If you want your high-level language to be as fast as C, it needs provably safe manual memory management (a.k.a. linear types) and provably safe unchecked array

If you want your high-level language to be as fast as C, it needs provably safe manual memory management (a.k.a. linear types) and provably safe unchecked array access (a.k.a. dependent types). Most high-level languages don't have these features, because in their current state they are really hard for programmers to use. See ATS for an example.