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Refactoring: Remove the "erased" attribute of Instance #12499

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Merged
merged 4 commits into from
Mar 31, 2022
Merged

Refactoring: Remove the "erased" attribute of Instance #12499

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96c67c2
Refactoring: Remove the "erased" attribute of Instance
JukkaL Mar 31, 2022
68c261c
Remove from `__slots__`
JukkaL Mar 31, 2022
dc77c52
Remove out-of-date comment
JukkaL Mar 31, 2022
e66b189
Remove additional stale comments
JukkaL Mar 31, 2022
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5 changes: 0 additions & 5 deletions mypy/checkexpr.py
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Original file line number Diff line number Diff line change
Expand Up @@ -3320,8 +3320,6 @@ def fast_container_type(
vt = join.join_type_list(values)
if not isinstance(vt, Instance):
return None
# TODO: update tests instead?
vt.erased = True
return self.chk.named_generic_type(container_fullname, [vt])

def check_lst_expr(self, items: List[Expression], fullname: str,
Expand Down Expand Up @@ -3448,9 +3446,6 @@ def fast_dict_type(self, e: DictExpr) -> Optional[Type]:
return None
if stargs and (stargs[0] != kt or stargs[1] != vt):
return None
# TODO: update tests instead?
kt.erased = True
vt.erased = True
return self.chk.named_generic_type('builtins.dict', [kt, vt])

def visit_dict_expr(self, e: DictExpr) -> Type:
Expand Down
7 changes: 1 addition & 6 deletions mypy/checkmember.py
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Expand Up @@ -842,12 +842,7 @@ def analyze_enum_class_attribute_access(itype: Instance,
return None

enum_literal = LiteralType(name, fallback=itype)
# When we analyze enums, the corresponding Instance is always considered to be erased
# due to how the signature of Enum.__new__ is `(cls: Type[_T], value: object) -> _T`
# in typeshed. However, this is really more of an implementation detail of how Enums
# are typed, and we really don't want to treat every single Enum value as if it were
# from type variable substitution. So we reset the 'erased' field here.
return itype.copy_modified(erased=False, last_known_value=enum_literal)
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Docstring should be modified too

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Removed the comment.

return itype.copy_modified(last_known_value=enum_literal)


def analyze_typeddict_access(name: str, typ: TypedDictType,
Expand Down
8 changes: 2 additions & 6 deletions mypy/expandtype.py
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Expand Up @@ -93,19 +93,15 @@ def visit_type_var(self, t: TypeVarType) -> Type:
repl = get_proper_type(self.variables.get(t.id, t))
if isinstance(repl, Instance):
inst = repl
# Return copy of instance with type erasure flag on.
return Instance(inst.type, inst.args, line=inst.line,
column=inst.column, erased=True)
return Instance(inst.type, inst.args, line=inst.line, column=inst.column)
else:
return repl

def visit_param_spec(self, t: ParamSpecType) -> Type:
repl = get_proper_type(self.variables.get(t.id, t))
if isinstance(repl, Instance):
inst = repl
# Return copy of instance with type erasure flag on.
return Instance(inst.type, inst.args, line=inst.line,
column=inst.column, erased=True)
return Instance(inst.type, inst.args, line=inst.line, column=inst.column)
elif isinstance(repl, ParamSpecType):
return repl.with_flavor(t.flavor)
else:
Expand Down
12 changes: 4 additions & 8 deletions mypy/types.py
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Expand Up @@ -1029,19 +1029,16 @@ def try_getting_instance_fallback(typ: ProperType) -> Optional[Instance]:

"""

__slots__ = ('type', 'args', 'erased', 'invalid', 'type_ref', 'last_known_value')
__slots__ = ('type', 'args', 'invalid', 'type_ref', 'last_known_value')

def __init__(self, typ: mypy.nodes.TypeInfo, args: Sequence[Type],
line: int = -1, column: int = -1, erased: bool = False,
line: int = -1, column: int = -1, *,
last_known_value: Optional['LiteralType'] = None) -> None:
super().__init__(line, column)
self.type = typ
self.args = tuple(args)
self.type_ref: Optional[str] = None

# True if result of type variable substitution
self.erased = erased

# True if recovered after incorrect number of type arguments error
self.invalid = False

Expand Down Expand Up @@ -1137,15 +1134,14 @@ def deserialize(cls, data: Union[JsonDict, str]) -> 'Instance':

def copy_modified(self, *,
args: Bogus[List[Type]] = _dummy,
erased: Bogus[bool] = _dummy,
last_known_value: Bogus[Optional['LiteralType']] = _dummy) -> 'Instance':
return Instance(
self.type,
args if args is not _dummy else self.args,
self.line,
self.column,
erased if erased is not _dummy else self.erased,
last_known_value if last_known_value is not _dummy else self.last_known_value,
last_known_value=last_known_value if last_known_value is not _dummy
else self.last_known_value,
)

def has_readable_member(self, name: str) -> bool:
Expand Down