# Buggy code
def handle_cannot_determine_type(self, name: str, context: Context) -> None:
    node = self.scope.top_non_lambda_function()
    if self.pass_num < self.last_pass and isinstance(node, FuncDef):
        # Don't report an error yet. Just defer. Note that we don't defer
        # lambdas because they are coupled to the surrounding function
        # through the binder and the inferred type of the lambda, so it
        # would get messy.
        if self.errors.type_name:
            type_name = self.errors.type_name[-1]
        else:
            type_name = None
        # Shouldn't we freeze the entire scope?
        enclosing_class = self.scope.enclosing_class()
        self.deferred_nodes.append(DeferredNode(node, type_name, enclosing_class))
        # Set a marker so that we won't infer additional types in this
        # function. Any inferred types could be bogus, because there's at
        # least one type that we don't know.
        self.current_node_deferred = True
    else:
        self.msg.cannot_determine_type(name, context)


# Traceback (AssertionError)
pymc3/model.py:672: error: Decorated property not supported
pymc3/variational/opvi.py:1556: error: Decorated property not supported
pymc3/variational/flows.py:193: error: Decorated property not supported
pymc3/__init__.py:25: error: Name 'utils' already defined (by an import)
pymc3/data.py:226: error: Need type annotation for 'RNG'
Traceback (most recent call last):
File "/Users/rpg/Library/Python/3.7/bin/mypy", line 11, in <module>
sys.exit(console_entry())
File "/Users/rpg/Library/Python/3.7/lib/python/site-packages/mypy/__main__.py", line 7, in console_entry
main(None)
File "/Users/rpg/Library/Python/3.7/lib/python/site-packages/mypy/main.py", line 91, in main
res = type_check_only(sources, bin_dir, options, flush_errors, fscache)  # noqa
File "/Users/rpg/Library/Python/3.7/lib/python/site-packages/mypy/main.py", line 148, in type_check_only
fscache=fscache)
File "/Users/rpg/Library/Python/3.7/lib/python/site-packages/mypy/build.py", line 177, in build
flush_errors, fscache)
File "/Users/rpg/Library/Python/3.7/lib/python/site-packages/mypy/build.py", line 350, in _build
graph = dispatch(sources, manager)
File "/Users/rpg/Library/Python/3.7/lib/python/site-packages/mypy/build.py", line 2560, in dispatch
process_graph(graph, manager)
File "/Users/rpg/Library/Python/3.7/lib/python/site-packages/mypy/build.py", line 2853, in process_graph
process_stale_scc(graph, scc, manager)
File "/Users/rpg/Library/Python/3.7/lib/python/site-packages/mypy/build.py", line 2976, in process_stale_scc
graph[id].type_check_first_pass()
File "/Users/rpg/Library/Python/3.7/lib/python/site-packages/mypy/build.py", line 2151, in type_check_first_pass
self.type_checker().check_first_pass()
File "/Users/rpg/Library/Python/3.7/lib/python/site-packages/mypy/checker.py", line 253, in check_first_pass
self.accept(d)
File "/Users/rpg/Library/Python/3.7/lib/python/site-packages/mypy/checker.py", line 352, in accept
stmt.accept(self)
File "/Users/rpg/Library/Python/3.7/lib/python/site-packages/mypy/nodes.py", line 808, in accept
return visitor.visit_class_def(self)
File "/Users/rpg/Library/Python/3.7/lib/python/site-packages/mypy/checker.py", line 1368, in visit_class_def
self.accept(defn.defs)
File "/Users/rpg/Library/Python/3.7/lib/python/site-packages/mypy/checker.py", line 352, in accept
stmt.accept(self)
File "/Users/rpg/Library/Python/3.7/lib/python/site-packages/mypy/nodes.py", line 873, in accept
return visitor.visit_block(self)
File "/Users/rpg/Library/Python/3.7/lib/python/site-packages/mypy/checker.py", line 1514, in visit_block
self.accept(s)
File "/Users/rpg/Library/Python/3.7/lib/python/site-packages/mypy/checker.py", line 352, in accept
stmt.accept(self)
File "/Users/rpg/Library/Python/3.7/lib/python/site-packages/mypy/nodes.py", line 443, in accept
return visitor.visit_overloaded_func_def(self)
File "/Users/rpg/Library/Python/3.7/lib/python/site-packages/mypy/checker.py", line 385, in visit_overloaded_func_def
self._visit_overloaded_func_def(defn)
File "/Users/rpg/Library/Python/3.7/lib/python/site-packages/mypy/checker.py", line 409, in _visit_overloaded_func_def
self.check_method_override(defn)
File "/Users/rpg/Library/Python/3.7/lib/python/site-packages/mypy/checker.py", line 1198, in check_method_override
self.check_method_or_accessor_override_for_base(defn, base)
File "/Users/rpg/Library/Python/3.7/lib/python/site-packages/mypy/checker.py", line 1208, in check_method_or_accessor_override_for_base
self.check_method_override_for_base_with_name(defn, name, base)
File "/Users/rpg/Library/Python/3.7/lib/python/site-packages/mypy/checker.py", line 1252, in check_method_override_for_base_with_name
assert False, str(base_attr.node)
AssertionError: Var(sampler_vars)

# Fixed code
def handle_cannot_determine_type(self, name: str, context: Context) -> None:
    node = self.scope.top_non_lambda_function()
    if self.pass_num < self.last_pass and isinstance(node, FuncDef):
        # Don't report an error yet. Just defer. Note that we don't defer
        # lambdas because they are coupled to the surrounding function
        # through the binder and the inferred type of the lambda, so it
        # would get messy.
        enclosing_class = self.scope.enclosing_class()
        self.defer_node(node, enclosing_class)
        # Set a marker so that we won't infer additional types in this
        # function. Any inferred types could be bogus, because there's at
        # least one type that we don't know.
        self.current_node_deferred = True
    else:
        self.msg.cannot_determine_type(name, context)