Shadow binding causes issues for cpp code gen

[djblue]

Issue Description

The following Clojure code will generate cpp which causes compiler errors:

;; pass-nested-closure.jank
(let* [f (fn* [])]
  (let* [f (fn* [] (f))]
    :success))

with the following cpp code:

auto &&clojure_core_f_79027(
                jank::runtime::make_box<::clojure::core::fn_79026>(clojure_core_f_79027));

and the following error:

input_line_2:10:581: error: variable 'clojure_core_f_79027' declared with deduced type 'auto &&' cannot appear in its own initializer

Reproduction Steps

JANK_PRINT_IR=1 jank run pass-nested-closure.jank

jank health check

─ system ───────────────────────────────────────────────────────────────────────────────────────────
─ ✅ operating system: linux
─ ✅ default triple: x86_64-unknown-linux-gnu

─ jank install ─────────────────────────────────────────────────────────────────────────────────────
─ ✅ jank version: jank-0.1-alpha
─ ⚠️ jank assertions are enabled; performance will be impacted 
─ ✅ jank resource dir: ../lib/jank/0.1 
─ ✅ jank resolved resource dir: /home/chris/repos/jank/compiler+runtime/build/../lib/jank/0.1 (ignored for dev build)
─ ✅ jank user cache dir: /home/chris/.cache/jank/x86_64-unknown-linux-gnu-971b4c64a0f7842416606f7386033dde995cb5811b35b069566e6a19f75d76d4 (not found)

─ clang install ────────────────────────────────────────────────────────────────────────────────────
─ ✅ configured clang path: /home/chris/repos/jank/compiler+runtime/build/llvm-install/usr/local/bin/clang++ (found)
─ ✅ configured clang resource dir: /home/chris/repos/jank/compiler+runtime/build/llvm-install/usr/local/lib/clang/22 (found)

─ jank runtime ─────────────────────────────────────────────────────────────────────────────────────
─ ✅ jank runtime initialized
─ ✅ jank pch path: /home/chris/.cache/jank/x86_64-unknown-linux-gnu-971b4c64a0f7842416606f7386033dde995cb5811b35b069566e6a19f75d76d4 (found)
─ ✅ jank can jit compile c++
─ ✅ jank can aot compile working binaries

Stack trace

No response

OS Version Information

WSL2

I acknowledge that:

• I have searched the jank repository (both open and closed Discussions and Issues) and confirm this is not a duplicate of an existing issue or discussion.
• I have checked the "Preview" tab on all text fields to ensure that everything looks right, and have wrapped all configuration and code in code blocks with a group of three backticks (```) on separate lines.

[jeaye]

Fixed here: #683