Adds __qualname__ to PyBuiltinFunction

extra_tests/snippets/builtin_type.py

@@ -109,3 +109,17 @@ assert MyTypeWithMethod().N.s.__qualname__ == 'MyTypeWithMethod.N.s'
 assert repr(str.replace) == "<method 'replace' of 'str' objects>"
 assert repr(str.replace) == str(str.replace)
 assert repr(int.to_bytes) == "<method 'to_bytes' of 'int' objects>"
+
+
+# Regression to
+# https://github.com/RustPython/RustPython/issues/2788
+
+assert iter.__qualname__ == iter.__name__ == 'iter'
+assert max.__qualname__ == max.__name__ == 'max'
+assert min.__qualname__ ==  min.__name__ == 'min'
+
+
+def custom_func():
+    pass
+
+assert custom_func.__qualname__ == 'custom_func'

vm/src/builtins/builtinfunc.rs

@@ -118,6 +118,10 @@ impl PyBuiltinFunction {
         self.value.name.clone()
     }
     #[pyproperty(magic)]
+    fn qualname(&self) -> PyStrRef {
+        self.name()
+    }
+    #[pyproperty(magic)]
     fn doc(&self) -> Option<PyStrRef> {
         self.value.doc.clone()
     }