diff --git a/packages/compiler/src/frontend/lowering/class-dynamic-dispatch.ts b/packages/compiler/src/frontend/lowering/class-dynamic-dispatch.ts index dda7c8c86..1c6df3d5c 100644 --- a/packages/compiler/src/frontend/lowering/class-dynamic-dispatch.ts +++ b/packages/compiler/src/frontend/lowering/class-dynamic-dispatch.ts @@ -6794,24 +6794,41 @@ export class ClassDynamicDispatch { type: result, loc, }; + // A void method dispatches its overrides with statements: a ternary + // has no void form. + let voidDispatch: IrStmt[] = [{ kind: "exprStmt", expr: call, loc }]; for (const override of overrides.toReversed()) { const subType: IrType = { kind: "object", className: override.cls.def.name }; + const isOverride: IrExpr = { + kind: "instanceOf", + value: receiver, + className: override.cls.def.name, + type: BOOL, + loc, + }; + const overrideCall: IrExpr = { + kind: "call", + callee: override.callee, + args: [{ kind: "downcast", value: receiver, type: subType, loc }, ...args], + type: result, + loc, + }; + if (result.kind === "void") { + voidDispatch = [ + { + kind: "if", + cond: isOverride, + then: [{ kind: "exprStmt", expr: overrideCall, loc }], + else_: voidDispatch, + loc, + }, + ]; + continue; + } call = { kind: "ternary", - cond: { - kind: "instanceOf", - value: receiver, - className: override.cls.def.name, - type: BOOL, - loc, - }, - then: { - kind: "call", - callee: override.callee, - args: [{ kind: "downcast", value: receiver, type: subType, loc }, ...args], - type: result, - loc, - }, + cond: isOverride, + then: overrideCall, else_: call, type: result, loc, @@ -6819,10 +6836,7 @@ export class ClassDynamicDispatch { } let body: IrStmt[]; if (result.kind === "void") - body = [ - { kind: "exprStmt", expr: call, loc }, - { kind: "return", value: dynUndefinedExpr(loc), loc }, - ]; + body = [...voidDispatch, { kind: "return", value: dynUndefinedExpr(loc), loc }]; else { const boxed = lowerer.coerceToExpected(call, DYN); if (boxed.type.kind !== "dyn") return fence(); diff --git a/packages/compiler/src/frontend/lowering/lower-calls.ts b/packages/compiler/src/frontend/lowering/lower-calls.ts index 0a845b3bd..7aed5a271 100644 --- a/packages/compiler/src/frontend/lowering/lower-calls.ts +++ b/packages/compiler/src/frontend/lowering/lower-calls.ts @@ -10107,7 +10107,13 @@ function lowerObjLitGenericMethodCall( type: DYN, loc, }; - return lowerer.coerceInto(call, invoked, lowerer.irTypeOf(call)); + const resultType = lowerer.irTypeOf(call); + // A void method's result stays the runtime's untyped value, as a + // call through a non-generic void member's dispatch keeps it: a class + // may implement the member with a method that returns a value, which + // JavaScript passes on (`console.log(c.publish(m))`). + if (resultType.kind === "void") return invoked; + return lowerer.coerceInto(call, invoked, resultType); } } if (onInterface) { diff --git a/packages/compiler/test/ts7/baselines/order-parity/tests/corpus/generic-interface-void-calls.ts.json b/packages/compiler/test/ts7/baselines/order-parity/tests/corpus/generic-interface-void-calls.ts.json new file mode 100644 index 000000000..a5c69b714 --- /dev/null +++ b/packages/compiler/test/ts7/baselines/order-parity/tests/corpus/generic-interface-void-calls.ts.json @@ -0,0 +1,6 @@ +{ + "order": [ + "/tests/corpus/generic-interface-void-calls.ts" + ], + "diags": [] +} diff --git a/tests/corpus/generic-interface-void-calls.ts b/tests/corpus/generic-interface-void-calls.ts new file mode 100644 index 000000000..63c137c10 --- /dev/null +++ b/tests/corpus/generic-interface-void-calls.ts @@ -0,0 +1,65 @@ +// Calling a void generic method through an interface value that classes +// implement (the receiver is a checked-dynamic object, and the call +// dispatches by name to the class's erased method) discards the result, as +// JavaScript does, instead of converting it to `void`. + +interface Message { + content: string; + details?: T; +} + +interface Channel { + name: string; + publish(message: Message): void; + count(items: T[]): number; +} + +const delivered: string[] = []; + +class LogChannel implements Channel { + name: string; + constructor(name: string) { + this.name = name; + } + publish(message: Message): void { + delivered.push(`${this.name}:${message.content}:${message.details === undefined ? "-" : JSON.stringify(message.details)}`); + } + count(items: T[]): number { + return items.length; + } +} + +class LoudChannel extends LogChannel { + publish(message: Message): void { + super.publish({ content: message.content.toUpperCase(), details: message.details }); + } +} + +const channels: Channel[] = [new LogChannel("quiet"), new LoudChannel("loud")]; +for (const channel of channels) { + channel.publish({ content: "hello", details: [1, 2] }); + channel.publish({ content: "bare" }); + const result = channel.publish({ content: "typed", details: "x" }); + console.log(channel.name, result === undefined, channel.count(["a", "b", "c"])); +} +console.log(delivered.join(" | ")); + +// A class may implement the void member with a method that returns a value; +// JavaScript passes that value on. +class CountingChannel implements Channel { + name = "counting"; + sent = 0; + publish(message: Message): number { + this.sent++; + return message.content.length; + } + count(items: T[]): number { + return items.length * 2; + } +} + +const counted: Channel[] = [new CountingChannel(), new LogChannel("plain")]; +for (const channel of counted) { + console.log(channel.name, channel.publish({ content: "four" })); + console.log(`sent ${channel.publish({ content: "again", details: 2 })}`); +} diff --git a/tests/harness/corpus-costs/generic-interface-void-calls.ts.json b/tests/harness/corpus-costs/generic-interface-void-calls.ts.json new file mode 100644 index 000000000..1254aa6e4 --- /dev/null +++ b/tests/harness/corpus-costs/generic-interface-void-calls.ts.json @@ -0,0 +1 @@ +{ "plain": 4000 }