v2.2.0

v2.2.0 — 2026-07-14

This release improves language correctness, brings new training features to the
standard library, adds let destructuring, fixes runtime bugs, and improves the
REPL experience.

Language improvements

• stop-gradient blocks gradient flow while passing the value through
  unchanged, similar to jax.lax.stop_gradient (b77e79a)
• sin, cos, tan: fully differentiable trigonometric primitives, for RoPE
  and sinusoidal position encodings (8e0a2c3)
• Destructuring bindings: (let [[a b] expr] ...) destructures vectors and
  tuples directly, including typed function parameters, with no interpreter
  fallback (aaa6629, 4016b87, 5a009c3)
• flip reverses a tensor or list along an axis (6b3905b)
• transpose accepts a quoted permutation such as (transpose x '[0 2 1]) in
  the value-and-grad path (dd0830d)

Standard library additions

• adamw-step and sgd-momentum-step optimizers (0acd028)
• Learning-rate schedulers: linear-warmup, inverse-sqrt-warmup (Noam),
  exponential-decay, step-decay, cosine-decay (f1724ad)
• dropout: inverted, differentiable dropout (cce366d)

Runtime

• Removed unnecessary unwrap() calls on infallible writeln! in the MLIR emitter
  (9485d03)
• A warning is now emitted when a scalar baked into a compiled graph changes
  value between calls, instead of failing silently with stale results (4d90969)
• Add a build script to build the IREE runtime without depending on the GitHub
  workflow (e6a366c)

Performance

• Host tensors are no longer redundantly cloned in the arithmetic builtins and
  IREE dispatch path (ensure_host_cow, Cow<ArrayD>) (5c95e8b, 156e00b)
• random-uniform now lowers to StableHLO, so compiled functions using it no
  longer fall back to the interpreter (c24c1c1)

Bug fixes

• io save now matches io load when using .safetensors files (184707b)
• JIT no longer bakes dict scalars unless required for tensor shapes (ee0c2dc)
• defn no longer infinite-loops when a parameter is referenced in its own body
  (01f3187)
• tril no longer panics on a missing argument (3acee0b)
• scan rejects ambiguous 2-element tensor returns with a clear error instead
  of misreading them as a carry/output pair (ad6b4cf)
• Runtime vectors of tensors are no longer implicitly stacked into a single
  tensor (d1574d9)
• The YAML test loader no longer drops multi-line test cases (c599ac7)

REPL

• Bracket matching with highlightning (bfe4d97)
• :show <name> now pretty-prints a function's source instead of a placeholder
  (1c0a35a)
• New :list command and a shared inline documentation module (18c8c18)
• Verbatim preservation of multi-line history instead of flattening it into a
  single line (1c0a35a)