Passing a vector to vec throws "invalid sequence"

[timmw]

Issue Description

This code:

(vec [])

produces:

"Uncaught exception: invalid sequence: []"

Full error

user=> (vec [])
Uncaught exception: invalid sequence: []

Stack trace (most recent call first):
#0  in get_adjusted_ptr(std::type_info const*, std::type_info const*, void**) at libstdc++.so.6
#4  in jank::runtime::oref<jank::runtime::obj::persistent_vector> jank::runtime::obj::persistent_vector::create(jank::runtime::oref<jank::runtime::object>)::$_0::operator()<jank::runtime::oref<jank::runtime::obj::persistent_vector> >(jank::runtime::oref<jank::runtime::obj::persistent_vector>) const at jank
#5  in jank::runtime::obj::persistent_vector::create(jank::runtime::oref<jank::runtime::object>) at jank
#6
#7  in jank::evaluate::eval(jtl::ref<jank::analyze::expr::cpp_call>) at jank
#8  in jank::evaluate::eval(jtl::ref<jank::analyze::expression>) at jank
#9  in jank::runtime::context::eval_string(jtl::immutable_string const&, jank::read::source_position const&) const at jank
#10 in jank::runtime::context::eval_file(jtl::immutable_string const&) at jank
#11 in main::$_0::operator()(int, char const**) const at jank
#12 in jank_init_dynamic at jank

Reproduction Steps

Run this in repl:

(vec [])

jank health check

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

─ jank install ────────────────────────────────────────────────────────────────
─ ✅ jank version: jank-0.1-alpha
─ ✅ jank cmake build type: Release
─ ✅ jank resource dir: ../lib/jank/0.1
─ ✅ jank resolved resource dir: /home/tim/.local/bin/../lib/jank/0.1 (found)
─ ✅ jank user cache dir: /home/tim/.cache/jank/x86_64-unknown-linux-gnu-5acfabba52afe16f52b7d453c209b2ba95bbfec5dd9715ff280234af21cc225b (found)

─ clang install ───────────────────────────────────────────────────────────────
─ ✅ configured clang path: /nix/store/yjvbvb8rm3pbws3hap8csf62jf9cgvfc-clang-wrapper-23.0.0-unstable-2026-06-21/bin/clang++ (found)
─ ✅ configured clang resource dir: /nix/store/yjvbvb8rm3pbws3hap8csf62jf9cgvfc-clang-wrapper-23.0.0-unstable-2026-06-21/resource-root (found)

─ jank runtime ────────────────────────────────────────────────────────────────
─ ✅ jank runtime initialized
─ ✅ jank pch path: /home/tim/.cache/jank/x86_64-unknown-linux-gnu-5acfabba52afe16f52b7d453c209b2ba95bbfec5dd9715ff280234af21cc225b (found)
─ ✅ jank can jit compile c++
─ ✅ jank can aot compile working binaries

─ support ─────────────────────────────────────────────────────────────────────
If you're having issues with jank, please either ask the jank community on the Clojurians Slack or report the issue on Github.

─ Slack: https://clojurians.slack.com/archives/C03SRH97FDK
─ Github: https://github.com/jank-lang/jank

Stack trace

Stack trace (most recent call first):
#0  in get_adjusted_ptr(std::type_info const*, std::type_info const*, void**) at libstdc++.so.6
#4  in jank::runtime::oref<jank::runtime::obj::persistent_vector> jank::runtime::obj::persistent_vector::create(jank::runtime::oref<jank::runtime::object>)::$_0::operator()<jank::runtime::oref<jank::runtime::obj::persistent_vector> >(jank::runtime::oref<jank::runtime::obj::persistent_vector>) const at jank
#5  in jank::runtime::obj::persistent_vector::create(jank::runtime::oref<jank::runtime::object>) at jank
#6
#7  in jank::evaluate::eval(jtl::ref<jank::analyze::expr::cpp_call>) at jank
#8  in jank::evaluate::eval(jtl::ref<jank::analyze::expression>) at jank
#9  in jank::runtime::context::eval_string(jtl::immutable_string const&, jank::read::source_position const&) const at jank
#10 in jank::runtime::context::eval_file(jtl::immutable_string const&) at jank
#11 in main::$_0::operator()(int, char const**) const at jank
#12 in jank_init_dynamic at jank

OS Version Information

Fedora 43

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]

Thanks! This will be covered by the clojure-test-suite tests for vec, but jank doesn't yet run that test due to a lack of array support. That's something I aim to tackle soon, so we'll be able to catch any issues with vec and other container fns which have array support.

@djblue you may be interested in this one, in the meantime. Or not!

[jeaye]

The vec tests, for reference: https://github.com/jank-lang/clojure-test-suite/blob/main/test/clojure/core_test/vec.cljc

[jeaye]

This has been fixed by @djblue here: #896