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Merged
merged 9 commits into from
Apr 30, 2019
Merged

Error when a class member is redefined #6686

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246f393
Fix
onlined Apr 17, 2019
76f9c77
Fix and make tests pass
onlined Apr 17, 2019
74643d7
Merge branch 'master' into fix/class-member-redefinition
onlined Apr 25, 2019
1f3de97
Change 'Name' to 'Attribute'
onlined Apr 26, 2019
bf042b0
Change tests
onlined Apr 26, 2019
79e6374
Remove redundant test
onlined Apr 29, 2019
0e36e11
Merge remote-tracking branch 'upstream/master' into fix/class-member-…
onlined Apr 29, 2019
4b7ab06
Add test
onlined Apr 29, 2019
f8fe217
Add comments
onlined Apr 30, 2019
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21 changes: 17 additions & 4 deletions mypy/newsemanal/semanal.py
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Original file line number Diff line number Diff line change
Expand Up @@ -2563,6 +2563,9 @@ def analyze_member_lvalue(self, lval: MemberExpr, explicit_type: bool, is_final:
if cur_node and is_final:
# Overrides will be checked in type checker.
self.fail("Cannot redefine an existing name as final", lval)
if (not lval.node and cur_node and isinstance(cur_node.node, Var) and
cur_node.node.is_inferred and explicit_type):
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TBH I don't follow the logic here, maybe add a comment explaining this?

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Yes, I can write a comment. But before, let me explain: Fail if passing first time, the node exists and it's a Var node, it's type is inferred, and new assignment has an explicit type.

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@ilevkivskyi ilevkivskyi Apr 26, 2019 •
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Basically yes. But please try to avoid this:

x += 1  # Increment x

Describe the intent and how the code achieves it.

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@onlined Are you going to add this comment (also in the old analyzer)?

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Yes, I will.

self.attribute_already_defined(lval.name, lval, cur_node)
# If the attribute of self is not defined in superclasses, create a new Var, ...
if ((node is None or isinstance(node.node, Var) and node.node.is_abstract_var) or
# ... also an explicit declaration on self also creates a new Var.
Expand Down Expand Up @@ -4298,9 +4301,9 @@ def name_not_defined(self, name: str, ctx: Context, namespace: Optional[str] = N
# Yes. Generate a helpful note.
self.add_fixture_note(fullname, ctx)

def name_already_defined(self, name: str, ctx: Context,
original_ctx: Optional[Union[SymbolTableNode, SymbolNode]] = None
) -> None:
def already_defined(self, name: str, ctx: Context,
original_ctx: Optional[Union[SymbolTableNode, SymbolNode]] = None, *,
noun: str) -> None:
if isinstance(original_ctx, SymbolTableNode):
node = original_ctx.node # type: Optional[SymbolNode]
elif isinstance(original_ctx, SymbolNode):
Expand All @@ -4319,7 +4322,17 @@ def name_already_defined(self, name: str, ctx: Context,
extra_msg = ' on line {}'.format(node.line)
else:
extra_msg = ' (possibly by an import)'
self.fail("Name '{}' already defined{}".format(unmangle(name), extra_msg), ctx)
self.fail("{} '{}' already defined{}".format(noun, unmangle(name), extra_msg), ctx)

def name_already_defined(self, name: str, ctx: Context,
original_ctx: Optional[Union[SymbolTableNode, SymbolNode]] = None
) -> None:
self.already_defined(name, ctx, original_ctx, noun='Name')

def attribute_already_defined(self, name: str, ctx: Context,
original_ctx: Optional[Union[SymbolTableNode, SymbolNode]] = None
) -> None:
self.already_defined(name, ctx, original_ctx, noun='Attribute')

def is_local_name(self, name: str) -> bool:
"""Does name look like reference to a definition in the current module?"""
Expand Down
20 changes: 17 additions & 3 deletions mypy/semanal.py
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Original file line number Diff line number Diff line change
Expand Up @@ -2288,6 +2288,9 @@ def analyze_member_lvalue(self, lval: MemberExpr, explicit_type: bool, is_final:
if cur_node and is_final:
# Overrides will be checked in type checker.
self.fail("Cannot redefine an existing name as final", lval)
if (cur_node and isinstance(cur_node.node, Var) and cur_node.node.is_inferred and
explicit_type):
self.attribute_already_defined(lval.name, lval, cur_node)
# If the attribute of self is not defined in superclasses, create a new Var, ...
if ((node is None or isinstance(node.node, Var) and node.node.is_abstract_var) or
# ... also an explicit declaration on self also creates a new Var.
Expand Down Expand Up @@ -3736,8 +3739,9 @@ def name_not_defined(self, name: str, ctx: Context) -> None:
# Yes. Generate a helpful note.
self.add_fixture_note(fullname, ctx)

def name_already_defined(self, name: str, ctx: Context,
original_ctx: Optional[Union[SymbolTableNode, SymbolNode]] = None) -> None:
def already_defined(self, name: str, ctx: Context,
original_ctx: Optional[Union[SymbolTableNode, SymbolNode]] = None, *,
noun: str) -> None:
if isinstance(original_ctx, SymbolTableNode):
node = original_ctx.node
elif isinstance(original_ctx, SymbolNode):
Expand All @@ -3752,7 +3756,17 @@ def name_already_defined(self, name: str, ctx: Context,
extra_msg = ' on line {}'.format(node.line)
else:
extra_msg = ' (possibly by an import)'
self.fail("Name '{}' already defined{}".format(unmangle(name), extra_msg), ctx)
self.fail("{} '{}' already defined{}".format(noun, unmangle(name), extra_msg), ctx)

def name_already_defined(self, name: str, ctx: Context,
original_ctx: Optional[Union[SymbolTableNode, SymbolNode]] = None
) -> None:
self.already_defined(name, ctx, original_ctx, noun='Name')

def attribute_already_defined(self, name: str, ctx: Context,
original_ctx: Optional[Union[SymbolTableNode, SymbolNode]] = None
) -> None:
self.already_defined(name, ctx, original_ctx, noun='Attribute')

def fail(self, msg: str, ctx: Context, serious: bool = False, *,
blocker: bool = False) -> None:
Expand Down
12 changes: 12 additions & 0 deletions test-data/unit/check-classes.test
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Expand Up @@ -5838,6 +5838,18 @@ def test() -> None:
reveal_type(x) # E: Revealed type is 'Union[Type[__main__.One], Type[__main__.Other]]'
[builtins fixtures/isinstancelist.pyi]

[case testMemberRedefinition]
class C:
def __init__(self) -> None:
self.foo = 12
self.foo: int = 12 # E: Attribute 'foo' already defined on line 3

[case testMemberRedefinitionDefinedInClass]
class C:
foo = 12
def __init__(self) -> None:
self.foo: int = 12 # E: Attribute 'foo' already defined on line 2

[case testAbstractInit]
from abc import abstractmethod, ABCMeta
class A(metaclass=ABCMeta):
Expand Down