Add messages to Option's and Result's must_use annotation for is_*
#62431
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rust-highfive
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czipperz
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Jul 6, 2019
| @@ -201,7 +201,8 @@ impl<T> Option<T> { | |||
| /// ``` | |||
| /// | |||
| /// [`None`]: #variant.None | |||
| #[must_use] | |||
| #[must_use = "if you intended to assert that this doesn't have a value, consider \ | |||
| `.and_then(|| panic!(\"`Option` had a value when expected `None`\"))` instead"] | |||
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I think this message is too long. How about the suggestion is .ok_or(()).unwrap_err()?
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I don't have a strong opinion; I just wanted to give a message as nice as the .unwrap() ones do.
Maybe there's a way to combine them? .ok_or("Option::None").unwrap_err() or similar?
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Can we just tell the user to wrap it in an assert!()?
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Really we should add an expect_none.
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📌 Commit 9b0623d has been approved by |
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…s_-methods, r=scottmcm Add messages to `Option`'s and `Result`'s `must_use` annotation for `is_*` r? @RalfJung
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Rollup of 12 pull requests Successful merges: - #61535 (Coherence test when a generic type param has a default value from an associated type) - #62274 (rustc_mir: follow FalseUnwind's real_target edge in qualify_consts.) - #62431 (Add messages to `Option`'s and `Result`'s `must_use` annotation for `is_*`) - #62453 (in which we suggest anonymizing single-use lifetimes in paths ) - #62568 (Replace unsafe_destructor_blind_to_params with may_dangle) - #62578 (Add test for #49919) - #62595 (Document that the crate keyword refers to the project root) - #62599 (move mem::uninitialized deprecation back by 1 release, to 1.39) - #62605 (Emit dropped unemitted errors to aid in ICE debugging) - #62607 (Correctly break out of recovery loop) - #62608 (`async unsafe fn` tests) - #62623 (downgrade indirect_structural_match lint to allow) Failed merges: r? @ghost
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r? @RalfJung