narrow on initial assignment

mypy/checker.py

@@ -3082,7 +3082,9 @@ def visit_assignment_stmt(self, s: AssignmentStmt) -> None:
         # as X | Y.
         if not (s.is_alias_def and self.is_stub):
             with self.enter_final_context(s.is_final_def):
-                self.check_assignment(s.lvalues[-1], s.rvalue, s.type is None, s.new_syntax)
+                self.check_assignment(
+                    s.lvalues[-1], s.rvalue, infer_lvalue_type=True, new_syntax=s.new_syntax
+                )
 
         if s.is_alias_def:
             self.check_type_alias_rvalue(s)
@@ -3110,7 +3112,7 @@ def visit_assignment_stmt(self, s: AssignmentStmt) -> None:
             rvalue = self.temp_node(self.lookup_type(s.rvalue), s)
             for lv in s.lvalues[:-1]:
                 with self.enter_final_context(s.is_final_def):
-                    self.check_assignment(lv, rvalue, s.type is None)
+                    self.check_assignment(lv, rvalue, infer_lvalue_type=True)
 
         self.check_final(s)
         if (

mypy/plugins/attrs.py

@@ -764,7 +764,6 @@ def _parse_converter(
         converter_info.init_type = AnyType(TypeOfAny.from_error)
         return converter_info
 
-    converter_type = get_proper_type(converter_type)
     if isinstance(converter_type, CallableType) and converter_type.arg_types:
         converter_info.init_type = converter_type.arg_types[0]
         if not is_attr_converters_optional:

mypy/semanal.py

@@ -6770,7 +6770,7 @@ def _get_node_for_class_scoped_import(
         # mypyc is absolutely convinced that `symbol_node` narrows to a Var in the following,
         # when it can also be a FuncBase. Once fixed, `f` in the following can be removed.
         # See also https://github.com/mypyc/mypyc/issues/892
-        f: Callable[[object], Any] = lambda x: x
+        f = cast(Callable[[object], Any], lambda x: x)
         if isinstance(f(symbol_node), (Decorator, FuncBase, Var)):
             # For imports in class scope, we construct a new node to represent the symbol and
             # set its `info` attribute to `self.type`.

mypy/types.py

@@ -2185,7 +2185,8 @@ def with_normalized_var_args(self) -> Self:
         types_suffix = self.arg_types[var_arg_index + 1 :]
         kinds_suffix = self.arg_kinds[var_arg_index + 1 :]
         names_suffix = self.arg_names[var_arg_index + 1 :]
-        no_name: str | None = None  # to silence mypy
+        names_middle: list[str | None]
+        no_name = cast("str | None", None)
 
         # Now we have something non-trivial to do.
         if unpack_index is None:
@@ -3731,12 +3732,6 @@ def find_unpack_in_list(items: Sequence[Type]) -> int | None:
     unpack_index: int | None = None
     for i, item in enumerate(items):
         if isinstance(item, UnpackType):
-            # We cannot fail here, so we must check this in an earlier
-            # semanal phase.
-            # Funky code here avoids mypyc narrowing the type of unpack_index.
-            old_index = unpack_index
-            assert old_index is None
-            # Don't return so that we can also sanity check there is only one.
             unpack_index = i
     return unpack_index