Counterexample: half of every language feature in C++ that got pushed into the library. Move semantics, discriminated unions, SFINAE (concepts mostly fixed this one), s̴͔̮̆̄ț̴̛̝d̴̨͓͆́:̵̖̭̒:̶̖̀͛ḯ̴̘́n̸̙̐i̸̜̤͘͝t̴̪̂i̵̛̭͒a̸̻̐̾ḷ̴̩͂ỉ̵̧z̸̩̱̓é̵̮͘r̵͇̖̈́_̷̖̟͛l̶͇̀͜i̷̮̗̿̉ṣ̴̿̋ṭ̴́͑ etc.