Dictionary order influences parseability

[apexys]

Hello everyone,
I'm currently using rustpython to embed an existing python library into a piece of software and I think I might have found a bug.
The goal is to create a dictionary with String keys and Callable entries somewhat like this:

new_dict = {
    **{x: lambda y: y + 2 for x in ["a", "b", "c"]}, 
    "d": lambda x: x +1,
}

If I try to run this code through the rustpython executable, I get the error message:

thread 'main' panicked at /home/valentinbuck/.cargo/registry/src/index.crates.io-6f17d22bba15001f/rustpython-codegen-0.3.0/src/compile.rs:311:9:
assertion failed: table.sub_tables.is_empty()
note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace

This differs from the error I get when I run this code through a VM I constructed myself:

thread 'main' panicked at /home/valentinbuck/.cargo/git/checkouts/rustpython-f8ef4d934ac33cd8/e6c6f96/compiler/codegen/src/compile.rs:481:57:
The symbol must be present in the symbol table, even when it is undefined in python.

However, when I swap the two lines in the dict, it compiles and runs fine:

new_dict = {
    "d": lambda x: x +1,
    **{x: lambda y: y + 2 for x in ["a", "b", "c"]}, 
}

I tried looking through the parser to find the place where this happens but had no luck.
Do you have an idea where I could start or what is going wrong?

Thanks a lot for your project!

[apexys]

Almost forgot: Both variants compile fine through CPython.

[youknowone]

Thank you for the report!
Somehow, x in "d": lambda x: x +1, doesn't exist in symbol table. How about starting comparing how the symbol put in or not put in by the order?

[apexys]

I think its a different problem. On the current main branch, if I run the working version (dict-comp-last), and log the symbol table stack before the code object gets popped in compile_expression->Expr::Lambda after the emit! of the return value , I get

ST stack [SymbolTable(2 symbols, 1 sub scopes), SymbolTable(1 symbols, 0 sub scopes)]
Sub Table Symbols None
ST stack [SymbolTable(2 symbols, 0 sub scopes), SymbolTable(2 symbols, 0 sub scopes), SymbolTable(1 symbols, 0 sub scopes)]

But if I run the non-working version (dict-comp-first), I get

ST stack [SymbolTable(2 symbols, 1 sub scopes), SymbolTable(2 symbols, 1 sub scopes)]

It almost looks like the entry gets put into the symbol table twice.
But why and where does that happen?