LibJS: Convert NativeFunction::{call,construct}() to ThrowCompletionOr

Both at the same time because many of them call construct() in call()
and I'm not keen on adding a bunch of temporary plumbing to turn
exceptions into throw completions.
Also changes the return value of construct() to Object* instead of Value
as it always needs to return an object; allowing an arbitrary Value is a
massive foot gun.

Userland/Libraries/LibJS/Runtime/Temporal/CalendarConstructor.cpp

@@ -32,34 +32,32 @@ void CalendarConstructor::initialize(GlobalObject& global_object)
 }
 
 // 12.2.1 Temporal.Calendar ( id ), https://tc39.es/proposal-temporal/#sec-temporal.calendar
-Value CalendarConstructor::call()
+ThrowCompletionOr<Value> CalendarConstructor::call()
 {
     auto& vm = this->vm();
 
     // 1. If NewTarget is undefined, then
     // a. Throw a TypeError exception.
-    vm.throw_exception<TypeError>(global_object(), ErrorType::ConstructorWithoutNew, "Temporal.Calendar");
-    return {};
+    return vm.throw_completion<TypeError>(global_object(), ErrorType::ConstructorWithoutNew, "Temporal.Calendar");
 }
 
 // 12.2.1 Temporal.Calendar ( id ), https://tc39.es/proposal-temporal/#sec-temporal.calendar
-Value CalendarConstructor::construct(FunctionObject& new_target)
+ThrowCompletionOr<Object*> CalendarConstructor::construct(FunctionObject& new_target)
 {
     auto& vm = this->vm();
     auto& global_object = this->global_object();
 
     // 2. Set id to ? ToString(id).
-    auto identifier = TRY_OR_DISCARD(vm.argument(0).to_string(global_object));
+    auto identifier = TRY(vm.argument(0).to_string(global_object));
 
     // 3. If ! IsBuiltinCalendar(id) is false, then
     if (!is_builtin_calendar(identifier)) {
         // a. Throw a RangeError exception.
-        vm.throw_exception<RangeError>(global_object, ErrorType::TemporalInvalidCalendarIdentifier, identifier);
-        return {};
+        return vm.throw_completion<RangeError>(global_object, ErrorType::TemporalInvalidCalendarIdentifier, identifier);
     }
 
     // 4. Return ? CreateTemporalCalendar(id, NewTarget).
-    return TRY_OR_DISCARD(create_temporal_calendar(global_object, identifier, &new_target));
+    return TRY(create_temporal_calendar(global_object, identifier, &new_target));
 }
 
 // 12.3.2 Temporal.Calendar.from ( item ), https://tc39.es/proposal-temporal/#sec-temporal.calendar.from

Userland/Libraries/LibJS/Runtime/Temporal/CalendarConstructor.h

@@ -18,8 +18,8 @@ public:
     virtual void initialize(GlobalObject&) override;
     virtual ~CalendarConstructor() override = default;
 
-    virtual Value call() override;
-    virtual Value construct(FunctionObject& new_target) override;
+    virtual ThrowCompletionOr<Value> call() override;
+    virtual ThrowCompletionOr<Object*> construct(FunctionObject& new_target) override;
 
 private:
     virtual bool has_constructor() const override { return true; }

Userland/Libraries/LibJS/Runtime/Temporal/DurationConstructor.cpp

@@ -34,54 +34,53 @@ void DurationConstructor::initialize(GlobalObject& global_object)
 }
 
 // 7.1.1 Temporal.Duration ( [ years [ , months [ , weeks [ , days [ , hours [ , minutes [ , seconds [ , milliseconds [ , microseconds [ , nanoseconds ] ] ] ] ] ] ] ] ] ] ), https://tc39.es/proposal-temporal/#sec-temporal.duration
-Value DurationConstructor::call()
+ThrowCompletionOr<Value> DurationConstructor::call()
 {
     auto& vm = this->vm();
 
     // 1. If NewTarget is undefined, then
     // a. Throw a TypeError exception.
-    vm.throw_exception<TypeError>(global_object(), ErrorType::ConstructorWithoutNew, "Temporal.Duration");
-    return {};
+    return vm.throw_completion<TypeError>(global_object(), ErrorType::ConstructorWithoutNew, "Temporal.Duration");
 }
 
 // 7.1.1 Temporal.Duration ( [ years [ , months [ , weeks [ , days [ , hours [ , minutes [ , seconds [ , milliseconds [ , microseconds [ , nanoseconds ] ] ] ] ] ] ] ] ] ] ), https://tc39.es/proposal-temporal/#sec-temporal.duration
-Value DurationConstructor::construct(FunctionObject& new_target)
+ThrowCompletionOr<Object*> DurationConstructor::construct(FunctionObject& new_target)
 {
     auto& vm = this->vm();
     auto& global_object = this->global_object();
 
     // 2. Let y be ? ToIntegerThrowOnInfinity(years).
-    auto y = TRY_OR_DISCARD(to_integer_throw_on_infinity(global_object, vm.argument(0), ErrorType::TemporalInvalidDuration));
+    auto y = TRY(to_integer_throw_on_infinity(global_object, vm.argument(0), ErrorType::TemporalInvalidDuration));
 
     // 3. Let mo be ? ToIntegerThrowOnInfinity(months).
-    auto mo = TRY_OR_DISCARD(to_integer_throw_on_infinity(global_object, vm.argument(1), ErrorType::TemporalInvalidDuration));
+    auto mo = TRY(to_integer_throw_on_infinity(global_object, vm.argument(1), ErrorType::TemporalInvalidDuration));
 
     // 4. Let w be ? ToIntegerThrowOnInfinity(weeks).
-    auto w = TRY_OR_DISCARD(to_integer_throw_on_infinity(global_object, vm.argument(2), ErrorType::TemporalInvalidDuration));
+    auto w = TRY(to_integer_throw_on_infinity(global_object, vm.argument(2), ErrorType::TemporalInvalidDuration));
 
     // 5. Let d be ? ToIntegerThrowOnInfinity(days).
-    auto d = TRY_OR_DISCARD(to_integer_throw_on_infinity(global_object, vm.argument(3), ErrorType::TemporalInvalidDuration));
+    auto d = TRY(to_integer_throw_on_infinity(global_object, vm.argument(3), ErrorType::TemporalInvalidDuration));
 
     // 6. Let h be ? ToIntegerThrowOnInfinity(hours).
-    auto h = TRY_OR_DISCARD(to_integer_throw_on_infinity(global_object, vm.argument(4), ErrorType::TemporalInvalidDuration));
+    auto h = TRY(to_integer_throw_on_infinity(global_object, vm.argument(4), ErrorType::TemporalInvalidDuration));
 
     // 7. Let m be ? ToIntegerThrowOnInfinity(minutes).
-    auto m = TRY_OR_DISCARD(to_integer_throw_on_infinity(global_object, vm.argument(5), ErrorType::TemporalInvalidDuration));
+    auto m = TRY(to_integer_throw_on_infinity(global_object, vm.argument(5), ErrorType::TemporalInvalidDuration));
 
     // 8. Let s be ? ToIntegerThrowOnInfinity(seconds).
-    auto s = TRY_OR_DISCARD(to_integer_throw_on_infinity(global_object, vm.argument(6), ErrorType::TemporalInvalidDuration));
+    auto s = TRY(to_integer_throw_on_infinity(global_object, vm.argument(6), ErrorType::TemporalInvalidDuration));
 
     // 9. Let ms be ? ToIntegerThrowOnInfinity(milliseconds).
-    auto ms = TRY_OR_DISCARD(to_integer_throw_on_infinity(global_object, vm.argument(7), ErrorType::TemporalInvalidDuration));
+    auto ms = TRY(to_integer_throw_on_infinity(global_object, vm.argument(7), ErrorType::TemporalInvalidDuration));
 
     // 10. Let mis be ? ToIntegerThrowOnInfinity(microseconds).
-    auto mis = TRY_OR_DISCARD(to_integer_throw_on_infinity(global_object, vm.argument(8), ErrorType::TemporalInvalidDuration));
+    auto mis = TRY(to_integer_throw_on_infinity(global_object, vm.argument(8), ErrorType::TemporalInvalidDuration));
 
     // 11. Let ns be ? ToIntegerThrowOnInfinity(nanoseconds).
-    auto ns = TRY_OR_DISCARD(to_integer_throw_on_infinity(global_object, vm.argument(9), ErrorType::TemporalInvalidDuration));
+    auto ns = TRY(to_integer_throw_on_infinity(global_object, vm.argument(9), ErrorType::TemporalInvalidDuration));
 
     // 12. Return ? CreateTemporalDuration(y, mo, w, d, h, m, s, ms, mis, ns, NewTarget).
-    return TRY_OR_DISCARD(create_temporal_duration(global_object, y, mo, w, d, h, m, s, ms, mis, ns, &new_target));
+    return TRY(create_temporal_duration(global_object, y, mo, w, d, h, m, s, ms, mis, ns, &new_target));
 }
 
 // 7.2.2 Temporal.Duration.from ( item ), https://tc39.es/proposal-temporal/#sec-temporal.duration.from

Userland/Libraries/LibJS/Runtime/Temporal/DurationConstructor.h

@@ -18,8 +18,8 @@ public:
     virtual void initialize(GlobalObject&) override;
     virtual ~DurationConstructor() override = default;
 
-    virtual Value call() override;
-    virtual Value construct(FunctionObject& new_target) override;
+    virtual ThrowCompletionOr<Value> call() override;
+    virtual ThrowCompletionOr<Object*> construct(FunctionObject& new_target) override;
 
 private:
     virtual bool has_constructor() const override { return true; }

Userland/Libraries/LibJS/Runtime/Temporal/InstantConstructor.cpp

@@ -39,33 +39,30 @@ void InstantConstructor::initialize(GlobalObject& global_object)
 }
 
 // 8.1.1 Temporal.Instant ( epochNanoseconds ), https://tc39.es/proposal-temporal/#sec-temporal.instant
-Value InstantConstructor::call()
+ThrowCompletionOr<Value> InstantConstructor::call()
 {
     auto& vm = this->vm();
 
     // 1. If NewTarget is undefined, then
     // a. Throw a TypeError exception.
-    vm.throw_exception<TypeError>(global_object(), ErrorType::ConstructorWithoutNew, "Temporal.Instant");
-    return {};
+    return vm.throw_completion<TypeError>(global_object(), ErrorType::ConstructorWithoutNew, "Temporal.Instant");
 }
 
 // 8.1.1 Temporal.Instant ( epochNanoseconds ), https://tc39.es/proposal-temporal/#sec-temporal.instant
-Value InstantConstructor::construct(FunctionObject& new_target)
+ThrowCompletionOr<Object*> InstantConstructor::construct(FunctionObject& new_target)
 {
     auto& vm = this->vm();
     auto& global_object = this->global_object();
 
     // 2. Let epochNanoseconds be ? ToBigInt(epochNanoseconds).
-    auto* epoch_nanoseconds = TRY_OR_DISCARD(vm.argument(0).to_bigint(global_object));
+    auto* epoch_nanoseconds = TRY(vm.argument(0).to_bigint(global_object));
 
     // 3. If ! IsValidEpochNanoseconds(epochNanoseconds) is false, throw a RangeError exception.
-    if (!is_valid_epoch_nanoseconds(*epoch_nanoseconds)) {
-        vm.throw_exception<RangeError>(global_object, ErrorType::TemporalInvalidEpochNanoseconds);
-        return {};
-    }
+    if (!is_valid_epoch_nanoseconds(*epoch_nanoseconds))
+        return vm.throw_completion<RangeError>(global_object, ErrorType::TemporalInvalidEpochNanoseconds);
 
     // 4. Return ? CreateTemporalInstant(epochNanoseconds, NewTarget).
-    return TRY_OR_DISCARD(create_temporal_instant(global_object, *epoch_nanoseconds, &new_target));
+    return TRY(create_temporal_instant(global_object, *epoch_nanoseconds, &new_target));
 }
 
 // 8.2.2 Temporal.Instant.from ( item ), https://tc39.es/proposal-temporal/#sec-temporal.instant.from

Userland/Libraries/LibJS/Runtime/Temporal/InstantConstructor.h

@@ -18,8 +18,8 @@ public:
     virtual void initialize(GlobalObject&) override;
     virtual ~InstantConstructor() override = default;
 
-    virtual Value call() override;
-    virtual Value construct(FunctionObject& new_target) override;
+    virtual ThrowCompletionOr<Value> call() override;
+    virtual ThrowCompletionOr<Object*> construct(FunctionObject& new_target) override;
 
 private:
     virtual bool has_constructor() const override { return true; }

Userland/Libraries/LibJS/Runtime/Temporal/PlainDateConstructor.cpp

@@ -37,43 +37,40 @@ void PlainDateConstructor::initialize(GlobalObject& global_object)
 }
 
 // 3.1.1 Temporal.PlainDate ( isoYear, isoMonth, isoDay [ , calendarLike ] ), https://tc39.es/proposal-temporal/#sec-temporal.plaindate
-Value PlainDateConstructor::call()
+ThrowCompletionOr<Value> PlainDateConstructor::call()
 {
     auto& vm = this->vm();
 
     // 1. If NewTarget is undefined, throw a TypeError exception.
-    vm.throw_exception<TypeError>(global_object(), ErrorType::ConstructorWithoutNew, "Temporal.PlainDate");
-    return {};
+    return vm.throw_completion<TypeError>(global_object(), ErrorType::ConstructorWithoutNew, "Temporal.PlainDate");
 }
 
 // 3.1.1 Temporal.PlainDate ( isoYear, isoMonth, isoDay [ , calendarLike ] ), https://tc39.es/proposal-temporal/#sec-temporal.plaindate
-Value PlainDateConstructor::construct(FunctionObject& new_target)
+ThrowCompletionOr<Object*> PlainDateConstructor::construct(FunctionObject& new_target)
 {
     auto& vm = this->vm();
     auto& global_object = this->global_object();
 
     // 2. Let y be ? ToIntegerThrowOnInfinity(isoYear).
-    auto y = TRY_OR_DISCARD(to_integer_throw_on_infinity(global_object, vm.argument(0), ErrorType::TemporalInvalidPlainDate));
+    auto y = TRY(to_integer_throw_on_infinity(global_object, vm.argument(0), ErrorType::TemporalInvalidPlainDate));
 
     // 3. Let m be ? ToIntegerThrowOnInfinity(isoMonth).
-    auto m = TRY_OR_DISCARD(to_integer_throw_on_infinity(global_object, vm.argument(1), ErrorType::TemporalInvalidPlainDate));
+    auto m = TRY(to_integer_throw_on_infinity(global_object, vm.argument(1), ErrorType::TemporalInvalidPlainDate));
 
     // 4. Let d be ? ToIntegerThrowOnInfinity(isoDay).
-    auto d = TRY_OR_DISCARD(to_integer_throw_on_infinity(global_object, vm.argument(2), ErrorType::TemporalInvalidPlainDate));
+    auto d = TRY(to_integer_throw_on_infinity(global_object, vm.argument(2), ErrorType::TemporalInvalidPlainDate));
 
     // 5. Let calendar be ? ToTemporalCalendarWithISODefault(calendarLike).
-    auto* calendar = TRY_OR_DISCARD(to_temporal_calendar_with_iso_default(global_object, vm.argument(3)));
+    auto* calendar = TRY(to_temporal_calendar_with_iso_default(global_object, vm.argument(3)));
 
     // IMPLEMENTATION DEFINED: This is an optimization that allows us to treat these doubles as normal integers from this point onwards.
     // This does not change the exposed behavior as the call to CreateTemporalDate will immediately check that these values are valid
     // ISO values (for years: -273975 - 273975, for months: 1 - 12, for days: 1 - 31) all of which are subsets of this check.
-    if (!AK::is_within_range<i32>(y) || !AK::is_within_range<u8>(m) || !AK::is_within_range<u8>(d)) {
-        vm.throw_exception<RangeError>(global_object, ErrorType::TemporalInvalidPlainDate);
-        return {};
-    }
+    if (!AK::is_within_range<i32>(y) || !AK::is_within_range<u8>(m) || !AK::is_within_range<u8>(d))
+        return vm.throw_completion<RangeError>(global_object, ErrorType::TemporalInvalidPlainDate);
 
     // 6. Return ? CreateTemporalDate(y, m, d, calendar, NewTarget).
-    return TRY_OR_DISCARD(create_temporal_date(global_object, y, m, d, *calendar, &new_target));
+    return TRY(create_temporal_date(global_object, y, m, d, *calendar, &new_target));
 }
 
 // 3.2.2 Temporal.PlainDate.from ( item [ , options ] ), https://tc39.es/proposal-temporal/#sec-temporal.plaindate.from

Userland/Libraries/LibJS/Runtime/Temporal/PlainDateConstructor.h

@@ -18,8 +18,8 @@ public:
     virtual void initialize(GlobalObject&) override;
     virtual ~PlainDateConstructor() override = default;
 
-    virtual Value call() override;
-    virtual Value construct(FunctionObject& new_target) override;
+    virtual ThrowCompletionOr<Value> call() override;
+    virtual ThrowCompletionOr<Object*> construct(FunctionObject& new_target) override;
 
 private:
     virtual bool has_constructor() const override { return true; }

Userland/Libraries/LibJS/Runtime/Temporal/PlainDateTimeConstructor.cpp

@@ -37,62 +37,59 @@ void PlainDateTimeConstructor::initialize(GlobalObject& global_object)
 }
 
 // 5.1.1 Temporal.PlainDateTime ( isoYear, isoMonth, isoDay [ , hour [ , minute [ , second [ , millisecond [ , microsecond [ , nanosecond [ , calendarLike ] ] ] ] ] ] ] ), https://tc39.es/proposal-temporal/#sec-temporal.plaindatetime
-Value PlainDateTimeConstructor::call()
+ThrowCompletionOr<Value> PlainDateTimeConstructor::call()
 {
     auto& vm = this->vm();
 
     // 1. If NewTarget is undefined, throw a TypeError exception.
-    vm.throw_exception<TypeError>(global_object(), ErrorType::ConstructorWithoutNew, "Temporal.PlainDateTime");
-    return {};
+    return vm.throw_completion<TypeError>(global_object(), ErrorType::ConstructorWithoutNew, "Temporal.PlainDateTime");
 }
 
 // 5.1.1 Temporal.PlainDateTime ( isoYear, isoMonth, isoDay [ , hour [ , minute [ , second [ , millisecond [ , microsecond [ , nanosecond [ , calendarLike ] ] ] ] ] ] ] ), https://tc39.es/proposal-temporal/#sec-temporal.plaindatetime
-Value PlainDateTimeConstructor::construct(FunctionObject& new_target)
+ThrowCompletionOr<Object*> PlainDateTimeConstructor::construct(FunctionObject& new_target)
 {
     auto& vm = this->vm();
     auto& global_object = this->global_object();
 
     // 2. Let isoYear be ? ToIntegerThrowOnInfinity(isoYear).
-    auto iso_year = TRY_OR_DISCARD(to_integer_throw_on_infinity(global_object, vm.argument(0), ErrorType::TemporalInvalidPlainDateTime));
+    auto iso_year = TRY(to_integer_throw_on_infinity(global_object, vm.argument(0), ErrorType::TemporalInvalidPlainDateTime));
 
     // 3. Let isoMonth be ? ToIntegerThrowOnInfinity(isoMonth).
-    auto iso_month = TRY_OR_DISCARD(to_integer_throw_on_infinity(global_object, vm.argument(1), ErrorType::TemporalInvalidPlainDateTime));
+    auto iso_month = TRY(to_integer_throw_on_infinity(global_object, vm.argument(1), ErrorType::TemporalInvalidPlainDateTime));
 
     // 4. Let isoDay be ? ToIntegerThrowOnInfinity(isoDay).
-    auto iso_day = TRY_OR_DISCARD(to_integer_throw_on_infinity(global_object, vm.argument(2), ErrorType::TemporalInvalidPlainDateTime));
+    auto iso_day = TRY(to_integer_throw_on_infinity(global_object, vm.argument(2), ErrorType::TemporalInvalidPlainDateTime));
 
     // 5. Let hour be ? ToIntegerThrowOnInfinity(hour).
-    auto hour = TRY_OR_DISCARD(to_integer_throw_on_infinity(global_object, vm.argument(3), ErrorType::TemporalInvalidPlainDateTime));
+    auto hour = TRY(to_integer_throw_on_infinity(global_object, vm.argument(3), ErrorType::TemporalInvalidPlainDateTime));
 
     // 6. Let minute be ? ToIntegerThrowOnInfinity(minute).
-    auto minute = TRY_OR_DISCARD(to_integer_throw_on_infinity(global_object, vm.argument(4), ErrorType::TemporalInvalidPlainDateTime));
+    auto minute = TRY(to_integer_throw_on_infinity(global_object, vm.argument(4), ErrorType::TemporalInvalidPlainDateTime));
 
     // 7. Let second be ? ToIntegerThrowOnInfinity(second).
-    auto second = TRY_OR_DISCARD(to_integer_throw_on_infinity(global_object, vm.argument(5), ErrorType::TemporalInvalidPlainDateTime));
+    auto second = TRY(to_integer_throw_on_infinity(global_object, vm.argument(5), ErrorType::TemporalInvalidPlainDateTime));
 
     // 8. Let millisecond be ? ToIntegerThrowOnInfinity(millisecond).
-    auto millisecond = TRY_OR_DISCARD(to_integer_throw_on_infinity(global_object, vm.argument(6), ErrorType::TemporalInvalidPlainDateTime));
+    auto millisecond = TRY(to_integer_throw_on_infinity(global_object, vm.argument(6), ErrorType::TemporalInvalidPlainDateTime));
 
     // 9. Let microsecond be ? ToIntegerThrowOnInfinity(microsecond).
-    auto microsecond = TRY_OR_DISCARD(to_integer_throw_on_infinity(global_object, vm.argument(7), ErrorType::TemporalInvalidPlainDateTime));
+    auto microsecond = TRY(to_integer_throw_on_infinity(global_object, vm.argument(7), ErrorType::TemporalInvalidPlainDateTime));
 
     // 10. Let nanosecond be ? ToIntegerThrowOnInfinity(nanosecond).
-    auto nanosecond = TRY_OR_DISCARD(to_integer_throw_on_infinity(global_object, vm.argument(8), ErrorType::TemporalInvalidPlainDateTime));
+    auto nanosecond = TRY(to_integer_throw_on_infinity(global_object, vm.argument(8), ErrorType::TemporalInvalidPlainDateTime));
 
     // 11. Let calendar be ? ToTemporalCalendarWithISODefault(calendarLike).
-    auto* calendar = TRY_OR_DISCARD(to_temporal_calendar_with_iso_default(global_object, vm.argument(9)));
+    auto* calendar = TRY(to_temporal_calendar_with_iso_default(global_object, vm.argument(9)));
 
     // IMPLEMENTATION DEFINED: This is an optimization that allows us to treat these doubles as normal integers from this point onwards.
     // This does not change the exposed behavior as the call to CreateTemporalDateTime will immediately check that these values are valid
     // ISO values (for years: -273975 - 273975, for months: 1 - 12, for days: 1 - 31, for hours: 0 - 23, for minutes and seconds: 0 - 59,
     // milliseconds, microseconds, and nanoseconds: 0 - 999) all of which are subsets of this check.
-    if (!AK::is_within_range<i32>(iso_year) || !AK::is_within_range<u8>(iso_month) || !AK::is_within_range<u8>(iso_day) || !AK::is_within_range<u8>(hour) || !AK::is_within_range<u8>(minute) || !AK::is_within_range<u8>(second) || !AK::is_within_range<u16>(millisecond) || !AK::is_within_range<u16>(microsecond) || !AK::is_within_range<u16>(nanosecond)) {
-        vm.throw_exception<RangeError>(global_object, ErrorType::TemporalInvalidPlainDateTime);
-        return {};
-    }
+    if (!AK::is_within_range<i32>(iso_year) || !AK::is_within_range<u8>(iso_month) || !AK::is_within_range<u8>(iso_day) || !AK::is_within_range<u8>(hour) || !AK::is_within_range<u8>(minute) || !AK::is_within_range<u8>(second) || !AK::is_within_range<u16>(millisecond) || !AK::is_within_range<u16>(microsecond) || !AK::is_within_range<u16>(nanosecond))
+        return vm.throw_completion<RangeError>(global_object, ErrorType::TemporalInvalidPlainDateTime);
 
     // 12. Return ? CreateTemporalDateTime(isoYear, isoMonth, isoDay, hour, minute, second, millisecond, microsecond, nanosecond, calendar, NewTarget).
-    return TRY_OR_DISCARD(create_temporal_date_time(global_object, iso_year, iso_month, iso_day, hour, minute, second, millisecond, microsecond, nanosecond, *calendar, &new_target));
+    return TRY(create_temporal_date_time(global_object, iso_year, iso_month, iso_day, hour, minute, second, millisecond, microsecond, nanosecond, *calendar, &new_target));
 }
 
 // 5.2.2 Temporal.PlainDateTime.from ( item [ , options ] ), https://tc39.es/proposal-temporal/#sec-temporal.plaindatetime.from

Userland/Libraries/LibJS/Runtime/Temporal/PlainDateTimeConstructor.h

@@ -18,8 +18,8 @@ public:
     virtual void initialize(GlobalObject&) override;
     virtual ~PlainDateTimeConstructor() override = default;
 
-    virtual Value call() override;
-    virtual Value construct(FunctionObject& new_target) override;
+    virtual ThrowCompletionOr<Value> call() override;
+    virtual ThrowCompletionOr<Object*> construct(FunctionObject& new_target) override;
 
 private:
     virtual bool has_constructor() const override { return true; }

Userland/Libraries/LibJS/Runtime/Temporal/PlainMonthDayConstructor.cpp

@@ -35,17 +35,16 @@ void PlainMonthDayConstructor::initialize(GlobalObject& global_object)
 }
 
 // 10.1.1 Temporal.PlainMonthDay ( isoMonth, isoDay [ , calendarLike [ , referenceISOYear ] ] ), https://tc39.es/proposal-temporal/#sec-temporal.plainmonthday
-Value PlainMonthDayConstructor::call()
+ThrowCompletionOr<Value> PlainMonthDayConstructor::call()
 {
     auto& vm = this->vm();
 
     // 1. If NewTarget is undefined, throw a TypeError exception.
-    vm.throw_exception<TypeError>(global_object(), ErrorType::ConstructorWithoutNew, "Temporal.PlainMonthDay");
-    return {};
+    return vm.throw_completion<TypeError>(global_object(), ErrorType::ConstructorWithoutNew, "Temporal.PlainMonthDay");
 }
 
 // 10.1.1 Temporal.PlainMonthDay ( isoMonth, isoDay [ , calendarLike [ , referenceISOYear ] ] ), https://tc39.es/proposal-temporal/#sec-temporal.plainmonthday
-Value PlainMonthDayConstructor::construct(FunctionObject& new_target)
+ThrowCompletionOr<Object*> PlainMonthDayConstructor::construct(FunctionObject& new_target)
 {
     auto& vm = this->vm();
     auto& global_object = this->global_object();
@@ -62,27 +61,25 @@ Value PlainMonthDayConstructor::construct(FunctionObject& new_target)
     }
 
     // 3. Let m be ? ToIntegerThrowOnInfinity(isoMonth).
-    auto m = TRY_OR_DISCARD(to_integer_throw_on_infinity(global_object, iso_month, ErrorType::TemporalInvalidPlainMonthDay));
+    auto m = TRY(to_integer_throw_on_infinity(global_object, iso_month, ErrorType::TemporalInvalidPlainMonthDay));
 
     // 4. Let d be ? ToIntegerThrowOnInfinity(isoDay).
-    auto d = TRY_OR_DISCARD(to_integer_throw_on_infinity(global_object, iso_day, ErrorType::TemporalInvalidPlainMonthDay));
+    auto d = TRY(to_integer_throw_on_infinity(global_object, iso_day, ErrorType::TemporalInvalidPlainMonthDay));
 
     // 5. Let calendar be ? ToTemporalCalendarWithISODefault(calendarLike).
-    auto* calendar = TRY_OR_DISCARD(to_temporal_calendar_with_iso_default(global_object, calendar_like));
+    auto* calendar = TRY(to_temporal_calendar_with_iso_default(global_object, calendar_like));
 
     // 6. Let ref be ? ToIntegerThrowOnInfinity(referenceISOYear).
-    auto ref = TRY_OR_DISCARD(to_integer_throw_on_infinity(global_object, reference_iso_year, ErrorType::TemporalInvalidPlainMonthDay));
+    auto ref = TRY(to_integer_throw_on_infinity(global_object, reference_iso_year, ErrorType::TemporalInvalidPlainMonthDay));
 
     // IMPLEMENTATION DEFINED: This is an optimization that allows us to treat these doubles as normal integers from this point onwards.
     // This does not change the exposed behavior as the call to CreateTemporalMonthDay will immediately check that these values are valid
     // ISO values (for years: -273975 - 273975, for months: 1 - 12, for days: 1 - 31) all of which are subsets of this check.
-    if (!AK::is_within_range<i32>(ref) || !AK::is_within_range<u8>(m) || !AK::is_within_range<u8>(d)) {
-        vm.throw_exception<RangeError>(global_object, ErrorType::TemporalInvalidPlainYearMonth);
-        return {};
-    }
+    if (!AK::is_within_range<i32>(ref) || !AK::is_within_range<u8>(m) || !AK::is_within_range<u8>(d))
+        return vm.throw_completion<RangeError>(global_object, ErrorType::TemporalInvalidPlainYearMonth);
 
     // 7. Return ? CreateTemporalMonthDay(m, d, calendar, ref, NewTarget).
-    return TRY_OR_DISCARD(create_temporal_month_day(global_object, m, d, *calendar, ref, &new_target));
+    return TRY(create_temporal_month_day(global_object, m, d, *calendar, ref, &new_target));
 }
 
 // 10.2.2 Temporal.PlainMonthDay.from ( item [ , options ] ), https://tc39.es/proposal-temporal/#sec-temporal.plainmonthday.from

Userland/Libraries/LibJS/Runtime/Temporal/PlainMonthDayConstructor.h

@@ -18,8 +18,8 @@ public:
     virtual void initialize(GlobalObject&) override;
     virtual ~PlainMonthDayConstructor() override = default;
 
-    virtual Value call() override;
-    virtual Value construct(FunctionObject& new_target) override;
+    virtual ThrowCompletionOr<Value> call() override;
+    virtual ThrowCompletionOr<Object*> construct(FunctionObject& new_target) override;
 
 private:
     virtual bool has_constructor() const override { return true; }

Userland/Libraries/LibJS/Runtime/Temporal/PlainTimeConstructor.cpp

@@ -35,50 +35,47 @@ void PlainTimeConstructor::initialize(GlobalObject& global_object)
 }
 
 // 4.1.1 Temporal.PlainTime ( [ hour [ , minute [ , second [ , millisecond [ , microsecond [ , nanosecond ] ] ] ] ] ] ), https://tc39.es/proposal-temporal/#sec-temporal.plaintime
-Value PlainTimeConstructor::call()
+ThrowCompletionOr<Value> PlainTimeConstructor::call()
 {
     auto& vm = this->vm();
 
     // 1. If NewTarget is undefined, throw a TypeError exception.
-    vm.throw_exception<TypeError>(global_object(), ErrorType::ConstructorWithoutNew, "Temporal.PlainTime");
-    return {};
+    return vm.throw_completion<TypeError>(global_object(), ErrorType::ConstructorWithoutNew, "Temporal.PlainTime");
 }
 
 // 4.1.1 Temporal.PlainTime ( [ hour [ , minute [ , second [ , millisecond [ , microsecond [ , nanosecond ] ] ] ] ] ] ), https://tc39.es/proposal-temporal/#sec-temporal.plaintime
-Value PlainTimeConstructor::construct(FunctionObject& new_target)
+ThrowCompletionOr<Object*> PlainTimeConstructor::construct(FunctionObject& new_target)
 {
     auto& vm = this->vm();
     auto& global_object = this->global_object();
 
     // 2. Let hour be ? ToIntegerThrowOnInfinity(hour).
-    auto hour = TRY_OR_DISCARD(to_integer_throw_on_infinity(global_object, vm.argument(0), ErrorType::TemporalInvalidPlainTime));
+    auto hour = TRY(to_integer_throw_on_infinity(global_object, vm.argument(0), ErrorType::TemporalInvalidPlainTime));
 
     // 3. Let minute be ? ToIntegerThrowOnInfinity(hour).
-    auto minute = TRY_OR_DISCARD(to_integer_throw_on_infinity(global_object, vm.argument(1), ErrorType::TemporalInvalidPlainTime));
+    auto minute = TRY(to_integer_throw_on_infinity(global_object, vm.argument(1), ErrorType::TemporalInvalidPlainTime));
 
     // 4. Let second be ? ToIntegerThrowOnInfinity(hour).
-    auto second = TRY_OR_DISCARD(to_integer_throw_on_infinity(global_object, vm.argument(2), ErrorType::TemporalInvalidPlainTime));
+    auto second = TRY(to_integer_throw_on_infinity(global_object, vm.argument(2), ErrorType::TemporalInvalidPlainTime));
 
     // 5. Let millisecond be ? ToIntegerThrowOnInfinity(hour).
-    auto millisecond = TRY_OR_DISCARD(to_integer_throw_on_infinity(global_object, vm.argument(3), ErrorType::TemporalInvalidPlainTime));
+    auto millisecond = TRY(to_integer_throw_on_infinity(global_object, vm.argument(3), ErrorType::TemporalInvalidPlainTime));
 
     // 6. Let microsecond be ? ToIntegerThrowOnInfinity(hour).
-    auto microsecond = TRY_OR_DISCARD(to_integer_throw_on_infinity(global_object, vm.argument(4), ErrorType::TemporalInvalidPlainTime));
+    auto microsecond = TRY(to_integer_throw_on_infinity(global_object, vm.argument(4), ErrorType::TemporalInvalidPlainTime));
 
     // 7. Let nanosecond be ? ToIntegerThrowOnInfinity(hour).
-    auto nanosecond = TRY_OR_DISCARD(to_integer_throw_on_infinity(global_object, vm.argument(5), ErrorType::TemporalInvalidPlainTime));
+    auto nanosecond = TRY(to_integer_throw_on_infinity(global_object, vm.argument(5), ErrorType::TemporalInvalidPlainTime));
 
     // IMPLEMENTATION DEFINED: This is an optimization that allows us to treat these doubles as normal integers from this point onwards.
     // This does not change the exposed behavior as the call to CreateTemporalTime will immediately check that these values are valid
     // ISO values (for hours: 0 - 23, for minutes and seconds: 0 - 59, milliseconds, microseconds, and nanoseconds: 0 - 999) all of which
     // are subsets of this check.
-    if (!AK::is_within_range<u8>(hour) || !AK::is_within_range<u8>(minute) || !AK::is_within_range<u8>(second) || !AK::is_within_range<u16>(millisecond) || !AK::is_within_range<u16>(microsecond) || !AK::is_within_range<u16>(nanosecond)) {
-        vm.throw_exception<RangeError>(global_object, ErrorType::TemporalInvalidPlainTime);
-        return {};
-    }
+    if (!AK::is_within_range<u8>(hour) || !AK::is_within_range<u8>(minute) || !AK::is_within_range<u8>(second) || !AK::is_within_range<u16>(millisecond) || !AK::is_within_range<u16>(microsecond) || !AK::is_within_range<u16>(nanosecond))
+        return vm.throw_completion<RangeError>(global_object, ErrorType::TemporalInvalidPlainTime);
 
     // 8. Return ? CreateTemporalTime(hour, minute, second, millisecond, microsecond, nanosecond, NewTarget).
-    return TRY_OR_DISCARD(create_temporal_time(global_object, hour, minute, second, millisecond, microsecond, nanosecond, &new_target));
+    return TRY(create_temporal_time(global_object, hour, minute, second, millisecond, microsecond, nanosecond, &new_target));
 }
 
 // 4.2.2 Temporal.PlainTime.from ( item [ , options ] ), https://tc39.es/proposal-temporal/#sec-temporal.plaintime.from

Userland/Libraries/LibJS/Runtime/Temporal/PlainTimeConstructor.h

@@ -18,8 +18,8 @@ public:
     virtual void initialize(GlobalObject&) override;
     virtual ~PlainTimeConstructor() override = default;
 
-    virtual Value call() override;
-    virtual Value construct(FunctionObject& new_target) override;
+    virtual ThrowCompletionOr<Value> call() override;
+    virtual ThrowCompletionOr<Object*> construct(FunctionObject& new_target) override;
 
 private:
     virtual bool has_constructor() const override { return true; }

Userland/Libraries/LibJS/Runtime/Temporal/PlainYearMonthConstructor.cpp

@@ -37,17 +37,16 @@ void PlainYearMonthConstructor::initialize(GlobalObject& global_object)
 }
 
 // 9.1.1 Temporal.PlainYearMonth ( isoYear, isoMonth [ , calendarLike [ , referenceISODay ] ] ), https://tc39.es/proposal-temporal/#sec-temporal.plainyearmonth
-Value PlainYearMonthConstructor::call()
+ThrowCompletionOr<Value> PlainYearMonthConstructor::call()
 {
     auto& vm = this->vm();
 
     // 1. If NewTarget is undefined, throw a TypeError exception.
-    vm.throw_exception<TypeError>(global_object(), ErrorType::ConstructorWithoutNew, "Temporal.PlainYearMonth");
-    return {};
+    return vm.throw_completion<TypeError>(global_object(), ErrorType::ConstructorWithoutNew, "Temporal.PlainYearMonth");
 }
 
 // 9.1.1 Temporal.PlainYearMonth ( isoYear, isoMonth [ , calendarLike [ , referenceISODay ] ] ), https://tc39.es/proposal-temporal/#sec-temporal.plainyearmonth
-Value PlainYearMonthConstructor::construct(FunctionObject& new_target)
+ThrowCompletionOr<Object*> PlainYearMonthConstructor::construct(FunctionObject& new_target)
 {
     auto& vm = this->vm();
     auto& global_object = this->global_object();
@@ -64,27 +63,25 @@ Value PlainYearMonthConstructor::construct(FunctionObject& new_target)
     }
 
     // 3. Let y be ? ToIntegerThrowOnInfinity(isoYear).
-    auto y = TRY_OR_DISCARD(to_integer_throw_on_infinity(global_object, iso_year, ErrorType::TemporalInvalidPlainYearMonth));
+    auto y = TRY(to_integer_throw_on_infinity(global_object, iso_year, ErrorType::TemporalInvalidPlainYearMonth));
 
     // 4. Let m be ? ToIntegerThrowOnInfinity(isoMonth).
-    auto m = TRY_OR_DISCARD(to_integer_throw_on_infinity(global_object, iso_month, ErrorType::TemporalInvalidPlainYearMonth));
+    auto m = TRY(to_integer_throw_on_infinity(global_object, iso_month, ErrorType::TemporalInvalidPlainYearMonth));
 
     // 5. Let calendar be ? ToTemporalCalendarWithISODefault(calendarLike).
-    auto* calendar = TRY_OR_DISCARD(to_temporal_calendar_with_iso_default(global_object, calendar_like));
+    auto* calendar = TRY(to_temporal_calendar_with_iso_default(global_object, calendar_like));
 
     // 6. Let ref be ? ToIntegerThrowOnInfinity(referenceISODay).
-    auto ref = TRY_OR_DISCARD(to_integer_throw_on_infinity(global_object, reference_iso_day, ErrorType::TemporalInvalidPlainYearMonth));
+    auto ref = TRY(to_integer_throw_on_infinity(global_object, reference_iso_day, ErrorType::TemporalInvalidPlainYearMonth));
 
     // IMPLEMENTATION DEFINED: This is an optimization that allows us to treat these doubles as normal integers from this point onwards.
     // This does not change the exposed behavior as the call to CreateTemporalYearMonth will immediately check that these values are valid
     // ISO values (for years: -273975 - 273975, for months: 1 - 12, for days: 1 - 31) all of which are subsets of this check.
-    if (!AK::is_within_range<i32>(y) || !AK::is_within_range<u8>(m) || !AK::is_within_range<u8>(ref)) {
-        vm.throw_exception<RangeError>(global_object, ErrorType::TemporalInvalidPlainYearMonth);
-        return {};
-    }
+    if (!AK::is_within_range<i32>(y) || !AK::is_within_range<u8>(m) || !AK::is_within_range<u8>(ref))
+        return vm.throw_completion<RangeError>(global_object, ErrorType::TemporalInvalidPlainYearMonth);
 
     // 7. Return ? CreateTemporalYearMonth(y, m, calendar, ref, NewTarget).
-    return TRY_OR_DISCARD(create_temporal_year_month(global_object, y, m, *calendar, ref, &new_target));
+    return TRY(create_temporal_year_month(global_object, y, m, *calendar, ref, &new_target));
 }
 
 // 9.2.2 Temporal.PlainYearMonth.from ( item [ , options ] ), https://tc39.es/proposal-temporal/#sec-temporal.plainyearmonth.from

Userland/Libraries/LibJS/Runtime/Temporal/PlainYearMonthConstructor.h

@@ -18,8 +18,8 @@ public:
     virtual void initialize(GlobalObject&) override;
     virtual ~PlainYearMonthConstructor() override = default;
 
-    virtual Value call() override;
-    virtual Value construct(FunctionObject& new_target) override;
+    virtual ThrowCompletionOr<Value> call() override;
+    virtual ThrowCompletionOr<Object*> construct(FunctionObject& new_target) override;
 
 private:
     virtual bool has_constructor() const override { return true; }

Userland/Libraries/LibJS/Runtime/Temporal/TimeZoneConstructor.cpp

@@ -32,31 +32,30 @@ void TimeZoneConstructor::initialize(GlobalObject& global_object)
 }
 
 // 11.2.1 Temporal.TimeZone ( identifier ), https://tc39.es/proposal-temporal/#sec-temporal.timezone
-Value TimeZoneConstructor::call()
+ThrowCompletionOr<Value> TimeZoneConstructor::call()
 {
     auto& vm = this->vm();
 
     // 1. If NewTarget is undefined, then
     // a. Throw a TypeError exception.
-    vm.throw_exception<TypeError>(global_object(), ErrorType::ConstructorWithoutNew, "Temporal.TimeZone");
-    return {};
+    return vm.throw_completion<TypeError>(global_object(), ErrorType::ConstructorWithoutNew, "Temporal.TimeZone");
 }
 
 // 11.2.1 Temporal.TimeZone ( identifier ), https://tc39.es/proposal-temporal/#sec-temporal.timezone
-Value TimeZoneConstructor::construct(FunctionObject& new_target)
+ThrowCompletionOr<Object*> TimeZoneConstructor::construct(FunctionObject& new_target)
 {
     auto& vm = this->vm();
     auto& global_object = this->global_object();
 
     // 2. Set identifier to ? ToString(identifier).
-    auto identifier = TRY_OR_DISCARD(vm.argument(0).to_string(global_object));
+    auto identifier = TRY(vm.argument(0).to_string(global_object));
 
     String canonical;
 
     // 3. If identifier satisfies the syntax of a TimeZoneNumericUTCOffset (see 13.33), then
     if (is_valid_time_zone_numeric_utc_offset_syntax(identifier)) {
         // a. Let offsetNanoseconds be ? ParseTimeZoneOffsetString(identifier).
-        auto offset_nanoseconds = TRY_OR_DISCARD(parse_time_zone_offset_string(global_object, identifier));
+        auto offset_nanoseconds = TRY(parse_time_zone_offset_string(global_object, identifier));
 
         // b. Let canonical be ! FormatTimeZoneOffsetString(offsetNanoseconds).
         canonical = format_time_zone_offset_string(offset_nanoseconds);
@@ -66,8 +65,7 @@ Value TimeZoneConstructor::construct(FunctionObject& new_target)
         // a. If ! IsValidTimeZoneName(identifier) is false, then
         if (!is_valid_time_zone_name(identifier)) {
             // i. Throw a RangeError exception.
-            vm.throw_exception<RangeError>(global_object, ErrorType::TemporalInvalidTimeZoneName);
-            return {};
+            return vm.throw_completion<RangeError>(global_object, ErrorType::TemporalInvalidTimeZoneName);
         }
 
         // b. Let canonical be ! CanonicalizeTimeZoneName(identifier).
@@ -75,7 +73,7 @@ Value TimeZoneConstructor::construct(FunctionObject& new_target)
     }
 
     // 5. Return ? CreateTemporalTimeZone(canonical, NewTarget).
-    return TRY_OR_DISCARD(create_temporal_time_zone(global_object, canonical, &new_target));
+    return TRY(create_temporal_time_zone(global_object, canonical, &new_target));
 }
 
 // 11.3.2 Temporal.TimeZone.from ( item ), https://tc39.es/proposal-temporal/#sec-temporal.timezone.from

Userland/Libraries/LibJS/Runtime/Temporal/TimeZoneConstructor.h

@@ -18,8 +18,8 @@ public:
     virtual void initialize(GlobalObject&) override;
     virtual ~TimeZoneConstructor() override = default;
 
-    virtual Value call() override;
-    virtual Value construct(FunctionObject& new_target) override;
+    virtual ThrowCompletionOr<Value> call() override;
+    virtual ThrowCompletionOr<Object*> construct(FunctionObject& new_target) override;
 
 private:
     virtual bool has_constructor() const override { return true; }

Userland/Libraries/LibJS/Runtime/Temporal/ZonedDateTimeConstructor.cpp

@@ -32,39 +32,36 @@ void ZonedDateTimeConstructor::initialize(GlobalObject& global_object)
 }
 
 // 6.1.1 Temporal.ZonedDateTime ( epochNanoseconds, timeZoneLike [ , calendarLike ] ), https://tc39.es/proposal-temporal/#sec-temporal.zoneddatetime
-Value ZonedDateTimeConstructor::call()
+ThrowCompletionOr<Value> ZonedDateTimeConstructor::call()
 {
     auto& vm = this->vm();
 
     // 1. If NewTarget is undefined, then
     // a. Throw a TypeError exception.
-    vm.throw_exception<TypeError>(global_object(), ErrorType::ConstructorWithoutNew, "Temporal.ZonedDateTime");
-    return {};
+    return vm.throw_completion<TypeError>(global_object(), ErrorType::ConstructorWithoutNew, "Temporal.ZonedDateTime");
 }
 
 // 6.1.1 Temporal.ZonedDateTime ( epochNanoseconds, timeZoneLike [ , calendarLike ] ), https://tc39.es/proposal-temporal/#sec-temporal.zoneddatetime
-Value ZonedDateTimeConstructor::construct(FunctionObject& new_target)
+ThrowCompletionOr<Object*> ZonedDateTimeConstructor::construct(FunctionObject& new_target)
 {
     auto& vm = this->vm();
     auto& global_object = this->global_object();
 
     // 2. Set epochNanoseconds to ? ToBigInt(epochNanoseconds).
-    auto* epoch_nanoseconds = TRY_OR_DISCARD(vm.argument(0).to_bigint(global_object));
+    auto* epoch_nanoseconds = TRY(vm.argument(0).to_bigint(global_object));
 
     // 3. If ! IsValidEpochNanoseconds(epochNanoseconds) is false, throw a RangeError exception.
-    if (!is_valid_epoch_nanoseconds(*epoch_nanoseconds)) {
-        vm.throw_exception<RangeError>(global_object, ErrorType::TemporalInvalidEpochNanoseconds);
-        return {};
-    }
+    if (!is_valid_epoch_nanoseconds(*epoch_nanoseconds))
+        return vm.throw_completion<RangeError>(global_object, ErrorType::TemporalInvalidEpochNanoseconds);
 
     // 4. Let timeZone be ? ToTemporalTimeZone(timeZoneLike).
-    auto* time_zone = TRY_OR_DISCARD(to_temporal_time_zone(global_object, vm.argument(1)));
+    auto* time_zone = TRY(to_temporal_time_zone(global_object, vm.argument(1)));
 
     // 5. Let calendar be ? ToTemporalCalendarWithISODefault(calendarLike).
-    auto* calendar = TRY_OR_DISCARD(to_temporal_calendar_with_iso_default(global_object, vm.argument(2)));
+    auto* calendar = TRY(to_temporal_calendar_with_iso_default(global_object, vm.argument(2)));
 
     // 6. Return ? CreateTemporalZonedDateTime(epochNanoseconds, timeZone, calendar, NewTarget).
-    return TRY_OR_DISCARD(create_temporal_zoned_date_time(global_object, *epoch_nanoseconds, *time_zone, *calendar, &new_target));
+    return TRY(create_temporal_zoned_date_time(global_object, *epoch_nanoseconds, *time_zone, *calendar, &new_target));
 }
 
 }

Userland/Libraries/LibJS/Runtime/Temporal/ZonedDateTimeConstructor.h

@@ -18,8 +18,8 @@ public:
     virtual void initialize(GlobalObject&) override;
     virtual ~ZonedDateTimeConstructor() override = default;
 
-    virtual Value call() override;
-    virtual Value construct(FunctionObject& new_target) override;
+    virtual ThrowCompletionOr<Value> call() override;
+    virtual ThrowCompletionOr<Object*> construct(FunctionObject& new_target) override;
 
 private:
     virtual bool has_constructor() const override { return true; }