Static STANDARD_LIBRARY 

pub static STANDARD_LIBRARY: &[StdBinding]

Every builtin method whose body has moved out of Rust and into the standard library.

Twenty-nine entries, and what is not here is as informative as what is.

Result.mapError is here, and it is the only one that needed a language change to arrive. While a callback’s arity was adapted rather than matched, a program could write mapError { ... } with a trailing closure naming no parameter, and no Cove body can call such a closure — body(error) passes one argument always. ADR 0044 removed that exception, and this row is what it bought.

Int.abs is here too now, and it is the first entry that can fail: the least Int has no positive counterpart. It waited on issue #258, which taught a trap raised from inside a standard-library body to name its caller instead of only the library’s own line — without that, moving abs here would have moved its diagnostic out of the caller’s source along with it.

Ten of the twenty-nine are Duration’s, and they are the first entries that come in pairs: micros, millis, seconds, minutes, and hours each name a method (d.millis(), the reader) and, separately, an associated function (Duration.millis(n), the builder) — see StdBindingKind. nanos is not among them and never will be: it is the one primitive Duration keeps, because something has to know how a duration is actually stored. Before this migration all six readers shared one table-driven Rust function and so did all six builders; a reader now divides by its unit’s constant and a builder multiplies by it, both written once in std.duration rather than once per backend.

Checking ADR 0043’s third condition before adding a row here

ADR 0043’s third migration condition is that the Rust an entry deletes is per-method: a method whose implementation is shared with others moves nothing by moving, and counting schema entries instead of implementations is the mistake that ADR corrects — which is exactly what made Duration wait until its shared table-driven function could be deleted outright rather than merely bypassed for five of its six units.

The check is: delete the dispatch arm in cove-runtime’s vm::builtins that calls the Rust function, leave the function itself defined, and run cargo clippy --workspace --all-targets --profile checked -- -D warnings. If the condition holds, clippy reports the now-unreachable function as dead code and the build fails; a build that stays green says the function still has another caller, which is exactly the shared-Rust case the condition rules out.

This only works because crates/cove-runtime/src/vm/mod.rs carries no module-wide #[allow(dead_code)] — it did once, and while it did this check passed silently for every candidate, moved or not, which is how Int.min and Int.max in PR #259 went unverified. Issue #274 narrowed that allow to the individual items that need it, each with its own comment saying why it has no caller outside its own tests; deleting a dispatch arm anywhere else in vm::builtins now reaches exactly one of two outcomes — a clippy failure, or a genuinely shared implementation — and never the third, silent one this note used to have to warn about.