better static checks on initializing CheckedDict variables with dictionary literals
LuKuangChen opened this issue · comments
a4a71ae
2021-12-20
What program did you run?
from __static__ import CheckedDict
class B: pass
def testfunc():
x: CheckedDict[B, int] = {object():42}
return xThis program is found in cinder/3.8/Lib/test/test_compiler/test_static/tests.py. This test is labeled test_compile_checked_dict_with_annotation_wrong_key_type. There is a similar test labeled test_compile_checked_dict_with_annotation_wrong_value_type.
What happened?
compiler.errors.TypedSyntaxError: type mismatch: Exact[chkdict[object, Literal[42]]] cannot be assigned to Exact[chkdict[__main__.B, int]]
What should have happened?
We expected a compile-time error complaining that object cannot be assigned to B. In general, we expect that everytime the type checker sees x: CheckedDict[T1, T2] = { e1: e2, ... }, it checks every key expression e1 against T1, and every e2 against T2.
