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Use isinstance information when type checking 'or' expressions #1709

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Merged
JukkaL merged 1 commit into from
Jun 17, 2016
Merged

Use isinstance information when type checking 'or' expressions #1709

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13 changes: 8 additions & 5 deletions mypy/checkexpr.py
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Original file line number Diff line number Diff line change
Expand Up @@ -1078,16 +1078,19 @@ def check_boolean_op(self, e: OpExpr, context: Context) -> Type:
left_type = self.accept(e.left, ctx)

if e.op == 'and':
# else_map unused
if_map, else_map = \
right_map, _ = \
mypy.checker.find_isinstance_check(e.left, self.chk.type_map,
self.chk.typing_mode_weak())
elif e.op == 'or':
_, right_map = \
mypy.checker.find_isinstance_check(e.left, self.chk.type_map,
self.chk.typing_mode_weak())
else:
if_map = None
right_map = None

self.chk.binder.push_frame()
if if_map:
for var, type in if_map.items():
if right_map:
for var, type in right_map.items():
self.chk.binder.push(var, type)

right_type = self.accept(e.right, left_type)
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6 changes: 6 additions & 0 deletions test-data/unit/check-isinstance.test
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Expand Up @@ -731,6 +731,12 @@ x = B() # type: A

if isinstance(x, B) and x.flag:
pass
if isinstance(x, B) or x.flag: # E: "A" has no attribute "flag"
pass
if not isinstance(x, B) or x.flag:
pass
if not isinstance(x, B) and x.flag: # E: "A" has no attribute "flag"
pass
[builtins fixtures/isinstancelist.py]
[case testIsinstanceExpression]
class A:
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