roc-lang/roc

A fast, friendly, functional language.

Stars: 6.1k
Forks: 418
Open beginner issues: 0
Indexed issues: 201
Avg merge: 15h 58m
Merged PRs (30d): 324

Dominant language: Zig
License: UPL-1.0
Last GitHub push: Sep 19, 2026
Latest indexed: Sep 20, 2026
Contributing guide: No contributing guide
Code of conduct: Code of conduct
Beginner labels: good first issue hacktoberfest help wanted

Beginner friendly Everything

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195 open issues indexed

roc build segfaults on an import that escapes the package root (roc check reports it cleanly) Open

Difficulty 3/5 1-2 days Newbie friendliness 68/100

roc-lang/roc#11475 · Opened Sep 20, 2026
`roc check` panics with `missing required method call parse_record_field` when `.len()` is called on a field of a `Json.parse` result whose `List` element type is an alias Open

Difficulty 4/5 3-5 days Newbie friendliness 48/100

roc-lang/roc#11471 · Opened Sep 19, 2026
`roc check` reports an anonymous recursion for a bare `?` and a `? Tag` on calls that share an error type variable when the called function adds a tag of its own Open

Difficulty 4/5 3-5 days Newbie friendliness 52/100

roc-lang/roc#11470 · Opened Sep 19, 2026
`roc check` reports an anonymous recursion when a callback does a bare `?` on the function value that the function it is passed to wraps with `? Tag` Open

roc-lang/roc#11469 · 1 assignee · Opened Sep 19, 2026
Segmentation fault when removing type annotation Open

Difficulty 4/5 3-5 days Newbie friendliness 58/100

roc-lang/roc#11468 · Opened Sep 19, 2026
Reported crash when an unannotated structural tag is consumed as a nominal tag type Open

Difficulty 4/5 3-5 days Newbie friendliness 48/100

roc-lang/roc#11467 · Opened Sep 19, 2026
Qualified numeric literal suffixes are rejected by the parser Open

Difficulty 4/5 3-5 days Newbie friendliness 50/100

roc-lang/roc#11466 · Opened Sep 19, 2026
Qualified record-builder suffix ignores its module qualifier Open

Difficulty 4/5 3-5 days Newbie friendliness 68/100

roc-lang/roc#11465 · Opened Sep 19, 2026
Nested types do not resolve through a re-exported type-module alias Open

Difficulty 4/5 3-5 days Newbie friendliness 68/100

roc-lang/roc#11464 · Opened Sep 19, 2026
`instantiation widened a closed record` on a record update passed through a method call in an unannotated function Open

Difficulty 4/5 3-5 days Newbie friendliness 48/100

roc-lang/roc#11463 · Opened Sep 19, 2026
`roc build --target=wasm32 --opt=dev` emits an invalid module (`values remaining on stack at end of block`) when a nominal tag union holding `Box({})` is the payload of a two-variant tag union Open

roc-lang/roc#11455 · 1 assignee · Opened Sep 18, 2026
`roc build --target=wasm32 --opt=speed` output traps with `indirect call type mismatch` when two `List.concat` calls have different refcounted element types Open

roc-lang/roc#11454 · 1 assignee · Opened Sep 18, 2026
`roc build --opt=dev` panics with `missing required method call encode_record` when a method does `Json.to_str` of three nested record aliases Open

Difficulty 4/5 3-5 days Newbie friendliness 52/100

roc-lang/roc#11453 · Opened Sep 18, 2026
LLVM 4x compile time regression from inlining Open

Difficulty 4/5 3-5 days Newbie friendliness 48/100

roc-lang/roc#11451 · Opened Sep 18, 2026
Dev backend frees still-referenced data since ARC worker emission (2e8927a9df1); worker count also changes emitted LIR Open

Difficulty 5/5 Over a week Newbie friendliness 30/100

roc-lang/roc#11449 · Opened Sep 18, 2026
Dev backend never reuses stack slots: multi-hundred-KiB page-probed frames in large procedures Open

Difficulty 5/5 Over a week Newbie friendliness 45/100

roc-lang/roc#11448 · Opened Sep 17, 2026
`roc build` segfaults when a package method returns the open error union of a file-level function that does `Json.to_str` of a record with two fields Open

Difficulty 4/5 3-5 days Newbie friendliness 45/100

roc-lang/roc#11444 · Opened Sep 17, 2026
`roc check` and `roc build` segfault when an unannotated top-level helper calls a method whose body does `Json.to_str` of a record holding its generic argument Open

Difficulty 4/5 3-5 days Newbie friendliness 55/100

roc-lang/roc#11441 · Opened Sep 17, 2026
`roc test`'s summary doesn't mention `expect`s with type errors Open

Difficulty 3/5 1-2 days Newbie friendliness 68/100

roc-lang/roc#11439 · Opened Sep 17, 2026
Flaky under load: Monotype creates two specializations for one closed request with four workers (issue 10831 regression test) Open

roc-lang/roc#11438 · 1 assignee · Opened Sep 17, 2026
nightly-2026-09-15 SIGTRAP compiling roc-gui device-configurator Open

Difficulty 4/5 3-5 days Newbie friendliness 48/100

roc-lang/roc#11424 · Opened Sep 16, 2026
Shared compile-time lowering triples build time and peak memory on roc-deflate Open

roc-lang/roc#11418 · 1 assignee · Opened Sep 15, 2026
Panic: Ident.Idx lookup in wrong store Open

Difficulty 3/5 1-2 days Newbie friendliness 72/100

roc-lang/roc#11407 · Opened Sep 14, 2026
Specialize procedures by the demand their bodies make on scheme variables, not by full request type Open

roc-lang/roc#11404 · 1 assignee · Opened Sep 14, 2026
`roc check` passes but `roc build` segfaults when a package type module's method on a nominal returns an open error union around `Json.to_str` of its `Str` argument Open

Difficulty 4/5 3-5 days Newbie friendliness 45/100

roc-lang/roc#11393 · Opened Sep 14, 2026
Panic: reached unreachable code Open

Difficulty 3/5 1-2 days Newbie friendliness 68/100

roc-lang/roc#11390 · Opened Sep 14, 2026
`roc test` writes a module cache that makes the next `roc check` or `roc build` panic with `reached unreachable code` in `hoistSelectionInvariant` Open

roc-lang/roc#11389 · 1 assignee · Opened Sep 14, 2026
Unsatisfiable `where` clause on a nominal's `to_inspect`, reached through a derived record `to_inspect`, segfaults the compiler Open

Difficulty 4/5 3-5 days Newbie friendliness 55/100

roc-lang/roc#11388 · Opened Sep 14, 2026
Json.parse panic: postcheck invariant violated: checked generated codec contract had overlapping direct call roles Open

Difficulty 4/5 3-5 days Newbie friendliness 48/100

roc-lang/roc#11384 · Opened Sep 14, 2026
Checked generic nominal collection construction hits RuntimeError before reading its first item Open

Difficulty 4/5 3-5 days Newbie friendliness 48/100

roc-lang/roc#11377 · Opened Sep 13, 2026
Panic: publication could not resolve a checked dispatch target for an owned method Open

Difficulty 4/5 3-5 days Newbie friendliness 58/100

roc-lang/roc#11369 · Opened Sep 13, 2026
Runtime error for non-top level expect when comparing different types Open

roc-lang/roc#11366 · 1 assignee · Opened Sep 13, 2026
Executable built with --opt=interpreter hangs when a provided root returns a 24-byte static string Open

Difficulty 4/5 3-5 days Newbie friendliness 68/100

roc-lang/roc#11364 · Opened Sep 13, 2026
Monotype specialization drain runs in fixed-size waves behind a barrier; replace it with a sliding window that commits shards as they arrive Open

roc-lang/roc#11361 · 1 assignee · Opened Sep 13, 2026
Boxy panic: checked nominal representation had no declaration backing Open

Difficulty 3/5 1-2 days Newbie friendliness 72/100

roc-lang/roc#11358 · Opened Sep 13, 2026
Boxy panic: generated parser result payload was not a record Open

Difficulty 4/5 3-5 days Newbie friendliness 52/100

roc-lang/roc#11357 · Opened Sep 13, 2026
Boxy panic: generated codec contract was missing a required method call Open

Difficulty 3/5 1-2 days Newbie friendliness 55/100

roc-lang/roc#11356 · Opened Sep 13, 2026
Boxy panic: boxy callable dictionary parameter had no checked call substitution or dispatch evidence Open

Difficulty 3/5 1-2 days Newbie friendliness 68/100

roc-lang/roc#11355 · Opened Sep 13, 2026
Boxy panic: local was assigned two different boxy descriptors Open

Difficulty 4/5 3-5 days Newbie friendliness 68/100

roc-lang/roc#11354 · Opened Sep 13, 2026
Boxy panic: boxy callable adapter descriptor mapping did not cover a descriptor capture Open

Difficulty 3/5 1-2 days Newbie friendliness 70/100

roc-lang/roc#11353 · Opened Sep 13, 2026
Boxy panic: one worker descriptor representation mapped to two call representations Open

Difficulty 4/5 3-5 days Newbie friendliness 48/100

roc-lang/roc#11352 · Opened Sep 13, 2026
Boxy panic: unresolved bare dynamic representation required a static descriptor Open

Difficulty 3/5 1-2 days Newbie friendliness 65/100

roc-lang/roc#11351 · 1 comment · Opened Sep 13, 2026
Canonicalization is quadratic in the number of type declarations: `refreshTypeBindingKindForStatement` scans every type binding in every scope once per declaration Open

Difficulty 4/5 3-5 days Newbie friendliness 68/100

roc-lang/roc#11349 · Opened Sep 13, 2026
Checked canonical type keys re-hash the entire subtree for every published root; make them compositional over closed acyclic children Open

roc-lang/roc#11348 · 1 assignee · Opened Sep 13, 2026
The default platform's allocator makes one `mmap` per heap value, and one `munmap` per free Open

Difficulty 4/5 3-5 days Newbie friendliness 52/100

roc-lang/roc#11335 · Opened Sep 12, 2026
Compile-time evaluation has no step limit: `roc check` never finishes on a program that loops forever Open

Difficulty 5/5 Over a week Newbie friendliness 35/100

roc-lang/roc#11334 · Opened Sep 12, 2026
Monotype specialization wall time is bounded by one lane lowering the widest route Open

roc-lang/roc#11326 · 1 assignee · Opened Sep 12, 2026
`body_clone.countReachableReads` allocates and zeroes a `store.localCount()`-sized table for every proc, so `LIR Passes` is quadratic in program size Open

roc-lang/roc#11325 · 1 assignee · Opened Sep 12, 2026
`roc build --opt=dev` ARC time is quadratic in the number of dismantle candidates: `arc_dismantle.compute` rescans every LIR statement once per candidate Open

roc-lang/roc#11321 · 1 assignee · Opened Sep 12, 2026
Panic: erroneous checked type reached Monotype instantiation Open

Difficulty 3/5 1-2 days Newbie friendliness 65/100

roc-lang/roc#11312 · Opened Sep 11, 2026

A short digest of beginner-friendly GitHub issues.