diff --git a/include/qapi/visitor.h b/include/qapi/visitor.h
index 8a2d5cc..a6678b1 100644
--- a/include/qapi/visitor.h
+++ b/include/qapi/visitor.h
@@ -79,6 +79,5 @@ void visit_type_str(Visitor *v, const char *name, char **obj, Error **errp);
 void visit_type_number(Visitor *v, const char *name, double *obj,
                        Error **errp);
 void visit_type_any(Visitor *v, const char *name, QObject **obj, Error **errp);
-bool visit_start_union(Visitor *v, bool data_present, Error **errp);

 #endif
diff --git a/include/qapi/visitor-impl.h b/include/qapi/visitor-impl.h
index 7905a28..c4af3e0 100644
--- a/include/qapi/visitor-impl.h
+++ b/include/qapi/visitor-impl.h
@@ -58,8 +58,6 @@ struct Visitor

     /* May be NULL; most useful for input visitors. */
     void (*optional)(Visitor *v, const char *name, bool *present);
-
-    bool (*start_union)(Visitor *v, bool data_present, Error **errp);
 };

 void input_type_enum(Visitor *v, const char *name, int *obj,
diff --git a/scripts/qapi-visit.py b/scripts/qapi-visit.py
index 367c459..d2c2dc0 100644
--- a/scripts/qapi-visit.py
+++ b/scripts/qapi-visit.py
@@ -15,10 +15,6 @@
 from qapi import *
 import re

-# visit_type_FOO_implicit() is emitted as needed; track if it has already
-# been output.
-implicit_structs_seen = set()
-
 # visit_type_FOO_fields() is always emitted; track if a forward declaration
 # or implementation has already been output.
 struct_fields_seen = set()
@@ -45,31 +41,6 @@ static void visit_type_%(c_type)s_fields(Visitor *v, %(c_type)s *obj, Error **er
                  c_type=typ.c_name())


-def gen_visit_implicit_struct(typ):
-    if typ in implicit_structs_seen:
-        return ''
-    implicit_structs_seen.add(typ)
-
-    ret = gen_visit_fields_decl(typ)
-
-    ret += mcgen('''
-
-static void visit_type_implicit_%(c_type)s(Visitor *v, %(c_type)s **obj, Error **errp)
-{
-    Error *err = NULL;
-
-    visit_start_implicit_struct(v, (void **)obj, sizeof(%(c_type)s), &err);
-    if (!err) {
-        visit_type_%(c_type)s_fields(v, *obj, errp);
-        visit_end_implicit_struct(v);
-    }
-    error_propagate(errp, err);
-}
-''',
-                 c_type=typ.c_name())
-    return ret
-
-
 def gen_visit_struct_fields(name, base, members, variants=None):
     ret = ''

diff --git a/qapi/qapi-visit-core.c b/qapi/qapi-visit-core.c
index b4a0f21..f7b9980 100644
--- a/qapi/qapi-visit-core.c
+++ b/qapi/qapi-visit-core.c
@@ -61,14 +61,6 @@ void visit_end_list(Visitor *v)
     v->end_list(v);
 }

-bool visit_start_union(Visitor *v, bool data_present, Error **errp)
-{
-    if (v->start_union) {
-        return v->start_union(v, data_present, errp);
-    }
-    return true;
-}
-
 bool visit_optional(Visitor *v, const char *name, bool *present)
 {
     if (v->optional) {
diff --git a/qapi/qapi-dealloc-visitor.c b/qapi/qapi-dealloc-visitor.c
index 6667e8c..4eae555 100644
--- a/qapi/qapi-dealloc-visitor.c
+++ b/qapi/qapi-dealloc-visitor.c
@@ -169,31 +169,6 @@ static void qapi_dealloc_type_enum(Visitor *v, const char *name, int *obj,
 {
 }

-/* If there's no data present, the dealloc visitor has nothing to free.
- * Thus, indicate to visitor code that the subsequent union fields can
- * be skipped. This is not an error condition, since the cleanup of the
- * rest of an object can continue unhindered, so leave errp unset in
- * these cases.
- *
- * NOTE: In cases where we're attempting to deallocate an object that
- * may have missing fields, the field indicating the union type may
- * be missing. In such a case, it's possible we don't have enough
- * information to differentiate data_present == false from a case where
- * data *is* present but happens to be a scalar with a value of 0.
- * This is okay, since in the case of the dealloc visitor there's no
- * work that needs to done in either situation.
- *
- * The current inability in QAPI code to more thoroughly verify a union
- * type in such cases will likely need to be addressed if we wish to
- * implement this interface for other types of visitors in the future,
- * however.
- */
-static bool qapi_dealloc_start_union(Visitor *v, bool data_present,
-                                     Error **errp)
-{
-    return data_present;
-}
-
 Visitor *qapi_dealloc_get_visitor(QapiDeallocVisitor *v)
 {
     return &v->visitor;
@@ -224,7 +199,6 @@ QapiDeallocVisitor *qapi_dealloc_visitor_new(void)
     v->visitor.type_str = qapi_dealloc_type_str;
     v->visitor.type_number = qapi_dealloc_type_number;
     v->visitor.type_any = qapi_dealloc_type_anything;
-    v->visitor.start_union = qapi_dealloc_start_union;

     QTAILQ_INIT(&v->stack);

