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New semantic analyzer: crash when function has multiple definitions #6432
Description
Conditionally redefining a function as an overloaded function results in a crash. Example:
from typing import overload
if int():
def f(x: int) -> None:
pass
else:
@overload
def f(x: int) -> None: ...
@overload
def f(x: str) -> None: ...
def f(x) -> None:
yadsfTraceback:
File "/Users/jukka/src/mypy/mypy/build.py", line 162, in build
result = _build(sources, options, alt_lib_path, flush_errors, fscache)
File "/Users/jukka/src/mypy/mypy/build.py", line 217, in _build
graph = dispatch(sources, manager)
File "/Users/jukka/src/mypy/mypy/build.py", line 2433, in dispatch
process_graph(graph, manager)
File "/Users/jukka/src/mypy/mypy/build.py", line 2738, in process_graph
process_stale_scc(graph, scc, manager)
File "/Users/jukka/src/mypy/mypy/build.py", line 2836, in process_stale_scc
semantic_analysis_for_scc(graph, scc, manager.errors)
File "/Users/jukka/src/mypy/mypy/newsemanal/semanal_main.py", line 62, in semantic_analysis_for_scc
check_type_arguments(graph, scc, errors)
File "/Users/jukka/src/mypy/mypy/newsemanal/semanal_main.py", line 214, in check_type_arguments
state.tree.accept(analyzer)
File "/Library/Frameworks/Python.framework/Versions/3.6/lib/python3.6/contextlib.py", line 99, in __exit__
self.gen.throw(type, value, traceback)
File "/Users/jukka/src/mypy/mypy/build.py", line 1754, in wrap_context
yield
File "/Users/jukka/src/mypy/mypy/newsemanal/semanal_main.py", line 214, in check_type_arguments
state.tree.accept(analyzer)
File "/Users/jukka/src/mypy/mypy/nodes.py", line 249, in accept
return visitor.visit_mypy_file(self)
File "/Users/jukka/src/mypy/mypy/newsemanal/semanal_typeargs.py", line 28, in visit_mypy_file
super().visit_mypy_file(o)
File "/Users/jukka/src/mypy/mypy/traverser.py", line 33, in visit_mypy_file
d.accept(self)
File "/Users/jukka/src/mypy/mypy/nodes.py", line 1102, in accept
return visitor.visit_if_stmt(self)
File "/Users/jukka/src/mypy/mypy/traverser.py", line 120, in visit_if_stmt
o.else_body.accept(self)
File "/Users/jukka/src/mypy/mypy/nodes.py", line 911, in accept
return visitor.visit_block(self)
File "/Users/jukka/src/mypy/mypy/newsemanal/semanal_typeargs.py", line 41, in visit_block
super().visit_block(o)
File "/Users/jukka/src/mypy/mypy/traverser.py", line 37, in visit_block
s.accept(self)
File "/Users/jukka/src/mypy/mypy/nodes.py", line 454, in accept
return visitor.visit_overloaded_func_def(self)
File "/Users/jukka/src/mypy/mypy/traverser.py", line 56, in visit_overloaded_func_def
item.accept(self)
File "/Users/jukka/src/mypy/mypy/nodes.py", line 689, in accept
return visitor.visit_decorator(self)
File "/Users/jukka/src/mypy/mypy/traverser.py", line 70, in visit_decorator
o.func.accept(self)
File "/Users/jukka/src/mypy/mypy/nodes.py", line 606, in accept
return visitor.visit_func_def(self)
File "/Users/jukka/src/mypy/mypy/traverser.py", line 52, in visit_func_def
self.visit_func(o)
File "/Users/jukka/src/mypy/mypy/newsemanal/semanal_typeargs.py", line 33, in visit_func
super().visit_func(defn)
File "/Users/jukka/src/mypy/mypy/mixedtraverser.py", line 23, in visit_func
self.visit_optional_type(o.type)
File "/Users/jukka/src/mypy/mypy/mixedtraverser.py", line 90, in visit_optional_type
t.accept(self)
File "/Users/jukka/src/mypy/mypy/types.py", line 929, in accept
return visitor.visit_callable_type(self)
File "/Users/jukka/src/mypy/mypy/typetraverser.py", line 52, in visit_callable_type
t.fallback.accept(self)
File "/Users/jukka/src/mypy/mypy/types.py", line 620, in accept
return visitor.visit_instance(self)
File "/Users/jukka/src/mypy/mypy/newsemanal/semanal_typeargs.py", line 47, in visit_instance
for (i, arg), tvar in zip(enumerate(t.args), info.defn.type_vars):
File "/Users/jukka/src/mypy/mypy/nodes.py", line 2525, in __getattribute__
raise AssertionError(object.__getattribute__(self, 'msg'))
AssertionError: fallback can't be filled out until semanal
Activity
JukkaL commentedon Feb 19, 2019
Follow-up to #6429.
JukkaL commentedon Apr 5, 2019
More generally, multiple definitions for a function can cause crashes, since some of the definitions are not reachable from the symbol table and thus won't be analyzed.
[-]New semantic analyzer: redefine function as overloaded function[/-][+]New semantic analyzer: crash when function has multiple definitions[/+]ilevkivskyi commentedon Apr 9, 2019
It looks like this blocks #6644
New semantic analyzer: fix redefining symbols as overloaded functions…