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| author | Zack M. Davis <code@zackmdavis.net> | 2017-09-22 15:45:47 -0700 |
|---|---|---|
| committer | Zack M. Davis <code@zackmdavis.net> | 2017-09-22 15:45:47 -0700 |
| commit | 8917616e6a295fb4080c8e29362dc1e5a477c479 (patch) | |
| tree | 954123bd881393e9172cf61defaba0a7fa2fa576 /src/test | |
| parent | 14039a42ac6365afc842214989613f9a688c9a66 (diff) | |
| download | rust-8917616e6a295fb4080c8e29362dc1e5a477c479.tar.gz rust-8917616e6a295fb4080c8e29362dc1e5a477c479.zip | |
add comparison operators to must-use lint (under `fn_must_use` feature)
Although RFC 1940 is about annotating functions with `#[must_use]`, a key part of the motivation was linting unused equality operators. (See https://github.com/rust-lang/rfcs/pull/1812#issuecomment-265695898—it seems to have not been clear to discussants at the time that marking the comparison methods as `must_use` would not give us the lints on comparison operators, at least in (what the present author understood as) the most straightforward implementation, as landed in #43728 (3645b062).) To rectify the situation, we here lint unused comparison operators as part of the unused-must-use lint (feature gated by the `fn_must_use` feature flag, which now arguably becomes a slight (tolerable in the opinion of the present author) misnomer). This is in the matter of #43302.
Diffstat (limited to 'src/test')
| -rw-r--r-- | src/test/ui/rfc_1940-must_use_on_functions/fn_must_use.rs | 7 | ||||
| -rw-r--r-- | src/test/ui/rfc_1940-must_use_on_functions/fn_must_use.stderr | 8 |
2 files changed, 10 insertions, 5 deletions
diff --git a/src/test/ui/rfc_1940-must_use_on_functions/fn_must_use.rs b/src/test/ui/rfc_1940-must_use_on_functions/fn_must_use.rs index 7eb4c32972a..821cd30c8df 100644 --- a/src/test/ui/rfc_1940-must_use_on_functions/fn_must_use.rs +++ b/src/test/ui/rfc_1940-must_use_on_functions/fn_must_use.rs @@ -61,10 +61,9 @@ fn main() { m.need_to_use_this_method_value(); m.is_even(); // trait method! - m.replace(3); + m.replace(3); // won't warn (annotation needs to be in trait definition) - 2.eq(&3); + 2.eq(&3); // comparison methods are `must_use` - // FIXME: operators should probably be `must_use` if underlying method is - 2 == 3; + 2 == 3; // lint includes comparison operators } diff --git a/src/test/ui/rfc_1940-must_use_on_functions/fn_must_use.stderr b/src/test/ui/rfc_1940-must_use_on_functions/fn_must_use.stderr index 69755c89b48..7fc0a4ce1ed 100644 --- a/src/test/ui/rfc_1940-must_use_on_functions/fn_must_use.stderr +++ b/src/test/ui/rfc_1940-must_use_on_functions/fn_must_use.stderr @@ -25,6 +25,12 @@ warning: unused return value of `EvenNature::is_even` which must be used: no sid warning: unused return value of `std::cmp::PartialEq::eq` which must be used --> $DIR/fn_must_use.rs:66:5 | -66 | 2.eq(&3); +66 | 2.eq(&3); // comparison methods are `must_use` | ^^^^^^^^^ +warning: unused comparison which must be used + --> $DIR/fn_must_use.rs:68:5 + | +68 | 2 == 3; // lint includes comparison operators + | ^^^^^^ + |