LibLocale+LibJS: Make locale data APIs infallible

These APIs only perform small allocations, and are only used by LibJS.
Callers which could only have failed from these APIs are also made to
be infallible here.

Meta/Lagom/Tools/CodeGenerators/LibLocale/GenerateDateTimeFormatData.cpp

@@ -2091,7 +2091,7 @@ Optional<@return_type@> get_regional_@lookup_type@(StringView region)
     append_regional_lookup("Weekday"sv, "weekend_end"sv);
 
     generator.append(R"~~~(
-static ErrorOr<CalendarData const*> find_calendar_data(StringView locale, StringView calendar)
+static CalendarData const* find_calendar_data(StringView locale, StringView calendar)
 {
     auto locale_value = locale_from_string(locale);
     if (!locale_value.has_value())
@@ -2118,7 +2118,7 @@ static ErrorOr<CalendarData const*> find_calendar_data(StringView locale, String
     if (auto const* calendar_data = lookup_calendar(calendar))
         return calendar_data;
 
-    auto default_calendar = TRY(get_preferred_keyword_value_for_locale(locale, "ca"sv));
+    auto default_calendar = get_preferred_keyword_value_for_locale(locale, "ca"sv);
     if (!default_calendar.has_value())
         return nullptr;
 
@@ -2127,7 +2127,7 @@ static ErrorOr<CalendarData const*> find_calendar_data(StringView locale, String
 
 ErrorOr<Optional<CalendarFormat>> get_calendar_date_format(StringView locale, StringView calendar)
 {
-    if (auto const* data = TRY(find_calendar_data(locale, calendar)); data != nullptr) {
+    if (auto const* data = find_calendar_data(locale, calendar); data != nullptr) {
         auto const& formats = s_calendar_formats.at(data->date_formats);
         return TRY(formats.to_unicode_calendar_format());
     }
@@ -2136,7 +2136,7 @@ ErrorOr<Optional<CalendarFormat>> get_calendar_date_format(StringView locale, St
 
 ErrorOr<Optional<CalendarFormat>> get_calendar_time_format(StringView locale, StringView calendar)
 {
-    if (auto const* data = TRY(find_calendar_data(locale, calendar)); data != nullptr) {
+    if (auto const* data = find_calendar_data(locale, calendar); data != nullptr) {
         auto const& formats = s_calendar_formats.at(data->time_formats);
         return TRY(formats.to_unicode_calendar_format());
     }
@@ -2145,7 +2145,7 @@ ErrorOr<Optional<CalendarFormat>> get_calendar_time_format(StringView locale, St
 
 ErrorOr<Optional<CalendarFormat>> get_calendar_date_time_format(StringView locale, StringView calendar)
 {
-    if (auto const* data = TRY(find_calendar_data(locale, calendar)); data != nullptr) {
+    if (auto const* data = find_calendar_data(locale, calendar); data != nullptr) {
         auto const& formats = s_calendar_formats.at(data->date_time_formats);
         return TRY(formats.to_unicode_calendar_format());
     }
@@ -2156,7 +2156,7 @@ ErrorOr<Vector<CalendarPattern>> get_calendar_available_formats(StringView local
 {
     Vector<CalendarPattern> result {};
 
-    if (auto const* data = TRY(find_calendar_data(locale, calendar)); data != nullptr) {
+    if (auto const* data = find_calendar_data(locale, calendar); data != nullptr) {
         auto const& available_formats = s_calendar_pattern_lists.at(data->available_formats);
         TRY(result.try_ensure_capacity(available_formats.size()));
 
@@ -2169,7 +2169,7 @@ ErrorOr<Vector<CalendarPattern>> get_calendar_available_formats(StringView local
 
 ErrorOr<Optional<CalendarRangePattern>> get_calendar_default_range_format(StringView locale, StringView calendar)
 {
-    if (auto const* data = TRY(find_calendar_data(locale, calendar)); data != nullptr) {
+    if (auto const* data = find_calendar_data(locale, calendar); data != nullptr) {
         auto const& pattern = s_calendar_range_patterns[data->default_range_format];
         return TRY(pattern.to_unicode_calendar_range_pattern());
     }
@@ -2181,7 +2181,7 @@ ErrorOr<Vector<CalendarRangePattern>> get_calendar_range_formats(StringView loca
 {
     Vector<CalendarRangePattern> result {};
 
-    if (auto const* data = TRY(find_calendar_data(locale, calendar)); data != nullptr) {
+    if (auto const* data = find_calendar_data(locale, calendar); data != nullptr) {
         auto const& range_formats = s_calendar_range_pattern_lists.at(data->range_formats);
 
         for (auto format : range_formats) {
@@ -2199,7 +2199,7 @@ ErrorOr<Vector<CalendarRangePattern>> get_calendar_range12_formats(StringView lo
 {
     Vector<CalendarRangePattern> result {};
 
-    if (auto const* data = TRY(find_calendar_data(locale, calendar)); data != nullptr) {
+    if (auto const* data = find_calendar_data(locale, calendar); data != nullptr) {
         auto const& range12_formats = s_calendar_range_pattern_lists.at(data->range12_formats);
 
         for (auto format : range12_formats) {
@@ -2215,7 +2215,7 @@ ErrorOr<Vector<CalendarRangePattern>> get_calendar_range12_formats(StringView lo
 
 static ErrorOr<ReadonlySpan<@string_index_type@>> find_calendar_symbols(StringView locale, StringView calendar, CalendarSymbol symbol, CalendarPatternStyle style)
 {
-    if (auto const* data = TRY(find_calendar_data(locale, calendar)); data != nullptr) {
+    if (auto const* data = find_calendar_data(locale, calendar); data != nullptr) {
         auto const& symbols_list = s_calendar_symbol_lists[data->symbols];
         auto symbol_index = to_underlying(symbol);
 

Meta/Lagom/Tools/CodeGenerators/LibLocale/GenerateLocaleData.cpp

@@ -1351,18 +1351,18 @@ static constexpr Array<@type@, @size@> @name@ { {)~~~");
 
 struct CanonicalLanguageID
 {
-    ErrorOr<LanguageID> to_unicode_language_id() const
+    LanguageID to_unicode_language_id() const
     {
         LanguageID language_id {};
-        TRY(language_id.variants.try_ensure_capacity(variants_size));
+        language_id.variants.ensure_capacity(variants_size);
 
-        language_id.language = TRY(String::from_utf8(decode_string(language)));
+        language_id.language = MUST(String::from_utf8(decode_string(language)));
         if (script != 0)
-            language_id.script = TRY(String::from_utf8(decode_string(script)));
+            language_id.script = MUST(String::from_utf8(decode_string(script)));
         if (region != 0)
-            language_id.region = TRY(String::from_utf8(decode_string(region)));
+            language_id.region = MUST(String::from_utf8(decode_string(region)));
         for (size_t i = 0; i < variants_size; ++i)
-            language_id.variants.append(TRY(String::from_utf8(decode_string(variants[i]))));
+            language_id.variants.append(MUST(String::from_utf8(decode_string(variants[i]))));
 
         return language_id;
     }
@@ -1674,13 +1674,13 @@ static ReadonlySpan<@string_index_type@> find_keyword_indices(StringView locale,
     return s_keyword_lists.at(keywords_index);
 }
 
-ErrorOr<Optional<StringView>> get_preferred_keyword_value_for_locale(StringView locale, StringView key)
+Optional<StringView> get_preferred_keyword_value_for_locale(StringView locale, StringView key)
 {
     // Hour cycle keywords are region-based rather than locale-based, so they need to be handled specially.
     // FIXME: Calendar keywords are also region-based, and will need to be handled here when we support non-Gregorian calendars:
     //        https://github.com/unicode-org/cldr-json/blob/main/cldr-json/cldr-core/supplemental/calendarPreferenceData.json
     if (key == "hc"sv) {
-        auto hour_cycles = TRY(get_locale_hour_cycles(locale));
+        auto hour_cycles = MUST(get_locale_hour_cycles(locale));
         if (hour_cycles.is_empty())
             return OptionalNone {};
 
@@ -1703,16 +1703,16 @@ ErrorOr<Optional<StringView>> get_preferred_keyword_value_for_locale(StringView
     return Optional<StringView> { decode_string(keyword_indices[0]) };
 }
 
-ErrorOr<Vector<StringView>> get_keywords_for_locale(StringView locale, StringView key)
+Vector<StringView> get_keywords_for_locale(StringView locale, StringView key)
 {
     // Hour cycle keywords are region-based rather than locale-based, so they need to be handled specially.
     // FIXME: Calendar keywords are also region-based, and will need to be handled here when we support non-Gregorian calendars:
     //        https://github.com/unicode-org/cldr-json/blob/main/cldr-json/cldr-core/supplemental/calendarPreferenceData.json
     if (key == "hc"sv) {
-        auto hour_cycles = TRY(get_locale_hour_cycles(locale));
+        auto hour_cycles = MUST(get_locale_hour_cycles(locale));
 
         Vector<StringView> values;
-        TRY(values.try_ensure_capacity(hour_cycles.size()));
+        values.ensure_capacity(hour_cycles.size());
 
         for (auto hour_cycle : hour_cycles)
             values.unchecked_append(hour_cycle_to_string(hour_cycle));
@@ -1727,7 +1727,7 @@ ErrorOr<Vector<StringView>> get_keywords_for_locale(StringView locale, StringVie
     auto keyword_indices = find_keyword_indices(locale, key);
 
     Vector<StringView> keywords;
-    TRY(keywords.try_ensure_capacity(keyword_indices.size()));
+    keywords.ensure_capacity(keyword_indices.size());
 
     for (auto keyword : keyword_indices)
         keywords.unchecked_append(decode_string(keyword));
@@ -1798,7 +1798,7 @@ Optional<CharacterOrder> character_order_for_locale(StringView locale)
     return {};
 }
 
-ErrorOr<void> resolve_complex_language_aliases(LanguageID& language_id)
+void resolve_complex_language_aliases(LanguageID& language_id)
 {
     for (auto const& map : s_complex_alias) {
         auto key_language = decode_string(map.key.language);
@@ -1814,7 +1814,7 @@ ErrorOr<void> resolve_complex_language_aliases(LanguageID& language_id)
         if (!map.key.matches_variants(language_id.variants))
             continue;
 
-        auto alias = TRY(map.alias.to_unicode_language_id());
+        auto alias = map.alias.to_unicode_language_id();
 
         if (alias.language == "und"sv)
             alias.language = move(language_id.language);
@@ -1828,11 +1828,9 @@ ErrorOr<void> resolve_complex_language_aliases(LanguageID& language_id)
         language_id = move(alias);
         break;
     }
-
-    return {};
 }
 
-ErrorOr<Optional<LanguageID>> add_likely_subtags(LanguageID const& language_id)
+Optional<LanguageID> add_likely_subtags(LanguageID const& language_id)
 {
     // https://www.unicode.org/reports/tr35/#Likely_Subtags
     auto const* likely_subtag = resolve_likely_subtag(language_id);
@@ -1849,19 +1847,19 @@ ErrorOr<Optional<LanguageID>> add_likely_subtags(LanguageID const& language_id)
     auto alias_region = decode_string(likely_subtag->alias.region);
 
     if (maximized.language == "und"sv)
-        maximized.language = TRY(String::from_utf8(alias_language));
+        maximized.language = MUST(String::from_utf8(alias_language));
     if (!maximized.script.has_value() || (!key_script.is_empty() && !alias_script.is_empty()))
-        maximized.script = TRY(String::from_utf8(alias_script));
+        maximized.script = MUST(String::from_utf8(alias_script));
     if (!maximized.region.has_value() || (!key_region.is_empty() && !alias_region.is_empty()))
-        maximized.region = TRY(String::from_utf8(alias_region));
+        maximized.region = MUST(String::from_utf8(alias_region));
 
     return maximized;
 }
 
-ErrorOr<Optional<String>> resolve_most_likely_territory(LanguageID const& language_id)
+Optional<String> resolve_most_likely_territory(LanguageID const& language_id)
 {
     if (auto const* likely_subtag = resolve_likely_subtag(language_id); likely_subtag != nullptr)
-        return String::from_utf8(decode_string(likely_subtag->alias.region));
+        return MUST(String::from_utf8(decode_string(likely_subtag->alias.region)));
     return OptionalNone {};
 }
 

Meta/Lagom/Tools/CodeGenerators/LibLocale/GenerateNumberFormatData.cpp

@@ -927,7 +927,7 @@ Optional<ReadonlySpan<u32>> get_digits_for_number_system(StringView system)
     return s_number_systems_digits[number_system_index];
 }
 
-static ErrorOr<NumberSystemData const*> find_number_system(StringView locale, StringView system)
+static NumberSystemData const* find_number_system(StringView locale, StringView system)
 {
     auto locale_value = locale_from_string(locale);
     if (!locale_value.has_value())
@@ -957,44 +957,44 @@ static ErrorOr<NumberSystemData const*> find_number_system(StringView locale, St
     if (auto const* number_system = lookup_number_system(system))
         return number_system;
 
-    auto default_number_system = TRY(get_preferred_keyword_value_for_locale(locale, "nu"sv));
+    auto default_number_system = get_preferred_keyword_value_for_locale(locale, "nu"sv);
     if (!default_number_system.has_value())
         return nullptr;
 
     return lookup_number_system(*default_number_system);
 }
 
-ErrorOr<Optional<StringView>> get_number_system_symbol(StringView locale, StringView system, NumericSymbol symbol)
+Optional<StringView> get_number_system_symbol(StringView locale, StringView system, NumericSymbol symbol)
 {
-    if (auto const* number_system = TRY(find_number_system(locale, system)); number_system != nullptr) {
+    if (auto const* number_system = find_number_system(locale, system); number_system != nullptr) {
         auto symbols = s_numeric_symbol_lists.at(number_system->symbols);
 
         auto symbol_index = to_underlying(symbol);
         if (symbol_index >= symbols.size())
-            return OptionalNone {};
+            return {};
 
-        return Optional<StringView> { decode_string(symbols[symbol_index]) };
+        return decode_string(symbols[symbol_index]);
     }
 
-    return OptionalNone {};
+    return {};
 }
 
-ErrorOr<Optional<NumberGroupings>> get_number_system_groupings(StringView locale, StringView system)
+Optional<NumberGroupings> get_number_system_groupings(StringView locale, StringView system)
 {
     auto locale_value = locale_from_string(locale);
     if (!locale_value.has_value())
-        return OptionalNone {};
+        return {};
 
     u8 minimum_grouping_digits = s_minimum_grouping_digits[to_underlying(*locale_value) - 1];
 
-    if (auto const* number_system = TRY(find_number_system(locale, system)); number_system != nullptr)
+    if (auto const* number_system = find_number_system(locale, system); number_system != nullptr)
         return NumberGroupings { minimum_grouping_digits, number_system->primary_grouping_size, number_system->secondary_grouping_size };
-    return OptionalNone {};
+    return {};
 }
 
 ErrorOr<Optional<NumberFormat>> get_standard_number_system_format(StringView locale, StringView system, StandardNumberFormatType type)
 {
-    if (auto const* number_system = TRY(find_number_system(locale, system)); number_system != nullptr) {
+    if (auto const* number_system = find_number_system(locale, system); number_system != nullptr) {
         @number_format_index_type@ format_index = 0;
 
         switch (type) {
@@ -1025,7 +1025,7 @@ ErrorOr<Vector<NumberFormat>> get_compact_number_system_formats(StringView local
 {
     Vector<NumberFormat> formats;
 
-    if (auto const* number_system = TRY(find_number_system(locale, system)); number_system != nullptr) {
+    if (auto const* number_system = find_number_system(locale, system); number_system != nullptr) {
         @number_format_list_index_type@ number_format_list_index { 0 };
 
         switch (type) {

Tests/LibLocale/TestLocale.cpp

@@ -104,11 +104,11 @@ template<typename LHS, typename RHS>
 TEST_CASE(parse_unicode_locale_id)
 {
     auto fail = [](StringView locale) {
-        auto locale_id = MUST(Locale::parse_unicode_locale_id(locale));
+        auto locale_id = Locale::parse_unicode_locale_id(locale);
         EXPECT(!locale_id.has_value());
     };
     auto pass = [](StringView locale, Optional<StringView> expected_language, Optional<StringView> expected_script, Optional<StringView> expected_region, Vector<StringView> expected_variants) {
-        auto locale_id = MUST(Locale::parse_unicode_locale_id(locale));
+        auto locale_id = Locale::parse_unicode_locale_id(locale);
         VERIFY(locale_id.has_value());
 
         EXPECT_EQ(locale_id->language_id.language, expected_language);
@@ -145,11 +145,11 @@ TEST_CASE(parse_unicode_locale_id_with_unicode_locale_extension)
     };
 
     auto fail = [](StringView locale) {
-        auto locale_id = MUST(Locale::parse_unicode_locale_id(locale));
+        auto locale_id = Locale::parse_unicode_locale_id(locale);
         EXPECT(!locale_id.has_value());
     };
     auto pass = [](StringView locale, LocaleExtension const& expected_extension) {
-        auto locale_id = MUST(Locale::parse_unicode_locale_id(locale));
+        auto locale_id = Locale::parse_unicode_locale_id(locale);
         VERIFY(locale_id.has_value());
         EXPECT_EQ(locale_id->extensions.size(), 1u);
 
@@ -209,11 +209,11 @@ TEST_CASE(parse_unicode_locale_id_with_transformed_extension)
     };
 
     auto fail = [](StringView locale) {
-        auto locale_id = MUST(Locale::parse_unicode_locale_id(locale));
+        auto locale_id = Locale::parse_unicode_locale_id(locale);
         EXPECT(!locale_id.has_value());
     };
     auto pass = [](StringView locale, TransformedExtension const& expected_extension) {
-        auto locale_id = MUST(Locale::parse_unicode_locale_id(locale));
+        auto locale_id = Locale::parse_unicode_locale_id(locale);
         VERIFY(locale_id.has_value());
         EXPECT_EQ(locale_id->extensions.size(), 1u);
 
@@ -280,11 +280,11 @@ TEST_CASE(parse_unicode_locale_id_with_other_extension)
     };
 
     auto fail = [](StringView locale) {
-        auto locale_id = MUST(Locale::parse_unicode_locale_id(locale));
+        auto locale_id = Locale::parse_unicode_locale_id(locale);
         EXPECT(!locale_id.has_value());
     };
     auto pass = [](StringView locale, OtherExtension const& expected_extension) {
-        auto locale_id = MUST(Locale::parse_unicode_locale_id(locale));
+        auto locale_id = Locale::parse_unicode_locale_id(locale);
         VERIFY(locale_id.has_value());
         EXPECT_EQ(locale_id->extensions.size(), 1u);
 
@@ -314,11 +314,11 @@ TEST_CASE(parse_unicode_locale_id_with_other_extension)
 TEST_CASE(parse_unicode_locale_id_with_private_use_extension)
 {
     auto fail = [](StringView locale) {
-        auto locale_id = MUST(Locale::parse_unicode_locale_id(locale));
+        auto locale_id = Locale::parse_unicode_locale_id(locale);
         EXPECT(!locale_id.has_value());
     };
     auto pass = [](StringView locale, Vector<StringView> const& expected_extension) {
-        auto locale_id = MUST(Locale::parse_unicode_locale_id(locale));
+        auto locale_id = Locale::parse_unicode_locale_id(locale);
         VERIFY(locale_id.has_value());
         EXPECT(compare_vectors(locale_id->private_use_extensions, expected_extension));
     };
@@ -338,10 +338,10 @@ TEST_CASE(parse_unicode_locale_id_with_private_use_extension)
 TEST_CASE(canonicalize_unicode_locale_id)
 {
     auto test = [](StringView locale, StringView expected_canonical_locale) {
-        auto locale_id = MUST(Locale::parse_unicode_locale_id(locale));
+        auto locale_id = Locale::parse_unicode_locale_id(locale);
         VERIFY(locale_id.has_value());
 
-        auto canonical_locale = MUST(Locale::canonicalize_unicode_locale_id(*locale_id));
+        auto canonical_locale = Locale::canonicalize_unicode_locale_id(*locale_id);
         EXPECT_EQ(*canonical_locale, expected_canonical_locale);
     };
 

Userland/Libraries/LibJS/Runtime/Intl/AbstractOperations.cpp

@@ -22,7 +22,7 @@ namespace JS::Intl {
 // 6.2.2 IsStructurallyValidLanguageTag ( locale ), https://tc39.es/ecma402/#sec-isstructurallyvalidlanguagetag
 ThrowCompletionOr<Optional<::Locale::LocaleID>> is_structurally_valid_language_tag(VM& vm, StringView locale)
 {
-    auto contains_duplicate_variant = [&](auto& variants) -> ThrowCompletionOr<bool> {
+    auto contains_duplicate_variant = [&](auto& variants) {
         if (variants.is_empty())
             return false;
 
@@ -39,7 +39,7 @@ ThrowCompletionOr<Optional<::Locale::LocaleID>> is_structurally_valid_language_t
     // IsStructurallyValidLanguageTag returns true if all of the following conditions hold, false otherwise:
 
     // locale can be generated from the EBNF grammar for unicode_locale_id in Unicode Technical Standard #35 LDML § 3.2 Unicode Locale Identifier;
-    auto locale_id = TRY_OR_THROW_OOM(vm, ::Locale::parse_unicode_locale_id(locale));
+    auto locale_id = ::Locale::parse_unicode_locale_id(locale);
     if (!locale_id.has_value())
         return OptionalNone {};
 
@@ -49,7 +49,7 @@ ThrowCompletionOr<Optional<::Locale::LocaleID>> is_structurally_valid_language_t
         return OptionalNone {};
 
     // the unicode_language_id within locale contains no duplicate unicode_variant_subtag subtags; and
-    if (TRY(contains_duplicate_variant(locale_id->language_id.variants)))
+    if (contains_duplicate_variant(locale_id->language_id.variants))
         return OptionalNone {};
 
     // if locale contains an extensions* component, that component
@@ -72,7 +72,7 @@ ThrowCompletionOr<Optional<::Locale::LocaleID>> is_structurally_valid_language_t
         // the tlang component contains no duplicate unicode_variant_subtag subtags.
         if (auto* transformed = extension.get_pointer<::Locale::TransformedExtension>()) {
             auto& language = transformed->language;
-            if (language.has_value() && TRY(contains_duplicate_variant(language->variants)))
+            if (language.has_value() && contains_duplicate_variant(language->variants))
                 return Optional<::Locale::LocaleID> {};
         }
     }
@@ -115,7 +115,7 @@ ThrowCompletionOr<String> canonicalize_unicode_locale_id(VM& vm, ::Locale::Local
 
     // 1. Let localeId be the string locale after performing the algorithm to transform it to canonical syntax per Unicode Technical Standard #35 LDML § 3.2.1 Canonical Unicode Locale Identifiers.
     // 2. Let localeId be the string localeId after performing the algorithm to transform it to canonical form.
-    auto locale_id = TRY_OR_THROW_OOM(vm, ::Locale::canonicalize_unicode_locale_id(locale));
+    auto locale_id = ::Locale::canonicalize_unicode_locale_id(locale);
     VERIFY(locale_id.has_value());
 
     // 4. Return localeId.
@@ -302,12 +302,12 @@ static ThrowCompletionOr<MatcherResult> lookup_matcher(VM& vm, Vector<String> co
 
     // 2. For each element locale of requestedLocales, do
     for (auto const& locale : requested_locales) {
-        auto locale_id = TRY_OR_THROW_OOM(vm, ::Locale::parse_unicode_locale_id(locale));
+        auto locale_id = ::Locale::parse_unicode_locale_id(locale);
         VERIFY(locale_id.has_value());
 
         // a. Let noExtensionsLocale be the String value that is locale with any Unicode locale extension sequences removed.
         auto extensions = locale_id->remove_extension_type<::Locale::LocaleExtension>();
-        auto no_extensions_locale = TRY_OR_THROW_OOM(vm, locale_id->to_string());
+        auto no_extensions_locale = locale_id->to_string();
 
         // b. Let availableLocale be ! BestAvailableLocale(availableLocales, noExtensionsLocale).
         auto available_locale = best_available_locale(no_extensions_locale);
@@ -433,7 +433,7 @@ ThrowCompletionOr<LocaleResult> resolve_locale(VM& vm, Vector<String> const& req
         // NOTE: ECMA-402 assumes keyLocaleData is sorted by locale preference. Our list is sorted
         //       alphabetically, so we get the locale's preferred value from LibUnicode.
         Optional<String> value;
-        if (auto preference = TRY_OR_THROW_OOM(vm, ::Locale::get_preferred_keyword_value_for_locale(found_locale, key)); preference.has_value())
+        if (auto preference = ::Locale::get_preferred_keyword_value_for_locale(found_locale, key); preference.has_value())
             value = TRY_OR_THROW_OOM(vm, String::from_utf8(*preference));
 
         // g. Let supportedExtensionAddition be "".
@@ -481,7 +481,7 @@ ThrowCompletionOr<LocaleResult> resolve_locale(VM& vm, Vector<String> const& req
         if (options_value.has_value()) {
             // 1. Let optionsValue be the string optionsValue after performing the algorithm steps to transform Unicode extension values to canonical syntax per Unicode Technical Standard #35 LDML § 3.2.1 Canonical Unicode Locale Identifiers, treating key as ukey and optionsValue as uvalue productions.
             // 2. Let optionsValue be the string optionsValue after performing the algorithm steps to replace Unicode extension values with their canonical form per Unicode Technical Standard #35 LDML § 3.2.1 Canonical Unicode Locale Identifiers, treating key as ukey and optionsValue as uvalue productions.
-            TRY_OR_THROW_OOM(vm, ::Locale::canonicalize_unicode_extension_values(key, *options_value, true));
+            ::Locale::canonicalize_unicode_extension_values(key, *options_value, true);
 
             // 3. If optionsValue is the empty String, then
             if (options_value->is_empty()) {
@@ -509,7 +509,7 @@ ThrowCompletionOr<LocaleResult> resolve_locale(VM& vm, Vector<String> const& req
 
     // 10. If supportedExtension is not "-u", then
     if (!supported_extension.keywords.is_empty()) {
-        auto locale_id = TRY_OR_THROW_OOM(vm, ::Locale::parse_unicode_locale_id(found_locale));
+        auto locale_id = ::Locale::parse_unicode_locale_id(found_locale);
         VERIFY(locale_id.has_value());
 
         // a. Set foundLocale to InsertUnicodeExtensionAndCanonicalize(foundLocale, supportedExtension).
@@ -531,12 +531,12 @@ static ThrowCompletionOr<Vector<String>> lookup_supported_locales(VM& vm, Vector
 
     // 2. For each element locale of requestedLocales, do
     for (auto const& locale : requested_locales) {
-        auto locale_id = TRY_OR_THROW_OOM(vm, ::Locale::parse_unicode_locale_id(locale));
+        auto locale_id = ::Locale::parse_unicode_locale_id(locale);
         VERIFY(locale_id.has_value());
 
         // a. Let noExtensionsLocale be the String value that is locale with any Unicode locale extension sequences removed.
         locale_id->remove_extension_type<::Locale::LocaleExtension>();
-        auto no_extensions_locale = TRY_OR_THROW_OOM(vm, locale_id->to_string());
+        auto no_extensions_locale = locale_id->to_string();
 
         // b. Let availableLocale be ! BestAvailableLocale(availableLocales, noExtensionsLocale).
         auto available_locale = best_available_locale(no_extensions_locale);

Userland/Libraries/LibJS/Runtime/Intl/DateTimeFormat.cpp

@@ -719,7 +719,7 @@ ThrowCompletionOr<Vector<PatternPartition>> format_date_time_pattern(VM& vm, Dat
         // Non-standard, TR-35 requires the decimal separator before injected {fractionalSecondDigits} partitions
         // to adhere to the selected locale. This depends on other generated data, so it is deferred to here.
         else if (part == "decimal"sv) {
-            auto decimal_symbol = TRY_OR_THROW_OOM(vm, ::Locale::get_number_system_symbol(data_locale, date_time_format.numbering_system(), ::Locale::NumericSymbol::Decimal)).value_or("."sv);
+            auto decimal_symbol = ::Locale::get_number_system_symbol(data_locale, date_time_format.numbering_system(), ::Locale::NumericSymbol::Decimal).value_or("."sv);
             TRY_OR_THROW_OOM(vm, result.try_append({ "literal"sv, TRY_OR_THROW_OOM(vm, String::from_utf8(decimal_symbol)) }));
         }
 

Userland/Libraries/LibJS/Runtime/Intl/DisplayNames.cpp

@@ -106,7 +106,7 @@ ThrowCompletionOr<Value> canonical_code_for_display_names(VM& vm, DisplayNames::
     // 1. If type is "language", then
     if (type == DisplayNames::Type::Language) {
         // a. If code does not match the unicode_language_id production, throw a RangeError exception.
-        if (!TRY_OR_THROW_OOM(vm, ::Locale::parse_unicode_language_id(code)).has_value())
+        if (!::Locale::parse_unicode_language_id(code).has_value())
             return vm.throw_completion<RangeError>(ErrorType::OptionIsNotValidValue, code, "language"sv);
 
         // b. If IsStructurallyValidLanguageTag(code) is false, throw a RangeError exception.

Userland/Libraries/LibJS/Runtime/Intl/DisplayNamesPrototype.cpp

@@ -63,7 +63,7 @@ JS_DEFINE_NATIVE_FUNCTION(DisplayNamesPrototype::of)
         }
 
         if (auto locale = MUST_OR_THROW_OOM(is_structurally_valid_language_tag(vm, code_string)); locale.has_value())
-            formatted_result = TRY_OR_THROW_OOM(vm, ::Locale::format_locale_for_display(display_names->locale(), locale.release_value()));
+            formatted_result = ::Locale::format_locale_for_display(display_names->locale(), locale.release_value());
         break;
     case DisplayNames::Type::Region:
         result = ::Locale::get_locale_territory_mapping(display_names->locale(), code_string);

Userland/Libraries/LibJS/Runtime/Intl/DurationFormat.cpp

@@ -482,7 +482,7 @@ ThrowCompletionOr<Vector<PatternPartition>> partition_duration_format_pattern(VM
                     // c. If nextValue is not 0 or nextDisplay is not "auto", then
                     if (next_value != 0.0 || next_display != DurationFormat::Display::Auto) {
                         // i. Let separator be dataLocaleData.[[formats]].[[digital]].[[separator]].
-                        auto separator = TRY_OR_THROW_OOM(vm, ::Locale::get_number_system_symbol(data_locale, duration_format.numbering_system(), ::Locale::NumericSymbol::TimeSeparator)).value_or(":"sv);
+                        auto separator = ::Locale::get_number_system_symbol(data_locale, duration_format.numbering_system(), ::Locale::NumericSymbol::TimeSeparator).value_or(":"sv);
 
                         // ii. Append the new Record { [[Type]]: "literal", [[Value]]: separator} to the end of result.
                         TRY_OR_THROW_OOM(vm, result.try_append({ "literal"sv, TRY_OR_THROW_OOM(vm, String::from_utf8(separator)) }));

Userland/Libraries/LibJS/Runtime/Intl/Locale.cpp

@@ -14,10 +14,10 @@
 
 namespace JS::Intl {
 
-ThrowCompletionOr<NonnullGCPtr<Locale>> Locale::create(Realm& realm, ::Locale::LocaleID locale_id)
+NonnullGCPtr<Locale> Locale::create(Realm& realm, ::Locale::LocaleID locale_id)
 {
     auto locale = realm.heap().allocate<Locale>(realm, realm.intrinsics().intl_locale_prototype());
-    locale->set_locale(TRY_OR_THROW_OOM(realm.vm(), locale_id.to_string()));
+    locale->set_locale(locale_id.to_string());
 
     for (auto& extension : locale_id.extensions) {
         if (!extension.has<::Locale::LocaleExtension>())
@@ -51,7 +51,7 @@ Locale::Locale(Object& prototype)
 }
 
 // 1.1.1 CreateArrayFromListOrRestricted ( list , restricted )
-static ThrowCompletionOr<NonnullGCPtr<Array>> create_array_from_list_or_restricted(VM& vm, Vector<StringView> list, Optional<String> restricted)
+static NonnullGCPtr<Array> create_array_from_list_or_restricted(VM& vm, Vector<StringView> list, Optional<String> restricted)
 {
     auto& realm = *vm.current_realm();
 
@@ -63,12 +63,12 @@ static ThrowCompletionOr<NonnullGCPtr<Array>> create_array_from_list_or_restrict
 
     // 2. Return ! CreateArrayFromList( list ).
     return Array::create_from<StringView>(realm, list, [&vm](auto value) {
-        return PrimitiveString::create(vm, String::from_utf8(value).release_value());
+        return PrimitiveString::create(vm, MUST(String::from_utf8(value)));
     });
 }
 
 // 1.1.2 CalendarsOfLocale ( loc ), https://tc39.es/proposal-intl-locale-info/#sec-calendars-of-locale
-ThrowCompletionOr<NonnullGCPtr<Array>> calendars_of_locale(VM& vm, Locale const& locale_object)
+NonnullGCPtr<Array> calendars_of_locale(VM& vm, Locale const& locale_object)
 {
     // 1. Let restricted be loc.[[Calendar]].
     Optional<String> restricted = locale_object.has_calendar() ? locale_object.calendar() : Optional<String> {};
@@ -77,17 +77,17 @@ ThrowCompletionOr<NonnullGCPtr<Array>> calendars_of_locale(VM& vm, Locale const&
     auto const& locale = locale_object.locale();
 
     // 3. Assert: locale matches the unicode_locale_id production.
-    VERIFY(TRY_OR_THROW_OOM(vm, ::Locale::parse_unicode_locale_id(locale)).has_value());
+    VERIFY(::Locale::parse_unicode_locale_id(locale).has_value());
 
     // 4. Let list be a List of 1 or more unique canonical calendar identifiers, which must be lower case String values conforming to the type sequence from UTS 35 Unicode Locale Identifier, section 3.2, sorted in descending preference of those in common use for date and time formatting in locale.
-    auto list = TRY_OR_THROW_OOM(vm, ::Locale::get_keywords_for_locale(locale, "ca"sv));
+    auto list = ::Locale::get_keywords_for_locale(locale, "ca"sv);
 
     // 5. Return ! CreateArrayFromListOrRestricted( list, restricted ).
     return create_array_from_list_or_restricted(vm, move(list), move(restricted));
 }
 
 // 1.1.3 CollationsOfLocale ( loc ), https://tc39.es/proposal-intl-locale-info/#sec-collations-of-locale
-ThrowCompletionOr<NonnullGCPtr<Array>> collations_of_locale(VM& vm, Locale const& locale_object)
+NonnullGCPtr<Array> collations_of_locale(VM& vm, Locale const& locale_object)
 {
     // 1. Let restricted be loc.[[Collation]].
     Optional<String> restricted = locale_object.has_collation() ? locale_object.collation() : Optional<String> {};
@@ -96,17 +96,17 @@ ThrowCompletionOr<NonnullGCPtr<Array>> collations_of_locale(VM& vm, Locale const
     auto const& locale = locale_object.locale();
 
     // 3. Assert: locale matches the unicode_locale_id production.
-    VERIFY(TRY_OR_THROW_OOM(vm, ::Locale::parse_unicode_locale_id(locale)).has_value());
+    VERIFY(::Locale::parse_unicode_locale_id(locale).has_value());
 
     // 4. Let list be a List of 1 or more unique canonical collation identifiers, which must be lower case String values conforming to the type sequence from UTS 35 Unicode Locale Identifier, section 3.2, ordered as if an Array of the same values had been sorted, using %Array.prototype.sort% using undefined as comparefn, of those in common use for string comparison in locale. The values "standard" and "search" must be excluded from list.
-    auto list = TRY_OR_THROW_OOM(vm, ::Locale::get_keywords_for_locale(locale, "co"sv));
+    auto list = ::Locale::get_keywords_for_locale(locale, "co"sv);
 
     // 5. Return ! CreateArrayFromListOrRestricted( list, restricted ).
     return create_array_from_list_or_restricted(vm, move(list), move(restricted));
 }
 
 // 1.1.4 HourCyclesOfLocale ( loc ), https://tc39.es/proposal-intl-locale-info/#sec-hour-cycles-of-locale
-ThrowCompletionOr<NonnullGCPtr<Array>> hour_cycles_of_locale(VM& vm, Locale const& locale_object)
+NonnullGCPtr<Array> hour_cycles_of_locale(VM& vm, Locale const& locale_object)
 {
     // 1. Let restricted be loc.[[HourCycle]].
     Optional<String> restricted = locale_object.has_hour_cycle() ? locale_object.hour_cycle() : Optional<String> {};
@@ -115,17 +115,17 @@ ThrowCompletionOr<NonnullGCPtr<Array>> hour_cycles_of_locale(VM& vm, Locale cons
     auto const& locale = locale_object.locale();
 
     // 3. Assert: locale matches the unicode_locale_id production.
-    VERIFY(TRY_OR_THROW_OOM(vm, ::Locale::parse_unicode_locale_id(locale)).has_value());
+    VERIFY(::Locale::parse_unicode_locale_id(locale).has_value());
 
     // 4. Let list be a List of 1 or more unique hour cycle identifiers, which must be lower case String values indicating either the 12-hour format ("h11", "h12") or the 24-hour format ("h23", "h24"), sorted in descending preference of those in common use for date and time formatting in locale.
-    auto list = TRY_OR_THROW_OOM(vm, ::Locale::get_keywords_for_locale(locale, "hc"sv));
+    auto list = ::Locale::get_keywords_for_locale(locale, "hc"sv);
 
     // 5. Return ! CreateArrayFromListOrRestricted( list, restricted ).
     return create_array_from_list_or_restricted(vm, move(list), move(restricted));
 }
 
 // 1.1.5 NumberingSystemsOfLocale ( loc ), https://tc39.es/proposal-intl-locale-info/#sec-numbering-systems-of-locale
-ThrowCompletionOr<NonnullGCPtr<Array>> numbering_systems_of_locale(VM& vm, Locale const& locale_object)
+NonnullGCPtr<Array> numbering_systems_of_locale(VM& vm, Locale const& locale_object)
 {
     // 1. Let restricted be loc.[[NumberingSystem]].
     Optional<String> restricted = locale_object.has_numbering_system() ? locale_object.numbering_system() : Optional<String> {};
@@ -134,10 +134,10 @@ ThrowCompletionOr<NonnullGCPtr<Array>> numbering_systems_of_locale(VM& vm, Local
     auto const& locale = locale_object.locale();
 
     // 3. Assert: locale matches the unicode_locale_id production.
-    VERIFY(TRY_OR_THROW_OOM(vm, ::Locale::parse_unicode_locale_id(locale)).has_value());
+    VERIFY(::Locale::parse_unicode_locale_id(locale).has_value());
 
     // 4. Let list be a List of 1 or more unique canonical numbering system identifiers, which must be lower case String values conforming to the type sequence from UTS 35 Unicode Locale Identifier, section 3.2, sorted in descending preference of those in common use for formatting numeric values in locale.
-    auto list = TRY_OR_THROW_OOM(vm, ::Locale::get_keywords_for_locale(locale, "nu"sv));
+    auto list = ::Locale::get_keywords_for_locale(locale, "nu"sv);
 
     // 5. Return ! CreateArrayFromListOrRestricted( list, restricted ).
     return create_array_from_list_or_restricted(vm, move(list), move(restricted));
@@ -145,7 +145,7 @@ ThrowCompletionOr<NonnullGCPtr<Array>> numbering_systems_of_locale(VM& vm, Local
 
 // 1.1.6 TimeZonesOfLocale ( loc ), https://tc39.es/proposal-intl-locale-info/#sec-time-zones-of-locale
 // NOTE: Our implementation takes a region rather than a Locale object to avoid needlessly parsing the locale twice.
-ThrowCompletionOr<NonnullGCPtr<Array>> time_zones_of_locale(VM& vm, StringView region)
+NonnullGCPtr<Array> time_zones_of_locale(VM& vm, StringView region)
 {
     auto& realm = *vm.current_realm();
 
@@ -164,13 +164,13 @@ ThrowCompletionOr<NonnullGCPtr<Array>> time_zones_of_locale(VM& vm, StringView r
 }
 
 // 1.1.7 CharacterDirectionOfLocale ( loc ), https://tc39.es/proposal-intl-locale-info/#sec-character-direction-of-locale
-ThrowCompletionOr<StringView> character_direction_of_locale(VM& vm, Locale const& locale_object)
+StringView character_direction_of_locale(Locale const& locale_object)
 {
     // 1. Let locale be loc.[[Locale]].
     auto const& locale = locale_object.locale();
 
     // 2. Assert: locale matches the unicode_locale_id production.
-    VERIFY(TRY_OR_THROW_OOM(vm, ::Locale::parse_unicode_locale_id(locale)).has_value());
+    VERIFY(::Locale::parse_unicode_locale_id(locale).has_value());
 
     // 3. If the default general ordering of characters (characterOrder) within a line in locale is right-to-left, return "rtl".
     // NOTE: LibUnicode handles both LTR and RTL character orders in this call, not just RTL. We then fallback to LTR
@@ -231,7 +231,7 @@ ThrowCompletionOr<WeekInfo> week_info_of_locale(VM& vm, Locale const& locale_obj
     auto const& locale = locale_object.locale();
 
     // 2. Assert: locale matches the unicode_locale_id production.
-    VERIFY(TRY_OR_THROW_OOM(vm, ::Locale::parse_unicode_locale_id(locale)).has_value());
+    VERIFY(::Locale::parse_unicode_locale_id(locale).has_value());
 
     // 3. Return a record whose fields are defined by Table 1, with values based on locale.
     WeekInfo week_info {};

Userland/Libraries/LibJS/Runtime/Intl/Locale.h

@@ -22,7 +22,7 @@ class Locale final : public Object {
     JS_OBJECT(Locale, Object);
 
 public:
-    static ThrowCompletionOr<NonnullGCPtr<Locale>> create(Realm&, ::Locale::LocaleID);
+    static NonnullGCPtr<Locale> create(Realm&, ::Locale::LocaleID);
 
     static constexpr auto relevant_extension_keys()
     {
@@ -82,12 +82,12 @@ struct WeekInfo {
     Vector<u8> weekend;    // [[Weekend]]
 };
 
-ThrowCompletionOr<NonnullGCPtr<Array>> calendars_of_locale(VM&, Locale const&);
-ThrowCompletionOr<NonnullGCPtr<Array>> collations_of_locale(VM&, Locale const& locale);
-ThrowCompletionOr<NonnullGCPtr<Array>> hour_cycles_of_locale(VM&, Locale const& locale);
-ThrowCompletionOr<NonnullGCPtr<Array>> numbering_systems_of_locale(VM&, Locale const&);
-ThrowCompletionOr<NonnullGCPtr<Array>> time_zones_of_locale(VM&, StringView region);
-ThrowCompletionOr<StringView> character_direction_of_locale(VM&, Locale const&);
+NonnullGCPtr<Array> calendars_of_locale(VM&, Locale const&);
+NonnullGCPtr<Array> collations_of_locale(VM&, Locale const& locale);
+NonnullGCPtr<Array> hour_cycles_of_locale(VM&, Locale const& locale);
+NonnullGCPtr<Array> numbering_systems_of_locale(VM&, Locale const&);
+NonnullGCPtr<Array> time_zones_of_locale(VM&, StringView region);
+StringView character_direction_of_locale(Locale const&);
 ThrowCompletionOr<WeekInfo> week_info_of_locale(VM&, Locale const&);
 
 }

Userland/Libraries/LibJS/Runtime/Intl/LocaleConstructor.cpp

@@ -69,7 +69,7 @@ static ThrowCompletionOr<String> apply_options_to_tag(VM& vm, StringView tag, Ob
     auto canonicalized_tag = MUST_OR_THROW_OOM(canonicalize_unicode_locale_id(vm, *locale_id));
 
     // 11. Assert: tag matches the unicode_locale_id production.
-    locale_id = TRY_OR_THROW_OOM(vm, ::Locale::parse_unicode_locale_id(canonicalized_tag));
+    locale_id = ::Locale::parse_unicode_locale_id(canonicalized_tag);
     VERIFY(locale_id.has_value());
 
     // 12. Let languageId be the substring of tag corresponding to the unicode_language_id production.
@@ -109,7 +109,7 @@ static ThrowCompletionOr<LocaleAndKeys> apply_unicode_extension_to_tag(VM& vm, S
 {
     // 1. Assert: Type(tag) is String.
     // 2. Assert: tag matches the unicode_locale_id production.
-    auto locale_id = TRY_OR_THROW_OOM(vm, ::Locale::parse_unicode_locale_id(tag));
+    auto locale_id = ::Locale::parse_unicode_locale_id(tag);
     VERIFY(locale_id.has_value());
 
     Vector<String> attributes;
@@ -198,7 +198,7 @@ static ThrowCompletionOr<LocaleAndKeys> apply_unicode_extension_to_tag(VM& vm, S
 
     // 7. Let locale be the String value that is tag with any Unicode locale extension sequences removed.
     locale_id->remove_extension_type<::Locale::LocaleExtension>();
-    auto locale = TRY_OR_THROW_OOM(vm, locale_id->to_string());
+    auto locale = locale_id->to_string();
 
     // 8. Let newExtension be a Unicode BCP 47 U Extension based on attributes and keywords.
     ::Locale::LocaleExtension new_extension { move(attributes), move(keywords) };

Userland/Libraries/LibJS/Runtime/Intl/LocalePrototype.cpp

@@ -61,15 +61,15 @@ JS_DEFINE_NATIVE_FUNCTION(LocalePrototype::maximize)
     // 2. Perform ? RequireInternalSlot(loc, [[InitializedLocale]]).
     auto locale_object = TRY(typed_this_object(vm));
 
-    auto locale = TRY_OR_THROW_OOM(vm, ::Locale::parse_unicode_locale_id(locale_object->locale()));
+    auto locale = ::Locale::parse_unicode_locale_id(locale_object->locale());
     VERIFY(locale.has_value());
 
     // 3. Let maximal be the result of the Add Likely Subtags algorithm applied to loc.[[Locale]]. If an error is signaled, set maximal to loc.[[Locale]].
-    if (auto maximal = TRY_OR_THROW_OOM(vm, ::Locale::add_likely_subtags(locale->language_id)); maximal.has_value())
+    if (auto maximal = ::Locale::add_likely_subtags(locale->language_id); maximal.has_value())
         locale->language_id = maximal.release_value();
 
     // 4. Return ! Construct(%Locale%, maximal).
-    return MUST_OR_THROW_OOM(Locale::create(realm, locale.release_value()));
+    return Locale::create(realm, locale.release_value());
 }
 
 // 14.3.4 Intl.Locale.prototype.minimize ( ), https://tc39.es/ecma402/#sec-Intl.Locale.prototype.minimize
@@ -81,15 +81,15 @@ JS_DEFINE_NATIVE_FUNCTION(LocalePrototype::minimize)
     // 2. Perform ? RequireInternalSlot(loc, [[InitializedLocale]]).
     auto locale_object = TRY(typed_this_object(vm));
 
-    auto locale = TRY_OR_THROW_OOM(vm, ::Locale::parse_unicode_locale_id(locale_object->locale()));
+    auto locale = ::Locale::parse_unicode_locale_id(locale_object->locale());
     VERIFY(locale.has_value());
 
     // 3. Let minimal be the result of the Remove Likely Subtags algorithm applied to loc.[[Locale]]. If an error is signaled, set minimal to loc.[[Locale]].
-    if (auto minimal = TRY_OR_THROW_OOM(vm, ::Locale::remove_likely_subtags(locale->language_id)); minimal.has_value())
+    if (auto minimal = ::Locale::remove_likely_subtags(locale->language_id); minimal.has_value())
         locale->language_id = minimal.release_value();
 
     // 4. Return ! Construct(%Locale%, minimal).
-    return MUST_OR_THROW_OOM(Locale::create(realm, locale.release_value()));
+    return Locale::create(realm, locale.release_value());
 }
 
 // 14.3.5 Intl.Locale.prototype.toString ( ), https://tc39.es/ecma402/#sec-Intl.Locale.prototype.toString
@@ -111,11 +111,11 @@ JS_DEFINE_NATIVE_FUNCTION(LocalePrototype::base_name)
     auto locale_object = TRY(typed_this_object(vm));
 
     // 3. Let locale be loc.[[Locale]].
-    auto locale = TRY_OR_THROW_OOM(vm, ::Locale::parse_unicode_locale_id(locale_object->locale()));
+    auto locale = ::Locale::parse_unicode_locale_id(locale_object->locale());
     VERIFY(locale.has_value());
 
     // 4. Return the substring of locale corresponding to the unicode_language_id production.
-    return PrimitiveString::create(vm, TRY_OR_THROW_OOM(vm, locale->language_id.to_string()));
+    return PrimitiveString::create(vm, locale->language_id.to_string());
 }
 
 #define JS_ENUMERATE_LOCALE_KEYWORD_PROPERTIES \
@@ -160,7 +160,7 @@ JS_DEFINE_NATIVE_FUNCTION(LocalePrototype::language)
     auto locale_object = TRY(typed_this_object(vm));
 
     // 3. Let locale be loc.[[Locale]].
-    auto locale = TRY_OR_THROW_OOM(vm, ::Locale::parse_unicode_locale_id(locale_object->locale()));
+    auto locale = ::Locale::parse_unicode_locale_id(locale_object->locale());
 
     // 4. Assert: locale matches the unicode_locale_id production.
     VERIFY(locale.has_value());
@@ -177,7 +177,7 @@ JS_DEFINE_NATIVE_FUNCTION(LocalePrototype::script)
     auto locale_object = TRY(typed_this_object(vm));
 
     // 3. Let locale be loc.[[Locale]].
-    auto locale = TRY_OR_THROW_OOM(vm, ::Locale::parse_unicode_locale_id(locale_object->locale()));
+    auto locale = ::Locale::parse_unicode_locale_id(locale_object->locale());
 
     // 4. Assert: locale matches the unicode_locale_id production.
     VERIFY(locale.has_value());
@@ -198,7 +198,7 @@ JS_DEFINE_NATIVE_FUNCTION(LocalePrototype::region)
     auto locale_object = TRY(typed_this_object(vm));
 
     // 3. Let locale be loc.[[Locale]].
-    auto locale = TRY_OR_THROW_OOM(vm, ::Locale::parse_unicode_locale_id(locale_object->locale()));
+    auto locale = ::Locale::parse_unicode_locale_id(locale_object->locale());
 
     // 4. Assert: locale matches the unicode_locale_id production.
     VERIFY(locale.has_value());
@@ -221,11 +221,11 @@ JS_DEFINE_NATIVE_FUNCTION(LocalePrototype::region)
 // 1.4.17 get Intl.Locale.prototype.collations, https://tc39.es/proposal-intl-locale-info/#sec-Intl.Locale.prototype.collations
 // 1.4.18 get Intl.Locale.prototype.hourCycles, https://tc39.es/proposal-intl-locale-info/#sec-Intl.Locale.prototype.hourCycles
 // 1.4.19 get Intl.Locale.prototype.numberingSystems, https://tc39.es/proposal-intl-locale-info/#sec-Intl.Locale.prototype.numberingSystems
-#define __JS_ENUMERATE(keyword)                                           \
-    JS_DEFINE_NATIVE_FUNCTION(LocalePrototype::keyword)                   \
-    {                                                                     \
-        auto locale_object = TRY(typed_this_object(vm));                  \
-        return MUST_OR_THROW_OOM(keyword##_of_locale(vm, locale_object)); \
+#define __JS_ENUMERATE(keyword)                          \
+    JS_DEFINE_NATIVE_FUNCTION(LocalePrototype::keyword)  \
+    {                                                    \
+        auto locale_object = TRY(typed_this_object(vm)); \
+        return keyword##_of_locale(vm, locale_object);   \
     }
 JS_ENUMERATE_LOCALE_INFO_PROPERTIES
 #undef __JS_ENUMERATE
@@ -238,14 +238,14 @@ JS_DEFINE_NATIVE_FUNCTION(LocalePrototype::time_zones)
     auto locale_object = TRY(typed_this_object(vm));
 
     // 3. Let locale be loc.[[Locale]].
-    auto locale = TRY_OR_THROW_OOM(vm, ::Locale::parse_unicode_locale_id(locale_object->locale()));
+    auto locale = ::Locale::parse_unicode_locale_id(locale_object->locale());
 
     // 4. If the unicode_language_id production of locale does not contain the ["-" unicode_region_subtag] sequence, return undefined.
     if (!locale.has_value() || !locale->language_id.region.has_value())
         return js_undefined();
 
     // 5. Return ! TimeZonesOfLocale(loc).
-    return MUST_OR_THROW_OOM(time_zones_of_locale(vm, locale->language_id.region.value()));
+    return time_zones_of_locale(vm, locale->language_id.region.value());
 }
 
 // 1.4.21 get Intl.Locale.prototype.textInfo, https://tc39.es/proposal-intl-locale-info/#sec-Intl.Locale.prototype.textInfo
@@ -261,7 +261,7 @@ JS_DEFINE_NATIVE_FUNCTION(LocalePrototype::text_info)
     auto info = Object::create(realm, realm.intrinsics().object_prototype());
 
     // 4. Let dir be ! CharacterDirectionOfLocale(loc).
-    auto direction = MUST_OR_THROW_OOM(character_direction_of_locale(vm, locale_object));
+    auto direction = character_direction_of_locale(locale_object);
 
     // 5. Perform ! CreateDataPropertyOrThrow(info, "direction", dir).
     MUST(info->create_data_property_or_throw(vm.names.direction, PrimitiveString::create(vm, direction)));

Userland/Libraries/LibJS/Runtime/Intl/NumberFormat.cpp

@@ -537,13 +537,13 @@ ThrowCompletionOr<Vector<PatternPartition>> partition_number_pattern(VM& vm, Num
     // 2. If x is not-a-number, then
     if (number.is_nan()) {
         // a. Let n be an implementation- and locale-dependent (ILD) String value indicating the NaN value.
-        auto symbol = TRY_OR_THROW_OOM(vm, ::Locale::get_number_system_symbol(number_format.data_locale(), number_format.numbering_system(), ::Locale::NumericSymbol::NaN)).value_or("NaN"sv);
+        auto symbol = ::Locale::get_number_system_symbol(number_format.data_locale(), number_format.numbering_system(), ::Locale::NumericSymbol::NaN).value_or("NaN"sv);
         formatted_string = TRY_OR_THROW_OOM(vm, String::from_utf8(symbol));
     }
     // 3. Else if x is positive-infinity, then
     else if (number.is_positive_infinity()) {
         // a. Let n be an ILD String value indicating positive infinity.
-        auto symbol = TRY_OR_THROW_OOM(vm, ::Locale::get_number_system_symbol(number_format.data_locale(), number_format.numbering_system(), ::Locale::NumericSymbol::Infinity)).value_or("infinity"sv);
+        auto symbol = ::Locale::get_number_system_symbol(number_format.data_locale(), number_format.numbering_system(), ::Locale::NumericSymbol::Infinity).value_or("infinity"sv);
         formatted_string = TRY_OR_THROW_OOM(vm, String::from_utf8(symbol));
     }
     // 4. Else if x is negative-infinity, then
@@ -551,7 +551,7 @@ ThrowCompletionOr<Vector<PatternPartition>> partition_number_pattern(VM& vm, Num
         // a. Let n be an ILD String value indicating negative infinity.
         // NOTE: The CLDR does not contain unique strings for negative infinity. The negative sign will
         //       be inserted by the pattern returned from GetNumberFormatPattern.
-        auto symbol = TRY_OR_THROW_OOM(vm, ::Locale::get_number_system_symbol(number_format.data_locale(), number_format.numbering_system(), ::Locale::NumericSymbol::Infinity)).value_or("infinity"sv);
+        auto symbol = ::Locale::get_number_system_symbol(number_format.data_locale(), number_format.numbering_system(), ::Locale::NumericSymbol::Infinity).value_or("infinity"sv);
         formatted_string = TRY_OR_THROW_OOM(vm, String::from_utf8(symbol));
     }
     // 5. Else,
@@ -617,7 +617,7 @@ ThrowCompletionOr<Vector<PatternPartition>> partition_number_pattern(VM& vm, Num
         // d. Else if p is equal to "plusSign", then
         else if (part == "plusSign"sv) {
             // i. Let plusSignSymbol be the ILND String representing the plus sign.
-            auto plus_sign_symbol = TRY_OR_THROW_OOM(vm, ::Locale::get_number_system_symbol(number_format.data_locale(), number_format.numbering_system(), ::Locale::NumericSymbol::PlusSign)).value_or("+"sv);
+            auto plus_sign_symbol = ::Locale::get_number_system_symbol(number_format.data_locale(), number_format.numbering_system(), ::Locale::NumericSymbol::PlusSign).value_or("+"sv);
             // ii. Append a new Record { [[Type]]: "plusSign", [[Value]]: plusSignSymbol } as the last element of result.
             TRY_OR_THROW_OOM(vm, result.try_append({ "plusSign"sv, TRY_OR_THROW_OOM(vm, String::from_utf8(plus_sign_symbol)) }));
         }
@@ -625,7 +625,7 @@ ThrowCompletionOr<Vector<PatternPartition>> partition_number_pattern(VM& vm, Num
         // e. Else if p is equal to "minusSign", then
         else if (part == "minusSign"sv) {
             // i. Let minusSignSymbol be the ILND String representing the minus sign.
-            auto minus_sign_symbol = TRY_OR_THROW_OOM(vm, ::Locale::get_number_system_symbol(number_format.data_locale(), number_format.numbering_system(), ::Locale::NumericSymbol::MinusSign)).value_or("-"sv);
+            auto minus_sign_symbol = ::Locale::get_number_system_symbol(number_format.data_locale(), number_format.numbering_system(), ::Locale::NumericSymbol::MinusSign).value_or("-"sv);
             // ii. Append a new Record { [[Type]]: "minusSign", [[Value]]: minusSignSymbol } as the last element of result.
             TRY_OR_THROW_OOM(vm, result.try_append({ "minusSign"sv, TRY_OR_THROW_OOM(vm, String::from_utf8(minus_sign_symbol)) }));
         }
@@ -633,7 +633,7 @@ ThrowCompletionOr<Vector<PatternPartition>> partition_number_pattern(VM& vm, Num
         // f. Else if p is equal to "percentSign" and numberFormat.[[Style]] is "percent", then
         else if ((part == "percentSign"sv) && (number_format.style() == NumberFormat::Style::Percent)) {
             // i. Let percentSignSymbol be the ILND String representing the percent sign.
-            auto percent_sign_symbol = TRY_OR_THROW_OOM(vm, ::Locale::get_number_system_symbol(number_format.data_locale(), number_format.numbering_system(), ::Locale::NumericSymbol::PercentSign)).value_or("%"sv);
+            auto percent_sign_symbol = ::Locale::get_number_system_symbol(number_format.data_locale(), number_format.numbering_system(), ::Locale::NumericSymbol::PercentSign).value_or("%"sv);
             // ii. Append a new Record { [[Type]]: "percentSign", [[Value]]: percentSignSymbol } as the last element of result.
             TRY_OR_THROW_OOM(vm, result.try_append({ "percentSign"sv, TRY_OR_THROW_OOM(vm, String::from_utf8(percent_sign_symbol)) }));
         }
@@ -744,7 +744,7 @@ ThrowCompletionOr<Vector<PatternPartition>> partition_notation_sub_pattern(VM& v
     // 1. Let result be a new empty List.
     Vector<PatternPartition> result;
 
-    auto grouping_sizes = TRY_OR_THROW_OOM(vm, ::Locale::get_number_system_groupings(number_format.data_locale(), number_format.numbering_system()));
+    auto grouping_sizes = ::Locale::get_number_system_groupings(number_format.data_locale(), number_format.numbering_system());
     if (!grouping_sizes.has_value())
         return Vector<PatternPartition> {};
 
@@ -827,7 +827,7 @@ ThrowCompletionOr<Vector<PatternPartition>> partition_notation_sub_pattern(VM& v
                 // 7. Else,
                 else {
                     // a. Let groupSepSymbol be the implementation-, locale-, and numbering system-dependent (ILND) String representing the grouping separator.
-                    auto group_sep_symbol = TRY_OR_THROW_OOM(vm, ::Locale::get_number_system_symbol(number_format.data_locale(), number_format.numbering_system(), ::Locale::NumericSymbol::Group)).value_or(","sv);
+                    auto group_sep_symbol = ::Locale::get_number_system_symbol(number_format.data_locale(), number_format.numbering_system(), ::Locale::NumericSymbol::Group).value_or(","sv);
 
                     // b. Let groups be a List whose elements are, in left to right order, the substrings defined by ILND set of locations within the integer, which may depend on the value of numberFormat.[[UseGrouping]].
                     auto groups = MUST_OR_THROW_OOM(separate_integer_into_groups(vm, *grouping_sizes, move(integer), number_format.use_grouping()));
@@ -854,7 +854,7 @@ ThrowCompletionOr<Vector<PatternPartition>> partition_notation_sub_pattern(VM& v
                 // 8. If fraction is not undefined, then
                 if (fraction.has_value()) {
                     // a. Let decimalSepSymbol be the ILND String representing the decimal separator.
-                    auto decimal_sep_symbol = TRY_OR_THROW_OOM(vm, ::Locale::get_number_system_symbol(number_format.data_locale(), number_format.numbering_system(), ::Locale::NumericSymbol::Decimal)).value_or("."sv);
+                    auto decimal_sep_symbol = ::Locale::get_number_system_symbol(number_format.data_locale(), number_format.numbering_system(), ::Locale::NumericSymbol::Decimal).value_or("."sv);
                     // b. Append a new Record { [[Type]]: "decimal", [[Value]]: decimalSepSymbol } as the last element of result.
                     TRY_OR_THROW_OOM(vm, result.try_append({ "decimal"sv, TRY_OR_THROW_OOM(vm, String::from_utf8(decimal_sep_symbol)) }));
                     // c. Append a new Record { [[Type]]: "fraction", [[Value]]: fraction } as the last element of result.
@@ -878,7 +878,7 @@ ThrowCompletionOr<Vector<PatternPartition>> partition_notation_sub_pattern(VM& v
             // vi. Else if p is equal to "scientificSeparator", then
             else if (part == "scientificSeparator"sv) {
                 // 1. Let scientificSeparator be the ILND String representing the exponent separator.
-                auto scientific_separator = TRY_OR_THROW_OOM(vm, ::Locale::get_number_system_symbol(number_format.data_locale(), number_format.numbering_system(), ::Locale::NumericSymbol::Exponential)).value_or("E"sv);
+                auto scientific_separator = ::Locale::get_number_system_symbol(number_format.data_locale(), number_format.numbering_system(), ::Locale::NumericSymbol::Exponential).value_or("E"sv);
                 // 2. Append a new Record { [[Type]]: "exponentSeparator", [[Value]]: scientificSeparator } as the last element of result.
                 TRY_OR_THROW_OOM(vm, result.try_append({ "exponentSeparator"sv, TRY_OR_THROW_OOM(vm, String::from_utf8(scientific_separator)) }));
             }
@@ -887,7 +887,7 @@ ThrowCompletionOr<Vector<PatternPartition>> partition_notation_sub_pattern(VM& v
                 // 1. If exponent < 0, then
                 if (exponent < 0) {
                     // a. Let minusSignSymbol be the ILND String representing the minus sign.
-                    auto minus_sign_symbol = TRY_OR_THROW_OOM(vm, ::Locale::get_number_system_symbol(number_format.data_locale(), number_format.numbering_system(), ::Locale::NumericSymbol::MinusSign)).value_or("-"sv);
+                    auto minus_sign_symbol = ::Locale::get_number_system_symbol(number_format.data_locale(), number_format.numbering_system(), ::Locale::NumericSymbol::MinusSign).value_or("-"sv);
 
                     // b. Append a new Record { [[Type]]: "exponentMinusSign", [[Value]]: minusSignSymbol } as the last element of result.
                     TRY_OR_THROW_OOM(vm, result.try_append({ "exponentMinusSign"sv, TRY_OR_THROW_OOM(vm, String::from_utf8(minus_sign_symbol)) }));
@@ -1854,7 +1854,7 @@ ThrowCompletionOr<Vector<PatternPartitionWithSource>> partition_number_range_pat
     }
 
     // 7. Let rangeSeparator be an ILND String value used to separate two numbers.
-    auto range_separator_symbol = TRY_OR_THROW_OOM(vm, ::Locale::get_number_system_symbol(number_format.data_locale(), number_format.numbering_system(), ::Locale::NumericSymbol::RangeSeparator)).value_or("-"sv);
+    auto range_separator_symbol = ::Locale::get_number_system_symbol(number_format.data_locale(), number_format.numbering_system(), ::Locale::NumericSymbol::RangeSeparator).value_or("-"sv);
     auto range_separator = TRY_OR_THROW_OOM(vm, ::Locale::augment_range_pattern(range_separator_symbol, result.last().value, end_result[0].value));
 
     // 8. Append a new Record { [[Type]]: "literal", [[Value]]: rangeSeparator, [[Source]]: "shared" } element to result.
@@ -1887,7 +1887,7 @@ ThrowCompletionOr<Vector<PatternPartitionWithSource>> partition_number_range_pat
 ThrowCompletionOr<Vector<PatternPartitionWithSource>> format_approximately(VM& vm, NumberFormat& number_format, Vector<PatternPartitionWithSource> result)
 {
     // 1. Let approximatelySign be an ILND String value used to signify that a number is approximate.
-    auto approximately_sign = TRY_OR_THROW_OOM(vm, ::Locale::get_number_system_symbol(number_format.data_locale(), number_format.numbering_system(), ::Locale::NumericSymbol::ApproximatelySign));
+    auto approximately_sign = ::Locale::get_number_system_symbol(number_format.data_locale(), number_format.numbering_system(), ::Locale::NumericSymbol::ApproximatelySign);
 
     // 2. If approximatelySign is not empty, insert a new Record { [[Type]]: "approximatelySign", [[Value]]: approximatelySign } at an ILND index in result. For example, if numberFormat has [[Locale]] "en-US" and [[NumberingSystem]] "latn" and [[Style]] "decimal", the new Record might be inserted before the first element of result.
     if (approximately_sign.has_value() && !approximately_sign->is_empty()) {

Userland/Libraries/LibJS/Runtime/StringPrototype.cpp

@@ -1262,18 +1262,18 @@ static ThrowCompletionOr<String> transform_case(VM& vm, String const& string, Va
     // 2. If requestedLocales is not an empty List, then
     if (!requested_locales.is_empty()) {
         // a. Let requestedLocale be requestedLocales[0].
-        requested_locale = TRY_OR_THROW_OOM(vm, Locale::parse_unicode_locale_id(requested_locales[0]));
+        requested_locale = Locale::parse_unicode_locale_id(requested_locales[0]);
     }
     // 3. Else,
     else {
         // a. Let requestedLocale be ! DefaultLocale().
-        requested_locale = TRY_OR_THROW_OOM(vm, Locale::parse_unicode_locale_id(Locale::default_locale()));
+        requested_locale = Locale::parse_unicode_locale_id(Locale::default_locale());
     }
     VERIFY(requested_locale.has_value());
 
     // 4. Let noExtensionsLocale be the String value that is requestedLocale with any Unicode locale extension sequences (6.2.1) removed.
     requested_locale->remove_extension_type<Locale::LocaleExtension>();
-    auto no_extensions_locale = TRY_OR_THROW_OOM(vm, requested_locale->to_string());
+    auto no_extensions_locale = requested_locale->to_string();
 
     // 5. Let availableLocales be a List with language tags that includes the languages for which the Unicode Character Database contains language sensitive case mappings. Implementations may add additional language tags if they support case mapping for additional locales.
     // 6. Let locale be ! BestAvailableLocale(availableLocales, noExtensionsLocale).

Userland/Libraries/LibLocale/DateTimeFormat.cpp

@@ -109,12 +109,12 @@ static ErrorOr<T> find_regional_values_for_locale(StringView locale, GetRegional
 
     auto return_default_values = [&]() { return get_regional_values("001"sv); };
 
-    auto language = TRY(parse_unicode_language_id(locale));
+    auto language = parse_unicode_language_id(locale);
     if (!language.has_value())
         return return_default_values();
 
     if (!language->region.has_value())
-        language = TRY(add_likely_subtags(*language));
+        language = add_likely_subtags(*language);
     if (!language.has_value() || !language->region.has_value())
         return return_default_values();
 
@@ -253,7 +253,7 @@ static ErrorOr<Optional<String>> format_time_zone_offset(StringView locale, Cale
     if (!formats.has_value())
         return OptionalNone {};
 
-    auto number_system = TRY(get_preferred_keyword_value_for_locale(locale, "nu"sv));
+    auto number_system = get_preferred_keyword_value_for_locale(locale, "nu"sv);
     if (!number_system.has_value())
         return OptionalNone {};
 

Userland/Libraries/LibLocale/Locale.cpp

@@ -91,7 +91,7 @@ bool is_type_identifier(StringView identifier)
     return lexer.is_eof() && (lexer.tell() > 0);
 }
 
-static ErrorOr<Optional<LanguageID>> parse_unicode_language_id(GenericLexer& lexer)
+static Optional<LanguageID> parse_unicode_language_id(GenericLexer& lexer)
 {
     // https://unicode.org/reports/tr35/#Unicode_language_identifier
     //
@@ -120,25 +120,25 @@ static ErrorOr<Optional<LanguageID>> parse_unicode_language_id(GenericLexer& lex
     while (!lexer.is_eof() && (state != ParseState::Done)) {
         auto segment = consume_next_segment(lexer, state != ParseState::ParsingLanguageOrScript);
         if (!segment.has_value())
-            return OptionalNone {};
+            return {};
 
         switch (state) {
         case ParseState::ParsingLanguageOrScript:
             if (is_unicode_language_subtag(*segment)) {
                 state = ParseState::ParsingScript;
-                language_id.language = TRY(String::from_utf8(*segment));
+                language_id.language = MUST(String::from_utf8(*segment));
             } else if (is_unicode_script_subtag(*segment)) {
                 state = ParseState::ParsingRegion;
-                language_id.script = TRY(String::from_utf8(*segment));
+                language_id.script = MUST(String::from_utf8(*segment));
             } else {
-                return OptionalNone {};
+                return {};
             }
             break;
 
         case ParseState::ParsingScript:
             if (is_unicode_script_subtag(*segment)) {
                 state = ParseState::ParsingRegion;
-                language_id.script = TRY(String::from_utf8(*segment));
+                language_id.script = MUST(String::from_utf8(*segment));
                 break;
             }
 
@@ -148,7 +148,7 @@ static ErrorOr<Optional<LanguageID>> parse_unicode_language_id(GenericLexer& lex
         case ParseState::ParsingRegion:
             if (is_unicode_region_subtag(*segment)) {
                 state = ParseState::ParsingVariant;
-                language_id.region = TRY(String::from_utf8(*segment));
+                language_id.region = MUST(String::from_utf8(*segment));
                 break;
             }
 
@@ -157,7 +157,7 @@ static ErrorOr<Optional<LanguageID>> parse_unicode_language_id(GenericLexer& lex
 
         case ParseState::ParsingVariant:
             if (is_unicode_variant_subtag(*segment)) {
-                TRY(language_id.variants.try_append(TRY(String::from_utf8(*segment))));
+                language_id.variants.append(MUST(String::from_utf8(*segment)));
             } else {
                 lexer.retreat(segment->length() + 1);
                 state = ParseState::Done;
@@ -172,7 +172,7 @@ static ErrorOr<Optional<LanguageID>> parse_unicode_language_id(GenericLexer& lex
     return language_id;
 }
 
-static ErrorOr<Optional<LocaleExtension>> parse_unicode_locale_extension(GenericLexer& lexer)
+static Optional<LocaleExtension> parse_unicode_locale_extension(GenericLexer& lexer)
 {
     // https://unicode.org/reports/tr35/#unicode_locale_extensions
     //
@@ -191,7 +191,7 @@ static ErrorOr<Optional<LocaleExtension>> parse_unicode_locale_extension(Generic
     while (!lexer.is_eof() && (state != ParseState::Done)) {
         auto segment = consume_next_segment(lexer);
         if (!segment.has_value())
-            return OptionalNone {};
+            return {};
 
         if (state == ParseState::ParsingAttributeOrKeyword)
             state = is_key(*segment) ? ParseState::ParsingKeyword : ParseState::ParsingAttribute;
@@ -199,7 +199,7 @@ static ErrorOr<Optional<LocaleExtension>> parse_unicode_locale_extension(Generic
         switch (state) {
         case ParseState::ParsingAttribute:
             if (is_attribute(*segment)) {
-                TRY(locale_extension.attributes.try_append(TRY(String::from_utf8(*segment))));
+                locale_extension.attributes.append(MUST(String::from_utf8(*segment)));
                 break;
             }
 
@@ -208,7 +208,7 @@ static ErrorOr<Optional<LocaleExtension>> parse_unicode_locale_extension(Generic
 
         case ParseState::ParsingKeyword: {
             // keyword = key (sep type)?
-            Keyword keyword { .key = TRY(String::from_utf8(*segment)) };
+            Keyword keyword { .key = MUST(String::from_utf8(*segment)) };
             Vector<StringView> keyword_values;
 
             if (!is_key(*segment)) {
@@ -226,14 +226,14 @@ static ErrorOr<Optional<LocaleExtension>> parse_unicode_locale_extension(Generic
                     break;
                 }
 
-                TRY(keyword_values.try_append(*type));
+                keyword_values.append(*type);
             }
 
             StringBuilder builder;
-            TRY(builder.try_join('-', keyword_values));
-            keyword.value = TRY(builder.to_string());
+            builder.join('-', keyword_values);
+            keyword.value = MUST(builder.to_string());
 
-            TRY(locale_extension.keywords.try_append(move(keyword)));
+            locale_extension.keywords.append(move(keyword));
             break;
         }
 
@@ -243,11 +243,11 @@ static ErrorOr<Optional<LocaleExtension>> parse_unicode_locale_extension(Generic
     }
 
     if (locale_extension.attributes.is_empty() && locale_extension.keywords.is_empty())
-        return OptionalNone {};
+        return {};
     return locale_extension;
 }
 
-static ErrorOr<Optional<TransformedExtension>> parse_transformed_extension(GenericLexer& lexer)
+static Optional<TransformedExtension> parse_transformed_extension(GenericLexer& lexer)
 {
     // https://unicode.org/reports/tr35/#transformed_extensions
     //
@@ -266,7 +266,7 @@ static ErrorOr<Optional<TransformedExtension>> parse_transformed_extension(Gener
     while (!lexer.is_eof() && (state != ParseState::Done)) {
         auto segment = consume_next_segment(lexer);
         if (!segment.has_value())
-            return OptionalNone {};
+            return {};
 
         if (state == ParseState::ParsingLanguageOrField)
             state = is_unicode_language_subtag(*segment) ? ParseState::ParsingLanguage : ParseState::ParsingField;
@@ -275,17 +275,17 @@ static ErrorOr<Optional<TransformedExtension>> parse_transformed_extension(Gener
         case ParseState::ParsingLanguage:
             lexer.retreat(segment->length());
 
-            if (auto language_id = TRY(parse_unicode_language_id(lexer)); language_id.has_value()) {
+            if (auto language_id = parse_unicode_language_id(lexer); language_id.has_value()) {
                 transformed_extension.language = language_id.release_value();
                 state = ParseState::ParsingField;
                 break;
             }
 
-            return OptionalNone {};
+            return {};
 
         case ParseState::ParsingField: {
             // tfield = tkey tvalue;
-            TransformedField field { .key = TRY(String::from_utf8(*segment)) };
+            TransformedField field { .key = MUST(String::from_utf8(*segment)) };
             Vector<StringView> field_values;
 
             if (!is_transformed_key(*segment)) {
@@ -303,17 +303,17 @@ static ErrorOr<Optional<TransformedExtension>> parse_transformed_extension(Gener
                     break;
                 }
 
-                TRY(field_values.try_append(*value));
+                field_values.append(*value);
             }
 
             if (field_values.is_empty())
-                return OptionalNone {};
+                return {};
 
             StringBuilder builder;
-            TRY(builder.try_join('-', field_values));
-            field.value = TRY(builder.to_string());
+            builder.join('-', field_values);
+            field.value = MUST(builder.to_string());
 
-            TRY(transformed_extension.fields.try_append(move(field)));
+            transformed_extension.fields.append(move(field));
             break;
         }
 
@@ -323,11 +323,11 @@ static ErrorOr<Optional<TransformedExtension>> parse_transformed_extension(Gener
     }
 
     if (!transformed_extension.language.has_value() && transformed_extension.fields.is_empty())
-        return OptionalNone {};
+        return {};
     return transformed_extension;
 }
 
-static ErrorOr<Optional<OtherExtension>> parse_other_extension(char key, GenericLexer& lexer)
+static Optional<OtherExtension> parse_other_extension(char key, GenericLexer& lexer)
 {
     // https://unicode.org/reports/tr35/#other_extensions
     //
@@ -336,7 +336,7 @@ static ErrorOr<Optional<OtherExtension>> parse_other_extension(char key, Generic
     Vector<StringView> other_values;
 
     if (!is_ascii_alphanumeric(key) || (key == 'x') || (key == 'X'))
-        return OptionalNone {};
+        return {};
 
     while (true) {
         auto segment = consume_next_segment(lexer);
@@ -348,20 +348,20 @@ static ErrorOr<Optional<OtherExtension>> parse_other_extension(char key, Generic
             break;
         }
 
-        TRY(other_values.try_append(*segment));
+        other_values.append(*segment);
     }
 
     if (other_values.is_empty())
-        return OptionalNone {};
+        return {};
 
     StringBuilder builder;
-    TRY(builder.try_join('-', other_values));
-    other_extension.value = TRY(builder.to_string());
+    builder.join('-', other_values);
+    other_extension.value = MUST(builder.to_string());
 
     return other_extension;
 }
 
-static ErrorOr<Optional<Extension>> parse_extension(GenericLexer& lexer)
+static Optional<Extension> parse_extension(GenericLexer& lexer)
 {
     // https://unicode.org/reports/tr35/#extensions
     //
@@ -372,28 +372,28 @@ static ErrorOr<Optional<Extension>> parse_extension(GenericLexer& lexer)
         switch (char key = (*header)[0]) {
         case 'u':
         case 'U':
-            if (auto extension = TRY(parse_unicode_locale_extension(lexer)); extension.has_value())
+            if (auto extension = parse_unicode_locale_extension(lexer); extension.has_value())
                 return Extension { extension.release_value() };
             break;
 
         case 't':
         case 'T':
-            if (auto extension = TRY(parse_transformed_extension(lexer)); extension.has_value())
+            if (auto extension = parse_transformed_extension(lexer); extension.has_value())
                 return Extension { extension.release_value() };
             break;
 
         default:
-            if (auto extension = TRY(parse_other_extension(key, lexer)); extension.has_value())
+            if (auto extension = parse_other_extension(key, lexer); extension.has_value())
                 return Extension { extension.release_value() };
             break;
         }
     }
 
     lexer.retreat(lexer.tell() - starting_position);
-    return OptionalNone {};
+    return {};
 }
 
-static ErrorOr<Vector<String>> parse_private_use_extensions(GenericLexer& lexer)
+static Vector<String> parse_private_use_extensions(GenericLexer& lexer)
 {
     // https://unicode.org/reports/tr35/#pu_extensions
     //
@@ -402,9 +402,9 @@ static ErrorOr<Vector<String>> parse_private_use_extensions(GenericLexer& lexer)
 
     auto header = consume_next_segment(lexer);
     if (!header.has_value())
-        return Vector<String> {};
+        return {};
 
-    auto parse_values = [&]() -> ErrorOr<Vector<String>> {
+    auto parse_values = [&]() {
         Vector<String> extensions;
 
         while (true) {
@@ -417,33 +417,33 @@ static ErrorOr<Vector<String>> parse_private_use_extensions(GenericLexer& lexer)
                 break;
             }
 
-            TRY(extensions.try_append(TRY(String::from_utf8(*segment))));
+            extensions.append(MUST(String::from_utf8(*segment)));
         }
 
         return extensions;
     };
 
     if ((header->length() == 1) && (((*header)[0] == 'x') || ((*header)[0] == 'X'))) {
-        if (auto extensions = TRY(parse_values()); !extensions.is_empty())
+        if (auto extensions = parse_values(); !extensions.is_empty())
             return extensions;
     }
 
     lexer.retreat(lexer.tell() - starting_position);
-    return Vector<String> {};
+    return {};
 }
 
-ErrorOr<Optional<LanguageID>> parse_unicode_language_id(StringView language)
+Optional<LanguageID> parse_unicode_language_id(StringView language)
 {
     GenericLexer lexer { language };
 
-    auto language_id = TRY(parse_unicode_language_id(lexer));
+    auto language_id = parse_unicode_language_id(lexer);
     if (!lexer.is_eof())
-        return OptionalNone {};
+        return {};
 
     return language_id;
 }
 
-ErrorOr<Optional<LocaleID>> parse_unicode_locale_id(StringView locale)
+Optional<LocaleID> parse_unicode_locale_id(StringView locale)
 {
     GenericLexer lexer { locale };
 
@@ -452,28 +452,28 @@ ErrorOr<Optional<LocaleID>> parse_unicode_locale_id(StringView locale)
     // unicode_locale_id = unicode_language_id
     //                     extensions*
     //                     pu_extensions?
-    auto language_id = TRY(parse_unicode_language_id(lexer));
+    auto language_id = parse_unicode_language_id(lexer);
     if (!language_id.has_value())
-        return OptionalNone {};
+        return {};
 
     LocaleID locale_id { language_id.release_value() };
 
     while (true) {
-        auto extension = TRY(parse_extension(lexer));
+        auto extension = parse_extension(lexer);
         if (!extension.has_value())
             break;
-        TRY(locale_id.extensions.try_append(extension.release_value()));
+        locale_id.extensions.append(extension.release_value());
     }
 
-    locale_id.private_use_extensions = TRY(parse_private_use_extensions(lexer));
+    locale_id.private_use_extensions = parse_private_use_extensions(lexer);
 
     if (!lexer.is_eof())
-        return OptionalNone {};
+        return {};
 
     return locale_id;
 }
 
-static ErrorOr<void> perform_hard_coded_key_value_substitutions(StringView key, String& value)
+static void perform_hard_coded_key_value_substitutions(StringView key, String& value)
 {
     // FIXME: In the XML export of CLDR, there are some aliases defined in the following files:
     // https://github.com/unicode-org/cldr-staging/blob/master/production/common/bcp47/calendar.xml
@@ -540,14 +540,13 @@ static ErrorOr<void> perform_hard_coded_key_value_substitutions(StringView key,
     }
 
     if (result.has_value())
-        value = TRY(String::from_utf8(*result));
-    return {};
+        value = MUST(String::from_utf8(*result));
 }
 
-ErrorOr<void> canonicalize_unicode_extension_values(StringView key, String& value, bool remove_true)
+void canonicalize_unicode_extension_values(StringView key, String& value, bool remove_true)
 {
-    value = TRY(value.to_lowercase());
-    TRY(perform_hard_coded_key_value_substitutions(key, value));
+    value = MUST(value.to_lowercase());
+    perform_hard_coded_key_value_substitutions(key, value);
 
     // Note: The spec says to remove "true" type and tfield values but that is believed to be a bug in the spec
     // because, for tvalues, that would result in invalid syntax:
@@ -556,7 +555,7 @@ ErrorOr<void> canonicalize_unicode_extension_values(StringView key, String& valu
     //     https://github.com/tc39/test262/blob/18bb955771669541c56c28748603f6afdb2e25ff/test/intl402/Intl/getCanonicalLocales/transformed-ext-canonical.js
     if (remove_true && (value == "true"sv)) {
         value = {};
-        return {};
+        return;
     }
 
     if (key.is_one_of("sd"sv, "rg"sv)) {
@@ -566,28 +565,26 @@ ErrorOr<void> canonicalize_unicode_extension_values(StringView key, String& valu
             // FIXME: Subdivision subtags do not appear in the CLDR likelySubtags.json file.
             //        Implement the spec's recommendation of using just the first alias for now,
             //        but we should determine if there's anything else needed here.
-            value = TRY(String::from_utf8(aliases[0]));
+            value = MUST(String::from_utf8(aliases[0]));
         }
     }
-
-    return {};
 }
 
-static ErrorOr<void> transform_unicode_locale_id_to_canonical_syntax(LocaleID& locale_id)
+static void transform_unicode_locale_id_to_canonical_syntax(LocaleID& locale_id)
 {
-    auto canonicalize_language = [&](LanguageID& language_id, bool force_lowercase) -> ErrorOr<void> {
-        language_id.language = TRY(language_id.language->to_lowercase());
+    auto canonicalize_language = [&](LanguageID& language_id, bool force_lowercase) {
+        language_id.language = MUST(language_id.language->to_lowercase());
         if (language_id.script.has_value())
-            language_id.script = TRY(language_id.script->to_titlecase());
+            language_id.script = MUST(language_id.script->to_titlecase());
         if (language_id.region.has_value())
-            language_id.region = TRY(language_id.region->to_uppercase());
+            language_id.region = MUST(language_id.region->to_uppercase());
         for (auto& variant : language_id.variants)
-            variant = TRY(variant.to_lowercase());
+            variant = MUST(variant.to_lowercase());
 
-        TRY(resolve_complex_language_aliases(language_id));
+        resolve_complex_language_aliases(language_id);
 
         if (auto alias = resolve_language_alias(*language_id.language); alias.has_value()) {
-            auto language_alias = TRY(parse_unicode_language_id(*alias));
+            auto language_alias = parse_unicode_language_id(*alias);
             VERIFY(language_alias.has_value());
 
             language_id.language = move(language_alias->language);
@@ -601,33 +598,31 @@ static ErrorOr<void> transform_unicode_locale_id_to_canonical_syntax(LocaleID& l
 
         if (language_id.script.has_value()) {
             if (auto alias = resolve_script_tag_alias(*language_id.script); alias.has_value())
-                language_id.script = TRY(String::from_utf8(*alias));
+                language_id.script = MUST(String::from_utf8(*alias));
         }
 
         if (language_id.region.has_value()) {
             if (auto alias = resolve_territory_alias(*language_id.region); alias.has_value())
-                language_id.region = TRY(resolve_most_likely_territory_alias(language_id, *alias));
+                language_id.region = resolve_most_likely_territory_alias(language_id, *alias);
         }
 
         quick_sort(language_id.variants);
 
         for (auto& variant : language_id.variants) {
-            variant = TRY(variant.to_lowercase());
+            variant = MUST(variant.to_lowercase());
             if (auto alias = resolve_variant_alias(variant); alias.has_value())
-                variant = TRY(String::from_utf8(*alias));
+                variant = MUST(String::from_utf8(*alias));
         }
 
         if (force_lowercase) {
             if (language_id.script.has_value())
-                language_id.script = TRY(language_id.script->to_lowercase());
+                language_id.script = MUST(language_id.script->to_lowercase());
             if (language_id.region.has_value())
-                language_id.region = TRY(language_id.region->to_lowercase());
+                language_id.region = MUST(language_id.region->to_lowercase());
         }
-
-        return {};
     };
 
-    TRY(canonicalize_language(locale_id.language_id, false));
+    canonicalize_language(locale_id.language_id, false);
 
     quick_sort(locale_id.extensions, [](auto const& left, auto const& right) {
         auto key = [](auto const& extension) {
@@ -641,114 +636,103 @@ static ErrorOr<void> transform_unicode_locale_id_to_canonical_syntax(LocaleID& l
     });
 
     for (auto& extension : locale_id.extensions) {
-        TRY(extension.visit(
-            [&](LocaleExtension& ext) -> ErrorOr<void> {
+        extension.visit(
+            [&](LocaleExtension& ext) {
                 for (auto& attribute : ext.attributes)
-                    attribute = TRY(attribute.to_lowercase());
+                    attribute = MUST(attribute.to_lowercase());
 
                 for (auto& keyword : ext.keywords) {
-                    keyword.key = TRY(keyword.key.to_lowercase());
-                    TRY(canonicalize_unicode_extension_values(keyword.key, keyword.value, true));
+                    keyword.key = MUST(keyword.key.to_lowercase());
+                    canonicalize_unicode_extension_values(keyword.key, keyword.value, true);
                 }
 
                 quick_sort(ext.attributes);
                 quick_sort(ext.keywords, [](auto const& a, auto const& b) { return a.key < b.key; });
-                return {};
             },
-            [&](TransformedExtension& ext) -> ErrorOr<void> {
+            [&](TransformedExtension& ext) {
                 if (ext.language.has_value())
-                    TRY(canonicalize_language(*ext.language, true));
+                    canonicalize_language(*ext.language, true);
 
                 for (auto& field : ext.fields) {
-                    field.key = TRY(field.key.to_lowercase());
-                    TRY(canonicalize_unicode_extension_values(field.key, field.value, false));
+                    field.key = MUST(field.key.to_lowercase());
+                    canonicalize_unicode_extension_values(field.key, field.value, false);
                 }
 
                 quick_sort(ext.fields, [](auto const& a, auto const& b) { return a.key < b.key; });
-                return {};
             },
-            [&](OtherExtension& ext) -> ErrorOr<void> {
+            [&](OtherExtension& ext) {
                 ext.key = static_cast<char>(to_ascii_lowercase(ext.key));
-                ext.value = TRY(ext.value.to_lowercase());
-                return {};
-            }));
+                ext.value = MUST(ext.value.to_lowercase());
+            });
     }
 
     for (auto& extension : locale_id.private_use_extensions)
-        extension = TRY(extension.to_lowercase());
-
-    return {};
+        extension = MUST(extension.to_lowercase());
 }
 
-ErrorOr<Optional<String>> canonicalize_unicode_locale_id(LocaleID& locale_id)
+Optional<String> canonicalize_unicode_locale_id(LocaleID& locale_id)
 {
     // https://unicode.org/reports/tr35/#Canonical_Unicode_Locale_Identifiers
     StringBuilder builder;
 
-    auto append_sep_and_string = [&](Optional<String> const& string) -> ErrorOr<void> {
+    auto append_sep_and_string = [&](Optional<String> const& string) {
         if (!string.has_value() || string->is_empty())
-            return {};
-        TRY(builder.try_appendff("-{}", *string));
-        return {};
+            return;
+        builder.appendff("-{}", *string);
     };
 
     if (!locale_id.language_id.language.has_value())
-        return OptionalNone {};
+        return {};
 
-    TRY(transform_unicode_locale_id_to_canonical_syntax(locale_id));
+    transform_unicode_locale_id_to_canonical_syntax(locale_id);
 
-    TRY(builder.try_append(TRY(locale_id.language_id.language->to_lowercase())));
-    TRY(append_sep_and_string(locale_id.language_id.script));
-    TRY(append_sep_and_string(locale_id.language_id.region));
+    builder.append(MUST(locale_id.language_id.language->to_lowercase()));
+    append_sep_and_string(locale_id.language_id.script);
+    append_sep_and_string(locale_id.language_id.region);
     for (auto const& variant : locale_id.language_id.variants)
-        TRY(append_sep_and_string(variant));
+        append_sep_and_string(variant);
 
     for (auto const& extension : locale_id.extensions) {
-        TRY(extension.visit(
-            [&](LocaleExtension const& ext) -> ErrorOr<void> {
-                TRY(builder.try_append("-u"sv));
+        extension.visit(
+            [&](LocaleExtension const& ext) {
+                builder.append("-u"sv);
 
                 for (auto const& attribute : ext.attributes)
-                    TRY(append_sep_and_string(attribute));
+                    append_sep_and_string(attribute);
                 for (auto const& keyword : ext.keywords) {
-                    TRY(append_sep_and_string(keyword.key));
-                    TRY(append_sep_and_string(keyword.value));
+                    append_sep_and_string(keyword.key);
+                    append_sep_and_string(keyword.value);
                 }
-
-                return {};
             },
-            [&](TransformedExtension const& ext) -> ErrorOr<void> {
-                TRY(builder.try_append("-t"sv));
+            [&](TransformedExtension const& ext) {
+                builder.append("-t"sv);
 
                 if (ext.language.has_value()) {
-                    TRY(append_sep_and_string(ext.language->language));
-                    TRY(append_sep_and_string(ext.language->script));
-                    TRY(append_sep_and_string(ext.language->region));
+                    append_sep_and_string(ext.language->language);
+                    append_sep_and_string(ext.language->script);
+                    append_sep_and_string(ext.language->region);
                     for (auto const& variant : ext.language->variants)
-                        TRY(append_sep_and_string(variant));
+                        append_sep_and_string(variant);
                 }
 
                 for (auto const& field : ext.fields) {
-                    TRY(append_sep_and_string(field.key));
-                    TRY(append_sep_and_string(field.value));
+                    append_sep_and_string(field.key);
+                    append_sep_and_string(field.value);
                 }
-
-                return {};
             },
-            [&](OtherExtension const& ext) -> ErrorOr<void> {
-                TRY(builder.try_appendff("-{:c}", to_ascii_lowercase(ext.key)));
-                TRY(append_sep_and_string(ext.value));
-                return {};
-            }));
+            [&](OtherExtension const& ext) {
+                builder.appendff("-{:c}", to_ascii_lowercase(ext.key));
+                append_sep_and_string(ext.value);
+            });
     }
 
     if (!locale_id.private_use_extensions.is_empty()) {
-        TRY(builder.try_append("-x"sv));
+        builder.append("-x"sv);
         for (auto const& extension : locale_id.private_use_extensions)
-            TRY(append_sep_and_string(extension));
+            append_sep_and_string(extension);
     }
 
-    return builder.to_string();
+    return MUST(builder.to_string());
 }
 
 StringView default_locale()
@@ -808,8 +792,8 @@ Optional<KeywordHours> __attribute__((weak)) keyword_hc_from_string(StringView)
 Optional<KeywordColCaseFirst> __attribute__((weak)) keyword_kf_from_string(StringView) { return {}; }
 Optional<KeywordColNumeric> __attribute__((weak)) keyword_kn_from_string(StringView) { return {}; }
 Optional<KeywordNumbers> __attribute__((weak)) keyword_nu_from_string(StringView) { return {}; }
-ErrorOr<Vector<StringView>> __attribute__((weak)) get_keywords_for_locale(StringView, StringView) { return Vector<StringView> {}; }
-ErrorOr<Optional<StringView>> __attribute__((weak)) get_preferred_keyword_value_for_locale(StringView, StringView) { return OptionalNone {}; }
+Vector<StringView> __attribute__((weak)) get_keywords_for_locale(StringView, StringView) { return {}; }
+Optional<StringView> __attribute__((weak)) get_preferred_keyword_value_for_locale(StringView, StringView) { return {}; }
 Optional<DisplayPattern> __attribute__((weak)) get_locale_display_patterns(StringView) { return {}; }
 Optional<StringView> __attribute__((weak)) get_locale_language_mapping(StringView, StringView) { return {}; }
 Optional<StringView> __attribute__((weak)) get_locale_territory_mapping(StringView, StringView) { return {}; }
@@ -824,14 +808,14 @@ Optional<StringView> __attribute__((weak)) get_locale_short_date_field_mapping(S
 Optional<StringView> __attribute__((weak)) get_locale_narrow_date_field_mapping(StringView, StringView) { return {}; }
 
 // https://www.unicode.org/reports/tr35/tr35-39/tr35-general.html#Display_Name_Elements
-ErrorOr<Optional<String>> format_locale_for_display(StringView locale, LocaleID locale_id)
+Optional<String> format_locale_for_display(StringView locale, LocaleID locale_id)
 {
     auto language_id = move(locale_id.language_id);
     VERIFY(language_id.language.has_value());
 
     auto patterns = get_locale_display_patterns(locale);
     if (!patterns.has_value())
-        return OptionalNone {};
+        return {};
 
     auto primary_tag = get_locale_language_mapping(locale, *language_id.language).value_or(*language_id.language);
     Optional<StringView> script;
@@ -845,21 +829,21 @@ ErrorOr<Optional<String>> format_locale_for_display(StringView locale, LocaleID
     Optional<String> secondary_tag;
 
     if (script.has_value() && region.has_value()) {
-        secondary_tag = TRY(String::from_utf8(patterns->locale_separator));
-        secondary_tag = TRY(secondary_tag->replace("{0}"sv, *script, ReplaceMode::FirstOnly));
-        secondary_tag = TRY(secondary_tag->replace("{1}"sv, *region, ReplaceMode::FirstOnly));
+        secondary_tag = MUST(String::from_utf8(patterns->locale_separator));
+        secondary_tag = MUST(secondary_tag->replace("{0}"sv, *script, ReplaceMode::FirstOnly));
+        secondary_tag = MUST(secondary_tag->replace("{1}"sv, *region, ReplaceMode::FirstOnly));
     } else if (script.has_value()) {
-        secondary_tag = TRY(String::from_utf8(*script));
+        secondary_tag = MUST(String::from_utf8(*script));
     } else if (region.has_value()) {
-        secondary_tag = TRY(String::from_utf8(*region));
+        secondary_tag = MUST(String::from_utf8(*region));
     }
 
     if (!secondary_tag.has_value())
-        return String::from_utf8(primary_tag);
+        return MUST(String::from_utf8(primary_tag));
 
-    auto result = TRY(String::from_utf8(patterns->locale_pattern));
-    result = TRY(result.replace("{0}"sv, primary_tag, ReplaceMode::FirstOnly));
-    result = TRY(result.replace("{1}"sv, *secondary_tag, ReplaceMode::FirstOnly));
+    auto result = MUST(String::from_utf8(patterns->locale_pattern));
+    result = MUST(result.replace("{0}"sv, primary_tag, ReplaceMode::FirstOnly));
+    result = MUST(result.replace("{1}"sv, *secondary_tag, ReplaceMode::FirstOnly));
 
     return result;
 }
@@ -873,10 +857,10 @@ Optional<StringView> __attribute__((weak)) resolve_territory_alias(StringView) {
 Optional<StringView> __attribute__((weak)) resolve_script_tag_alias(StringView) { return {}; }
 Optional<StringView> __attribute__((weak)) resolve_variant_alias(StringView) { return {}; }
 Optional<StringView> __attribute__((weak)) resolve_subdivision_alias(StringView) { return {}; }
-ErrorOr<void> __attribute__((weak)) resolve_complex_language_aliases(LanguageID&) { return {}; }
-ErrorOr<Optional<LanguageID>> __attribute__((weak)) add_likely_subtags(LanguageID const&) { return OptionalNone {}; }
+void __attribute__((weak)) resolve_complex_language_aliases(LanguageID&) { }
+Optional<LanguageID> __attribute__((weak)) add_likely_subtags(LanguageID const&) { return {}; }
 
-ErrorOr<Optional<LanguageID>> remove_likely_subtags(LanguageID const& language_id)
+Optional<LanguageID> remove_likely_subtags(LanguageID const& language_id)
 {
     // https://www.unicode.org/reports/tr35/#Likely_Subtags
     auto return_language_and_variants = [](auto language, auto variants) {
@@ -885,9 +869,9 @@ ErrorOr<Optional<LanguageID>> remove_likely_subtags(LanguageID const& language_i
     };
 
     // 1. First get max = AddLikelySubtags(inputLocale). If an error is signaled, return it.
-    auto maximized = TRY(add_likely_subtags(language_id));
+    auto maximized = add_likely_subtags(language_id);
     if (!maximized.has_value())
-        return OptionalNone {};
+        return {};
 
     // 2. Remove the variants from max.
     auto variants = move(maximized->variants);
@@ -899,113 +883,108 @@ ErrorOr<Optional<LanguageID>> remove_likely_subtags(LanguageID const& language_i
 
     // 4. Then for trial in {languagemax, languagemax_regionmax, languagemax_scriptmax}:
     //    If AddLikelySubtags(trial) = max, then return trial + variants.
-    auto run_trial = [&](Optional<String> language, Optional<String> script, Optional<String> region) -> ErrorOr<Optional<LanguageID>> {
+    auto run_trial = [&](Optional<String> language, Optional<String> script, Optional<String> region) -> Optional<LanguageID> {
         LanguageID trial { .language = move(language), .script = move(script), .region = move(region) };
 
-        if (TRY(add_likely_subtags(trial)) == maximized)
+        if (add_likely_subtags(trial) == maximized)
             return return_language_and_variants(move(trial), move(variants));
-        return OptionalNone {};
+        return {};
     };
 
-    if (auto trial = TRY(run_trial(language_max, {}, {})); trial.has_value())
+    if (auto trial = run_trial(language_max, {}, {}); trial.has_value())
         return trial;
-    if (auto trial = TRY(run_trial(language_max, {}, region_max)); trial.has_value())
+    if (auto trial = run_trial(language_max, {}, region_max); trial.has_value())
         return trial;
-    if (auto trial = TRY(run_trial(language_max, script_max, {})); trial.has_value())
+    if (auto trial = run_trial(language_max, script_max, {}); trial.has_value())
         return trial;
 
     // 5. If you do not get a match, return max + variants.
     return return_language_and_variants(maximized.release_value(), move(variants));
 }
 
-ErrorOr<Optional<String>> __attribute__((weak)) resolve_most_likely_territory(LanguageID const&) { return OptionalNone {}; }
+Optional<String> __attribute__((weak)) resolve_most_likely_territory(LanguageID const&) { return {}; }
 
-ErrorOr<String> resolve_most_likely_territory_alias(LanguageID const& language_id, StringView territory_alias)
+String resolve_most_likely_territory_alias(LanguageID const& language_id, StringView territory_alias)
 {
     auto aliases = territory_alias.split_view(' ');
 
     if (aliases.size() > 1) {
-        auto territory = TRY(resolve_most_likely_territory(language_id));
+        auto territory = resolve_most_likely_territory(language_id);
         if (territory.has_value() && aliases.contains_slow(*territory))
             return territory.release_value();
     }
 
-    return String::from_utf8(aliases[0]);
+    return MUST(String::from_utf8(aliases[0]));
 }
 
-ErrorOr<String> LanguageID::to_string() const
+String LanguageID::to_string() const
 {
     StringBuilder builder;
 
-    auto append_segment = [&](Optional<String> const& segment) -> ErrorOr<void> {
+    auto append_segment = [&](Optional<String> const& segment) {
         if (!segment.has_value())
-            return {};
+            return;
         if (!builder.is_empty())
-            TRY(builder.try_append('-'));
-        TRY(builder.try_append(*segment));
-        return {};
+            builder.append('-');
+        builder.append(*segment);
     };
 
-    TRY(append_segment(language));
-    TRY(append_segment(script));
-    TRY(append_segment(region));
+    append_segment(language);
+    append_segment(script);
+    append_segment(region);
     for (auto const& variant : variants)
-        TRY(append_segment(variant));
+        append_segment(variant);
 
-    return builder.to_string();
+    return MUST(builder.to_string());
 }
 
-ErrorOr<String> LocaleID::to_string() const
+String LocaleID::to_string() const
 {
     StringBuilder builder;
 
-    auto append_segment = [&](auto const& segment) -> ErrorOr<void> {
+    auto append_segment = [&](auto const& segment) {
         if (segment.is_empty())
-            return {};
+            return;
         if (!builder.is_empty())
-            TRY(builder.try_append('-'));
-        TRY(builder.try_append(segment));
-        return {};
+            builder.append('-');
+        builder.append(segment);
     };
 
-    TRY(append_segment(TRY(language_id.to_string())));
+    append_segment(language_id.to_string());
 
     for (auto const& extension : extensions) {
-        TRY(extension.visit(
-            [&](LocaleExtension const& ext) -> ErrorOr<void> {
-                TRY(builder.try_append("-u"sv));
+        extension.visit(
+            [&](LocaleExtension const& ext) {
+                builder.append("-u"sv);
                 for (auto const& attribute : ext.attributes)
-                    TRY(append_segment(attribute));
+                    append_segment(attribute);
                 for (auto const& keyword : ext.keywords) {
-                    TRY(append_segment(keyword.key));
-                    TRY(append_segment(keyword.value));
+                    append_segment(keyword.key);
+                    append_segment(keyword.value);
                 }
-                return {};
             },
-            [&](TransformedExtension const& ext) -> ErrorOr<void> {
-                TRY(builder.try_append("-t"sv));
+            [&](TransformedExtension const& ext) {
+                builder.append("-t"sv);
                 if (ext.language.has_value())
-                    TRY(append_segment(TRY(ext.language->to_string())));
+                    append_segment(ext.language->to_string());
                 for (auto const& field : ext.fields) {
-                    TRY(append_segment(field.key));
-                    TRY(append_segment(field.value));
+                    append_segment(field.key);
+                    append_segment(field.value);
                 }
-                return {};
             },
-            [&](OtherExtension const& ext) -> ErrorOr<void> {
-                TRY(builder.try_appendff("-{}", ext.key));
-                TRY(append_segment(ext.value));
-                return {};
-            }));
+            [&](OtherExtension const& ext) {
+                builder.appendff("-{}", ext.key);
+                append_segment(ext.value);
+            });
     }
 
     if (!private_use_extensions.is_empty()) {
-        TRY(builder.try_append("-x"sv));
+        builder.append("-x"sv);
         for (auto const& extension : private_use_extensions)
-            TRY(append_segment(extension));
+            append_segment(extension);
     }
 
-    return builder.to_string();
+    return MUST(builder.to_string());
 }
 
 }

Userland/Libraries/LibLocale/Locale.h

@@ -7,7 +7,6 @@
 #pragma once
 
 #include <AK/CharacterTypes.h>
-#include <AK/Error.h>
 #include <AK/Optional.h>
 #include <AK/String.h>
 #include <AK/StringView.h>
@@ -18,7 +17,7 @@
 namespace Locale {
 
 struct LanguageID {
-    ErrorOr<String> to_string() const;
+    String to_string() const;
     bool operator==(LanguageID const&) const = default;
 
     bool is_root { false };
@@ -56,7 +55,7 @@ struct OtherExtension {
 using Extension = AK::Variant<LocaleExtension, TransformedExtension, OtherExtension>;
 
 struct LocaleID {
-    ErrorOr<String> to_string() const;
+    String to_string() const;
 
     template<typename ExtensionType>
     Vector<Extension> remove_extension_type()
@@ -137,11 +136,11 @@ constexpr bool is_unicode_variant_subtag(StringView subtag)
 
 bool is_type_identifier(StringView);
 
-ErrorOr<Optional<LanguageID>> parse_unicode_language_id(StringView);
-ErrorOr<Optional<LocaleID>> parse_unicode_locale_id(StringView);
+Optional<LanguageID> parse_unicode_language_id(StringView);
+Optional<LocaleID> parse_unicode_locale_id(StringView);
 
-ErrorOr<void> canonicalize_unicode_extension_values(StringView key, String& value, bool remove_true);
-ErrorOr<Optional<String>> canonicalize_unicode_locale_id(LocaleID&);
+void canonicalize_unicode_extension_values(StringView key, String& value, bool remove_true);
+Optional<String> canonicalize_unicode_locale_id(LocaleID&);
 
 StringView default_locale();
 bool is_locale_available(StringView locale);
@@ -173,11 +172,11 @@ Optional<KeywordHours> keyword_hc_from_string(StringView hc);
 Optional<KeywordColCaseFirst> keyword_kf_from_string(StringView kf);
 Optional<KeywordColNumeric> keyword_kn_from_string(StringView kn);
 Optional<KeywordNumbers> keyword_nu_from_string(StringView nu);
-ErrorOr<Vector<StringView>> get_keywords_for_locale(StringView locale, StringView key);
-ErrorOr<Optional<StringView>> get_preferred_keyword_value_for_locale(StringView locale, StringView key);
+Vector<StringView> get_keywords_for_locale(StringView locale, StringView key);
+Optional<StringView> get_preferred_keyword_value_for_locale(StringView locale, StringView key);
 
 Optional<DisplayPattern> get_locale_display_patterns(StringView locale);
-ErrorOr<Optional<String>> format_locale_for_display(StringView locale, LocaleID locale_id);
+Optional<String> format_locale_for_display(StringView locale, LocaleID locale_id);
 
 Optional<StringView> get_locale_language_mapping(StringView locale, StringView language);
 Optional<StringView> get_locale_territory_mapping(StringView locale, StringView territory);
@@ -202,12 +201,12 @@ Optional<StringView> resolve_territory_alias(StringView territory);
 Optional<StringView> resolve_script_tag_alias(StringView script_tag);
 Optional<StringView> resolve_variant_alias(StringView variant);
 Optional<StringView> resolve_subdivision_alias(StringView subdivision);
-ErrorOr<void> resolve_complex_language_aliases(LanguageID& language_id);
+void resolve_complex_language_aliases(LanguageID& language_id);
 
-ErrorOr<Optional<LanguageID>> add_likely_subtags(LanguageID const& language_id);
-ErrorOr<Optional<LanguageID>> remove_likely_subtags(LanguageID const& language_id);
+Optional<LanguageID> add_likely_subtags(LanguageID const& language_id);
+Optional<LanguageID> remove_likely_subtags(LanguageID const& language_id);
 
-ErrorOr<Optional<String>> resolve_most_likely_territory(LanguageID const& language_id);
-ErrorOr<String> resolve_most_likely_territory_alias(LanguageID const& language_id, StringView territory_alias);
+Optional<String> resolve_most_likely_territory(LanguageID const& language_id);
+String resolve_most_likely_territory_alias(LanguageID const& language_id, StringView territory_alias);
 
 }

Userland/Libraries/LibLocale/NumberFormat.cpp

@@ -16,8 +16,8 @@
 
 namespace Locale {
 
-ErrorOr<Optional<StringView>> __attribute__((weak)) get_number_system_symbol(StringView, StringView, NumericSymbol) { return OptionalNone {}; }
-ErrorOr<Optional<NumberGroupings>> __attribute__((weak)) get_number_system_groupings(StringView, StringView) { return OptionalNone {}; }
+Optional<StringView> __attribute__((weak)) get_number_system_symbol(StringView, StringView, NumericSymbol) { return {}; }
+Optional<NumberGroupings> __attribute__((weak)) get_number_system_groupings(StringView, StringView) { return {}; }
 ErrorOr<Optional<NumberFormat>> __attribute__((weak)) get_standard_number_system_format(StringView, StringView, StandardNumberFormatType) { return OptionalNone {}; }
 ErrorOr<Vector<NumberFormat>> __attribute__((weak)) get_compact_number_system_formats(StringView, StringView, CompactNumberFormatType) { return Vector<NumberFormat> {}; }
 ErrorOr<Vector<NumberFormat>> __attribute__((weak)) get_unit_formats(StringView, StringView, Style) { return Vector<NumberFormat> {}; }

Userland/Libraries/LibLocale/NumberFormat.h

@@ -61,8 +61,8 @@ enum class NumericSymbol : u8 {
     TimeSeparator,
 };
 
-ErrorOr<Optional<StringView>> get_number_system_symbol(StringView locale, StringView system, NumericSymbol symbol);
-ErrorOr<Optional<NumberGroupings>> get_number_system_groupings(StringView locale, StringView system);
+Optional<StringView> get_number_system_symbol(StringView locale, StringView system, NumericSymbol symbol);
+Optional<NumberGroupings> get_number_system_groupings(StringView locale, StringView system);
 
 Optional<ReadonlySpan<u32>> get_digits_for_number_system(StringView system);
 ErrorOr<String> replace_digits_for_number_system(StringView system, StringView number);