Pass literals as kwargs

[vickyhuo]

Closes #10023

Checks if kwarg is Mapping type AND check if list of strings extracted from mapping key type is not empty.

[97littleleaf11]

Could you please merge the conflicts?

btw, just one code style nit: how about expand the compound bool expressions into several if and else branches (with True or False returns)?

[97littleleaf11]

Previous PR: #9629

[97littleleaf11]

Actually I don't know how this line works. Could somebody elaborate? @JukkaL @momohatt

[momohatt]

Sorry for being late.
As we discussed in #9629, this check is added to avoid false-positive errors when empty dictionaries are passed with double-stars (e.g., **{}). This condition is needed because the type of an empty dictionary is inferred to be dict[<nothing>, <nothing>], which is not a subtype of Mapping[str, Any].

[97littleleaf11]

@momohatt Thanks!

[github-actions]

Diff from mypy_primer, showing the effect of this PR on open source code:

boostedblob (https://github.com/hauntsaninja/boostedblob)
- Warning: unused section(s) in mypy.ini: [mypy-tests.*]
+ boostedblob/globals.py:144: error: INTERNAL ERROR -- Please try using mypy master on GitHub:
+ https://mypy.readthedocs.io/en/stable/common_issues.html#using-a-development-mypy-build
+ Please report a bug at https://github.com/python/mypy/issues
+ version: 0.970+dev.cb7c148c62d50edc1c70943b209b82d1e0940fd7
+ boostedblob/globals.py:144: : note: use --pdb to drop into pdb
+ Traceback (most recent call last):
+   File "", line 8, in <module>
+     sys.exit(console_entry())
+   File "/__main__.py", line 12, in console_entry
+     main(None, sys.stdout, sys.stderr)
+   File "/main.py", line 96, in main
+     res, messages, blockers = run_build(sources, options, fscache, t0, stdout, stderr)
+   File "/main.py", line 173, in run_build
+     res = build.build(sources, options, None, flush_errors, fscache, stdout, stderr)
+   File "/build.py", line 154, in build
+     result = _build(
+   File "/build.py", line 230, in _build
+     graph = dispatch(sources, manager, stdout)
+   File "/build.py", line 2729, in dispatch
+     process_graph(graph, manager)
+   File "/build.py", line 3087, in process_graph
+     process_stale_scc(graph, scc, manager)
+   File "/build.py", line 3185, in process_stale_scc
+     graph[id].type_check_first_pass()
+   File "/build.py", line 2180, in type_check_first_pass
+     self.type_checker().check_first_pass()
+   File "/checker.py", line 325, in check_first_pass
+     self.accept(d)
+   File "/checker.py", line 431, in accept
+     stmt.accept(self)
+   File "/nodes.py", line 840, in accept
+     return visitor.visit_decorator(self)
+   File "/checker.py", line 3984, in visit_decorator
+     self.check_func_item(e.func, name=e.func.name)
+   File "/checker.py", line 848, in check_func_item
+     self.check_func_def(defn, typ, name)
+   File "/checker.py", line 1033, in check_func_def
+     self.accept(item.body)
+   File "/checker.py", line 431, in accept
+     stmt.accept(self)
+   File "/nodes.py", line 1100, in accept
+     return visitor.visit_block(self)
+   File "/checker.py", line 2178, in visit_block
+     self.accept(s)
+   File "/checker.py", line 431, in accept
+     stmt.accept(self)
+   File "/nodes.py", line 1118, in accept
+     return visitor.visit_expression_stmt(self)
+   File "/checker.py", line 3487, in visit_expression_stmt
+     expr_type = self.expr_checker.accept(s.expr, allow_none_return=True, always_allow_any=True)
+   File "/checkexpr.py", line 4006, in accept
+     typ = self.visit_call_expr(node, allow_none_return=True)
+   File "/checkexpr.py", line 305, in visit_call_expr
+     return self.visit_call_expr_inner(e, allow_none_return=allow_none_return)
+   File "/checkexpr.py", line 383, in visit_call_expr_inner
+     ret_type = self.check_call_expr_with_callee_type(callee_type, e, fullname,
+   File "/checkexpr.py", line 892, in check_call_expr_with_callee_type
+     ret_type, callee_type = self.check_call(
+   File "/checkexpr.py", line 960, in check_call
+     return self.check_overload_call(callee, args, arg_kinds, arg_names, callable_name,
+   File "/checkexpr.py", line 1608, in check_overload_call
+     plausible_targets = self.plausible_overload_call_targets(arg_types, arg_kinds,
+   File "/checkexpr.py", line 1737, in plausible_overload_call_targets
+     if self.check_argument_count(typ, arg_types, arg_kinds, arg_names,
+   File "/checkexpr.py", line 1417, in check_argument_count
+     ok, is_unexpected_arg_error = self.check_for_extra_actual_arguments(
+   File "/checkexpr.py", line 1499, in check_for_extra_actual_arguments
+     if messages and supertype.args:
+ NameError: name 'messages' is not defined

mypy_primer (https://github.com/hauntsaninja/mypy_primer)
+ /tmp/mypy_primer/projects/mypy_primer/mypy_primer.py:99: error: INTERNAL ERROR -- Please try using mypy master on GitHub:
+ https://mypy.readthedocs.io/en/stable/common_issues.html#using-a-development-mypy-build
+ Please report a bug at https://github.com/python/mypy/issues
+ version: 0.970+dev.cb7c148c62d50edc1c70943b209b82d1e0940fd7
+ Traceback (most recent call last):
+   File "", line 8, in <module>
+     sys.exit(console_entry())
+   File "/__main__.py", line 12, in console_entry
+     main(None, sys.stdout, sys.stderr)
+   File "/main.py", line 96, in main
+     res, messages, blockers = run_build(sources, options, fscache, t0, stdout, stderr)
+   File "/main.py", line 173, in run_build
+     res = build.build(sources, options, None, flush_errors, fscache, stdout, stderr)
+   File "/build.py", line 154, in build
+     result = _build(
+   File "/build.py", line 230, in _build
+     graph = dispatch(sources, manager, stdout)
+   File "/build.py", line 2729, in dispatch
+     process_graph(graph, manager)
+   File "/build.py", line 3087, in process_graph
+     process_stale_scc(graph, scc, manager)
+   File "/build.py", line 3185, in process_stale_scc
+     graph[id].type_check_first_pass()
+   File "/build.py", line 2180, in type_check_first_pass
+     self.type_checker().check_first_pass()
+   File "/checker.py", line 325, in check_first_pass
+     self.accept(d)
+   File "/checker.py", line 431, in accept
+     stmt.accept(self)
+   File "/nodes.py", line 748, in accept
+     return visitor.visit_func_def(self)
+   File "/checker.py", line 782, in visit_func_def
+     self._visit_func_def(defn)
+   File "/checker.py", line 786, in _visit_func_def
+     self.check_func_item(defn, name=defn.name)
+   File "/checker.py", line 848, in check_func_item
+     self.check_func_def(defn, typ, name)
+   File "/checker.py", line 1033, in check_func_def
+     self.accept(item.body)
+   File "/checker.py", line 431, in accept
+     stmt.accept(self)
+   File "/nodes.py", line 1100, in accept
+     return visitor.visit_block(self)
+   File "/checker.py", line 2178, in visit_block
+     self.accept(s)
+   File "/checker.py", line 431, in accept
+     stmt.accept(self)
+   File "/nodes.py", line 1397, in accept
+     return visitor.visit_with_stmt(self)
+   File "/checker.py", line 4078, in visit_with_stmt
+     self.accept(s.body)
+   File "/checker.py", line 431, in accept
+     stmt.accept(self)
+   File "/nodes.py", line 1100, in accept
+     return visitor.visit_block(self)
+   File "/checker.py", line 2178, in visit_block
+     self.accept(s)
+   File "/checker.py", line 431, in accept
+     stmt.accept(self)
+   File "/nodes.py", line 1324, in accept
+     return visitor.visit_if_stmt(self)
+   File "/checker.py", line 3597, in visit_if_stmt
+     self.accept(b)
+   File "/checker.py", line 431, in accept
+     stmt.accept(self)
+   File "/nodes.py", line 1100, in accept
+     return visitor.visit_block(self)
+   File "/checker.py", line 2178, in visit_block
+     self.accept(s)
+   File "/checker.py", line 431, in accept
+     stmt.accept(self)
+   File "/nodes.py", line 1166, in accept
+     return visitor.visit_assignment_stmt(self)
+   File "/checker.py", line 2220, in visit_assignment_stmt
+     self.check_assignment(s.lvalues[-1], s.rvalue, s.type is None, s.new_syntax)
+   File "/checker.py", line 2414, in check_assignment
+     rvalue_type = self.expr_checker.accept(rvalue)
+   File "/checkexpr.py", line 4012, in accept
+     typ = node.accept(self)
+   File "/nodes.py", line 2508, in accept
+     return visitor.visit_await_expr(self)
+   File "/checkexpr.py", line 4137, in visit_await_expr
+     actual_type = get_proper_type(self.accept(e.expr, expected_type))
+   File "/checkexpr.py", line 4012, in accept
+     typ = node.accept(self)
+   File "/nodes.py", line 1761, in accept
+     return visitor.visit_call_expr(self)
+   File "/checkexpr.py", line 305, in visit_call_expr
+     return self.visit_call_expr_inner(e, allow_none_return=allow_none_return)
+   File "/checkexpr.py", line 383, in visit_call_expr_inner
+     ret_type = self.check_call_expr_with_callee_type(callee_type, e, fullname,
+   File "/checkexpr.py", line 892, in check_call_expr_with_callee_type
+     ret_type, callee_type = self.check_call(
+   File "/checkexpr.py", line 957, in check_call
+     return self.check_callable_call(callee, args, arg_kinds, context, arg_names,
+   File "/checkexpr.py", line 1067, in check_callable_call
+     self.check_argument_count(callee, arg_types, arg_kinds,
+   File "/checkexpr.py", line 1417, in check_argument_count
+     ok, is_unexpected_arg_error = self.check_for_extra_actual_arguments(
+   File "/checkexpr.py", line 1499, in check_for_extra_actual_arguments
+     if messages and supertype.args:
+ NameError: name 'messages' is not defined

ignite (https://github.com/pytorch/ignite)
+ ignite/distributed/comp_models/base.py:175: error: INTERNAL ERROR -- Please try using mypy master on GitHub:
+ https://mypy.readthedocs.io/en/stable/common_issues.html#using-a-development-mypy-build
+ Please report a bug at https://github.com/python/mypy/issues
+ version: 0.970+dev.cb7c148c62d50edc1c70943b209b82d1e0940fd7
+ ignite/distributed/comp_models/base.py:175: : note: use --pdb to drop into pdb
- ignite/engine/deterministic.py:38: error: Class cannot subclass "BatchSampler" (has type "Any")  [misc]
- ignite/engine/deterministic.py:227: error: Unused "type: ignore" comment
- ignite/engine/deterministic.py:254: error: Unused "type: ignore" comment
- ignite/engine/deterministic.py:259: error: Unused "type: ignore" comment
- ignite/distributed/auto.py:282: error: Class cannot subclass "DistributedSampler" (has type "Any")  [misc]
- ignite/distributed/auto.py:308: error: Unused "type: ignore" comment
- ignite/distributed/auto.py:351: error: Class cannot subclass "Optimizer" (has type "Any")  [misc]
- ignite/distributed/auto.py:353: error: Unused "type: ignore" comment
- ignite/metrics/precision.py:50: error: Unused "type: ignore" comment
- ignite/metrics/precision.py:51: error: Unused "type: ignore" comment
- ignite/metrics/metric.py:267: error: Untyped decorator makes function "iteration_completed" untyped  [misc]
- ignite/metrics/gan/utils.py:8: error: Class cannot subclass "Module" (has type "Any")  [misc]
- ignite/metrics/gan/utils.py:33: error: Untyped decorator makes function "forward" untyped  [misc]
- ignite/metrics/gan/utils.py:64: error: Cannot determine type of "_feature_extractor"  [has-type]
- ignite/engine/__init__.py:375: error: Unused "type: ignore" comment
- ignite/handlers/param_scheduler.py:854: error: Unused "type: ignore" comment
- ignite/handlers/param_scheduler.py:864: error: Unused "type: ignore" comment
- ignite/handlers/param_scheduler.py:870: error: Unused "type: ignore" comment
- ignite/handlers/param_scheduler.py:875: error: Unused "type: ignore" comment
- ignite/handlers/param_scheduler.py:877: error: Unused "type: ignore" comment
- ignite/handlers/param_scheduler.py:911: error: Unused "type: ignore" comment
- ignite/handlers/param_scheduler.py:924: error: Unused "type: ignore" comment
- ignite/handlers/param_scheduler.py:1406: error: Unused "type: ignore" comment
- ignite/handlers/param_scheduler.py:1411: error: Unused "type: ignore" comment
- ignite/handlers/param_scheduler.py:1413: error: Unused "type: ignore" comment
- ignite/handlers/param_scheduler.py:1420: error: Unused "type: ignore" comment
- ignite/handlers/param_scheduler.py:1544: error: Unused "type: ignore" comment
- ignite/handlers/param_scheduler.py:1564: error: Unused "type: ignore" comment
- ignite/handlers/param_scheduler.py:1565: error: Unused "type: ignore" comment
- ignite/handlers/lr_finder.py:476: error: Class cannot subclass "_LRScheduler" (has type "Any")  [misc]
- ignite/handlers/lr_finder.py:498: error: Unused "type: ignore" comment
- ignite/handlers/lr_finder.py:499: error: Unused "type: ignore" comment
- ignite/contrib/handlers/wandb_logger.py:138: error: Unused "type: ignore" comment
- ignite/contrib/handlers/visdom_logger.py:188: error: Unused "type: ignore" comment
- ignite/contrib/handlers/visdom_logger.py:196: error: Unused "type: ignore" comment
- ignite/contrib/handlers/visdom_logger.py:241: error: Unused "type: ignore" comment
- ignite/contrib/handlers/tensorboard_logger.py:153: error: Unused "type: ignore" comment
+ Traceback (most recent call last):
+   File "", line 8, in <module>
+     sys.exit(console_entry())
+   File "/__main__.py", line 12, in console_entry
+     main(None, sys.stdout, sys.stderr)
+   File "/main.py", line 96, in main
+     res, messages, blockers = run_build(sources, options, fscache, t0, stdout, stderr)
+   File "/main.py", line 173, in run_build
+     res = build.build(sources, options, None, flush_errors, fscache, stdout, stderr)
+   File "/build.py", line 154, in build
+     result = _build(
+   File "/build.py", line 230, in _build
+     graph = dispatch(sources, manager, stdout)
+   File "/build.py", line 2729, in dispatch
+     process_graph(graph, manager)
+   File "/build.py", line 3087, in process_graph
+     process_stale_scc(graph, scc, manager)
+   File "/build.py", line 3185, in process_stale_scc
+     graph[id].type_check_first_pass()
+   File "/build.py", line 2180, in type_check_first_pass
+     self.type_checker().check_first_pass()
+   File "/checker.py", line 325, in check_first_pass
+     self.accept(d)
+   File "/checker.py", line 431, in accept
+     stmt.accept(self)
+   File "/nodes.py", line 1029, in accept
+     return visitor.visit_class_def(self)
+   File "/checker.py", line 1816, in visit_class_def
+     self.accept(defn.defs)
+   File "/checker.py", line 431, in accept
+     stmt.accept(self)
+   File "/nodes.py", line 1100, in accept
+     return visitor.visit_block(self)
+   File "/checker.py", line 2178, in visit_block
+     self.accept(s)
+   File "/checker.py", line 431, in accept
+     stmt.accept(self)
+   File "/nodes.py", line 748, in accept
+     return visitor.visit_func_def(self)
+   File "/checker.py", line 782, in visit_func_def
+     self._visit_func_def(defn)
+   File "/checker.py", line 786, in _visit_func_def
+     self.check_func_item(defn, name=defn.name)
+   File "/checker.py", line 848, in check_func_item
+     self.check_func_def(defn, typ, name)
+   File "/checker.py", line 1033, in check_func_def
+     self.accept(item.body)
+   File "/checker.py", line 431, in accept
+     stmt.accept(self)
+   File "/nodes.py", line 1100, in accept
+     return visitor.visit_block(self)
+   File "/checker.py", line 2178, in visit_block
+     self.accept(s)
+   File "/checker.py", line 431, in accept
+     stmt.accept(self)
+   File "/nodes.py", line 1166, in accept
+     return visitor.visit_assignment_stmt(self)
+   File "/checker.py", line 2220, in visit_assignment_stmt
+     self.check_assignment(s.lvalues[-1], s.rvalue, s.type is None, s.new_syntax)
+   File "/checker.py", line 2389, in check_assignment
+     rvalue_type = self.check_simple_assignment(lvalue_type, rvalue, context=rvalue,
+   File "/checker.py", line 3307, in check_simple_assignment
+     rvalue_type = self.expr_checker.accept(rvalue, lvalue_type,
+   File "/checkexpr.py", line 4012, in accept
+     typ = node.accept(self)
+   File "/nodes.py", line 1761, in accept
+     return visitor.visit_call_expr(self)
+   File "/checkexpr.py", line 305, in visit_call_expr
+     return self.visit_call_expr_inner(e, allow_none_return=allow_none_return)
+   File "/checkexpr.py", line 383, in visit_call_expr_inner
+     ret_type = self.check_call_expr_with_callee_type(callee_type, e, fullname,
+   File "/checkexpr.py", line 892, in check_call_expr_with_callee_type
+     ret_type, callee_type = self.check_call(
+   File "/checkexpr.py", line 957, in check_call
+     return self.check_callable_call(callee, args, arg_kinds, context, arg_names,
+   File "/checkexpr.py", line 1067, in check_callable_call
+     self.check_argument_count(callee, arg_types, arg_kinds,
+   File "/checkexpr.py", line 1417, in check_argument_count
+     ok, is_unexpected_arg_error = self.check_for_extra_actual_arguments(
+   File "/checkexpr.py", line 1499, in check_for_extra_actual_arguments
+     if messages and supertype.args:
+ NameError: name 'messages' is not defined

bidict (https://github.com/jab/bidict)
+ bidict/_base.py:453: error: INTERNAL ERROR -- Please try using mypy master on GitHub:
+ https://mypy.readthedocs.io/en/stable/common_issues.html#using-a-development-mypy-build
+ Please report a bug at https://github.com/python/mypy/issues
+ version: 0.970+dev.cb7c148c62d50edc1c70943b209b82d1e0940fd7
+ bidict/_base.py:453: : note: use --pdb to drop into pdb
+ Traceback (most recent call last):
+   File "", line 8, in <module>
+     sys.exit(console_entry())
+   File "/__main__.py", line 12, in console_entry
+     main(None, sys.stdout, sys.stderr)
+   File "/main.py", line 96, in main
+     res, messages, blockers = run_build(sources, options, fscache, t0, stdout, stderr)
+   File "/main.py", line 173, in run_build
+     res = build.build(sources, options, None, flush_errors, fscache, stdout, stderr)
+   File "/build.py", line 154, in build
+     result = _build(
+   File "/build.py", line 230, in _build
+     graph = dispatch(sources, manager, stdout)
+   File "/build.py", line 2729, in dispatch
+     process_graph(graph, manager)
+   File "/build.py", line 3087, in process_graph
+     process_stale_scc(graph, scc, manager)
+   File "/build.py", line 3185, in process_stale_scc
+     graph[id].type_check_first_pass()
+   File "/build.py", line 2180, in type_check_first_pass
+     self.type_checker().check_first_pass()
+   File "/checker.py", line 325, in check_first_pass
+     self.accept(d)
+   File "/checker.py", line 431, in accept
+     stmt.accept(self)
+   File "/nodes.py", line 1029, in accept
+     return visitor.visit_class_def(self)
+   File "/checker.py", line 1816, in visit_class_def
+     self.accept(defn.defs)
+   File "/checker.py", line 431, in accept
+     stmt.accept(self)
+   File "/nodes.py", line 1100, in accept
+     return visitor.visit_block(self)
+   File "/checker.py", line 2178, in visit_block
+     self.accept(s)
+   File "/checker.py", line 431, in accept
+     stmt.accept(self)
+   File "/nodes.py", line 748, in accept
+     return visitor.visit_func_def(self)
+   File "/checker.py", line 782, in visit_func_def
+     self._visit_func_def(defn)
+   File "/checker.py", line 786, in _visit_func_def
+     self.check_func_item(defn, name=defn.name)
+   File "/checker.py", line 848, in check_func_item
+     self.check_func_def(defn, typ, name)
+   File "/checker.py", line 1033, in check_func_def
+     self.accept(item.body)
+   File "/checker.py", line 431, in accept
+     stmt.accept(self)
+   File "/nodes.py", line 1100, in accept
+     return visitor.visit_block(self)
+   File "/checker.py", line 2178, in visit_block
+     self.accept(s)
+   File "/checker.py", line 431, in accept
+     stmt.accept(self)
+   File "/nodes.py", line 1244, in accept
+     return visitor.visit_for_stmt(self)
+   File "/checker.py", line 3895, in visit_for_stmt
+     iterator_type, item_type = self.analyze_iterable_item_type(s.expr)
+   File "/checker.py", line 3914, in analyze_iterable_item_type
+     iterable = get_proper_type(echk.accept(expr))
+   File "/checkexpr.py", line 4012, in accept
+     typ = node.accept(self)
+   File "/nodes.py", line 1761, in accept
+     return visitor.visit_call_expr(self)
+   File "/checkexpr.py", line 305, in visit_call_expr
+     return self.visit_call_expr_inner(e, allow_none_return=allow_none_return)
+   File "/checkexpr.py", line 383, in visit_call_expr_inner
+     ret_type = self.check_call_expr_with_callee_type(callee_type, e, fullname,
+   File "/checkexpr.py", line 892, in check_call_expr_with_callee_type
+     ret_type, callee_type = self.check_call(
+   File "/checkexpr.py", line 957, in check_call
+     return self.check_callable_call(callee, args, arg_kinds, context, arg_names,
+   File "/checkexpr.py", line 1067, in check_callable_call
+     self.check_argument_count(callee, arg_types, arg_kinds,
+   File "/checkexpr.py", line 1417, in check_argument_count
+     ok, is_unexpected_arg_error = self.check_for_extra_actual_arguments(
+   File "/checkexpr.py", line 1499, in check_for_extra_actual_arguments
+     if messages and supertype.args:
+ NameError: name 'messages' is not defined

python-sop (https://gitlab.com/dkg/python-sop)
+ sop/__init__.py:456: error: INTERNAL ERROR -- Please try using mypy master on GitHub:
+ https://mypy.readthedocs.io/en/stable/common_issues.html#using-a-development-mypy-build
+ Please report a bug at https://github.com/python/mypy/issues
+ version: 0.970+dev.cb7c148c62d50edc1c70943b209b82d1e0940fd7
+ sop/__init__.py:456: : note: use --pdb to drop into pdb
+ Traceback (most recent call last):
+   File "", line 8, in <module>
+     sys.exit(console_entry())
+   File "/__main__.py", line 12, in console_entry
+     main(None, sys.stdout, sys.stderr)
+   File "/main.py", line 96, in main
+     res, messages, blockers = run_build(sources, options, fscache, t0, stdout, stderr)
+   File "/main.py", line 173, in run_build
+     res = build.build(sources, options, None, flush_errors, fscache, stdout, stderr)
+   File "/build.py", line 154, in build
+     result = _build(
+   File "/build.py", line 230, in _build
+     graph = dispatch(sources, manager, stdout)
+   File "/build.py", line 2729, in dispatch
+     process_graph(graph, manager)
+   File "/build.py", line 3087, in process_graph
+     process_stale_scc(graph, scc, manager)
+   File "/build.py", line 3185, in process_stale_scc
+     graph[id].type_check_first_pass()
+   File "/build.py", line 2180, in type_check_first_pass
+     self.type_checker().check_first_pass()
+   File "/checker.py", line 325, in check_first_pass
+     self.accept(d)
+   File "/checker.py", line 431, in accept
+     stmt.accept(self)
+   File "/nodes.py", line 1029, in accept
+     return visitor.visit_class_def(self)
+   File "/checker.py", line 1816, in visit_class_def
+     self.accept(defn.defs)
+   File "/checker.py", line 431, in accept
+     stmt.accept(self)
+   File "/nodes.py", line 1100, in accept
+     return visitor.visit_block(self)
+   File "/checker.py", line 2178, in visit_block
+     self.accept(s)
+   File "/checker.py", line 431, in accept
+     stmt.accept(self)
+   File "/nodes.py", line 748, in accept
+     return visitor.visit_func_def(self)
+   File "/checker.py", line 782, in visit_func_def
+     self._visit_func_def(defn)
+   File "/checker.py", line 786, in _visit_func_def
+     self.check_func_item(defn, name=defn.name)
+   File "/checker.py", line 848, in check_func_item
+     self.check_func_def(defn, typ, name)
+   File "/checker.py", line 1033, in check_func_def
+     self.accept(item.body)
+   File "/checker.py", line 431, in accept
+     stmt.accept(self)
+   File "/nodes.py", line 1100, in accept
+     return visitor.visit_block(self)
+   File "/checker.py", line 2178, in visit_block
+     self.accept(s)
+   File "/checker.py", line 431, in accept
+     stmt.accept(self)
+   File "/nodes.py", line 1257, in accept
+     return visitor.visit_return_stmt(self)
+   File "/checker.py", line 3498, in visit_return_stmt
+     self.check_return_stmt(s)
+   File "/checker.py", line 3530, in check_return_stmt
+     typ = get_proper_type(self.expr_checker.accept(
+   File "/checkexpr.py", line 4012, in accept
+     typ = node.accept(self)
+   File "/nodes.py", line 1761, in accept
+     return visitor.visit_call_expr(self)
+   File "/checkexpr.py", line 305, in visit_call_expr
+     return self.visit_call_expr_inner(e, allow_none_return=allow_none_return)
+   File "/checkexpr.py", line 383, in visit_call_expr_inner
+     ret_type = self.check_call_expr_with_callee_type(callee_type, e, fullname,
+   File "/checkexpr.py", line 892, in check_call_expr_with_callee_type
+     ret_type, callee_type = self.check_call(
+   File "/checkexpr.py", line 957, in check_call
+     return self.check_callable_call(callee, args, arg_kinds, context, arg_names,
+   File "/checkexpr.py", line 1067, in check_callable_call
+     self.check_argument_count(callee, arg_types, arg_kinds,
+   File "/checkexpr.py", line 1417, in check_argument_count
+     ok, is_unexpected_arg_error = self.check_for_extra_actual_arguments(
+   File "/checkexpr.py", line 1499, in check_for_extra_actual_arguments
+     if messages and supertype.args:
+ NameError: name 'messages' is not defined

pegen (https://github.com/we-like-parsers/pegen)
- src/pegen/parser.py:297: error: "Parser" has no attribute "start"  [attr-defined]
- src/pegen/python_generator.py:220: error: Need type annotation for "cleanup_statements" (hint: "cleanup_statements: List[<type>] = ...")  [var-annotated]
- src/pegen/utils.py:19: error: Argument 1 to "module_from_spec" has incompatible type "Optional[ModuleSpec]"; expected "ModuleSpec"  [arg-type]
- src/pegen/utils.py:23: error: Item "None" of "Optional[ModuleSpec]" has no attribute "loader"  [union-attr]
- src/pegen/utils.py:52: error: "Parser" has no attribute "start"  [attr-defined]
+ src/pegen/grammar.py:31: error: INTERNAL ERROR -- Please try using mypy master on GitHub:
+ https://mypy.readthedocs.io/en/stable/common_issues.html#using-a-development-mypy-build
+ Please report a bug at https://github.com/python/mypy/issues
+ version: 0.970+dev.cb7c148c62d50edc1c70943b209b82d1e0940fd7
+ src/pegen/grammar.py:31: : note: use --pdb to drop into pdb
+ Traceback (most recent call last):
+   File "", line 8, in <module>
+     sys.exit(console_entry())
+   File "/__main__.py", line 12, in console_entry
+     main(None, sys.stdout, sys.stderr)
+   File "/main.py", line 96, in main
+     res, messages, blockers = run_build(sources, options, fscache, t0, stdout, stderr)
+   File "/main.py", line 173, in run_build
+     res = build.build(sources, options, None, flush_errors, fscache, stdout, stderr)
+   File "/build.py", line 154, in build
+     result = _build(
+   File "/build.py", line 230, in _build
+     graph = dispatch(sources, manager, stdout)
+   File "/build.py", line 2729, in dispatch
+     process_graph(graph, manager)
+   File "/build.py", line 3087, in process_graph
+     process_stale_scc(graph, scc, manager)
+   File "/build.py", line 3185, in process_stale_scc
+     graph[id].type_check_first_pass()
+   File "/build.py", line 2180, in type_check_first_pass
+     self.type_checker().check_first_pass()
+   File "/checker.py", line 325, in check_first_pass
+     self.accept(d)
+   File "/checker.py", line 431, in accept
+     stmt.accept(self)
+   File "/nodes.py", line 1029, in accept
+     return visitor.visit_class_def(self)
+   File "/checker.py", line 1816, in visit_class_def
+     self.accept(defn.defs)
+   File "/checker.py", line 431, in accept
+     stmt.accept(self)
+   File "/nodes.py", line 1100, in accept
+     return visitor.visit_block(self)
+   File "/checker.py", line 2178, in visit_block
+     self.accept(s)
+   File "/checker.py", line 431, in accept
+     stmt.accept(self)
+   File "/nodes.py", line 748, in accept
+     return visitor.visit_func_def(self)
+   File "/checker.py", line 782, in visit_func_def
+     self._visit_func_def(defn)
+   File "/checker.py", line 786, in _visit_func_def
+     self.check_func_item(defn, name=defn.name)
+   File "/checker.py", line 848, in check_func_item
+     self.check_func_def(defn, typ, name)
+   File "/checker.py", line 1033, in check_func_def
+     self.accept(item.body)
+   File "/checker.py", line 431, in accept
+     stmt.accept(self)
+   File "/nodes.py", line 1100, in accept
+     return visitor.visit_block(self)
+   File "/checker.py", line 2178, in visit_block
+     self.accept(s)
+   File "/checker.py", line 431, in accept
+     stmt.accept(self)
+   File "/nodes.py", line 1257, in accept
+     return visitor.visit_return_stmt(self)
+   File "/checker.py", line 3498, in visit_return_stmt
+     self.check_return_stmt(s)
+   File "/checker.py", line 3530, in check_return_stmt
+     typ = get_proper_type(self.expr_checker.accept(
+   File "/checkexpr.py", line 4006, in accept
+     typ = self.visit_call_expr(node, allow_none_return=True)
+   File "/checkexpr.py", line 305, in visit_call_expr
+     return self.visit_call_expr_inner(e, allow_none_return=allow_none_return)
+   File "/checkexpr.py", line 383, in visit_call_expr_inner
+     ret_type = self.check_call_expr_with_callee_type(callee_type, e, fullname,
+   File "/checkexpr.py", line 892, in check_call_expr_with_callee_type
+     ret_type, callee_type = self.check_call(
+   File "/checkexpr.py", line 965, in check_call
+     return self.check_union_call(callee, args, arg_kinds, arg_names, context)
+   File "/checkexpr.py", line 2080, in check_union_call
+     results = [
+   File "/checkexpr.py", line 2081, in <listcomp>
+     self.check_call(
+   File "/checkexpr.py", line 957, in check_call
+     return self.check_callable_call(callee, args, arg_kinds, context, arg_names,
+   File "/checkexpr.py", line 1067, in check_callable_call
+     self.check_argument_count(callee, arg_types, arg_kinds,
+   File "/checkexpr.py", line 1417, in check_argument_count
+     ok, is_unexpected_arg_error = self.check_for_extra_actual_arguments(
+   File "/checkexpr.py", line 1499, in check_for_extra_actual_arguments
+     if messages and supertype.args:
+ NameError: name 'messages' is not defined

SinbadCogs (https://github.com/mikeshardmind/SinbadCogs)
- Warning: unused section(s) in mypy.ini: [mypy-websockets.*], [mypy-numba.*], [mypy-numpy.*]
+ ./rolemanagement/converters.py:46: error: INTERNAL ERROR -- Please try using mypy master on GitHub:
+ https://mypy.readthedocs.io/en/stable/common_issues.html#using-a-development-mypy-build
+ Please report a bug at https://github.com/python/mypy/issues
+ version: 0.970+dev.cb7c148c62d50edc1c70943b209b82d1e0940fd7
+ ./rolemanagement/converters.py:46: : note: use --pdb to drop into pdb
- devtools/runner.py:26: error: Unused "type: ignore" comment
- scheduler/message.py:87: error: Unused "type: ignore" comment
- schedul

... (truncated 533294 chars) ...

[andersk]

#12699 deleted messages in favor of self.msg.