diff --git a/packages/compiler/src/frontend/type-mapper.ts b/packages/compiler/src/frontend/type-mapper.ts index edb3cf144..140ace355 100644 --- a/packages/compiler/src/frontend/type-mapper.ts +++ b/packages/compiler/src/frontend/type-mapper.ts @@ -1255,6 +1255,10 @@ export interface TypeMapperCtx { * (erasedGenericMemberType): the signature's own type parameters * resolve to `unknown` instead of refusing the mapping. */ erasingSignature?: ts.Signature; + /** Set with erasingSignature: the signature's own type parameters, and + * whether the erasure consulted an enclosing binding. An erasure that + * resolved only its own parameters answers the same in every context. */ + erasedMember?: { own: ReadonlySet; outerConsulted: boolean }; /** True while an erased generic body lowers (its type parameters are * bound to `unknown`). */ isErasing?: () => boolean; @@ -1835,6 +1839,7 @@ export function mapType(type: ts.Type, ctx: TypeMapperCtx): IrType | null { memoKey !== null && topLevel && contextResolutions === sensitivityAtEntry && + ctx.erasingSignature === undefined && (ctx.canMemoizeType?.() ?? true) ) { ctx.typeMemo?.set(memoKey, mapped); @@ -1991,7 +1996,7 @@ function mapTypeInner(type: ts.Type, ctx: TypeMapperCtx): IrType | null { !ERASURE_KEPT_CONTAINERS.has(ts.symbolNameOf(type.getSymbol()) ?? "") && mentionsErasedTypeParam(type, ctx, 0) ) { - contextResolutions++; + if (!ctx.erasedMember || ctx.erasedMember.outerConsulted) contextResolutions++; return DYN; } // Readonly over a program class (Object.freeze's result type) is the @@ -2001,7 +2006,7 @@ function mapTypeInner(type: ts.Type, ctx: TypeMapperCtx): IrType | null { if (resolveTypeParam && type.flags & ts.TypeFlags.TypeParameter) { const bound = resolveTypeParam(type); if (bound) { - contextResolutions++; + if (!ctx.erasedMember?.own.has(type)) contextResolutions++; return bound; } } @@ -7335,10 +7340,21 @@ export function erasedGenericMemberType(t: ts.Type, ctx: TypeMapperCtx): IrType const sig = sigs[0]!; const own = new Set(sig.getTypeParameters()); const outer = ctx.resolveTypeParam; + // Resolving only the member's own parameters does not make the erasure + // context-sensitive, so a recursive record holding a generic method + // (`interface Sub extends Base { send(m: Msg): void }` reached + // from Base) still closes its knot. Consulting an enclosing binding does. + const erasedMember = { own, outerConsulted: false }; const erased = mapType(t, { ...ctx, erasingSignature: sig, - resolveTypeParam: (param) => (own.has(param) ? DYN : (outer?.(param) ?? null)), + erasedMember, + resolveTypeParam: (param) => { + if (own.has(param)) return DYN; + if (outer === undefined) return null; + erasedMember.outerConsulted = true; + return outer(param); + }, }); return erased?.kind === "func" ? erased : undefined; } diff --git a/packages/compiler/test/ts7/baselines/order-parity/tests/corpus/recursive-generic-method-members.ts.json b/packages/compiler/test/ts7/baselines/order-parity/tests/corpus/recursive-generic-method-members.ts.json new file mode 100644 index 000000000..6c3590ab8 --- /dev/null +++ b/packages/compiler/test/ts7/baselines/order-parity/tests/corpus/recursive-generic-method-members.ts.json @@ -0,0 +1,6 @@ +{ + "order": [ + "/tests/corpus/recursive-generic-method-members.ts" + ], + "diags": [] +} diff --git a/tests/corpus/recursive-generic-method-members.ts b/tests/corpus/recursive-generic-method-members.ts new file mode 100644 index 000000000..1f4d8372d --- /dev/null +++ b/tests/corpus/recursive-generic-method-members.ts @@ -0,0 +1,58 @@ +// A recursive record that declares a generic method compiles. Erasing the +// method's own type parameters does not depend on any enclosing generic +// binding, so the record still closes its recursive knot: a parent +// interface whose child is a subinterface declaring a generic method, and a +// list node whose generic method sits beside a self-referencing field. + +interface Message { + content: string; + details?: T; +} + +interface TreeNode { + name: string; + child?: SendingNode; +} + +interface SendingNode extends TreeNode { + send(message: Message): string; +} + +interface ListNode { + value: number; + next: ListNode | null; + map(f: (value: number) => U): string; +} + +function describe(node: TreeNode): string { + const inner = node.child; + return inner ? `${node.name} > ${describe(inner)}` : node.name; +} + +function leaf(name: string): SendingNode { + return { name, send: () => `${name} got a message` }; +} + +const tree: SendingNode = { + name: "root", + child: { name: "middle", child: leaf("leaf"), send: () => "middle got a message" }, + send: () => "root got a message", +}; +console.log(describe(tree)); +console.log(tree.send({ content: "hello" })); +const middle = tree.child; +if (middle !== undefined) console.log(middle.send({ content: "hi", details: 42 })); + +function cons(value: number, next: ListNode | null): ListNode { + return { value, next, map: () => `node ${value}` }; +} + +let list: ListNode | null = cons(1, cons(2, cons(3, null))); +const values: number[] = []; +let labels = ""; +while (list !== null) { + values.push(list.value); + labels += `[${list.map((v) => v * 2)}]`; + list = list.next; +} +console.log(values.join(","), labels); diff --git a/tests/harness/corpus-costs/recursive-generic-method-members.ts.json b/tests/harness/corpus-costs/recursive-generic-method-members.ts.json new file mode 100644 index 000000000..1254aa6e4 --- /dev/null +++ b/tests/harness/corpus-costs/recursive-generic-method-members.ts.json @@ -0,0 +1 @@ +{ "plain": 4000 }