Description

swamishiju

opened on Feb 24, 2025

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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

1. amritamishra01 commented on Nov 24, 2025

   

   amritamishra01

   on Nov 24, 2025

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   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!
2. amritamishra01

   added a commit that references this issue on Dec 8, 2025

   Fix: Raise SemanticError for unsupported inline class instantiation l…

   fd3fbcc

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