> I'd argue that accidentally quadratic algorithms are easier to hide in a concise language. Writing out a quadratic loop explicitly takes space, and that space alone might make people pay more attention than some subtle implicit language construct. Either way, the most common source of unintended quadratic (or higher) behavior is helper functions and library calls.

I disagree. When every loop is full of cruft around setting up the iterators, it's easy to drift past what's actually happening. In a language where looping over a list takes a single syntactic token, it's a lot more obvious when you've nested several such loops.

> The other thing to keep in mind when it comes to algorithms is that cache behavior and therefore memory layout matters a lot for performance on modern hardware. Managed languages really stand in the way of optimizing memory layout, which can be a systematic performance disadvantage compared to C++.

C++ doesn't really make cache behaviour clear either though. I agree that we need better tooling for handling those aspects of high-performance code, but they actually need to come from somewhere lower-level than C++.