Closure environments aren't added to a closure's parameters

[alehander92]

Aim

Try to assign to a value using a captured mutable reference to it in a closure:

(example by @jfecher ):

fn main() {
    let x1 = &mut 42;
    let set_x1 = |y| { *x1 = y; };

    assert(*x1 == 42);
    set_x1(44);
    assert(*x1 == 44);
    set_x1(*x1);
    assert(*x1 == 44);
}

run nargo execute in this project

Expected Behavior

assertions pass correctly, no error

Bug

A lookup ssa ICE:

The application panicked (crashed).
Message:  lookup: variable not defined
Location: crates/noirc_evaluator/src/ssa_refactor/ssa_gen/context.rs:418
This is a bug. We may have already fixed this in newer versions of Nargo so try searching for similar issues at https://github.com/noir-lang/noir/issues/.

If there isn't an open issue for this bug, consider opening one at https://github.com/noir-lang/noir/issues/new?labels=bug&template=bug_report.yml
━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━ BACKTRACE ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━

⋮ 8 frames hidden ⋮

9: core::panicking::panic_display::h29316b4d8276b58d

at /rustc/69f9c33d71c871fc16ac445211281c6e7a340943/library/core/src/panicking.rs:139

10: core::panicking::panic_str::hdb14547b30ece385

at /rustc/69f9c33d71c871fc16ac445211281c6e7a340943/library/core/src/panicking.rs:123

11: core::option::expect_failed::h1c9d589f6e6349ed

at /rustc/69f9c33d71c871fc16ac445211281c6e7a340943/library/core/src/option.rs:1879

12: core::option::Option::expect::h4358a8adecd3fa90

at /rustc/69f9c33d71c871fc16ac445211281c6e7a340943/library/core/src/option.rs:741

13: noirc_evaluator::ssa_refactor::ssa_gen::context::FunctionContext::lookup::h9248c1e85392b3f2

at /home/al/noir/crates/noirc_evaluator/src/ssa_refactor/ssa_gen/context.rs:418

14: noirc_evaluator::ssa_refactor::ssa_gen::context::FunctionContext::ident_lvalue::h139e67ba738052c6

at /home/al/noir/crates/noirc_evaluator/src/ssa_refactor/ssa_gen/context.rs:520

15: noirc_evaluator::ssa_refactor::ssa_gen::context::FunctionContext::extract_current_value_recursive::hd12835bcfdf47006

at /home/al/noir/crates/noirc_evaluator/src/ssa_refactor/ssa_gen/context.rs:543

16: noirc_evaluator::ssa_refactor::ssa_gen::context::FunctionContext::extract_current_value::h98d5aedb18d85c15

at /home/al/noir/crates/noirc_evaluator/src/ssa_refactor/ssa_gen/context.rs:503

17: noirc_evaluator::ssa_refactor::ssa_gen::::codegen_assign::h0ae74c0605bce610

at /home/al/noir/crates/noirc_evaluator/src/ssa_refactor/ssa_gen/mod.rs:433

18: noirc_evaluator::ssa_refactor::ssa_gen::::codegen_expression::hbed02fe13302f1d6

at /home/al/noir/crates/noirc_evaluator/src/ssa_refactor/ssa_gen/mod.rs:81

19: noirc_evaluator::ssa_refactor::ssa_gen::::codegen_block::h1f4442e155ad6e66

at /home/al/noir/crates/noirc_evaluator/src/ssa_refactor/ssa_gen/mod.rs:178

20: noirc_evaluator::ssa_refactor::ssa_gen::::codegen_expression::hbed02fe13302f1d6

at /home/al/noir/crates/noirc_evaluator/src/ssa_refactor/ssa_gen/mod.rs:65

21: noirc_evaluator::ssa_refactor::ssa_gen::::codegen_function_body::h3a30d7fadb672b15

at /home/al/noir/crates/noirc_evaluator/src/ssa_refactor/ssa_gen/mod.rs:56

22: noirc_evaluator::ssa_refactor::ssa_gen::generate_ssa::heca22e4cc66763e8

at /home/al/noir/crates/noirc_evaluator/src/ssa_refactor/ssa_gen/mod.rs:46

23: noirc_evaluator::ssa_refactor::optimize_into_acir::hc5b0e6998a74d50a

at /home/al/noir/crates/noirc_evaluator/src/ssa_refactor.rs:43

24: noirc_evaluator::ssa_refactor::create_circuit::ha30ce1b0ce7adb30

at /home/al/noir/crates/noirc_evaluator/src/ssa_refactor.rs:87

25: noirc_driver::compile_no_check::h6c12ded194d20b7f

at /home/al/noir/crates/noirc_driver/src/lib.rs:277

26: noirc_driver::compile_main::he8205448c3365dc5

at /home/al/noir/crates/noirc_driver/src/lib.rs:166

27: nargo_cli::cli::compile_cmd::compile_circuit::hfe072f713cdd406f

at /home/al/noir/crates/nargo_cli/src/cli/compile_cmd.rs:136

28: nargo_cli::cli::execute_cmd::execute_package::hfc05356ee1f8318e

at /home/al/noir/crates/nargo_cli/src/cli/execute_cmd.rs:73

29: nargo_cli::cli::execute_cmd::run::h4995f87b92c6170a

at /home/al/noir/crates/nargo_cli/src/cli/execute_cmd.rs:51

30: nargo_cli::cli::start_cli::hed1ec5e662c4cab2

at /home/al/noir/crates/nargo_cli/src/cli/mod.rs:79

31: nargo::main::hd4a820dc8ea83d4b

at /home/al/noir/crates/nargo_cli/src/main.rs:14

32: core::ops::function::FnOnce::call_once::h341ee90d78f8ccb6

at /rustc/69f9c33d71c871fc16ac445211281c6e7a340943/library/core/src/ops/function.rs:251

⋮ 16 frames hidden ⋮

To Reproduce

No response

Installation Method

Compiled from source

Nargo Version

nargo 0.9.0 (git version hash: 39610af, is dirty: true)

Additional Context

originated here #1959 (comment)

Would you like to submit a PR for this Issue?

No

Support Needs

No response

[jfecher]

Looking at the lambda from this example in the monomorphized IR:

fn lambda$f1(y$l1: Field) -> () {
    *x1$l0 = y$l1
}

We can see that the "variable not found" panic is correct since x1 isn't defined within the lambda at all. It is part of the closure environment but was never added as a parameter to the lambda. I'll keep this issue open to track adding environment parameters to closures, but it is not an SSA or references related issue.

[jfecher]

Also, this may help with debugging:

To get the above output I added a println of the monomorphized IR after the call to monomorphize in crates/noirc_driver/src/lib.rs

[alexvitkov]

@jfecher I've submitted a PR that should fix this this: #2257
Here's the monomorphized AST for the lambda with the fix:

fn lambda$f1(mut env$l2: (&mut Field), y$l1: Field) -> () {
    *env$l2.0 = y$l1
}

However another unrelated codegen issue popped up, that still prevents this example from working properly: #2255