[ryansolid]

Requested by Ryan · project thread

Why

R-1 said "a Promise-valued expression without await is an ordinary value of type Promise and is never pending." The compiled app does something else. x = fetchUser(id) lowers to a memo, and Solid's memo consumes a promise its function returns. Checked on the pinned next (ac28157a): createMemo(() => promise) read by an effect gives 42, not a Promise. So the spec, the interpreter and the checker treated x as a value, while the compiled app treated it as pending.

What

• spec/04 R-1a (new, ruled 2026-10-28). An equation's value is never a promise or an async iterable. Where the type is known, an equation that may be one on any branch is MISSING_AWAIT. A promise inside a value ({ p }, [a, b]) is not consumed. Where the type is any, the check is silent and Solid still consumes the promise. Refusing an any-typed JS import call without await is noted as possible future work, not adopted.
• spec/13 TY-5b. Equations are projected as __.eq(e, true). The new prelude eq<T> refuses a promise or a stream, following the same pattern as WIRE_VALUE (TY-5a). There is no run-time cost.
• Diagnostics. MISSING_AWAIT rows added to the 04 table and to 99.
• ref/ and the crate, kept in step. ref/types/project.ts, ref/types/run.ts (reports MISSING_AWAIT by name), compiler/src/project.rs and compiler/src/prelude.ts.
• S-types-1. Two new type-check variants: a bare promise, and a promise on one branch of ?:.

await stays the marker for where async enters the graph (R-1, AC-1b/c/d, ASYNC_WATERFALL). This change only makes the missing marker an error instead of silently doing something different.

Checked

• npm run types: 146 pass, 0 fail. No existing scenario or example equation held a promise.
• RX_CRATE=1 npm run types: 146 pass, 0 fail.
• npm run crate: 307/307 programs agree. npm run crate -- --project: 178/178 projections are identical, and all position mappings hold.
• npm test: all scenarios pass. cargo test: passes.

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