We flag this, but the error message is bogus:

    bad-if-not.json:2: 'if' condition [] of struct is useless

The next commit will fix it.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
---
 tests/qapi-schema/bad-if-not.err  | 2 ++
 tests/qapi-schema/bad-if-not.json | 3 +++
 tests/qapi-schema/bad-if-not.out  | 0
 tests/qapi-schema/meson.build     | 1 +
 4 files changed, 6 insertions(+)
 create mode 100644 tests/qapi-schema/bad-if-not.err
 create mode 100644 tests/qapi-schema/bad-if-not.json
 create mode 100644 tests/qapi-schema/bad-if-not.out

diff --git a/tests/qapi-schema/bad-if-not.err b/tests/qapi-schema/bad-if-not.err
new file mode 100644
index 0000000000..b3acdd679a
--- /dev/null
+++ b/tests/qapi-schema/bad-if-not.err
@@ -0,0 +1,2 @@
+bad-if-not.json: In struct 'TestIfStruct':
+bad-if-not.json:2: 'if' condition [] of struct is useless
diff --git a/tests/qapi-schema/bad-if-not.json b/tests/qapi-schema/bad-if-not.json
new file mode 100644
index 0000000000..9fdaacc47b
--- /dev/null
+++ b/tests/qapi-schema/bad-if-not.json
@@ -0,0 +1,3 @@
+# check 'if not' with empy argument
+{ 'struct': 'TestIfStruct', 'data': { 'foo': 'int' },
+  'if': { 'not': '' } }
diff --git a/tests/qapi-schema/bad-if-not.out b/tests/qapi-schema/bad-if-not.out
new file mode 100644
index 0000000000..e69de29bb2
diff --git a/tests/qapi-schema/meson.build b/tests/qapi-schema/meson.build
index 4697c070bc..6b2a4ce41a 100644
--- a/tests/qapi-schema/meson.build
+++ b/tests/qapi-schema/meson.build
@@ -43,6 +43,7 @@ schemas = [
   'bad-if-key.json',
   'bad-if-keys.json',
   'bad-if-list.json',
+  'bad-if-not.json',
   'bad-type-bool.json',
   'bad-type-dict.json',
   'bad-type-int.json',
-- 
2.31.1