diff --git a/scripts/qapi/expr.py b/scripts/qapi/expr.py
index 4ebed4c488..de7fc16fac 100644
--- a/scripts/qapi/expr.py
+++ b/scripts/qapi/expr.py
@@ -146,30 +146,29 @@ def check_flags(expr: _JSONObject, info: QAPISourceInfo) -> None:
 
 def check_if(expr: _JSONObject, info: QAPISourceInfo, source: str) -> None:
 
-    def check_if_str(ifcond: object) -> None:
-        if not isinstance(ifcond, str):
+    ifcond = expr.get('if')
+    if ifcond is None:
+        return
+
+    if isinstance(ifcond, list):
+        if not ifcond:
+            raise QAPISemError(
+                info, "'if' condition [] of %s is useless" % source)
+    else:
+        # Normalize to a list
+        ifcond = expr['if'] = [ifcond]
+
+    for elt in ifcond:
+        if not isinstance(elt, str):
             raise QAPISemError(
                 info,
                 "'if' condition of %s must be a string or a list of strings"
                 % source)
-        if ifcond.strip() == '':
+        if not elt.strip():
             raise QAPISemError(
                 info,
                 "'if' condition '%s' of %s makes no sense"
-                % (ifcond, source))
-
-    ifcond = expr.get('if')
-    if ifcond is None:
-        return
-    if isinstance(ifcond, list):
-        if ifcond == []:
-            raise QAPISemError(
-                info, "'if' condition [] of %s is useless" % source)
-        for elt in ifcond:
-            check_if_str(elt)
-    else:
-        check_if_str(ifcond)
-        expr['if'] = [ifcond]
+                % (elt, source))
 
 
 def normalize_members(members: object) -> None: