LibWeb/CSS: Remove tiny-oom propagation from CSS Tokenizer

Author: https://github.com/AtkinsSJ
Commit: 89c5f25016
Pull-request: https://github.com/LadybirdBrowser/ladybird/pull/846

Userland/Libraries/LibWeb/CSS/Parser/Parser.cpp

@@ -95,7 +95,7 @@ namespace Web::CSS::Parser {
 
 ErrorOr<Parser> Parser::create(ParsingContext const& context, StringView input, StringView encoding)
 {
-    auto tokens = TRY(Tokenizer::tokenize(input, encoding));
+    auto tokens = Tokenizer::tokenize(input, encoding);
     return Parser { context, move(tokens) };
 }
 

Userland/Libraries/LibWeb/CSS/Parser/Tokenizer.cpp

@@ -195,14 +195,14 @@ static inline bool is_E(u32 code_point)
     return code_point == 0x45;
 }
 
-ErrorOr<Vector<Token>> Tokenizer::tokenize(StringView input, StringView encoding)
+Vector<Token> Tokenizer::tokenize(StringView input, StringView encoding)
 {
     // https://www.w3.org/TR/css-syntax-3/#css-filter-code-points
-    auto filter_code_points = [](StringView input, auto encoding) -> ErrorOr<String> {
+    auto filter_code_points = [](StringView input, auto encoding) -> String {
         auto decoder = TextCodec::decoder_for(encoding);
         VERIFY(decoder.has_value());
 
-        auto decoded_input = TRY(decoder->to_utf8(input));
+        auto decoded_input = MUST(decoder->to_utf8(input));
 
         // OPTIMIZATION: If the input doesn't contain any CR or FF, we can skip the filtering
         bool const contains_cr_or_ff = [&] {
@@ -227,25 +227,25 @@ ErrorOr<Vector<Token>> Tokenizer::tokenize(StringView input, StringView encoding
             // in input by a single U+000A LINE FEED (LF) code point.
             if (code_point == '\r') {
                 if (last_was_carriage_return) {
-                    TRY(builder.try_append('\n'));
+                    builder.append('\n');
                 } else {
                     last_was_carriage_return = true;
                 }
             } else {
                 if (last_was_carriage_return)
-                    TRY(builder.try_append('\n'));
+                    builder.append('\n');
 
                 if (code_point == '\n') {
                     if (!last_was_carriage_return)
-                        TRY(builder.try_append('\n'));
+                        builder.append('\n');
 
                 } else if (code_point == '\f') {
-                    TRY(builder.try_append('\n'));
+                    builder.append('\n');
                     // Replace any U+0000 NULL or surrogate code points in input with U+FFFD REPLACEMENT CHARACTER (<28>).
                 } else if (code_point == 0x00 || (code_point >= 0xD800 && code_point <= 0xDFFF)) {
-                    TRY(builder.try_append_code_point(REPLACEMENT_CHARACTER));
+                    builder.append_code_point(REPLACEMENT_CHARACTER);
                 } else {
-                    TRY(builder.try_append_code_point(code_point));
+                    builder.append_code_point(code_point);
                 }
 
                 last_was_carriage_return = false;
@@ -254,7 +254,7 @@ ErrorOr<Vector<Token>> Tokenizer::tokenize(StringView input, StringView encoding
         return builder.to_string_without_validation();
     };
 
-    Tokenizer tokenizer { TRY(filter_code_points(input, encoding)) };
+    Tokenizer tokenizer { filter_code_points(input, encoding) };
     return tokenizer.tokenize();
 }
 
@@ -265,15 +265,15 @@ Tokenizer::Tokenizer(String decoded_input)
 {
 }
 
-ErrorOr<Vector<Token>> Tokenizer::tokenize()
+Vector<Token> Tokenizer::tokenize()
 {
     Vector<Token> tokens;
     for (;;) {
         auto token_start = m_position;
-        auto token = TRY(consume_a_token());
+        auto token = consume_a_token();
         token.m_start_position = token_start;
         token.m_end_position = m_position;
-        TRY(tokens.try_append(token));
+        tokens.append(token);
 
         if (token.is(Token::Type::EndOfFile)) {
             return tokens;
@@ -441,14 +441,14 @@ u32 Tokenizer::consume_escaped_code_point()
 }
 
 // https://www.w3.org/TR/css-syntax-3/#consume-ident-like-token
-ErrorOr<Token> Tokenizer::consume_an_ident_like_token()
+Token Tokenizer::consume_an_ident_like_token()
 {
     // This section describes how to consume an ident-like token from a stream of code points.
     // It returns an <ident-token>, <function-token>, <url-token>, or <bad-url-token>.
 
     // Consume an ident sequence, and let string be the result.
     auto start_byte_offset = current_byte_offset();
-    auto string = TRY(consume_an_ident_sequence());
+    auto string = consume_an_ident_sequence();
 
     // If string’s value is an ASCII case-insensitive match for "url", and the next input code
     // point is U+0028 LEFT PARENTHESIS ((), consume it.
@@ -470,7 +470,7 @@ ErrorOr<Token> Tokenizer::consume_an_ident_like_token()
         // <function-token> with its value set to string and return it.
         auto next_two = peek_twin();
         if (is_quotation_mark(next_two.first) || is_apostrophe(next_two.first) || (is_whitespace(next_two.first) && (is_quotation_mark(next_two.second) || is_apostrophe(next_two.second)))) {
-            return create_value_token(Token::Type::Function, move(string), TRY(input_since(start_byte_offset)));
+            return create_value_token(Token::Type::Function, move(string), input_since(start_byte_offset));
         }
 
         // Otherwise, consume a url token, and return it.
@@ -482,11 +482,11 @@ ErrorOr<Token> Tokenizer::consume_an_ident_like_token()
         (void)next_code_point();
 
         // Create a <function-token> with its value set to string and return it.
-        return create_value_token(Token::Type::Function, move(string), TRY(input_since(start_byte_offset)));
+        return create_value_token(Token::Type::Function, move(string), input_since(start_byte_offset));
     }
 
     // Otherwise, create an <ident-token> with its value set to string and return it.
-    return create_value_token(Token::Type::Ident, move(string), TRY(input_since(start_byte_offset)));
+    return create_value_token(Token::Type::Ident, move(string), input_since(start_byte_offset));
 }
 
 // https://www.w3.org/TR/css-syntax-3/#consume-number
@@ -595,7 +595,7 @@ double Tokenizer::convert_a_string_to_a_number(StringView string)
 }
 
 // https://www.w3.org/TR/css-syntax-3/#consume-name
-ErrorOr<FlyString> Tokenizer::consume_an_ident_sequence()
+FlyString Tokenizer::consume_an_ident_sequence()
 {
     // This section describes how to consume an ident sequence from a stream of code points.
     // It returns a string containing the largest name that can be formed from adjacent
@@ -619,14 +619,14 @@ ErrorOr<FlyString> Tokenizer::consume_an_ident_sequence()
         // name code point
         if (is_ident_code_point(input)) {
             // Append the code point to result.
-            TRY(result.try_append_code_point(input));
+            result.append_code_point(input);
             continue;
         }
 
         // the stream starts with a valid escape
         if (is_valid_escape_sequence(start_of_input_stream_twin())) {
             // Consume an escaped code point. Append the returned code point to result.
-            TRY(result.try_append_code_point(consume_escaped_code_point()));
+            result.append_code_point(consume_escaped_code_point());
             continue;
         }
 
@@ -640,7 +640,7 @@ ErrorOr<FlyString> Tokenizer::consume_an_ident_sequence()
 }
 
 // https://www.w3.org/TR/css-syntax-3/#consume-url-token
-ErrorOr<Token> Tokenizer::consume_a_url_token()
+Token Tokenizer::consume_a_url_token()
 {
     // This section describes how to consume a url token from a stream of code points.
     // It returns either a <url-token> or a <bad-url-token>.
@@ -659,9 +659,9 @@ ErrorOr<Token> Tokenizer::consume_a_url_token()
     // 2. Consume as much whitespace as possible.
     consume_as_much_whitespace_as_possible();
 
-    auto make_token = [&]() -> ErrorOr<Token> {
+    auto make_token = [&]() -> Token {
-        token.m_value = TRY(FlyString::from_utf8(builder.string_view()));
+        token.m_value = builder.to_fly_string_without_validation();
-        token.m_representation = TRY(input_since(start_byte_offset));
+        token.m_representation = input_since(start_byte_offset);
         return token;
     };
 
@@ -705,7 +705,7 @@ ErrorOr<Token> Tokenizer::consume_a_url_token()
             // otherwise, consume the remnants of a bad url, create a <bad-url-token>, and return it.
             consume_the_remnants_of_a_bad_url();
             auto bad_url_token = create_new_token(Token::Type::BadUrl);
-            bad_url_token.m_representation = TRY(input_since(start_byte_offset));
+            bad_url_token.m_representation = input_since(start_byte_offset);
             return bad_url_token;
         }
 
@@ -718,7 +718,7 @@ ErrorOr<Token> Tokenizer::consume_a_url_token()
             log_parse_error();
             consume_the_remnants_of_a_bad_url();
             auto bad_url_token = create_new_token(Token::Type::BadUrl);
-            bad_url_token.m_representation = TRY(input_since(start_byte_offset));
+            bad_url_token.m_representation = input_since(start_byte_offset);
             return bad_url_token;
         }
 
@@ -735,7 +735,7 @@ ErrorOr<Token> Tokenizer::consume_a_url_token()
                 // Consume the remnants of a bad url, create a <bad-url-token>, and return it.
                 consume_the_remnants_of_a_bad_url();
                 auto bad_url_token = create_new_token(Token::Type::BadUrl);
-                bad_url_token.m_representation = TRY(input_since(start_byte_offset));
+                bad_url_token.m_representation = input_since(start_byte_offset);
                 return bad_url_token;
             }
         }
@@ -792,7 +792,7 @@ void Tokenizer::reconsume_current_input_code_point()
 }
 
 // https://www.w3.org/TR/css-syntax-3/#consume-numeric-token
-ErrorOr<Token> Tokenizer::consume_a_numeric_token()
+Token Tokenizer::consume_a_numeric_token()
 {
     // This section describes how to consume a numeric token from a stream of code points.
     // It returns either a <number-token>, <percentage-token>, or <dimension-token>.
@@ -810,13 +810,13 @@ ErrorOr<Token> Tokenizer::consume_a_numeric_token()
         token.m_number_value = number;
 
         // 2. Consume an ident sequence. Set the <dimension-token>’s unit to the returned value.
-        auto unit = TRY(consume_an_ident_sequence());
+        auto unit = consume_an_ident_sequence();
         VERIFY(!unit.is_empty());
         // NOTE: We intentionally store this in the `value`, to save space.
         token.m_value = move(unit);
 
         // 3. Return the <dimension-token>.
-        token.m_representation = TRY(input_since(start_byte_offset));
+        token.m_representation = input_since(start_byte_offset);
         return token;
     }
 
@@ -827,14 +827,14 @@ ErrorOr<Token> Tokenizer::consume_a_numeric_token()
         // Create a <percentage-token> with the same value as number, and return it.
         auto token = create_new_token(Token::Type::Percentage);
         token.m_number_value = number;
-        token.m_representation = TRY(input_since(start_byte_offset));
+        token.m_representation = input_since(start_byte_offset);
         return token;
     }
 
     // Otherwise, create a <number-token> with the same value and type flag as number, and return it.
     auto token = create_new_token(Token::Type::Number);
     token.m_number_value = number;
-    token.m_representation = TRY(input_since(start_byte_offset));
+    token.m_representation = input_since(start_byte_offset);
     return token;
 }
 
@@ -949,7 +949,7 @@ bool Tokenizer::would_start_an_ident_sequence(U32Triplet values)
 }
 
 // https://www.w3.org/TR/css-syntax-3/#consume-string-token
-ErrorOr<Token> Tokenizer::consume_string_token(u32 ending_code_point)
+Token Tokenizer::consume_string_token(u32 ending_code_point)
 {
     // This section describes how to consume a string token from a stream of code points.
     // It returns either a <string-token> or <bad-string-token>.
@@ -963,9 +963,9 @@ ErrorOr<Token> Tokenizer::consume_string_token(u32 ending_code_point)
     auto token = create_new_token(Token::Type::String);
     StringBuilder builder;
 
-    auto make_token = [&]() -> ErrorOr<Token> {
+    auto make_token = [&]() -> Token {
-        token.m_value = TRY(FlyString::from_utf8(builder.string_view()));
+        token.m_value = builder.to_fly_string_without_validation();
-        token.m_representation = TRY(input_since(start_byte_offset));
+        token.m_representation = input_since(start_byte_offset);
         return token;
     };
 
@@ -990,7 +990,7 @@ ErrorOr<Token> Tokenizer::consume_string_token(u32 ending_code_point)
             // <bad-string-token>, and return it.
             reconsume_current_input_code_point();
             auto bad_string_token = create_new_token(Token::Type::BadString);
-            bad_string_token.m_representation = TRY(input_since(start_byte_offset));
+            bad_string_token.m_representation = input_since(start_byte_offset);
             return bad_string_token;
         }
 
@@ -1059,7 +1059,7 @@ start:
 }
 
 // https://www.w3.org/TR/css-syntax-3/#consume-token
-ErrorOr<Token> Tokenizer::consume_a_token()
+Token Tokenizer::consume_a_token()
 {
     // This section describes how to consume a token from a stream of code points.
     // It will return a single token of any type.
@@ -1077,7 +1077,7 @@ ErrorOr<Token> Tokenizer::consume_a_token()
         // Consume as much whitespace as possible. Return a <whitespace-token>.
         consume_as_much_whitespace_as_possible();
         auto token = create_new_token(Token::Type::Whitespace);
-        token.m_representation = TRY(input_since(start_byte_offset));
+        token.m_representation = input_since(start_byte_offset);
         return token;
     }
 
@@ -1107,16 +1107,16 @@ ErrorOr<Token> Tokenizer::consume_a_token()
                 token.m_hash_type = Token::HashType::Id;
 
             // 3. Consume an ident sequence, and set the <hash-token>’s value to the returned string.
-            auto name = TRY(consume_an_ident_sequence());
+            auto name = consume_an_ident_sequence();
             token.m_value = move(name);
 
             // 4. Return the <hash-token>.
-            token.m_representation = TRY(input_since(start_byte_offset));
+            token.m_representation = input_since(start_byte_offset);
             return token;
         }
 
         // Otherwise, return a <delim-token> with its value set to the current input code point.
-        return create_value_token(Token::Type::Delim, input, TRY(input_since(start_byte_offset)));
+        return create_value_token(Token::Type::Delim, input, input_since(start_byte_offset));
     }
 
     // U+0027 APOSTROPHE (')
@@ -1131,7 +1131,7 @@ ErrorOr<Token> Tokenizer::consume_a_token()
         dbgln_if(CSS_TOKENIZER_DEBUG, "is left paren");
         // Return a <(-token>.
         Token token = create_new_token(Token::Type::OpenParen);
-        token.m_representation = TRY(input_since(start_byte_offset));
+        token.m_representation = input_since(start_byte_offset);
         return token;
     }
 
@@ -1140,7 +1140,7 @@ ErrorOr<Token> Tokenizer::consume_a_token()
         dbgln_if(CSS_TOKENIZER_DEBUG, "is right paren");
         // Return a <)-token>.
         Token token = create_new_token(Token::Type::CloseParen);
-        token.m_representation = TRY(input_since(start_byte_offset));
+        token.m_representation = input_since(start_byte_offset);
         return token;
     }
 
@@ -1155,7 +1155,7 @@ ErrorOr<Token> Tokenizer::consume_a_token()
         }
 
         // Otherwise, return a <delim-token> with its value set to the current input code point.
-        return create_value_token(Token::Type::Delim, input, TRY(input_since(start_byte_offset)));
+        return create_value_token(Token::Type::Delim, input, input_since(start_byte_offset));
     }
 
     // U+002C COMMA (,)
@@ -1163,7 +1163,7 @@ ErrorOr<Token> Tokenizer::consume_a_token()
         dbgln_if(CSS_TOKENIZER_DEBUG, "is comma");
         // Return a <comma-token>.
         Token token = create_new_token(Token::Type::Comma);
-        token.m_representation = TRY(input_since(start_byte_offset));
+        token.m_representation = input_since(start_byte_offset);
         return token;
     }
 
@@ -1185,7 +1185,7 @@ ErrorOr<Token> Tokenizer::consume_a_token()
             (void)next_code_point();
 
             Token token = create_new_token(Token::Type::CDC);
-            token.m_representation = TRY(input_since(start_byte_offset));
+            token.m_representation = input_since(start_byte_offset);
             return token;
         }
 
@@ -1197,7 +1197,7 @@ ErrorOr<Token> Tokenizer::consume_a_token()
         }
 
         // Otherwise, return a <delim-token> with its value set to the current input code point.
-        return create_value_token(Token::Type::Delim, input, TRY(input_since(start_byte_offset)));
+        return create_value_token(Token::Type::Delim, input, input_since(start_byte_offset));
     }
 
     // U+002E FULL STOP (.)
@@ -1211,7 +1211,7 @@ ErrorOr<Token> Tokenizer::consume_a_token()
         }
 
         // Otherwise, return a <delim-token> with its value set to the current input code point.
-        return create_value_token(Token::Type::Delim, input, TRY(input_since(start_byte_offset)));
+        return create_value_token(Token::Type::Delim, input, input_since(start_byte_offset));
     }
 
     // U+003A COLON (:)
@@ -1219,7 +1219,7 @@ ErrorOr<Token> Tokenizer::consume_a_token()
         dbgln_if(CSS_TOKENIZER_DEBUG, "is colon");
         // Return a <colon-token>.
         Token token = create_new_token(Token::Type::Colon);
-        token.m_representation = TRY(input_since(start_byte_offset));
+        token.m_representation = input_since(start_byte_offset);
         return token;
     }
 
@@ -1228,7 +1228,7 @@ ErrorOr<Token> Tokenizer::consume_a_token()
         dbgln_if(CSS_TOKENIZER_DEBUG, "is semicolon");
         // Return a <semicolon-token>.
         Token token = create_new_token(Token::Type::Semicolon);
-        token.m_representation = TRY(input_since(start_byte_offset));
+        token.m_representation = input_since(start_byte_offset);
         return token;
     }
 
@@ -1244,12 +1244,12 @@ ErrorOr<Token> Tokenizer::consume_a_token()
             (void)next_code_point();
 
             Token token = create_new_token(Token::Type::CDO);
-            token.m_representation = TRY(input_since(start_byte_offset));
+            token.m_representation = input_since(start_byte_offset);
             return token;
         }
 
         // Otherwise, return a <delim-token> with its value set to the current input code point.
-        return create_value_token(Token::Type::Delim, input, TRY(input_since(start_byte_offset)));
+        return create_value_token(Token::Type::Delim, input, input_since(start_byte_offset));
     }
 
     // U+0040 COMMERCIAL AT (@)
@@ -1258,12 +1258,12 @@ ErrorOr<Token> Tokenizer::consume_a_token()
         // If the next 3 input code points would start an ident sequence, consume an ident sequence, create
         // an <at-keyword-token> with its value set to the returned value, and return it.
         if (would_start_an_ident_sequence(peek_triplet())) {
-            auto name = TRY(consume_an_ident_sequence());
+            auto name = consume_an_ident_sequence();
-            return create_value_token(Token::Type::AtKeyword, move(name), TRY(input_since(start_byte_offset)));
+            return create_value_token(Token::Type::AtKeyword, move(name), input_since(start_byte_offset));
         }
 
         // Otherwise, return a <delim-token> with its value set to the current input code point.
-        return create_value_token(Token::Type::Delim, input, TRY(input_since(start_byte_offset)));
+        return create_value_token(Token::Type::Delim, input, input_since(start_byte_offset));
     }
 
     // U+005B LEFT SQUARE BRACKET ([)
@@ -1271,7 +1271,7 @@ ErrorOr<Token> Tokenizer::consume_a_token()
         dbgln_if(CSS_TOKENIZER_DEBUG, "is open square");
         // Return a <[-token>.
         Token token = create_new_token(Token::Type::OpenSquare);
-        token.m_representation = TRY(input_since(start_byte_offset));
+        token.m_representation = input_since(start_byte_offset);
         return token;
     }
 
@@ -1288,7 +1288,7 @@ ErrorOr<Token> Tokenizer::consume_a_token()
         // Otherwise, this is a parse error. Return a <delim-token> with its value set to the
         // current input code point.
         log_parse_error();
-        return create_value_token(Token::Type::Delim, input, TRY(input_since(start_byte_offset)));
+        return create_value_token(Token::Type::Delim, input, input_since(start_byte_offset));
     }
 
     // U+005D RIGHT SQUARE BRACKET (])
@@ -1296,7 +1296,7 @@ ErrorOr<Token> Tokenizer::consume_a_token()
         dbgln_if(CSS_TOKENIZER_DEBUG, "is closed square");
         // Return a <]-token>.
         Token token = create_new_token(Token::Type::CloseSquare);
-        token.m_representation = TRY(input_since(start_byte_offset));
+        token.m_representation = input_since(start_byte_offset);
         return token;
     }
 
@@ -1305,7 +1305,7 @@ ErrorOr<Token> Tokenizer::consume_a_token()
         dbgln_if(CSS_TOKENIZER_DEBUG, "is open curly");
         // Return a <{-token>.
         Token token = create_new_token(Token::Type::OpenCurly);
-        token.m_representation = TRY(input_since(start_byte_offset));
+        token.m_representation = input_since(start_byte_offset);
         return token;
     }
 
@@ -1314,7 +1314,7 @@ ErrorOr<Token> Tokenizer::consume_a_token()
         dbgln_if(CSS_TOKENIZER_DEBUG, "is closed curly");
         // Return a <}-token>.
         Token token = create_new_token(Token::Type::CloseCurly);
-        token.m_representation = TRY(input_since(start_byte_offset));
+        token.m_representation = input_since(start_byte_offset);
         return token;
     }
 
@@ -1343,7 +1343,7 @@ ErrorOr<Token> Tokenizer::consume_a_token()
     // anything else
     dbgln_if(CSS_TOKENIZER_DEBUG, "is delimiter");
     // Return a <delim-token> with its value set to the current input code point.
-    return create_value_token(Token::Type::Delim, input, TRY(input_since(start_byte_offset)));
+    return create_value_token(Token::Type::Delim, input, input_since(start_byte_offset));
 }
 
 size_t Tokenizer::current_byte_offset() const
@@ -1351,9 +1351,9 @@ size_t Tokenizer::current_byte_offset() const
     return m_utf8_iterator.ptr() - m_utf8_view.bytes();
 }
 
-ErrorOr<String> Tokenizer::input_since(size_t offset) const
+String Tokenizer::input_since(size_t offset) const
 {
-    return m_decoded_input.substring_from_byte_offset_with_shared_superstring(offset, current_byte_offset() - offset);
+    return MUST(m_decoded_input.substring_from_byte_offset_with_shared_superstring(offset, current_byte_offset() - offset));
 }
 
 }

Userland/Libraries/LibWeb/CSS/Parser/Tokenizer.h

@@ -59,17 +59,17 @@ public:
 
 class Tokenizer {
 public:
-    static ErrorOr<Vector<Token>> tokenize(StringView input, StringView encoding);
+    static Vector<Token> tokenize(StringView input, StringView encoding);
 
     [[nodiscard]] static Token create_eof_token();
 
 private:
     explicit Tokenizer(String decoded_input);
 
-    [[nodiscard]] ErrorOr<Vector<Token>> tokenize();
+    [[nodiscard]] Vector<Token> tokenize();
 
     size_t current_byte_offset() const;
-    ErrorOr<String> input_since(size_t offset) const;
+    String input_since(size_t offset) const;
 
     [[nodiscard]] u32 next_code_point();
     [[nodiscard]] u32 peek_code_point(size_t offset = 0) const;
@@ -82,15 +82,15 @@ private:
     [[nodiscard]] static Token create_new_token(Token::Type);
     [[nodiscard]] static Token create_value_token(Token::Type, FlyString&& value, String&& representation);
     [[nodiscard]] static Token create_value_token(Token::Type, u32 value, String&& representation);
-    [[nodiscard]] ErrorOr<Token> consume_a_token();
+    [[nodiscard]] Token consume_a_token();
-    [[nodiscard]] ErrorOr<Token> consume_string_token(u32 ending_code_point);
+    [[nodiscard]] Token consume_string_token(u32 ending_code_point);
-    [[nodiscard]] ErrorOr<Token> consume_a_numeric_token();
+    [[nodiscard]] Token consume_a_numeric_token();
-    [[nodiscard]] ErrorOr<Token> consume_an_ident_like_token();
+    [[nodiscard]] Token consume_an_ident_like_token();
     [[nodiscard]] Number consume_a_number();
     [[nodiscard]] double convert_a_string_to_a_number(StringView);
-    [[nodiscard]] ErrorOr<FlyString> consume_an_ident_sequence();
+    [[nodiscard]] FlyString consume_an_ident_sequence();
     [[nodiscard]] u32 consume_escaped_code_point();
-    [[nodiscard]] ErrorOr<Token> consume_a_url_token();
+    [[nodiscard]] Token consume_a_url_token();
     void consume_the_remnants_of_a_bad_url();
     void consume_comments();
     void consume_as_much_whitespace_as_possible();

Userland/Libraries/LibWeb/CSS/SyntaxHighlighter/SyntaxHighlighter.cpp

@@ -45,7 +45,7 @@ void SyntaxHighlighter::rehighlight(Palette const& palette)
             false);
     };
 
-    auto tokens = CSS::Parser::Tokenizer::tokenize(text, "utf-8"sv).release_value_but_fixme_should_propagate_errors();
+    auto tokens = CSS::Parser::Tokenizer::tokenize(text, "utf-8"sv);
     for (auto const& token : tokens) {
         if (token.is(Parser::Token::Type::EndOfFile))
             break;