LibJS: Mark infallible operations that may throw only due to OOM

18 files changed, 48 insertions, 69 deletions

diff --git a/Userland/Libraries/LibJS/Runtime/GlobalObject.cpp b/Userland/Libraries/LibJS/Runtime/GlobalObject.cpp
index 6b64f02602..83f29af207 100644
--- a/Userland/Libraries/LibJS/Runtime/GlobalObject.cpp
+++ b/Userland/Libraries/LibJS/Runtime/GlobalObject.cpp
@@ -231,8 +231,7 @@ JS_DEFINE_NATIVE_FUNCTION(GlobalObject::parse_float)
     auto input_string = TRY(vm.argument(0).to_deprecated_string(vm));
 
     // 2. Let trimmedString be ! TrimString(inputString, start).
-    // NOTE: We TRY this operation only to propagate OOM errors.
-    auto trimmed_string = TRY(trim_string(vm, PrimitiveString::create(vm, input_string), TrimMode::Left));
+    auto trimmed_string = MUST_OR_THROW_OOM(trim_string(vm, PrimitiveString::create(vm, input_string), TrimMode::Left));
     if (trimmed_string.is_empty())
         return js_nan();
 
diff --git a/Userland/Libraries/LibJS/Runtime/Intl/AbstractOperations.cpp b/Userland/Libraries/LibJS/Runtime/Intl/AbstractOperations.cpp
index f0722a4499..e6255318b9 100644
--- a/Userland/Libraries/LibJS/Runtime/Intl/AbstractOperations.cpp
+++ b/Userland/Libraries/LibJS/Runtime/Intl/AbstractOperations.cpp
@@ -245,13 +245,12 @@ ThrowCompletionOr<Vector<String>> canonicalize_locale_list(VM& vm, Value locales
             }
 
             // v. If ! IsStructurallyValidLanguageTag(tag) is false, throw a RangeError exception.
-            auto locale_id = TRY(is_structurally_valid_language_tag(vm, tag));
+            auto locale_id = MUST_OR_THROW_OOM(is_structurally_valid_language_tag(vm, tag));
             if (!locale_id.has_value())
                 return vm.throw_completion<RangeError>(ErrorType::IntlInvalidLanguageTag, tag);
 
             // vi. Let canonicalizedTag be ! CanonicalizeUnicodeLocaleId(tag).
-            // NOTE: We TRY this operation only to propagate OOM errors.
-            auto canonicalized_tag = TRY(canonicalize_unicode_locale_id(vm, *locale_id));
+            auto canonicalized_tag = MUST_OR_THROW_OOM(canonicalize_unicode_locale_id(vm, *locale_id));
 
             // vii. If canonicalizedTag is not an element of seen, append canonicalizedTag as the last element of seen.
             if (!seen.contains_slow(canonicalized_tag))
@@ -354,7 +353,7 @@ ThrowCompletionOr<String> insert_unicode_extension_and_canonicalize(VM& vm, ::Lo
     // of that string. LibUnicode gives us the parsed locale in a structure, so we can mutate that
     // structure directly.
     TRY_OR_THROW_OOM(vm, locale.extensions.try_append(move(extension)));
-    return canonicalize_unicode_locale_id(vm, locale);
+    return MUST_OR_THROW_OOM(canonicalize_unicode_locale_id(vm, locale));
 }
 
 template<typename T>
@@ -387,14 +386,12 @@ ThrowCompletionOr<LocaleResult> resolve_locale(VM& vm, Vector<String> const& req
     // 2. If matcher is "lookup", then
     if (matcher.is_string() && (TRY(matcher.as_string().utf8_string_view()) == "lookup"sv)) {
         // a. Let r be ! LookupMatcher(availableLocales, requestedLocales).
-        // NOTE: We TRY this operation only to propagate OOM errors.
-        matcher_result = TRY(lookup_matcher(vm, requested_locales));
+        matcher_result = MUST_OR_THROW_OOM(lookup_matcher(vm, requested_locales));
     }
     // 3. Else,
     else {
         // a. Let r be ! BestFitMatcher(availableLocales, requestedLocales).
-        // NOTE: We TRY this operation only to propagate OOM errors.
-        matcher_result = TRY(best_fit_matcher(vm, requested_locales));
+        matcher_result = MUST_OR_THROW_OOM(best_fit_matcher(vm, requested_locales));
     }
 
     // 4. Let foundLocale be r.[[locale]].
@@ -516,7 +513,7 @@ ThrowCompletionOr<LocaleResult> resolve_locale(VM& vm, Vector<String> const& req
         VERIFY(locale_id.has_value());
 
         // a. Set foundLocale to InsertUnicodeExtensionAndCanonicalize(foundLocale, supportedExtension).
-        found_locale = TRY(insert_unicode_extension_and_canonicalize(vm, locale_id.release_value(), move(supported_extension)));
+        found_locale = MUST_OR_THROW_OOM(insert_unicode_extension_and_canonicalize(vm, locale_id.release_value(), move(supported_extension)));
     }
 
     // 11. Set result.[[locale]] to foundLocale.
diff --git a/Userland/Libraries/LibJS/Runtime/Intl/CollatorConstructor.cpp b/Userland/Libraries/LibJS/Runtime/Intl/CollatorConstructor.cpp
index 1718d76356..dc0534536a 100644
--- a/Userland/Libraries/LibJS/Runtime/Intl/CollatorConstructor.cpp
+++ b/Userland/Libraries/LibJS/Runtime/Intl/CollatorConstructor.cpp
@@ -62,10 +62,8 @@ static ThrowCompletionOr<Collator*> initialize_collator(VM& vm, Collator& collat
     // 14. If numeric is not undefined, then
     //     a. Let numeric be ! ToString(numeric).
     // 15. Set opt.[[kn]] to numeric.
-    if (!numeric.is_undefined()) {
-        // NOTE: We TRY this operation only to propagate OOM errors.
-        opt.kn = TRY(numeric.to_string(vm));
-    }
+    if (!numeric.is_undefined())
+        opt.kn = MUST_OR_THROW_OOM(numeric.to_string(vm));
 
     // 16. Let caseFirst be ? GetOption(options, "caseFirst", string, « "upper", "lower", "false" », undefined).
     // 17. Set opt.[[kf]] to caseFirst.
@@ -77,7 +75,7 @@ static ThrowCompletionOr<Collator*> initialize_collator(VM& vm, Collator& collat
     auto relevant_extension_keys = Collator::relevant_extension_keys();
 
     // 19. Let r be ResolveLocale(%Collator%.[[AvailableLocales]], requestedLocales, opt, relevantExtensionKeys, localeData).
-    auto result = TRY(resolve_locale(vm, requested_locales, opt, relevant_extension_keys));
+    auto result = MUST_OR_THROW_OOM(resolve_locale(vm, requested_locales, opt, relevant_extension_keys));
 
     // 20. Set collator.[[Locale]] to r.[[locale]].
     collator.set_locale(move(result.locale));
diff --git a/Userland/Libraries/LibJS/Runtime/Intl/DateTimeFormat.cpp b/Userland/Libraries/LibJS/Runtime/Intl/DateTimeFormat.cpp
index 9d88f9fad9..29f03eb5d6 100644
--- a/Userland/Libraries/LibJS/Runtime/Intl/DateTimeFormat.cpp
+++ b/Userland/Libraries/LibJS/Runtime/Intl/DateTimeFormat.cpp
@@ -621,7 +621,7 @@ ThrowCompletionOr<Vector<PatternPartition>> format_date_time_pattern(VM& vm, Dat
             value = floor(value * pow(10, static_cast<int>(*fractional_second_digits) - 3));
 
             // iii. Let fv be FormatNumeric(nf3, v).
-            auto formatted_value = TRY(format_numeric(vm, *number_format3, Value(value)));
+            auto formatted_value = MUST_OR_THROW_OOM(format_numeric(vm, *number_format3, Value(value)));
 
             // iv. Append a new Record { [[Type]]: "fractionalSecond", [[Value]]: fv } as the last element of result.
             result.append({ "fractionalSecond"sv, move(formatted_value) });
@@ -705,13 +705,13 @@ ThrowCompletionOr<Vector<PatternPartition>> format_date_time_pattern(VM& vm, Dat
             // viii. If f is "numeric", then
             case ::Locale::CalendarPatternStyle::Numeric:
                 // 1. Let fv be FormatNumeric(nf, v).
-                formatted_value = TRY(format_numeric(vm, *number_format, Value(value)));
+                formatted_value = MUST_OR_THROW_OOM(format_numeric(vm, *number_format, Value(value)));
                 break;
 
             // ix. Else if f is "2-digit", then
             case ::Locale::CalendarPatternStyle::TwoDigit:
                 // 1. Let fv be FormatNumeric(nf2, v).
-                formatted_value = TRY(format_numeric(vm, *number_format2, Value(value)));
+                formatted_value = MUST_OR_THROW_OOM(format_numeric(vm, *number_format2, Value(value)));
 
                 // 2. If the "length" property of fv is greater than 2, let fv be the substring of fv containing the last two characters.
                 // NOTE: The first length check here isn't enough, but lets us avoid UTF-16 transcoding when the formatted value is ASCII.
@@ -820,7 +820,7 @@ ThrowCompletionOr<Vector<PatternPartition>> format_date_time_pattern(VM& vm, Dat
 ThrowCompletionOr<Vector<PatternPartition>> partition_date_time_pattern(VM& vm, DateTimeFormat& date_time_format, double time)
 {
     // 1. Let patternParts be PartitionPattern(dateTimeFormat.[[Pattern]]).
-    auto pattern_parts = TRY(partition_pattern(vm, date_time_format.pattern()));
+    auto pattern_parts = MUST_OR_THROW_OOM(partition_pattern(vm, date_time_format.pattern()));
 
     // 2. Let result be ? FormatDateTimePattern(dateTimeFormat, patternParts, x, undefined).
     auto result = TRY(format_date_time_pattern(vm, date_time_format, move(pattern_parts), time, nullptr));
@@ -1067,7 +1067,7 @@ ThrowCompletionOr<Vector<PatternPartitionWithSource>> partition_date_time_range_
         auto const& pattern = date_time_format.pattern();
 
         // b. Let patternParts be PartitionPattern(pattern).
-        auto pattern_parts = TRY(partition_pattern(vm, pattern));
+        auto pattern_parts = MUST_OR_THROW_OOM(partition_pattern(vm, pattern));
 
         // c. Let result be ? FormatDateTimePattern(dateTimeFormat, patternParts, x, undefined).
         auto raw_result = TRY(format_date_time_pattern(vm, date_time_format, move(pattern_parts), start, nullptr));
@@ -1124,7 +1124,7 @@ ThrowCompletionOr<Vector<PatternPartitionWithSource>> partition_date_time_range_
         auto time = ((source == "startRange") || (source == "shared")) ? start : end;
 
         // e. Let patternParts be PartitionPattern(pattern).
-        auto pattern_parts = TRY(partition_pattern(vm, pattern));
+        auto pattern_parts = MUST_OR_THROW_OOM(partition_pattern(vm, pattern));
 
         // f. Let partResult be ? FormatDateTimePattern(dateTimeFormat, patternParts, z, rangePattern).
         auto raw_part_result = TRY(format_date_time_pattern(vm, date_time_format, move(pattern_parts), time, &range_pattern.value()));
diff --git a/Userland/Libraries/LibJS/Runtime/Intl/DateTimeFormatConstructor.cpp b/Userland/Libraries/LibJS/Runtime/Intl/DateTimeFormatConstructor.cpp
index 52781e3aff..b67e35f8c9 100644
--- a/Userland/Libraries/LibJS/Runtime/Intl/DateTimeFormatConstructor.cpp
+++ b/Userland/Libraries/LibJS/Runtime/Intl/DateTimeFormatConstructor.cpp
@@ -144,7 +144,7 @@ ThrowCompletionOr<DateTimeFormat*> initialize_date_time_format(VM& vm, DateTimeF
 
     // 16. Let localeData be %DateTimeFormat%.[[LocaleData]].
     // 17. Let r be ResolveLocale(%DateTimeFormat%.[[AvailableLocales]], requestedLocales, opt, %DateTimeFormat%.[[RelevantExtensionKeys]], localeData).
-    auto result = TRY(resolve_locale(vm, requested_locales, opt, DateTimeFormat::relevant_extension_keys()));
+    auto result = MUST_OR_THROW_OOM(resolve_locale(vm, requested_locales, opt, DateTimeFormat::relevant_extension_keys()));
 
     // 18. Set dateTimeFormat.[[Locale]] to r.[[locale]].
     date_time_format.set_locale(move(result.locale));
diff --git a/Userland/Libraries/LibJS/Runtime/Intl/DisplayNames.cpp b/Userland/Libraries/LibJS/Runtime/Intl/DisplayNames.cpp
index 14dddfdc36..a851732a39 100644
--- a/Userland/Libraries/LibJS/Runtime/Intl/DisplayNames.cpp
+++ b/Userland/Libraries/LibJS/Runtime/Intl/DisplayNames.cpp
@@ -110,13 +110,12 @@ ThrowCompletionOr<Value> canonical_code_for_display_names(VM& vm, DisplayNames::
             return vm.throw_completion<RangeError>(ErrorType::OptionIsNotValidValue, code, "language"sv);
 
         // b. If IsStructurallyValidLanguageTag(code) is false, throw a RangeError exception.
-        auto locale_id = TRY(is_structurally_valid_language_tag(vm, code));
+        auto locale_id = MUST_OR_THROW_OOM(is_structurally_valid_language_tag(vm, code));
         if (!locale_id.has_value())
             return vm.throw_completion<RangeError>(ErrorType::IntlInvalidLanguageTag, code);
 
         // c. Return ! CanonicalizeUnicodeLocaleId(code).
-        // NOTE: We TRY this operation only to propagate OOM errors.
-        auto canonicalized_tag = TRY(canonicalize_unicode_locale_id(vm, *locale_id));
+        auto canonicalized_tag = MUST_OR_THROW_OOM(canonicalize_unicode_locale_id(vm, *locale_id));
         return PrimitiveString::create(vm, move(canonicalized_tag));
     }
 
diff --git a/Userland/Libraries/LibJS/Runtime/Intl/DisplayNamesPrototype.cpp b/Userland/Libraries/LibJS/Runtime/Intl/DisplayNamesPrototype.cpp
index d8ae16a5a6..01f74a9eb7 100644
--- a/Userland/Libraries/LibJS/Runtime/Intl/DisplayNamesPrototype.cpp
+++ b/Userland/Libraries/LibJS/Runtime/Intl/DisplayNamesPrototype.cpp
@@ -62,7 +62,7 @@ JS_DEFINE_NATIVE_FUNCTION(DisplayNamesPrototype::of)
                 break;
         }
 
-        if (auto locale = TRY(is_structurally_valid_language_tag(vm, code_string)); locale.has_value())
+        if (auto locale = MUST_OR_THROW_OOM(is_structurally_valid_language_tag(vm, code_string)); locale.has_value())
             formatted_result = ::Locale::format_locale_for_display(display_names->locale(), locale.release_value());
         break;
     case DisplayNames::Type::Region:
diff --git a/Userland/Libraries/LibJS/Runtime/Intl/DurationFormat.cpp b/Userland/Libraries/LibJS/Runtime/Intl/DurationFormat.cpp
index f3c3b7e526..ee6921ec29 100644
--- a/Userland/Libraries/LibJS/Runtime/Intl/DurationFormat.cpp
+++ b/Userland/Libraries/LibJS/Runtime/Intl/DurationFormat.cpp
@@ -445,8 +445,7 @@ ThrowCompletionOr<Vector<PatternPartition>> partition_duration_format_pattern(VM
                 // 3. Let dataLocaleData be %DurationFormat%.[[LocaleData]].[[<dataLocale>]].
 
                 // 4. Let num be ! FormatNumeric(nf, 𝔽(value)).
-                // NOTE: We TRY this operation only to propagate OOM errors.
-                auto number = TRY(format_numeric(vm, *number_format, MathematicalValue(value)));
+                auto number = MUST_OR_THROW_OOM(format_numeric(vm, *number_format, MathematicalValue(value)));
 
                 // 5. Append the new Record { [[Type]]: unit, [[Value]]: num} to the end of result.
                 result.append({ unit, number });
@@ -505,8 +504,7 @@ ThrowCompletionOr<Vector<PatternPartition>> partition_duration_format_pattern(VM
                 auto* number_format = static_cast<NumberFormat*>(MUST(construct(vm, *realm.intrinsics().intl_number_format_constructor(), PrimitiveString::create(vm, duration_format.locale()), number_format_options)).ptr());
 
                 // 5. Let parts be ! PartitionNumberPattern(nf, 𝔽(value)).
-                // NOTE: We TRY this operation only to propagate OOM errors.
-                auto parts = TRY(partition_number_pattern(vm, *number_format, MathematicalValue(value)));
+                auto parts = MUST_OR_THROW_OOM(partition_number_pattern(vm, *number_format, MathematicalValue(value)));
 
                 // 6. Let concat be an empty String.
                 StringBuilder concat;
@@ -566,8 +564,7 @@ ThrowCompletionOr<Vector<PatternPartition>> partition_duration_format_pattern(VM
     }
 
     // 10. Set result to ! CreatePartsFromList(lf, result).
-    // NOTE: We TRY this operation only to propagate OOM errors.
-    auto final_result = TRY(create_parts_from_list(vm, *list_format, string_result));
+    auto final_result = MUST_OR_THROW_OOM(create_parts_from_list(vm, *list_format, string_result));
 
     // 11. Return result.
     return final_result;
diff --git a/Userland/Libraries/LibJS/Runtime/Intl/DurationFormatConstructor.cpp b/Userland/Libraries/LibJS/Runtime/Intl/DurationFormatConstructor.cpp
index 204b312beb..12161f3867 100644
--- a/Userland/Libraries/LibJS/Runtime/Intl/DurationFormatConstructor.cpp
+++ b/Userland/Libraries/LibJS/Runtime/Intl/DurationFormatConstructor.cpp
@@ -77,7 +77,7 @@ ThrowCompletionOr<NonnullGCPtr<Object>> DurationFormatConstructor::construct(Fun
     opt.nu = numbering_system.is_undefined() ? Optional<String>() : TRY(numbering_system.as_string().utf8_string());
 
     // 9. Let r be ResolveLocale(%DurationFormat%.[[AvailableLocales]], requestedLocales, opt, %DurationFormat%.[[RelevantExtensionKeys]], %DurationFormat%.[[LocaleData]]).
-    auto result = TRY(resolve_locale(vm, requested_locales, opt, DurationFormat::relevant_extension_keys()));
+    auto result = MUST_OR_THROW_OOM(resolve_locale(vm, requested_locales, opt, DurationFormat::relevant_extension_keys()));
 
     // 10. Let locale be r.[[locale]].
     auto locale = move(result.locale);
diff --git a/Userland/Libraries/LibJS/Runtime/Intl/DurationFormatPrototype.cpp b/Userland/Libraries/LibJS/Runtime/Intl/DurationFormatPrototype.cpp
index 913cfe7a70..a8600a8f5b 100644
--- a/Userland/Libraries/LibJS/Runtime/Intl/DurationFormatPrototype.cpp
+++ b/Userland/Libraries/LibJS/Runtime/Intl/DurationFormatPrototype.cpp
@@ -43,7 +43,7 @@ JS_DEFINE_NATIVE_FUNCTION(DurationFormatPrototype::format)
     auto record = TRY(to_duration_record(vm, vm.argument(0)));
 
     // 4. Let parts be PartitionDurationFormatPattern(df, record).
-    auto parts = TRY(partition_duration_format_pattern(vm, *duration_format, record));
+    auto parts = MUST_OR_THROW_OOM(partition_duration_format_pattern(vm, *duration_format, record));
 
     // 5. Let result be a new empty String.
     StringBuilder result;
@@ -71,7 +71,7 @@ JS_DEFINE_NATIVE_FUNCTION(DurationFormatPrototype::format_to_parts)
     auto record = TRY(to_duration_record(vm, vm.argument(0)));
 
     // 4. Let parts be PartitionDurationFormatPattern(df, record).
-    auto parts = TRY(partition_duration_format_pattern(vm, *duration_format, record));
+    auto parts = MUST_OR_THROW_OOM(partition_duration_format_pattern(vm, *duration_format, record));
 
     // 5. Let result be ! ArrayCreate(0).
     auto result = MUST(Array::create(realm, 0));
diff --git a/Userland/Libraries/LibJS/Runtime/Intl/ListFormat.cpp b/Userland/Libraries/LibJS/Runtime/Intl/ListFormat.cpp
index 017106556a..2b5b0b522c 100644
--- a/Userland/Libraries/LibJS/Runtime/Intl/ListFormat.cpp
+++ b/Userland/Libraries/LibJS/Runtime/Intl/ListFormat.cpp
@@ -49,8 +49,7 @@ StringView ListFormat::type_string() const
 ThrowCompletionOr<Vector<PatternPartition>> deconstruct_pattern(VM& vm, StringView pattern, Placeables placeables)
 {
     // 1. Let patternParts be ! PartitionPattern(pattern).
-    // NOTE: We TRY this operation only to propagate OOM errors.
-    auto pattern_parts = TRY(partition_pattern(vm, pattern));
+    auto pattern_parts = MUST_OR_THROW_OOM(partition_pattern(vm, pattern));
 
     // 2. Let result be a new empty List.
     Vector<PatternPartition> result {};
@@ -127,7 +126,7 @@ ThrowCompletionOr<Vector<PatternPartition>> create_parts_from_list(VM& vm, ListF
         placeables.set("1"sv, move(second));
 
         // f. Return ! DeconstructPattern(pattern, placeables).
-        return deconstruct_pattern(vm, pattern, move(placeables));
+        return MUST_OR_THROW_OOM(deconstruct_pattern(vm, pattern, move(placeables)));
     }
 
     // 4. Let last be a new Record { [[Type]]: "element", [[Value]]: list[size - 1] }.
@@ -173,8 +172,7 @@ ThrowCompletionOr<Vector<PatternPartition>> create_parts_from_list(VM& vm, ListF
         placeables.set("1"sv, move(parts));
 
         // g. Set parts to ! DeconstructPattern(pattern, placeables).
-        // NOTE: We TRY this operation only to propagate OOM errors.
-        parts = TRY(deconstruct_pattern(vm, pattern, move(placeables)));
+        parts = MUST_OR_THROW_OOM(deconstruct_pattern(vm, pattern, move(placeables)));
 
         // h. Decrement i by 1.
     } while (i-- != 0);
@@ -187,8 +185,7 @@ ThrowCompletionOr<Vector<PatternPartition>> create_parts_from_list(VM& vm, ListF
 ThrowCompletionOr<DeprecatedString> format_list(VM& vm, ListFormat const& list_format, Vector<DeprecatedString> const& list)
 {
     // 1. Let parts be ! CreatePartsFromList(listFormat, list).
-    // NOTE: We TRY this operation only to propagate OOM errors.
-    auto parts = TRY(create_parts_from_list(vm, list_format, list));
+    auto parts = MUST_OR_THROW_OOM(create_parts_from_list(vm, list_format, list));
 
     // 2. Let result be an empty String.
     StringBuilder result;
@@ -209,8 +206,7 @@ ThrowCompletionOr<Array*> format_list_to_parts(VM& vm, ListFormat const& list_fo
     auto& realm = *vm.current_realm();
 
     // 1. Let parts be ! CreatePartsFromList(listFormat, list).
-    // NOTE: We TRY this operation only to propagate OOM errors.
-    auto parts = TRY(create_parts_from_list(vm, list_format, list));
+    auto parts = MUST_OR_THROW_OOM(create_parts_from_list(vm, list_format, list));
 
     // 2. Let result be ! ArrayCreate(0).
     auto result = MUST(Array::create(realm, 0));
diff --git a/Userland/Libraries/LibJS/Runtime/Intl/ListFormatPrototype.cpp b/Userland/Libraries/LibJS/Runtime/Intl/ListFormatPrototype.cpp
index b3ea2e24e7..18c94ef60e 100644
--- a/Userland/Libraries/LibJS/Runtime/Intl/ListFormatPrototype.cpp
+++ b/Userland/Libraries/LibJS/Runtime/Intl/ListFormatPrototype.cpp
@@ -46,8 +46,7 @@ JS_DEFINE_NATIVE_FUNCTION(ListFormatPrototype::format)
     auto string_list = TRY(string_list_from_iterable(vm, list));
 
     // 4. Return ! FormatList(lf, stringList).
-    // NOTE: We TRY this operation only to propagate OOM errors.
-    auto formatted = TRY(format_list(vm, *list_format, string_list));
+    auto formatted = MUST_OR_THROW_OOM(format_list(vm, *list_format, string_list));
     return PrimitiveString::create(vm, move(formatted));
 }
 
@@ -64,8 +63,7 @@ JS_DEFINE_NATIVE_FUNCTION(ListFormatPrototype::format_to_parts)
     auto string_list = TRY(string_list_from_iterable(vm, list));
 
     // 4. Return ! FormatListToParts(lf, stringList).
-    // NOTE: We TRY this operation only to propagate OOM errors.
-    return TRY(format_list_to_parts(vm, *list_format, string_list));
+    return MUST_OR_THROW_OOM(format_list_to_parts(vm, *list_format, string_list));
 }
 
 // 13.3.5 Intl.ListFormat.prototype.resolvedOptions ( ), https://tc39.es/ecma402/#sec-Intl.ListFormat.prototype.resolvedoptions
diff --git a/Userland/Libraries/LibJS/Runtime/Intl/LocaleConstructor.cpp b/Userland/Libraries/LibJS/Runtime/Intl/LocaleConstructor.cpp
index e0d8fc3a3b..e6b002a512 100644
--- a/Userland/Libraries/LibJS/Runtime/Intl/LocaleConstructor.cpp
+++ b/Userland/Libraries/LibJS/Runtime/Intl/LocaleConstructor.cpp
@@ -47,7 +47,7 @@ static ThrowCompletionOr<String> apply_options_to_tag(VM& vm, StringView tag, Ob
     // 2. Assert: Type(options) is Object.
 
     // 3. If ! IsStructurallyValidLanguageTag(tag) is false, throw a RangeError exception.
-    auto locale_id = TRY(is_structurally_valid_language_tag(vm, tag));
+    auto locale_id = MUST_OR_THROW_OOM(is_structurally_valid_language_tag(vm, tag));
     if (!locale_id.has_value())
         return vm.throw_completion<RangeError>(ErrorType::IntlInvalidLanguageTag, tag);
 
@@ -67,8 +67,7 @@ static ThrowCompletionOr<String> apply_options_to_tag(VM& vm, StringView tag, Ob
     auto region = TRY(get_string_option(vm, options, vm.names.region, ::Locale::is_unicode_region_subtag));
 
     // 10. Set tag to ! CanonicalizeUnicodeLocaleId(tag).
-    // NOTE: We TRY this operation only to propagate OOM errors.
-    auto canonicalized_tag = TRY(canonicalize_unicode_locale_id(vm, *locale_id));
+    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));
@@ -103,7 +102,7 @@ static ThrowCompletionOr<String> apply_options_to_tag(VM& vm, StringView tag, Ob
 
     // 16. Set tag to tag with the substring corresponding to the unicode_language_id production replaced by the string languageId.
     // 17. Return ! CanonicalizeUnicodeLocaleId(tag).
-    return canonicalize_unicode_locale_id(vm, *locale_id);
+    return MUST_OR_THROW_OOM(canonicalize_unicode_locale_id(vm, *locale_id));
 }
 
 // 14.1.3 ApplyUnicodeExtensionToTag ( tag, options, relevantExtensionKeys ), https://tc39.es/ecma402/#sec-apply-unicode-extension-to-tag
@@ -208,7 +207,7 @@ static ThrowCompletionOr<LocaleAndKeys> apply_unicode_extension_to_tag(VM& vm, S
     // 9. If newExtension is not the empty String, then
     if (!new_extension.attributes.is_empty() || !new_extension.keywords.is_empty()) {
         // a. Let locale be ! InsertUnicodeExtensionAndCanonicalize(locale, newExtension).
-        locale = TRY(insert_unicode_extension_and_canonicalize(vm, locale_id.release_value(), move(new_extension)));
+        locale = MUST_OR_THROW_OOM(insert_unicode_extension_and_canonicalize(vm, locale_id.release_value(), move(new_extension)));
     }
 
     // 10. Set result.[[locale]] to locale.
@@ -324,8 +323,7 @@ ThrowCompletionOr<NonnullGCPtr<Object>> LocaleConstructor::construct(FunctionObj
     opt.nu = TRY(get_string_option(vm, *options, vm.names.numberingSystem, ::Locale::is_type_identifier));
 
     // 29. Let r be ! ApplyUnicodeExtensionToTag(tag, opt, relevantExtensionKeys).
-    // NOTE: We TRY this operation only to propagate OOM errors.
-    auto result = TRY(apply_unicode_extension_to_tag(vm, tag, move(opt), relevant_extension_keys));
+    auto result = MUST_OR_THROW_OOM(apply_unicode_extension_to_tag(vm, tag, move(opt), relevant_extension_keys));
 
     // 30. Set locale.[[Locale]] to r.[[locale]].
     locale->set_locale(move(result.locale));
diff --git a/Userland/Libraries/LibJS/Runtime/Intl/LocalePrototype.cpp b/Userland/Libraries/LibJS/Runtime/Intl/LocalePrototype.cpp
index 5cd19a0f6d..a6a05826ac 100644
--- a/Userland/Libraries/LibJS/Runtime/Intl/LocalePrototype.cpp
+++ b/Userland/Libraries/LibJS/Runtime/Intl/LocalePrototype.cpp
@@ -69,8 +69,7 @@ JS_DEFINE_NATIVE_FUNCTION(LocalePrototype::maximize)
         locale->language_id = maximal.release_value();
 
     // 4. Return ! Construct(%Locale%, maximal).
-    // NOTE: We TRY this operation only to propagate OOM errors.
-    return TRY(Locale::create(realm, locale.release_value()));
+    return MUST_OR_THROW_OOM(Locale::create(realm, locale.release_value()));
 }
 
 // 14.3.4 Intl.Locale.prototype.minimize ( ), https://tc39.es/ecma402/#sec-Intl.Locale.prototype.minimize
@@ -90,8 +89,7 @@ JS_DEFINE_NATIVE_FUNCTION(LocalePrototype::minimize)
         locale->language_id = minimal.release_value();
 
     // 4. Return ! Construct(%Locale%, minimal).
-    // NOTE: We TRY this operation only to propagate OOM errors.
-    return TRY(Locale::create(realm, locale.release_value()));
+    return MUST_OR_THROW_OOM(Locale::create(realm, locale.release_value()));
 }
 
 // 14.3.5 Intl.Locale.prototype.toString ( ), https://tc39.es/ecma402/#sec-Intl.Locale.prototype.toString
diff --git a/Userland/Libraries/LibJS/Runtime/Intl/NumberFormat.cpp b/Userland/Libraries/LibJS/Runtime/Intl/NumberFormat.cpp
index 32bd9b8656..d153870c2d 100644
--- a/Userland/Libraries/LibJS/Runtime/Intl/NumberFormat.cpp
+++ b/Userland/Libraries/LibJS/Runtime/Intl/NumberFormat.cpp
@@ -581,7 +581,7 @@ ThrowCompletionOr<Vector<PatternPartition>> partition_number_pattern(VM& vm, Num
     Vector<PatternPartition> result;
 
     // 8. Let patternParts be PartitionPattern(pattern).
-    auto pattern_parts = TRY(pattern->visit([&](auto const& p) { return partition_pattern(vm, p); }));
+    auto pattern_parts = MUST_OR_THROW_OOM(pattern->visit([&](auto const& p) { return partition_pattern(vm, p); }));
 
     // 9. For each Record { [[Type]], [[Value]] } patternPart of patternParts, do
     for (auto& pattern_part : pattern_parts) {
@@ -597,7 +597,7 @@ ThrowCompletionOr<Vector<PatternPartition>> partition_number_pattern(VM& vm, Num
         // c. Else if p is equal to "number", then
         else if (part == "number"sv) {
             // i. Let notationSubParts be PartitionNotationSubPattern(numberFormat, x, n, exponent).
-            auto notation_sub_parts = TRY(partition_notation_sub_pattern(vm, number_format, number, formatted_string, exponent));
+            auto notation_sub_parts = MUST_OR_THROW_OOM(partition_notation_sub_pattern(vm, number_format, number, formatted_string, exponent));
             // ii. Append all elements of notationSubParts to result.
             result.extend(move(notation_sub_parts));
         }
@@ -742,7 +742,7 @@ ThrowCompletionOr<Vector<PatternPartition>> partition_notation_sub_pattern(VM& v
             return Vector<PatternPartition> {};
 
         // b. Let patternParts be PartitionPattern(notationSubPattern).
-        auto pattern_parts = TRY(partition_pattern(vm, *notation_sub_pattern));
+        auto pattern_parts = MUST_OR_THROW_OOM(partition_pattern(vm, *notation_sub_pattern));
 
         // c. For each Record { [[Type]], [[Value]] } patternPart of patternParts, do
         for (auto& pattern_part : pattern_parts) {
diff --git a/Userland/Libraries/LibJS/Runtime/Intl/NumberFormatConstructor.cpp b/Userland/Libraries/LibJS/Runtime/Intl/NumberFormatConstructor.cpp
index 68f0bf7a32..30e4dbb816 100644
--- a/Userland/Libraries/LibJS/Runtime/Intl/NumberFormatConstructor.cpp
+++ b/Userland/Libraries/LibJS/Runtime/Intl/NumberFormatConstructor.cpp
@@ -112,7 +112,7 @@ ThrowCompletionOr<NumberFormat*> initialize_number_format(VM& vm, NumberFormat&
 
     // 9. Let localeData be %NumberFormat%.[[LocaleData]].
     // 10. Let r be ResolveLocale(%NumberFormat%.[[AvailableLocales]], requestedLocales, opt, %NumberFormat%.[[RelevantExtensionKeys]], localeData).
-    auto result = TRY(resolve_locale(vm, requested_locales, opt, NumberFormat::relevant_extension_keys()));
+    auto result = MUST_OR_THROW_OOM(resolve_locale(vm, requested_locales, opt, NumberFormat::relevant_extension_keys()));
 
     // 11. Set numberFormat.[[Locale]] to r.[[locale]].
     number_format.set_locale(move(result.locale));
diff --git a/Userland/Libraries/LibJS/Runtime/Intl/RelativeTimeFormat.cpp b/Userland/Libraries/LibJS/Runtime/Intl/RelativeTimeFormat.cpp
index 21738faebb..801627e6e5 100644
--- a/Userland/Libraries/LibJS/Runtime/Intl/RelativeTimeFormat.cpp
+++ b/Userland/Libraries/LibJS/Runtime/Intl/RelativeTimeFormat.cpp
@@ -174,8 +174,7 @@ ThrowCompletionOr<Vector<PatternPartitionWithUnit>> partition_relative_time_patt
     auto patterns = find_patterns_for_tense_or_number(tense);
 
     // 20. Let fv be ! PartitionNumberPattern(relativeTimeFormat.[[NumberFormat]], value).
-    // NOTE: We TRY this operation only to propagate OOM errors.
-    auto value_partitions = TRY(partition_number_pattern(vm, relative_time_format.number_format(), Value(value)));
+    auto value_partitions = MUST_OR_THROW_OOM(partition_number_pattern(vm, relative_time_format.number_format(), Value(value)));
 
     // 21. Let pr be ! ResolvePlural(relativeTimeFormat.[[PluralRules]], value).
     auto plurality = resolve_plural(relative_time_format.plural_rules(), Value(value));
@@ -186,14 +185,14 @@ ThrowCompletionOr<Vector<PatternPartitionWithUnit>> partition_relative_time_patt
         return Vector<PatternPartitionWithUnit> {};
 
     // 23. Return ! MakePartsList(pattern, unit, fv).
-    return make_parts_list(vm, pattern->pattern, ::Locale::time_unit_to_string(time_unit), move(value_partitions));
+    return MUST_OR_THROW_OOM(make_parts_list(vm, pattern->pattern, ::Locale::time_unit_to_string(time_unit), move(value_partitions)));
 }
 
 // 17.5.3 MakePartsList ( pattern, unit, parts ), https://tc39.es/ecma402/#sec-makepartslist
 ThrowCompletionOr<Vector<PatternPartitionWithUnit>> make_parts_list(VM& vm, StringView pattern, StringView unit, Vector<PatternPartition> parts)
 {
     // 1. Let patternParts be PartitionPattern(pattern).
-    auto pattern_parts = TRY(partition_pattern(vm, pattern));
+    auto pattern_parts = MUST_OR_THROW_OOM(partition_pattern(vm, pattern));
 
     // 2. Let result be a new empty List.
     Vector<PatternPartitionWithUnit> result;
diff --git a/Userland/Libraries/LibJS/Runtime/Intl/RelativeTimeFormatConstructor.cpp b/Userland/Libraries/LibJS/Runtime/Intl/RelativeTimeFormatConstructor.cpp
index 2381a3b575..0f59839606 100644
--- a/Userland/Libraries/LibJS/Runtime/Intl/RelativeTimeFormatConstructor.cpp
+++ b/Userland/Libraries/LibJS/Runtime/Intl/RelativeTimeFormatConstructor.cpp
@@ -110,7 +110,7 @@ ThrowCompletionOr<RelativeTimeFormat*> initialize_relative_time_format(VM& vm, R
 
     // 9. Let localeData be %RelativeTimeFormat%.[[LocaleData]].
     // 10. Let r be ResolveLocale(%RelativeTimeFormat%.[[AvailableLocales]], requestedLocales, opt, %RelativeTimeFormat%.[[RelevantExtensionKeys]], localeData).
-    auto result = TRY(resolve_locale(vm, requested_locales, opt, RelativeTimeFormat::relevant_extension_keys()));
+    auto result = MUST_OR_THROW_OOM(resolve_locale(vm, requested_locales, opt, RelativeTimeFormat::relevant_extension_keys()));
 
     // 11. Let locale be r.[[locale]].
     auto locale = move(result.locale);