diff --git a/Userland/Libraries/LibJS/Parser.cpp b/Userland/Libraries/LibJS/Parser.cpp index b787ae1f87..3fbe0657ca 100644 --- a/Userland/Libraries/LibJS/Parser.cpp +++ b/Userland/Libraries/LibJS/Parser.cpp @@ -4252,6 +4252,7 @@ Token Parser::consume() if (old_token.is_identifier_name() && (m_state.current_token.type() == TokenType::Slash || m_state.current_token.type() == TokenType::SlashEquals)) { m_state.current_token = m_state.lexer.force_slash_as_regex(); } + m_state.previous_token_was_period = old_token.type() == TokenType::Period; return old_token; } @@ -4259,11 +4260,17 @@ Token Parser::consume_and_allow_division() { auto old_token = m_state.current_token; m_state.current_token = m_state.lexer.next(); - // NOTE: This is the bare minimum needed to decide whether we might need an arguments object - // in a function expression or declaration. ("might" because the AST implements some further - // conditions from the spec that rule out the need for allocating one) - if (old_token.type() == TokenType::Identifier && old_token.value().is_one_of("arguments"sv, "eval"sv)) + + // NOTE: This is the bare minimum needed to decide whether we might need an `arguments` object + // in a function expression or declaration. ("Might" because ESFO implements some further + // conditions from the spec that rule out the need for allocating one.) + // Basically any freestanding use of `arguments` in a function body. This is not perfect + // but avoids a lot of unnecessary arguments objects. We check if the previous token was + // a period to avoid creating `arguments` due to an unrelated property access (`o.arguments`) + if (old_token.type() == TokenType::Identifier && old_token.value().is_one_of("arguments"sv, "eval"sv) && !m_state.previous_token_was_period) m_state.function_might_need_arguments_object = true; + + m_state.previous_token_was_period = old_token.type() == TokenType::Period; return old_token; } diff --git a/Userland/Libraries/LibJS/Parser.h b/Userland/Libraries/LibJS/Parser.h index 0a08894ffd..06c0ce47ac 100644 --- a/Userland/Libraries/LibJS/Parser.h +++ b/Userland/Libraries/LibJS/Parser.h @@ -305,6 +305,7 @@ private: struct ParserState { Lexer lexer; Token current_token; + bool previous_token_was_period { false }; Vector errors; ScopePusher* current_scope_pusher { nullptr };