Allow any Displayable type for expect.

[clarfonthey]

Formal RFC for #1922.

Rendered

[mark-i-m]

I am not sure I understand how this saves on ergonomics... Wouldn't you still need to wrap the displayed value of the argument in text to get a coherent error message? Alternately, you could define Display yourself for some type, which seems to dwarf the overhead of simply writing expect(|e| panic!(...)) unless you are printing the same messages in many places.

Have I missed something?

[aturon]

Thanks for the RFC! However, I personally feel like the benefits here don't outweigh the added complexity of the API signature.

This is a case where method-style macros would be nice, to allow for something more akin to format!. But sadly method-style macros have numerous issues.

In any case, this feels quite niche to me, and I think the current ways of achieving the mentioned goals suffice, so I'm going to move to close.

@rfcbot fcp close

[rfcbot]

Team member @aturon has proposed to close this. The next step is review by the rest of the tagged teams:

• @BurntSushi
• @Kimundi
• @alexcrichton
• @aturon
• @brson
• @sfackler

No concerns currently listed.

Once these reviewers reach consensus, this will enter its final comment period. If you spot a major issue that hasn't been raised at any point in this process, please speak up!

See this document for info about what commands tagged team members can give me.

[aturon]

Ping @BurntSushi @Kimundi @brson @sfackler

[rfcbot]

🔔 This is now entering its final comment period, as per the review above. 🔔

[rfcbot]

The final comment period is now complete.

[alexcrichton]

Ok looks like not much more discussion happened during FCP, so I'm going to close this. Thanks again though for the RFC @clarcharr!