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Short circuiting introduces conditional branching. If you call a function on the right hand side of a || or && it might or might not be executed depending on th

by phire 6y ago

Short circuiting introduces conditional branching. If you call a function on the right hand side of a || or && it might or might not be executed depending on the value of the left hand side. Until this version of rust, all conditional branches were banned from const functions. I guess to keep things simple they just banned any feature that might cause branching.

marricks 6y ago
Ahh that makes a lot of sense, if you're going to have a compiler insert the result of a function having conditional branching seems a bit gnarly I guess?
- kibwen 6y ago
  For the history of this feature request, see https://github.com/rust-lang/rust/issues/29608 https://github.com/rust-lang/rust/issues/29608 as a starting point.
- Filligree 6y ago
  It's conditional based on what's ultimately constant data, so you end up with predictable output regardless.
marton78 6y ago
Why is branching a problem? Since `if` is now enabled in a const fn, it's trivial to rewrite && with & and if.
- kibwen 6y ago
  `if` wasn't enabled before, so `&&` wasn't enabled. Now that `if` is enabled, `&&` now works too.