};
+		return_type = ft->Yield();
 		}
 	}
 
diff --git a/src/Stmt.cc b/src/Stmt.cc
index b778e93ab1..420e27fe3e 100644
--- a/src/Stmt.cc
+++ b/src/Stmt.cc
@@ -1148,18 +1148,17 @@ ForStmt::ForStmt(id_list* arg_loop_vars,
 
 	if ( e->Type()->IsTable() )
 		{
-		BroType* yield_type = e->Type()->AsTableType()->YieldType();
+		const auto& yield_type = e->Type()->AsTableType()->Yield();
 
 		// Verify value_vars type if its already been defined
 		if ( value_var->Type() )
 			{
-			if ( ! same_type(value_var->Type(), yield_type) )
-				value_var->Type()->Error("type clash in iteration", yield_type);
+			if ( ! same_type(value_var->Type(), yield_type.get()) )
+				value_var->Type()->Error("type clash in iteration", yield_type.get());
 			}
 		else
 			{
-			add_local(value_var, {NewRef{}, yield_type}, INIT_NONE,
-			                 nullptr, nullptr, VAR_REGULAR);
+			add_local(value_var, yield_type, INIT_NONE, nullptr, nullptr, VAR_REGULAR);
 			}
 		}
 	else
@@ -1424,7 +1423,7 @@ ReturnStmt::ReturnStmt(IntrusivePtr<Expr> arg_e)
 		}
 
 	FuncType* ft = s->ScopeID()->Type()->AsFuncType();
-	BroType* yt = ft->YieldType();
+	const auto& yt = ft->Yield();
 
 	if ( s->ScopeID()->DoInferReturnType() )
 		{
@@ -1449,7 +1448,7 @@ ReturnStmt::ReturnStmt(IntrusivePtr<Expr> arg_e)
 
 	else
 		{
-		auto promoted_e = check_and_promote_expr(e.get(), yt);
+		auto promoted_e = check_and_promote_expr(e.get(), yt.get());
 
 		if ( promoted_e )
 			e = std::move(promoted_e);
diff --git a/src/Type.cc b/src/Type.cc
index d4cbfd0f15..0fcbd5bf58 100644
--- a/src/Type.cc
+++ b/src/Type.cc
@@ -109,9 +109,10 @@ int BroType::MatchesIndex(ListExpr* const index) const
 	return DOES_NOT_MATCH_INDEX;
 	}
 
-BroType* BroType::YieldType()
+const IntrusivePtr<BroType>& BroType::Yield() const
 	{
-	return nullptr;
+	static IntrusivePtr<BroType> nil;
+	return nil;
 	}
 
 bool BroType::HasField(const char* /* field */) const
@@ -234,16 +235,6 @@ int IndexType::MatchesIndex(ListExpr* const index) const
 			MATCHES_INDEX_SCALAR : DOES_NOT_MATCH_INDEX;
 	}
 
-BroType* IndexType::YieldType()
-	{
-	return yield_type.get();
-	}
-
-const BroType* IndexType::YieldType() const
-	{
-	return yield_type.get();
-	}
-
 void IndexType::Describe(ODesc* d) const
 	{
 	BroType::Describe(d);
@@ -481,16 +472,6 @@ string FuncType::FlavorString() const
 
 FuncType::~FuncType() = default;
 
-BroType* FuncType::YieldType()
-	{
-	return yield.get();
-	}
-
-const BroType* FuncType::YieldType() const
-	{
-	return yield.get();
-	}
-
 int FuncType::MatchesIndex(ListExpr* const index) const
 	{
 	return check_and_promote_args(index, args.get()) ?
@@ -785,7 +766,7 @@ static string container_type_name(const BroType* ft)
 	if ( ft->Tag() == TYPE_RECORD )
 		s = "record " + ft->GetName();
 	else if ( ft->Tag() == TYPE_VECTOR )
-		s = "vector of " + container_type_name(ft->YieldType());
+		s = "vector of " + container_type_name(ft->Yield().get());
 	else if ( ft->Tag() == TYPE_TABLE )
 		{
 		if ( ft->IsSet() )
@@ -802,10 +783,10 @@ static string container_type_name(const BroType* ft)
 			s += container_type_name(tl[i].get());
 			}
 		s += "]";
-		if ( ft->YieldType() )
+		if ( ft->Yield() )
 			{
 			s += " of ";
-			s += container_type_name(ft->YieldType());
+			s += container_type_name(ft->Yield().get());
 			}
 		}
 	else
@@ -1070,11 +1051,6 @@ FileType::FileType(IntrusivePtr<BroType> yield_type)
 
 FileType::~FileType() = default;
 
-BroType* FileType::YieldType()
-	{
-	return yield.get();
-	}
-
 void FileType::Describe(ODesc* d) const
 	{
 	if ( d->IsReadable() )
@@ -1358,33 +1334,16 @@ IntrusivePtr<BroType> VectorType::ShallowClone()
 
 VectorType::~VectorType() = default;
 
-BroType* VectorType::YieldType()
+const IntrusivePtr<BroType>& VectorType::Yield() const
 	{
 	// Work around the fact that we use void internally to mark a vector
 	// as being unspecified. When looking at its yield type, we need to
 	// return any as that's what other code historically expects for type
 	// comparisions.
 	if ( IsUnspecifiedVector() )
-		return ::base_type(TYPE_ANY).get();
+		return ::base_type(TYPE_ANY);
 
-	return yield_type.get();
-	}
-
-const BroType* VectorType::YieldType() const
-	{
-	// Work around the fact that we use void internally to mark a vector
-	// as being unspecified. When looking at its yield type, we need to
-	// return any as that's what other code historically expects for type
-	// comparisions.
-	if ( IsUnspecifiedVector() )
-		{
-		auto ret = ::base_type(TYPE_ANY);
-		assert(ret);
-		// release, because this won't be held by anyone.
-		return ret.release();
-		}
-
-	return yield_type.get();
+	return yield_type;
 	}
 
 int VectorType::MatchesIndex(ListExpr* const index) const
@@ -1397,8 +1356,8 @@ int VectorType::MatchesIndex(ListExpr* const index) const
 	if ( el.length() == 2 )
 		return MATCHES_INDEX_VECTOR;
 	else if ( el[0]->Type()->Tag() == TYPE_VECTOR )
-		return (IsIntegral(el[0]->Type()->YieldType()->Tag()) ||
-			 IsBool(el[0]->Type()->YieldType()->Tag())) ?
+		return (IsIntegral(el[0]->Type()->Yield()->Tag()) ||
+			 IsBool(el[0]->Type()->Yield()->Tag())) ?
 				MATCHES_INDEX_VECTOR : DOES_NOT_MATCH_INDEX;
 	else
 		return (IsIntegral(el[0]->Type()->Tag()) ||
@@ -1528,8 +1487,8 @@ bool same_type(const BroType* t1, const BroType* t2, bool is_init, bool match_re
 				return false;
 			}
 
-		const BroType* y1 = t1->YieldType();
-		const BroType* y2 = t2->YieldType();
+		const BroType* y1 = t1->Yield().get();
+		const BroType* y2 = t2->Yield().get();
 
 		if ( y1 || y2 )
 			{
@@ -1548,10 +1507,10 @@ bool same_type(const BroType* t1, const BroType* t2, bool is_init, bool match_re
 		if ( ft1->Flavor() != ft2->Flavor() )
 			return false;
 
-		if ( t1->YieldType() || t2->YieldType() )
+		if ( t1->Yield() || t2->Yield() )
 			{
-			if ( ! t1->YieldType() || ! t2->YieldType() ||
-			     ! same_type(t1->YieldType(), t2->YieldType(), is_init, match_record_field_names) )
+			if ( ! t1->Yield() || ! t2->Yield() ||
+			     ! same_type(t1->Yield().get(), t2->Yield().get(), is_init, match_record_field_names) )
 				return false;
 			}
 
@@ -1596,7 +1555,7 @@ bool same_type(const BroType* t1, const BroType* t2, bool is_init, bool match_re
 
 	case TYPE_VECTOR:
 	case TYPE_FILE:
-		return same_type(t1->YieldType(), t2->YieldType(), is_init, match_record_field_names);
+		return same_type(t1->Yield().get(), t2->Yield().get(), is_init, match_record_field_names);
 
 	case TYPE_OPAQUE:
 		{
@@ -1848,8 +1807,8 @@ IntrusivePtr<BroType> merge_types(const BroType* t1, const BroType* t2)
 			tl3->Append(std::move(tl3_i));
 			}
 
-		const BroType* y1 = t1->YieldType();
-		const BroType* y2 = t2->YieldType();
+		const BroType* y1 = t1->Yield().get();
+		const BroType* y2 = t2->Yield().get();
 		IntrusivePtr<BroType> y3;
 
 		if ( y1 || y2 )
@@ -1882,8 +1841,8 @@ IntrusivePtr<BroType> merge_types(const BroType* t1, const BroType* t2)
 		const FuncType* ft1 = (const FuncType*) t1;
 		const FuncType* ft2 = (const FuncType*) t1;
 		auto args = cast_intrusive<RecordType>(merge_types(ft1->Args(), ft2->Args()));
-		auto yield = t1->YieldType() ?
-			merge_types(t1->YieldType(), t2->YieldType()) : nullptr;
+		auto yield = t1->Yield() ?
+			merge_types(t1->Yield().get(), t2->Yield().get()) : nullptr;
 
 		return make_intrusive<FuncType>(std::move(args), std::move(yield),
 		                                ft1->Flavor());
@@ -1967,22 +1926,22 @@ IntrusivePtr<BroType> merge_types(const BroType* t1, const BroType* t2)
 		}
 
 	case TYPE_VECTOR:
-		if ( ! same_type(t1->YieldType(), t2->YieldType()) )
+		if ( ! same_type(t1->Yield().get(), t2->Yield().get()) )
 			{
 			t1->Error("incompatible types", t2);
 			return nullptr;
 			}
 
-		return make_intrusive<VectorType>(merge_types(t1->YieldType(), t2->YieldType()));
+		return make_intrusive<VectorType>(merge_types(t1->Yield().get(), t2->Yield().get()));
 
 	case TYPE_FILE:
-		if ( ! same_type(t1->YieldType(), t2->YieldType()) )
+		if ( ! same_type(t1->Yield().get(), t2->Yield().get()) )
 			{
 			t1->Error("incompatible types", t2);
 			return nullptr;
 			}
 
-		return make_intrusive<FileType>(merge_types(t1->YieldType(), t2->YieldType()));
+		return make_intrusive<FileType>(merge_types(t1->Yield().get(), t2->Yield().get()));
 
 	case TYPE_UNION:
 		reporter->InternalError("union type in merge_types()");
diff --git a/src/Type.h b/src/Type.h
index d8c24e365a..c215603c82 100644
--- a/src/Type.h
+++ b/src/Type.h
@@ -171,9 +171,14 @@ public:
 	// Returns the type yielded by this type.  For example, if
 	// this type is a table[string] of port, then returns the "port"
 	// type.  Returns nil if this is not an index type.
-	virtual BroType* YieldType();
+	virtual const IntrusivePtr<BroType>& Yield() const;
+
+	[[deprecated("Remove in v4.1.  Use Yield() instead.")]]
+	virtual BroType* YieldType()
+		{ return Yield().get(); }
+	[[deprecated("Remove in v4.1.  Use Yield() instead.")]]
 	virtual const BroType* YieldType() const
-		{ return ((BroType*) this)->YieldType(); }
+		{ return Yield().get(); }
 
 	// Returns true if this type is a record and contains the
 	// given field, false otherwise.
@@ -307,12 +312,12 @@ public:
 
 	bool IsSet() const
 		{
-		return tag == TYPE_TABLE && (YieldType() == nullptr);
+		return tag == TYPE_TABLE && ! Yield();
 		}
 
 	bool IsTable() const
 		{
-		return tag == TYPE_TABLE && (YieldType() != nullptr);
+		return tag == TYPE_TABLE && Yield();
 		}
 
 	BroType* Ref()		{ ::Ref(this); return this; }
@@ -398,8 +403,8 @@ public:
 	const std::vector<IntrusivePtr<BroType>>& IndexTypes() const
 		{ return indices->Types(); }
 
-	BroType* YieldType() override;
-	const BroType* YieldType() const override;
+	const IntrusivePtr<BroType>& Yield() const override
+		{ return yield_type; }
 
 	void Describe(ODesc* d) const override;
 	void DescribeReST(ODesc* d, bool roles_only = false) const override;
@@ -469,8 +474,10 @@ public:
 	~FuncType() override;
 
 	RecordType* Args() const	{ return args.get(); }
-	BroType* YieldType() override;
-	const BroType* YieldType() const override;
+
+	const IntrusivePtr<BroType>& Yield() const override
+		{ return yield; }
+
 	void SetYieldType(IntrusivePtr<BroType> arg_yield)	{ yield = std::move(arg_yield); }
 	function_flavor Flavor() const { return flavor; }
 	std::string FlavorString() const;
@@ -646,7 +653,8 @@ public:
 	IntrusivePtr<BroType> ShallowClone() override { return make_intrusive<FileType>(yield); }
 	~FileType() override;
 
-	BroType* YieldType() override;
+	const IntrusivePtr<BroType>& Yield() const override
+		{ return yield; }
 
 	void Describe(ODesc* d) const override;
 
@@ -729,8 +737,8 @@ public:
 	explicit VectorType(IntrusivePtr<BroType> t);
 	IntrusivePtr<BroType> ShallowClone() override;
 	~VectorType() override;
-	BroType* YieldType() override;
-	const BroType* YieldType() const override;
+
+	const IntrusivePtr<BroType>& Yield() const override;
 
 	int MatchesIndex(ListExpr* index) const override;
 
diff --git a/src/Val.cc b/src/Val.cc
index 8d1a1707e7..cf76a1771f 100644
--- a/src/Val.cc
+++ b/src/Val.cc
@@ -1348,7 +1348,7 @@ static void find_nested_record_types(BroType* t, std::set<RecordType*>* found)
 		return;
 	case TYPE_TABLE:
 		find_nested_record_types(t->AsTableType()->Indices(), found);
-		find_nested_record_types(t->AsTableType()->YieldType(), found);
+		find_nested_record_types(t->AsTableType()->Yield().get(), found);
 		return;
 	case TYPE_LIST:
 		{
@@ -1358,10 +1358,10 @@ static void find_nested_record_types(BroType* t, std::set<RecordType*>* found)
 		return;
 	case TYPE_FUNC:
 		find_nested_record_types(t->AsFuncType()->Args(), found);
-		find_nested_record_types(t->AsFuncType()->YieldType(), found);
+		find_nested_record_types(t->AsFuncType()->Yield().get(), found);
 		return;
 	case TYPE_VECTOR:
-		find_nested_record_types(t->AsVectorType()->YieldType(), found);
+		find_nested_record_types(t->AsVectorType()->Yield().get(), found);
 		return;
 	case TYPE_TYPE:
 		find_nested_record_types(t->AsTypeType()->Type(), found);
@@ -1439,7 +1439,7 @@ int TableVal::RecursiveSize() const
 	int n = AsTable()->Length();
 
 	if ( Type()->IsSet() ||
-	     const_cast<TableType*>(Type()->AsTableType())->YieldType()->Tag()
+	     const_cast<TableType*>(Type()->AsTableType())->Yield()->Tag()
 			!= TYPE_TABLE )
 		return n;
 
@@ -1809,11 +1809,11 @@ IntrusivePtr<Val> TableVal::Default(Val* index)
 
 	if ( ! def_val )
 		{
-		BroType* ytype = Type()->YieldType();
+		const auto& ytype = Type()->Yield();
 		BroType* dtype = def_attr->AttrExpr()->Type();
 
 		if ( dtype->Tag() == TYPE_RECORD && ytype->Tag() == TYPE_RECORD &&
-		     ! same_type(dtype, ytype) &&
+		     ! same_type(dtype, ytype.get()) &&
 		     record_promotion_compatible(dtype->AsRecordType(),
 						 ytype->AsRecordType()) )
 			{
@@ -1834,7 +1834,7 @@ IntrusivePtr<Val> TableVal::Default(Val* index)
 		}
 
 	if ( def_val->Type()->Tag() != TYPE_FUNC ||
-	     same_type(def_val->Type(), Type()->YieldType()) )
+	     same_type(def_val->Type(), Type()->Yield().get()) )
 		{
 		if ( def_attr->AttrExpr()->IsConst() )
 			return def_val;
@@ -2305,11 +2305,11 @@ void TableVal::InitDefaultFunc(Frame* f)
 	if ( ! def_attr )
 		return;
 
-	BroType* ytype = Type()->YieldType();
+	const auto& ytype = Type()->Yield();
 	BroType* dtype = def_attr->AttrExpr()->Type();
 
 	if ( dtype->Tag() == TYPE_RECORD && ytype->Tag() == TYPE_RECORD &&
-	     ! same_type(dtype, ytype) &&
+	     ! same_type(dtype, ytype.get()) &&
 	     record_promotion_compatible(dtype->AsRecordType(),
 					 ytype->AsRecordType()) )
 		return; // TableVal::Default will handle this.
@@ -3001,7 +3001,7 @@ IntrusivePtr<Val> VectorVal::SizeVal() const
 bool VectorVal::Assign(unsigned int index, IntrusivePtr<Val> element)
 	{
 	if ( element &&
-	     ! same_type(element->Type(), vector_type->YieldType(), false) )
+	     ! same_type(element->Type(), vector_type->Yield().get(), false) )
 		return false;
 
 	Val* val_at_index = nullptr;
@@ -3042,7 +3042,7 @@ bool VectorVal::AssignRepeat(unsigned int index, unsigned int how_many,
 bool VectorVal::Insert(unsigned int index, Val* element)
 	{
 	if ( element &&
-	     ! same_type(element->Type(), vector_type->YieldType(), false) )
+	     ! same_type(element->Type(), vector_type->Yield().get(), false) )
 		{
 		Unref(element);
 		return false;
diff --git a/src/Var.cc b/src/Var.cc
index 33cbc7916e..a9881b6c3b 100644
--- a/src/Var.cc
+++ b/src/Var.cc
@@ -459,7 +459,7 @@ void begin_func(ID* id, const char* module_name, function_flavor flavor,
 	{
 	if ( flavor == FUNC_FLAVOR_EVENT )
 		{
-		const BroType* yt = t->YieldType();
+		const auto& yt = t->Yield();
 
 		if ( yt && yt->Tag() != TYPE_VOID )
 			id->Error("event cannot yield a value", t.get());
diff --git a/src/broker/Data.cc b/src/broker/Data.cc
index 2e405e1f1e..cbed055db3 100644
--- a/src/broker/Data.cc
+++ b/src/broker/Data.cc
@@ -314,7 +314,7 @@ struct val_converter {
 				}
 
 			auto value_val = bro_broker::data_to_val(move(item.second),
-			                                         tt->YieldType());
+			                                         tt->Yield().get());
 
 			if ( ! value_val )
 				return nullptr;
@@ -334,7 +334,7 @@ struct val_converter {
 
 			for ( auto& item : a )
 				{
-				auto item_val = bro_broker::data_to_val(move(item), vt->YieldType());
+				auto item_val = bro_broker::data_to_val(move(item), vt->Yield().get());
 
 				if ( ! item_val )
 					return nullptr;
@@ -667,7 +667,7 @@ struct type_checker {
 					return false;
 				}
 
-			if ( ! data_type_check(item.second, tt->YieldType()) )
+			if ( ! data_type_check(item.second, tt->Yield().get()) )
 				return false;
 			}
 
@@ -682,7 +682,7 @@ struct type_checker {
 
 			for ( auto& item : a )
 				{
-				if ( ! data_type_check(item, vt->YieldType()) )
+				if ( ! data_type_check(item, vt->Yield().get()) )
 					return false;
 				}
 
diff --git a/src/input/Manager.cc b/src/input/Manager.cc
index 766a0c559a..a72f7a5894 100644
--- a/src/input/Manager.cc
+++ b/src/input/Manager.cc
@@ -522,13 +522,13 @@ bool Manager::CreateTableStream(RecordVal* fval)
 
 	if ( val )
 		{
-		const BroType* table_yield = dst->Type()->AsTableType()->YieldType();
+		const auto& table_yield = dst->Type()->AsTableType()->Yield();
 		const BroType* compare_type = val.get();
 
 		if ( want_record->InternalInt() == 0 )
 			compare_type = val->GetFieldType(0).get();
 
-		if ( ! same_type(table_yield, compare_type) )
+		if ( ! same_type(table_yield.get(), compare_type) )
 			{
 			ODesc desc1;
 			ODesc desc2;
@@ -821,7 +821,7 @@ bool Manager::IsCompatibleType(BroType* t, bool atomic_only)
 		if ( atomic_only )
 			return false;
 
-		return IsCompatibleType(t->AsVectorType()->YieldType(), true);
+		return IsCompatibleType(t->AsVectorType()->Yield().get(), true);
 		}
 
 	default:
@@ -945,7 +945,7 @@ bool Manager::UnrollRecordType(vector<Field*> *fields, const RecordType *rec,
 				st = rec->GetFieldType(i)->AsSetType()->Indices()->GetPureType()->Tag();
 
 			else if ( ty == TYPE_VECTOR )
-				st = rec->GetFieldType(i)->AsVectorType()->YieldType()->Tag();
+				st = rec->GetFieldType(i)->AsVectorType()->Yield()->Tag();
 
 			else if ( ty == TYPE_PORT &&
 				  rec->FieldDecl(i)->FindAttr(ATTR_TYPE_COLUMN) )
@@ -2354,16 +2354,14 @@ Val* Manager::ValueToVal(const Stream* i, const Value* val, BroType* request_typ
 	case TYPE_VECTOR:
 		{
 		// all entries have to have the same type...
-		BroType* type = request_type->AsVectorType()->YieldType();
-		VectorType* vt = new VectorType({NewRef{}, type});
-		VectorVal* v = new VectorVal(vt);
-		for ( int j = 0; j < val->val.vector_val.size; j++ )
-			{
-			v->Assign(j, ValueToVal(i, val->val.vector_val.vals[j], type, have_error));
-			}
+		const auto& type = request_type->AsVectorType()->Yield();
+		auto vt = make_intrusive<VectorType>(type);
+		auto v = make_intrusive<VectorVal>(vt.get());
 
-		Unref(vt);
-		return v;
+		for ( int j = 0; j < val->val.vector_val.size; j++ )
+			v->Assign(j, ValueToVal(i, val->val.vector_val.vals[j], type.get(), have_error));
+
+		return v.release();
 		}
 
 	case TYPE_ENUM: {
diff --git a/src/input/readers/config/Config.cc b/src/input/readers/config/Config.cc
index 22433453fe..cc2866f63d 100644
--- a/src/input/readers/config/Config.cc
+++ b/src/input/readers/config/Config.cc
@@ -47,7 +47,7 @@ Config::Config(ReaderFrontend *frontend) : ReaderBackend(frontend)
 		if ( primary == TYPE_TABLE )
 			secondary = id->Type()->AsSetType()->Indices()->GetPureType()->Tag();
 		else if ( primary == TYPE_VECTOR )
-			secondary = id->Type()->AsVectorType()->YieldType()->Tag();
+			secondary = id->Type()->AsVectorType()->Yield()->Tag();
 
 		option_types[id->Name()] = std::make_tuple(primary, secondary);
 		}
diff --git a/src/logging/Manager.cc b/src/logging/Manager.cc
index 44327ee43e..2a190ba53a 100644
--- a/src/logging/Manager.cc
+++ b/src/logging/Manager.cc
@@ -401,7 +401,7 @@ bool Manager::TraverseRecord(Stream* stream, Filter* filter, RecordType* rt,
 		if ( j < num_ext_fields )
 			{
 			i = j;
-			rtype = filter->ext_func->FType()->YieldType()->AsRecordType();
+			rtype = filter->ext_func->FType()->Yield()->AsRecordType();
 			}
 		else
 			{
@@ -520,7 +520,7 @@ bool Manager::TraverseRecord(Stream* stream, Filter* filter, RecordType* rt,
 			st = t->AsSetType()->Indices()->GetPureType()->Tag();
 
 		else if ( t->Tag() == TYPE_VECTOR )
-			st = t->AsVectorType()->YieldType()->Tag();
+			st = t->AsVectorType()->Yield()->Tag();
 
 		bool optional = rtype->FieldDecl(i)->FindAttr(ATTR_OPTIONAL);
 
@@ -587,18 +587,18 @@ bool Manager::AddFilter(EnumVal* id, RecordVal* fval)
 	filter->num_ext_fields = 0;
 	if ( filter->ext_func )
 		{
-		if ( filter->ext_func->FType()->YieldType()->Tag() == TYPE_RECORD )
+		if ( filter->ext_func->FType()->Yield()->Tag() == TYPE_RECORD )
 			{
-			filter->num_ext_fields = filter->ext_func->FType()->YieldType()->AsRecordType()->NumFields();
+			filter->num_ext_fields = filter->ext_func->FType()->Yield()->AsRecordType()->NumFields();
 			}
-		else if ( filter->ext_func->FType()->YieldType()->Tag() == TYPE_VOID )
+		else if ( filter->ext_func->FType()->Yield()->Tag() == TYPE_VOID )
 			{
 			// This is a special marker for the default no-implementation
 			// of the ext_func and we'll allow it to slide.
 			}
 		else
 			{
-			reporter->Error("Return value of log_ext is not a record (got %s)", type_name(filter->ext_func->FType()->YieldType()->Tag()));
+			reporter->Error("Return value of log_ext is not a record (got %s)", type_name(filter->ext_func->FType()->Yield()->Tag()));
 			delete filter;
 			return false;
 			}
@@ -1038,7 +1038,7 @@ threading::Value* Manager::ValToLogVal(Val* val, BroType* ty)
 			{
 			lval->val.vector_val.vals[i] =
 				ValToLogVal(vec->Lookup(i),
-					    vec->Type()->YieldType());
+					    vec->Type()->Yield().get());
 			}
 
 		break;
diff --git a/src/option.bif b/src/option.bif
index dd534811a8..2105054cfc 100644
--- a/src/option.bif
+++ b/src/option.bif
@@ -199,10 +199,10 @@ function Option::set_change_handler%(ID: string, on_change: any, priority: int &
 		return val_mgr->False();
 		}
 
-	if ( ! same_type(on_change->Type()->AsFuncType()->YieldType(), i->Type()) )
+	if ( ! same_type(on_change->Type()->AsFuncType()->Yield().get(), i->Type()) )
 		{
 		builtin_error(fmt("Passed function needs to return type '%s' for ID '%s'; got '%s'",
-			type_name(i->Type()->Tag()), ID->CheckString(), type_name(on_change->Type()->AsFuncType()->YieldType()->Tag())));
+			type_name(i->Type()->Tag()), ID->CheckString(), type_name(on_change->Type()->AsFuncType()->Yield()->Tag())));
 		return val_mgr->False();
 		}
 
diff --git a/src/threading/SerialTypes.cc b/src/threading/SerialTypes.cc
index 2d39fecf51..189b40798a 100644
--- a/src/threading/SerialTypes.cc
+++ b/src/threading/SerialTypes.cc
@@ -154,7 +154,7 @@ bool Value::IsCompatibleType(BroType* t, bool atomic_only)
 		if ( atomic_only )
 			return false;
 
-		return IsCompatibleType(t->AsVectorType()->YieldType(), true);
+		return IsCompatibleType(t->AsVectorType()->Yield().get(), true);
 		}
 
 	default:
diff --git a/src/zeek.bif b/src/zeek.bif
index bea7c94761..fc14bbb892 100644
--- a/src/zeek.bif
+++ b/src/zeek.bif
@@ -804,7 +804,7 @@ function sha256_hash_finish%(handle: opaque of sha256%): string
 function paraglob_init%(v: any%) : opaque of paraglob
 	%{
 	if ( v->Type()->Tag() != TYPE_VECTOR ||
-	     v->Type()->YieldType()->Tag() != TYPE_STRING )
+	     v->Type()->Yield()->Tag() != TYPE_STRING )
 		{
 		// reporter->Error will throw an exception.
 		reporter->Error("paraglob requires a vector of strings for initialization.");
@@ -1281,7 +1281,7 @@ function resize%(aggr: any, newsize: count%) : count
 function any_set%(v: any%) : bool
 	%{
 	if ( v->Type()->Tag() != TYPE_VECTOR ||
-	     v->Type()->YieldType()->Tag() != TYPE_BOOL )
+	     v->Type()->Yield()->Tag() != TYPE_BOOL )
 		{
 		builtin_error("any_set() requires vector of bool");
 		return val_mgr->False();
@@ -1310,7 +1310,7 @@ function any_set%(v: any%) : bool
 function all_set%(v: any%) : bool
 	%{
 	if ( v->Type()->Tag() != TYPE_VECTOR ||
-	     v->Type()->YieldType()->Tag() != TYPE_BOOL )
+	     v->Type()->Yield()->Tag() != TYPE_BOOL )
 		{
 		builtin_error("all_set() requires vector of bool");
 		return val_mgr->False();
@@ -1408,7 +1408,7 @@ function sort%(v: any, ...%) : any
 		return rval;
 		}
 
-	BroType* elt_type = v->Type()->YieldType();
+	const auto& elt_type = v->Type()->Yield();
 	Func* comp = 0;
 
 	if ( @ARG@.size() > 2 )
@@ -1434,7 +1434,7 @@ function sort%(v: any, ...%) : any
 	if ( comp )
 		{
 		FuncType* comp_type = comp->FType()->AsFuncType();
-		if ( comp_type->YieldType()->Tag() != TYPE_INT ||
+		if ( comp_type->Yield()->Tag() != TYPE_INT ||
 		     ! comp_type->ArgTypes()->AllMatch(elt_type, 0) )
 			{
 			builtin_error("invalid comparison function in call to sort()");
@@ -1478,7 +1478,7 @@ function order%(v: any, ...%) : index_vec
 		return result_v;
 		}
 
-	BroType* elt_type = v->Type()->YieldType();
+	const auto& elt_type = v->Type()->Yield();
 	Func* comp = 0;
 
 	if ( @ARG@.size() > 2 )
@@ -1516,7 +1516,7 @@ function order%(v: any, ...%) : index_vec
 	if ( comp )
 		{
 		FuncType* comp_type = comp->FType()->AsFuncType();
-		if ( comp_type->YieldType()->Tag() != TYPE_INT ||
+		if ( comp_type->Yield()->Tag() != TYPE_INT ||
 		     ! comp_type->ArgTypes()->AllMatch(elt_type, 0) )
 			{
 			builtin_error("invalid comparison function in call to order()");