[PATCH 06/19] qapi/schema: adjust type narrowing for mypy's benefit

[John Snow]

We already take care to perform some type narrowing for arg_type and
ret_type, but not in a way where mypy can utilize the result. A simple
change to use a temporary variable helps the medicine go down.

Signed-off-by: John Snow <jsnow@redhat.com>
---
 scripts/qapi/schema.py | 17 +++++++++--------
 1 file changed, 9 insertions(+), 8 deletions(-)

diff --git a/scripts/qapi/schema.py b/scripts/qapi/schema.py
index 4600a566005..a1094283828 100644
--- a/scripts/qapi/schema.py
+++ b/scripts/qapi/schema.py
@@ -825,13 +825,14 @@ def __init__(self, name, info, doc, ifcond, features,
     def check(self, schema):
         super().check(schema)
         if self._arg_type_name:
-            self.arg_type = schema.resolve_type(
+            arg_type = schema.resolve_type(
                 self._arg_type_name, self.info, "command's 'data'")
-            if not isinstance(self.arg_type, QAPISchemaObjectType):
+            if not isinstance(arg_type, QAPISchemaObjectType):
                 raise QAPISemError(
                     self.info,
                     "command's 'data' cannot take %s"
-                    % self.arg_type.describe())
+                    % arg_type.describe())
+            self.arg_type = arg_type
             if self.arg_type.variants and not self.boxed:
                 raise QAPISemError(
                     self.info,
@@ -848,8 +849,7 @@ def check(self, schema):
             if self.name not in self.info.pragma.command_returns_exceptions:
                 typ = self.ret_type
                 if isinstance(typ, QAPISchemaArrayType):
-                    typ = self.ret_type.element_type
-                    assert typ
+                    typ = typ.element_type
                 if not isinstance(typ, QAPISchemaObjectType):
                     raise QAPISemError(
                         self.info,
@@ -885,13 +885,14 @@ def __init__(self, name, info, doc, ifcond, features, 
arg_type, boxed):
     def check(self, schema):
         super().check(schema)
         if self._arg_type_name:
-            self.arg_type = schema.resolve_type(
+            typ = schema.resolve_type(
                 self._arg_type_name, self.info, "event's 'data'")
-            if not isinstance(self.arg_type, QAPISchemaObjectType):
+            if not isinstance(typ, QAPISchemaObjectType):
                 raise QAPISemError(
                     self.info,
                     "event's 'data' cannot take %s"
-                    % self.arg_type.describe())
+                    % typ.describe())
+            self.arg_type = typ
             if self.arg_type.variants and not self.boxed:
                 raise QAPISemError(
                     self.info,
-- 
2.41.0