[eriknstr]

While it's too late to change the name "expect", could one create an alias for it and call it say, "on_error"?

[eximius]

I'd expect 'on_error' to take a function as a callback, not a string. But yes, a better named function could be added

[skybrian]

Perhaps or_die, similar to Perl?

[sanderjd]

Yep, this is what I always wanted it to be! But maybe or_panic would be better. Naming things is hard.

[allan_s]

or_fail_with("") ?

[eternalban]

expect[ing_error]("could not open the file")

[rootlocus]

You're not expecting an error. On the contrary, you're expecting a value or throwing an error.

[eternalban]

You're expecting specific errors.

[edmccard]

In my Rust crates, I use a custom trait[1], with implementations for Option and Result, that provides an expected() method which, if it panics, prefixes the message with "expected: ". So you can write

  foo().pop().expected("foo length >= 1");

and if it fails, the error is something like "panicked at 'expected foo length >= 1'".

[1]https://gist.github.com/edmccard/8898dd397eec0ff3595c28ada52...

[dleslie]

A failed expectation for one user isn't always an error for other users; calling out on_error may confuse people because it indicates an error may occur and must be handled.

[IshKebab]

Or `unwrap_msg()`?