diff --git a/scripts/qapi/common.py b/scripts/qapi/common.py
index ef7c7be4fd..a58e904978 100644
--- a/scripts/qapi/common.py
+++ b/scripts/qapi/common.py
@@ -877,14 +877,13 @@ def check_union(expr, info):
         discriminator_value = base_members.get(discriminator)
         if not discriminator_value:
             raise QAPISemError(info,
-                               "Discriminator '%s' is not a member of base "
-                               "struct '%s'"
-                               % (discriminator, base))
+                               "Discriminator '%s' is not a member of 'base'"
+                               % discriminator)
         if discriminator_value.get('if'):
             raise QAPISemError(
                 info,
-                "The discriminator %s.%s for union %s must not be conditional"
-                % (base, discriminator, name))
+                "The discriminator '%s' for union %s must not be conditional"
+                % (discriminator, name))
         enum_define = enum_types.get(discriminator_value['type'])
         # Do not allow string discriminator
         if not enum_define:
diff --git a/tests/qapi-schema/flat-union-invalid-discriminator.err b/tests/qapi-schema/flat-union-invalid-discriminator.err
index 947a6b73aa..495d5a520e 100644
--- a/tests/qapi-schema/flat-union-invalid-discriminator.err
+++ b/tests/qapi-schema/flat-union-invalid-discriminator.err
@@ -1 +1 @@
-tests/qapi-schema/flat-union-invalid-discriminator.json:11: Discriminator 'enum_wrong' is not a member of base struct 'OrderedDict([('enum1', {'type': 'TestEnum'})])'
+tests/qapi-schema/flat-union-invalid-discriminator.json:10: Discriminator 'enum_wrong' is not a member of 'base'
diff --git a/tests/qapi-schema/flat-union-invalid-discriminator.json b/tests/qapi-schema/flat-union-invalid-discriminator.json
index de86cf0760..c4fce97362 100644
--- a/tests/qapi-schema/flat-union-invalid-discriminator.json
+++ b/tests/qapi-schema/flat-union-invalid-discriminator.json
@@ -1,4 +1,3 @@
-# FIXME error message shows base as OrderedDict
 { 'enum': 'TestEnum',
   'data': [ 'value1', 'value2' ] }
 
diff --git a/tests/qapi-schema/flat-union-invalid-if-discriminator.err b/tests/qapi-schema/flat-union-invalid-if-discriminator.err
index ec04c4840c..cc5c3fb80b 100644
--- a/tests/qapi-schema/flat-union-invalid-if-discriminator.err
+++ b/tests/qapi-schema/flat-union-invalid-if-discriminator.err
@@ -1 +1 @@
-tests/qapi-schema/flat-union-invalid-if-discriminator.json:11: The discriminator OrderedDict([('enum1', OrderedDict([('type', 'TestEnum'), ('if', 'FOO')]))]).enum1 for union TestUnion must not be conditional
+tests/qapi-schema/flat-union-invalid-if-discriminator.json:10: The discriminator 'enum1' for union TestUnion must not be conditional
diff --git a/tests/qapi-schema/flat-union-invalid-if-discriminator.json b/tests/qapi-schema/flat-union-invalid-if-discriminator.json
index bbaa9a3f82..e49992b798 100644
--- a/tests/qapi-schema/flat-union-invalid-if-discriminator.json
+++ b/tests/qapi-schema/flat-union-invalid-if-discriminator.json
@@ -1,4 +1,3 @@
-# FIXME error message shows base as OrderedDict
 { 'enum': 'TestEnum',
   'data': [ 'value1', 'value2' ] }
 
diff --git a/tests/qapi-schema/flat-union-optional-discriminator.err b/tests/qapi-schema/flat-union-optional-discriminator.err
index 8b4a4ba847..45f5407c34 100644
--- a/tests/qapi-schema/flat-union-optional-discriminator.err
+++ b/tests/qapi-schema/flat-union-optional-discriminator.err
@@ -1 +1 @@
-tests/qapi-schema/flat-union-optional-discriminator.json:7: Discriminator 'switch' is not a member of base struct 'Base'
+tests/qapi-schema/flat-union-optional-discriminator.json:7: Discriminator 'switch' is not a member of 'base'
diff --git a/tests/qapi-schema/union-base-empty.err b/tests/qapi-schema/union-base-empty.err
index 7695806d81..9453720ede 100644
--- a/tests/qapi-schema/union-base-empty.err
+++ b/tests/qapi-schema/union-base-empty.err
@@ -1 +1 @@
-tests/qapi-schema/union-base-empty.json:5: Discriminator 'type' is not a member of base struct 'Empty'
+tests/qapi-schema/union-base-empty.json:5: Discriminator 'type' is not a member of 'base'