8000 Don't crash on aliases like C = C by ilevkivskyi · Pull Request #5632 · python/mypy · GitHub
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Don't crash on aliases like C = C #5632

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Merged
merged 3 commits into from
Sep 19, 2018
Merged

Don't crash on aliases like C = C #5632

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44aa288
Don't crash on aliases like C = C
Sep 18, 2018
8667ccf
Add a test
Sep 18, 2018
f533d8d
Tweak tests
Sep 18, 2018
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5 changes: 4 additions & 1 deletion mypy/fixup.py
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Original file line number Diff line number Diff line change
Expand Up @@ -236,7 +236,10 @@ def lookup_qualified_typeinfo(modules: Dict[str, MypyFile], name: str,
return node
else:
# Looks like a missing TypeInfo in quick mode, put something there
assert quick_and_dirty, "Should never get here in normal mode"
assert quick_and_dirty, "Should never get here in normal mode," \
" got {}:{} instead of TypeInfo".format(type(node).__name__,
node.fullname() if node
else '')
return stale_info(modules)


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4 changes: 4 additions & 0 deletions mypy/semanal.py
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Expand Up @@ -1931,6 +1931,10 @@ def check_and_set_up_type_alias(self, s: AssignmentStmt) -> None:
res, alias_tvars, depends_on, qualified_tvars = self.analyze_alias(rvalue)
if not res:
return
if (isinstance(res, Instance) and res.type.name() == lvalue.name and
res.type.module_name == self.cur_mod_id):
# Aliases like C = C is a no-op.
return
s.is_alias_def = True
node = self.lookup(lvalue.name, lvalue)
assert node is not None
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114 changes: 114 additions & 0 deletions test-data/unit/check-incremental.test
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Expand Up @@ -5193,3 +5193,117 @@ def f(x: str) -> None: pass
[out]
[out2]
tmp/main.py:2: error: Argument 1 to "f" has incompatible type "int"; expected "str"

[case testOverrideByIdemAlias]
import a
[file a.py]
import lib
x = 1
[file a.py.2]
import lib
x = 2
[file lib.py]
C = C
class C: # type: ignore
pass
[out]
[out2]

[case testOverrideByIdemAliasReversed]
import a
[file a.py]
import lib
x = 1
[file a.py.2]
import lib
x = 2
[file lib.py]
class C:
pass
C = C # type: ignore
x: C
[out]
[out2]

[case testOverrideByIdemAliasGeneric]
import a
[file a.py]
import lib
x = 1
[file a.py.2]
import lib
x = 2
[file lib.py]
from typing import Generic, TypeVar

T = TypeVar('T')

class C(Generic[T]):
pass
C = C[int] # type: ignore
x: C
[out]
[out2]

[case testOverrideByIdemAliasImported]
import a
[file a.py]
import lib
x = 1
[file a.py.2]
import lib
x = 2
[file lib.py]
from other import C
C = C # type: ignore
x: C
[file other.py]
class C:
pass
[out]
[out2]

[case testOverrideByIdemAliasImportedReversed]
import a
[file a.py]
import lib
x = 1
[file a.py.2]
import lib
x = 2
[file lib.py]
C = C # type: ignore
from other import C
[file other.py]
class C:
pass
[out]
[out2]

[case testConditionalExceptionAliasOverride]
import a
[file a.py]
import lib
try:
x = 1
except lib.Exception as e:
pass
[file a.py.2]
import lib
try:
x = 2
except lib.Exception as e:
pass
[file lib.py]
try:
Exception = Exception
except BaseException:
class Exception(BaseException): pass # type: ignore

try:
pass
except Exception as e:
pass
[builtins fixtures/exception.pyi]
[out]
[out2]
39 changes: 39 additions & 0 deletions test-data/unit/check-type-aliases.test
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Expand Up @@ -518,3 +518,42 @@ def foo(x: Bogus[int]) -> None:
reveal_type(x) # E: Revealed type is 'builtins.int'

[builtins fixtures/dict.pyi]

[case testOverrideByIdemAliasCorrectType]
C = C
class C: # type: ignore
pass
x: C
reveal_type(x) # E: Revealed type is '__main__.C'
[out]

[case testOverrideByIdemAliasCorrectTypeReversed]
class C:
pass
C = C # type: ignore
x: C
reveal_type(x) # E: Revealed type is '__main__.C'
[out]

[case testOverrideByIdemAliasCorrectTypeImported]
from other import C as B
C = B
x: C
reveal_type(x) # E: Revealed type is 'other.C'
[file other.py]
class C:
pass
[out]

[case testConditionalExceptionAlias]
try:
E = E
except BaseException:
class E(BaseException): pass # type: ignore

try:
pass
except E as e:
reveal_type(e) # E: Revealed type is '__main__.E'
[builtins fixtures/exception.pyi]
[out]
1 change: 1 addition & 0 deletions test-data/unit/fixtures/exception.pyi
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Original file line number Diff line number Diff line change
Expand Up @@ -14,3 +14,4 @@ class bool: pass
class ellipsis: pass

class BaseException: pass
class Exception(BaseException): pass
0