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Inplace class definitions causes infinite looping #2826
Description
class Foo:
def __init__(self: "Foo", bar: i32):
self.bar: i32 = bar
def __repr__(self: "Foo") -> str:
return str(self.bar)
def main():
a: Foo = Foo(10)
print(a)
main()Works fine but if we make a Foo instance inplace in print
def main():
print(Foo(10))this causes an infinite loop.
This also happens in case of functions taking in a Foo param
def foobar(a: Foo):
print(a)I imagine we need to add an error for as of now unsupported feature
PS: I had encountered a similar problem in my PR I simply threw an error for that case
Activity
amritamishra01 commentedon Nov 24, 2025
Hi! I'd like to work on this issue.
Since this bug is still open and unassigned, I’d like to investigate why inline class instantiation (e.g., print(Foo(10))) leads to an infinite loop and propose a fix — likely by detecting unsupported inline class construction and raising a clear semantic error, or by adjusting the lowering logic if appropriate.
Please let me know if that’s okay — I can start working on it.
Thanks!
Fix: Raise SemanticError for unsupported inline class instantiation l…