diff --git a/scripts/qapi/schema.py b/scripts/qapi/schema.py
index ef4d6a7def..e52930a48a 100644
--- a/scripts/qapi/schema.py
+++ b/scripts/qapi/schema.py
@@ -123,10 +123,8 @@ def __init__(
         ifcond: Optional[QAPISchemaIfCond] = None,
         features: Optional[List[QAPISchemaFeature]] = None,
     ):
-        assert isinstance(name, str)
         super().__init__(info)
         for f in features or []:
-            assert isinstance(f, QAPISchemaFeature)
             f.set_defined_in(name)
         self.name = name
         self.doc = doc
@@ -163,7 +161,6 @@ def is_implicit(self) -> bool:
         return not self.info
 
     def describe(self) -> str:
-        assert self.meta
         return "%s '%s'" % (self.meta, self.name)
 
 
@@ -377,7 +374,6 @@ def check(self, schema: QAPISchema) -> None:
                     f"feature '{feat.name}' is not supported for types")
 
     def describe(self) -> str:
-        assert self.meta
         return "%s type '%s'" % (self.meta, self.name)
 
 
@@ -386,7 +382,6 @@ class QAPISchemaBuiltinType(QAPISchemaType):
 
     def __init__(self, name: str, json_type: str, c_type: str):
         super().__init__(name, None, None)
-        assert not c_type or isinstance(c_type, str)
         assert json_type in ('string', 'number', 'int', 'boolean', 'null',
                              'value')
         self._json_type_name = json_type
@@ -429,9 +424,7 @@ def __init__(
     ):
         super().__init__(name, info, doc, ifcond, features)
         for m in members:
-            assert isinstance(m, QAPISchemaEnumMember)
             m.set_defined_in(name)
-        assert prefix is None or isinstance(prefix, str)
         self.members = members
         self.prefix = prefix
 
@@ -474,7 +467,6 @@ def __init__(
         self, name: str, info: Optional[QAPISourceInfo], element_type: str
     ):
         super().__init__(name, info, None)
-        assert isinstance(element_type, str)
         self._element_type_name = element_type
         self.element_type: QAPISchemaType
 
@@ -519,7 +511,6 @@ def visit(self, visitor: QAPISchemaVisitor) -> None:
                                  self.element_type)
 
     def describe(self) -> str:
-        assert self.meta
         return "%s type ['%s']" % (self.meta, self._element_type_name)
 
 
@@ -539,12 +530,9 @@ def __init__(
         # union has base, variants, and no local_members
         super().__init__(name, info, doc, ifcond, features)
         self.meta = 'union' if variants else 'struct'
-        assert base is None or isinstance(base, str)
         for m in local_members:
-            assert isinstance(m, QAPISchemaObjectTypeMember)
             m.set_defined_in(name)
         if variants is not None:
-            assert isinstance(variants, QAPISchemaVariants)
             variants.set_defined_in(name)
         self._base_name = base
         self.base = None
@@ -666,7 +654,6 @@ def __init__(
         variants: QAPISchemaVariants,
     ):
         super().__init__(name, info, doc, ifcond, features)
-        assert isinstance(variants, QAPISchemaVariants)
         assert variants.tag_member
         variants.set_defined_in(name)
         variants.tag_member.set_defined_in(self.name)
@@ -742,8 +729,6 @@ def __init__(
         assert bool(tag_member) != bool(tag_name)
         assert (isinstance(tag_name, str) or
                 isinstance(tag_member, QAPISchemaObjectTypeMember))
-        for v in variants:
-            assert isinstance(v, QAPISchemaVariant)
         self._tag_name = tag_name
         self.info = info
         self._tag_member = tag_member
@@ -858,7 +843,6 @@ def __init__(
         info: Optional[QAPISourceInfo],
         ifcond: Optional[QAPISchemaIfCond] = None,
     ):
-        assert isinstance(name, str)
         self.name = name
         self.info = info
         self.ifcond = ifcond or QAPISchemaIfCond()
@@ -926,7 +910,6 @@ def __init__(
     ):
         super().__init__(name, info, ifcond)
         for f in features or []:
-            assert isinstance(f, QAPISchemaFeature)
             f.set_defined_in(name)
         self.features = features or []
 
@@ -955,10 +938,7 @@ def __init__(
         features: Optional[List[QAPISchemaFeature]] = None,
     ):
         super().__init__(name, info, ifcond)
-        assert isinstance(typ, str)
-        assert isinstance(optional, bool)
         for f in features or []:
-            assert isinstance(f, QAPISchemaFeature)
             f.set_defined_in(name)
         self._type_name = typ
         self.type: QAPISchemaType  # set during check()
@@ -966,7 +946,6 @@ def __init__(
         self.features = features or []
 
     def need_has(self) -> bool:
-        assert self.type
         return self.optional and self.type.need_has_if_optional()
 
     def check(self, schema: QAPISchema) -> None:
@@ -1017,8 +996,6 @@ def __init__(
         coroutine: bool,
     ):
         super().__init__(name, info, doc, ifcond, features)
-        assert not arg_type or isinstance(arg_type, str)
-        assert not ret_type or isinstance(ret_type, str)
         self._arg_type_name = arg_type
         self.arg_type: Optional[QAPISchemaObjectType] = None
         self._ret_type_name = ret_type
@@ -1058,7 +1035,6 @@ def check(self, schema: QAPISchema) -> None:
             if self.name not in self.info.pragma.command_returns_exceptions:
                 typ = self.ret_type
                 if isinstance(typ, QAPISchemaArrayType):
-                    assert typ
                     typ = typ.element_type
                 if not isinstance(typ, QAPISchemaObjectType):
                     raise QAPISemError(
@@ -1096,7 +1072,6 @@ def __init__(
         boxed: bool,
     ):
         super().__init__(name, info, doc, ifcond, features)
-        assert not arg_type or isinstance(arg_type, str)
         self._arg_type_name = arg_type
         self.arg_type: Optional[QAPISchemaObjectType] = None
         self.boxed = boxed
