biomejs/biome · error

Promise is missing

Error message

Promise is missing {}

What it means

The lowering compares the methods found on Promise/PromiseConstructor against a fixed PROMISE_METHOD_SPECIFICATIONS table (with PROMISE_METHOD_COUNT entries). If any required specification (identified by specification.global_name) was not observed on either the instance or static side, this error names the missing method and aborts.

Solutions

1. Restore the missing method to the Promise interface or PromiseConstructor interface in the lib sources
2. Update PROMISE_METHOD_SPECIFICATIONS / PROMISE_METHOD_COUNT in lower.rs if the required set intentionally changed
3. Check target lib configuration (es2015 vs es2018 etc.) so the snapshot includes all required methods

Example fix

// before
interface Promise<T> { then(...): ...; }
// after
interface Promise<T> { then(...): ...; catch(...): ...; finally(...): ...; }

const REQUIRED = ["then","catch","finally","resolve","reject","all","allSettled","any","race"];
const names = new Set([...promiseDecl.members, ...promiseConstructorDecl.members].map(m => m.name));
const missing = REQUIRED.filter(n => !names.has(n));
if (missing.length) throw new Error("Snapshot is missing Promise methods: " + missing.join(", "));

When it happens

Trigger: Running generate_global_types when a required Promise method (e.g. then, catch, finally, resolve, reject, all, allSettled, any, race) is missing, optional, or renamed in the lib sources.

Common situations: A TypeScript lib version bump that removes or moves a method (e.g. finally living only in lib.es2018); a snapshot prune that dropped methods; an extension header (like bluebird-style helpers) altering the shape.

Understand the failure class

Background: Schema validation failed / invalid input schema: payload rejected because its shape doesn't match the expected schema — this error's family across 28 libraries.

Related errors

• bogus members are not supported in
• bogus members are not supported in the Error global
• declare var Promise is missing a type annotation
• getter signatures are not supported in
• metavariables are not supported in

AI-assisted analysis of biomejs/biome@17a2560fb5 (2026-09-13). Data as JSON: /api/errors/446c229b0afae730. Report an issue: GitHub.

Appendix: source

Thrown at xtask/codegen/src/generate_global_types/lower.rs:964

            PromiseMemberLocation::Static,
            &mut saw_methods,
        )?;
        for member in declaration.members() {
            if let AnyTsTypeMember::TsConstructSignatureTypeMember(member) = member {
                validate_promise_construct_signature(&member)?;
                saw_construct_signature = true;
            }
        }
    }
    if !saw_constructor_interface {
        bail!("PromiseConstructor must include an interface declaration");
    }
    if !saw_construct_signature {
        bail!("PromiseConstructor is missing a construct signature");
    }
    for (index, specification) in PROMISE_METHOD_SPECIFICATIONS.iter().enumerate() {
        if !saw_methods[index] {
            bail!("Promise is missing {}", specification.global_name);
        }
    }

    let members = std::iter::once(LoweredTypeMember {
        name: Text::from("constructor"),
        kind: LoweredMemberKind::Constructor,
        type_reference: LoweredTypeReference::Predefined("GLOBAL_PROMISE_CONSTRUCTOR_ID"),
    })
    .chain(PROMISE_METHOD_SPECIFICATIONS.map(promise_member))
    .collect();
    globals.push(LoweredGlobal {
        local_types: Box::default(),
        name: Text::from("Promise"),
        id_constant: "PROMISE_ID_GLOBAL_TYPE_ID",
        data: LoweredTypeData::Class(LoweredClass {
            name: Text::from("Promise"),
            type_parameters: Box::new([LoweredTypeReference::Predefined("GLOBAL_T_ID")]),
            members,

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