mirror of
https://github.com/vercel-labs/scriptc.git
synced 2026-10-02 08:35:07 +08:00
Chris Tate
b49052a389
- mapType back-references mint placeholder shapes/unions finalized at frame exit; identity is per checker type, and context-sensitive (generic/mixin) knots stay fenced - every type walk survives cyclic shape graphs: coinductive JSON/dyn-safety predicates, guarded formatIrType/jsvalLiftable, cycle headers via the existing collector fixpoint on both backends - JSON.stringify throws V8's byte-exact circular TypeError (hop lines, ellipsis rule); cyclic values crossing into checked-dynamic slots trap instead of hanging - console.log/util.inspect render <ref *N>/[Circular *N] exactly (SEMANTICS 129 resolved; depth:null lowers) and deepStrictEqual terminates through Node's pair memo - corpus 2480-2488 green on C, LLVM, and the sanitized RC-audit lane, which proves child->parent cycles collect
28 lines
830 B
TypeScript
28 lines
830 B
TypeScript
// Mutually recursive record types: the knot passes through TWO shapes and
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// an optional-field union (A -> B[] -> a?: A). Both intern as named
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// recursive shapes; the optional back edge is an undefined-armed union.
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interface A { b: B[] }
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interface B { a?: A }
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const inner: A = { b: [{}] };
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const outer: A = { b: [{ a: inner }, {}] };
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function countB(a: A): number {
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let n = 0;
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for (const b of a.b) {
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n += 1;
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if (b.a !== undefined) n += countB(b.a);
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}
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return n;
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}
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console.log(countB(inner));
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console.log(countB(outer));
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// The back edge assigns after construction too — a genuine runtime
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// reference cycle (collected by the cycle collector; see the RC-audit
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// lane). Traversals here stay acyclic on purpose.
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const b0: B = {};
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const a0: A = { b: [b0] };
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b0.a = a0;
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console.log(b0.a === a0, a0.b[0] === b0);
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