diff --git a/liblangutil/Exceptions.h b/liblangutil/Exceptions.h
index c441a6d2f962..2f2fdcb4c997 100644
--- a/liblangutil/Exceptions.h
+++ b/liblangutil/Exceptions.h
@@ -163,7 +163,7 @@ struct ErrorId
 	bool operator!=(ErrorId const& _rhs) const { return !(*this == _rhs); }
 	bool operator<(ErrorId const& _rhs) const { return error < _rhs.error; }
 };
-constexpr ErrorId operator"" _error(unsigned long long _error) { return ErrorId{ _error }; }
+constexpr ErrorId operator""_error(unsigned long long _error) { return ErrorId{ _error }; }
 
 class Error: virtual public util::Exception
 {
diff --git a/libyul/YulString.h b/libyul/YulString.h
index 329825a4465b..80d58f3ed788 100644
--- a/libyul/YulString.h
+++ b/libyul/YulString.h
@@ -163,7 +163,7 @@ class YulString
 	YulStringRepository::Handle m_handle{ 0, YulStringRepository::emptyHash() };
 };
 
-inline YulString operator "" _yulname(char const* _string, std::size_t _size)
+inline YulString operator""_yulname(char const* _string, std::size_t _size)
 {
 	return YulString(std::string_view(_string, _size));
 }