diff --git a/clippy_lints/src/methods.rs b/clippy_lints/src/methods.rs index 6d3a3f39d1a2..ca0d72302299 100644 --- a/clippy_lints/src/methods.rs +++ b/clippy_lints/src/methods.rs @@ -1150,29 +1150,37 @@ fn lint_ok_expect(cx: &LateContext, expr: &hir::Expr, ok_args: &[hir::Expr]) { fn lint_map_unwrap_or(cx: &LateContext, expr: &hir::Expr, map_args: &[hir::Expr], unwrap_args: &[hir::Expr]) { // lint if the caller of `map()` is an `Option` if match_type(cx, cx.tables.expr_ty(&map_args[0]), &paths::OPTION) { - // lint message - let msg = "called `map(f).unwrap_or(a)` on an Option value. This can be done more directly by calling \ - `map_or(a, f)` instead"; // get snippets for args to map() and unwrap_or() let map_snippet = snippet(cx, map_args[1].span, ".."); let unwrap_snippet = snippet(cx, unwrap_args[1].span, ".."); + // lint message + // comparing the snippet from source to raw text ("None") below is safe + // because we already have checked the type. + let arg = if unwrap_snippet == "None" { "None" } else { "a" }; + let suggest = if unwrap_snippet == "None" { "and_then(f)" } else { "map_or(a, f)" }; + let msg = &format!( + "called `map(f).unwrap_or({})` on an Option value. \ + This can be done more directly by calling `{}` instead", + arg, + suggest + ); // lint, with note if neither arg is > 1 line and both map() and // unwrap_or() have the same span let multiline = map_snippet.lines().count() > 1 || unwrap_snippet.lines().count() > 1; let same_span = map_args[1].span.ctxt() == unwrap_args[1].span.ctxt(); if same_span && !multiline { - span_note_and_lint( - cx, - OPTION_MAP_UNWRAP_OR, - expr.span, - msg, - expr.span, - &format!( - "replace `map({0}).unwrap_or({1})` with `map_or({1}, {0})`", - map_snippet, - unwrap_snippet - ), + let suggest = if unwrap_snippet == "None" { + format!("and_then({})", map_snippet) + } else { + format!("map_or({}, {})", unwrap_snippet, map_snippet) + }; + let note = format!( + "replace `map({}).unwrap_or({})` with `{}`", + map_snippet, + unwrap_snippet, + suggest ); + span_note_and_lint(cx, OPTION_MAP_UNWRAP_OR, expr.span, msg, expr.span, ¬e); } else if same_span && multiline { span_lint(cx, OPTION_MAP_UNWRAP_OR, expr.span, msg); }; diff --git a/tests/ui/methods.rs b/tests/ui/methods.rs index 08ff47714205..3395280ba057 100644 --- a/tests/ui/methods.rs +++ b/tests/ui/methods.rs @@ -108,6 +108,16 @@ fn option_methods() { .unwrap_or({ 0 }); + // single line `map(f).unwrap_or(None)` case + let _ = opt.map(|x| Some(x + 1)).unwrap_or(None); + // multiline `map(f).unwrap_or(None)` cases + let _ = opt.map(|x| { + Some(x + 1) + } + ).unwrap_or(None); + let _ = opt + .map(|x| Some(x + 1)) + .unwrap_or(None); // macro case let _ = opt_map!(opt, |x| x + 1).unwrap_or(0); // should not lint diff --git a/tests/ui/methods.stderr b/tests/ui/methods.stderr index c5fab711fe1f..a1bc219eaf87 100644 --- a/tests/ui/methods.stderr +++ b/tests/ui/methods.stderr @@ -134,705 +134,734 @@ error: called `map(f).unwrap_or(a)` on an Option value. This can be done more di 110 | | }); | |__________________^ -error: called `map(f).unwrap_or_else(g)` on an Option value. This can be done more directly by calling `map_or_else(g, f)` instead - --> $DIR/methods.rs:116:13 +error: called `map(f).unwrap_or(None)` on an Option value. This can be done more directly by calling `and_then(f)` instead + --> $DIR/methods.rs:112:13 | -116 | let _ = opt.map(|x| x + 1) +112 | let _ = opt.map(|x| Some(x + 1)).unwrap_or(None); + | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ + | + = note: replace `map(|x| Some(x + 1)).unwrap_or(None)` with `and_then(|x| Some(x + 1))` + +error: called `map(f).unwrap_or(None)` on an Option value. This can be done more directly by calling `and_then(f)` instead + --> $DIR/methods.rs:114:13 + | +114 | let _ = opt.map(|x| { | _____________^ -117 | | -118 | | .unwrap_or_else(|| 0); // should lint even though this call is on a separate line +115 | | Some(x + 1) +116 | | } +117 | | ).unwrap_or(None); + | |_____________________^ + +error: called `map(f).unwrap_or(None)` on an Option value. This can be done more directly by calling `and_then(f)` instead + --> $DIR/methods.rs:118:13 + | +118 | let _ = opt + | _____________^ +119 | | .map(|x| Some(x + 1)) +120 | | .unwrap_or(None); + | |________________________^ + | + = note: replace `map(|x| Some(x + 1)).unwrap_or(None)` with `and_then(|x| Some(x + 1))` + +error: called `map(f).unwrap_or_else(g)` on an Option value. This can be done more directly by calling `map_or_else(g, f)` instead + --> $DIR/methods.rs:126:13 + | +126 | let _ = opt.map(|x| x + 1) + | _____________^ +127 | | +128 | | .unwrap_or_else(|| 0); // should lint even though this call is on a separate line | |____________________________________^ | = note: `-D option-map-unwrap-or-else` implied by `-D warnings` = note: replace `map(|x| x + 1).unwrap_or_else(|| 0)` with `map_or_else(|| 0, |x| x + 1)` error: called `map(f).unwrap_or_else(g)` on an Option value. This can be done more directly by calling `map_or_else(g, f)` instead - --> $DIR/methods.rs:120:13 + --> $DIR/methods.rs:130:13 | -120 | let _ = opt.map(|x| { +130 | let _ = opt.map(|x| { | _____________^ -121 | | x + 1 -122 | | } -123 | | ).unwrap_or_else(|| 0); +131 | | x + 1 +132 | | } +133 | | ).unwrap_or_else(|| 0); | |____________________________________^ error: called `map(f).unwrap_or_else(g)` on an Option value. This can be done more directly by calling `map_or_else(g, f)` instead - --> $DIR/methods.rs:124:13 + --> $DIR/methods.rs:134:13 | -124 | let _ = opt.map(|x| x + 1) +134 | let _ = opt.map(|x| x + 1) | _____________^ -125 | | .unwrap_or_else(|| -126 | | 0 -127 | | ); +135 | | .unwrap_or_else(|| +136 | | 0 +137 | | ); | |_________________^ error: unnecessary structure name repetition - --> $DIR/methods.rs:153:24 + --> $DIR/methods.rs:163:24 | -153 | fn filter(self) -> IteratorFalsePositives { +163 | fn filter(self) -> IteratorFalsePositives { | ^^^^^^^^^^^^^^^^^^^^^^ help: use the applicable keyword: `Self` error: unnecessary structure name repetition - --> $DIR/methods.rs:157:22 + --> $DIR/methods.rs:167:22 | -157 | fn next(self) -> IteratorFalsePositives { +167 | fn next(self) -> IteratorFalsePositives { | ^^^^^^^^^^^^^^^^^^^^^^ help: use the applicable keyword: `Self` error: unnecessary structure name repetition - --> $DIR/methods.rs:177:32 + --> $DIR/methods.rs:187:32 | -177 | fn skip(self, _: usize) -> IteratorFalsePositives { +187 | fn skip(self, _: usize) -> IteratorFalsePositives { | ^^^^^^^^^^^^^^^^^^^^^^ help: use the applicable keyword: `Self` error: called `filter(p).next()` on an `Iterator`. This is more succinctly expressed by calling `.find(p)` instead. - --> $DIR/methods.rs:196:13 + --> $DIR/methods.rs:206:13 | -196 | let _ = v.iter().filter(|&x| *x < 0).next(); +206 | let _ = v.iter().filter(|&x| *x < 0).next(); | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ | = note: `-D filter-next` implied by `-D warnings` = note: replace `filter(|&x| *x < 0).next()` with `find(|&x| *x < 0)` error: called `filter(p).next()` on an `Iterator`. This is more succinctly expressed by calling `.find(p)` instead. - --> $DIR/methods.rs:199:13 + --> $DIR/methods.rs:209:13 | -199 | let _ = v.iter().filter(|&x| { +209 | let _ = v.iter().filter(|&x| { | _____________^ -200 | | *x < 0 -201 | | } -202 | | ).next(); +210 | | *x < 0 +211 | | } +212 | | ).next(); | |___________________________^ error: called `is_some()` after searching an `Iterator` with find. This is more succinctly expressed by calling `any()`. - --> $DIR/methods.rs:214:13 + --> $DIR/methods.rs:224:13 | -214 | let _ = v.iter().find(|&x| *x < 0).is_some(); +224 | let _ = v.iter().find(|&x| *x < 0).is_some(); | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ | = note: `-D search-is-some` implied by `-D warnings` = note: replace `find(|&x| *x < 0).is_some()` with `any(|&x| *x < 0)` error: called `is_some()` after searching an `Iterator` with find. This is more succinctly expressed by calling `any()`. - --> $DIR/methods.rs:217:13 + --> $DIR/methods.rs:227:13 | -217 | let _ = v.iter().find(|&x| { +227 | let _ = v.iter().find(|&x| { | _____________^ -218 | | *x < 0 -219 | | } -220 | | ).is_some(); +228 | | *x < 0 +229 | | } +230 | | ).is_some(); | |______________________________^ error: called `is_some()` after searching an `Iterator` with position. This is more succinctly expressed by calling `any()`. - --> $DIR/methods.rs:223:13 + --> $DIR/methods.rs:233:13 | -223 | let _ = v.iter().position(|&x| x < 0).is_some(); +233 | let _ = v.iter().position(|&x| x < 0).is_some(); | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ | = note: replace `position(|&x| x < 0).is_some()` with `any(|&x| x < 0)` error: called `is_some()` after searching an `Iterator` with position. This is more succinctly expressed by calling `any()`. - --> $DIR/methods.rs:226:13 + --> $DIR/methods.rs:236:13 | -226 | let _ = v.iter().position(|&x| { +236 | let _ = v.iter().position(|&x| { | _____________^ -227 | | x < 0 -228 | | } -229 | | ).is_some(); +237 | | x < 0 +238 | | } +239 | | ).is_some(); | |______________________________^ error: called `is_some()` after searching an `Iterator` with rposition. This is more succinctly expressed by calling `any()`. - --> $DIR/methods.rs:232:13 + --> $DIR/methods.rs:242:13 | -232 | let _ = v.iter().rposition(|&x| x < 0).is_some(); +242 | let _ = v.iter().rposition(|&x| x < 0).is_some(); | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ | = note: replace `rposition(|&x| x < 0).is_some()` with `any(|&x| x < 0)` error: called `is_some()` after searching an `Iterator` with rposition. This is more succinctly expressed by calling `any()`. - --> $DIR/methods.rs:235:13 + --> $DIR/methods.rs:245:13 | -235 | let _ = v.iter().rposition(|&x| { +245 | let _ = v.iter().rposition(|&x| { | _____________^ -236 | | x < 0 -237 | | } -238 | | ).is_some(); +246 | | x < 0 +247 | | } +248 | | ).is_some(); | |______________________________^ error: unnecessary structure name repetition - --> $DIR/methods.rs:252:21 + --> $DIR/methods.rs:262:21 | -252 | fn new() -> Foo { Foo } +262 | fn new() -> Foo { Foo } | ^^^ help: use the applicable keyword: `Self` error: use of `unwrap_or` followed by a function call - --> $DIR/methods.rs:270:5 + --> $DIR/methods.rs:280:5 | -270 | with_constructor.unwrap_or(make()); +280 | with_constructor.unwrap_or(make()); | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try this: `with_constructor.unwrap_or_else(make)` | = note: `-D or-fun-call` implied by `-D warnings` error: use of `unwrap_or` followed by a call to `new` - --> $DIR/methods.rs:273:5 + --> $DIR/methods.rs:283:5 | -273 | with_new.unwrap_or(Vec::new()); +283 | with_new.unwrap_or(Vec::new()); | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try this: `with_new.unwrap_or_default()` error: use of `unwrap_or` followed by a function call - --> $DIR/methods.rs:276:5 + --> $DIR/methods.rs:286:5 | -276 | with_const_args.unwrap_or(Vec::with_capacity(12)); +286 | with_const_args.unwrap_or(Vec::with_capacity(12)); | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try this: `with_const_args.unwrap_or_else(|| Vec::with_capacity(12))` error: use of `unwrap_or` followed by a function call - --> $DIR/methods.rs:279:5 + --> $DIR/methods.rs:289:5 | -279 | with_err.unwrap_or(make()); +289 | with_err.unwrap_or(make()); | ^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try this: `with_err.unwrap_or_else(|_| make())` error: use of `unwrap_or` followed by a function call - --> $DIR/methods.rs:282:5 + --> $DIR/methods.rs:292:5 | -282 | with_err_args.unwrap_or(Vec::with_capacity(12)); +292 | with_err_args.unwrap_or(Vec::with_capacity(12)); | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try this: `with_err_args.unwrap_or_else(|_| Vec::with_capacity(12))` error: use of `unwrap_or` followed by a call to `default` - --> $DIR/methods.rs:285:5 + --> $DIR/methods.rs:295:5 | -285 | with_default_trait.unwrap_or(Default::default()); +295 | with_default_trait.unwrap_or(Default::default()); | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try this: `with_default_trait.unwrap_or_default()` error: use of `unwrap_or` followed by a call to `default` - --> $DIR/methods.rs:288:5 + --> $DIR/methods.rs:298:5 | -288 | with_default_type.unwrap_or(u64::default()); +298 | with_default_type.unwrap_or(u64::default()); | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try this: `with_default_type.unwrap_or_default()` error: use of `unwrap_or` followed by a function call - --> $DIR/methods.rs:291:5 + --> $DIR/methods.rs:301:5 | -291 | with_vec.unwrap_or(vec![]); +301 | with_vec.unwrap_or(vec![]); | ^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try this: `with_vec.unwrap_or_else(|| < [ _ ] > :: into_vec ( box [ $ ( $ x ) , * ] ))` error: use of `unwrap_or` followed by a function call - --> $DIR/methods.rs:296:5 + --> $DIR/methods.rs:306:5 | -296 | without_default.unwrap_or(Foo::new()); +306 | without_default.unwrap_or(Foo::new()); | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try this: `without_default.unwrap_or_else(Foo::new)` error: use of `or_insert` followed by a function call - --> $DIR/methods.rs:299:5 + --> $DIR/methods.rs:309:5 | -299 | map.entry(42).or_insert(String::new()); +309 | map.entry(42).or_insert(String::new()); | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try this: `map.entry(42).or_insert_with(String::new)` error: use of `or_insert` followed by a function call - --> $DIR/methods.rs:302:5 + --> $DIR/methods.rs:312:5 | -302 | btree.entry(42).or_insert(String::new()); +312 | btree.entry(42).or_insert(String::new()); | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try this: `btree.entry(42).or_insert_with(String::new)` error: use of `unwrap_or` followed by a function call - --> $DIR/methods.rs:305:13 + --> $DIR/methods.rs:315:13 | -305 | let _ = stringy.unwrap_or("".to_owned()); +315 | let _ = stringy.unwrap_or("".to_owned()); | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try this: `stringy.unwrap_or_else(|| "".to_owned())` error: called `.iter().nth()` on a Vec. Calling `.get()` is both faster and more readable - --> $DIR/methods.rs:316:23 + --> $DIR/methods.rs:326:23 | -316 | let bad_vec = some_vec.iter().nth(3); +326 | let bad_vec = some_vec.iter().nth(3); | ^^^^^^^^^^^^^^^^^^^^^^ | = note: `-D iter-nth` implied by `-D warnings` error: called `.iter().nth()` on a slice. Calling `.get()` is both faster and more readable - --> $DIR/methods.rs:317:26 + --> $DIR/methods.rs:327:26 | -317 | let bad_slice = &some_vec[..].iter().nth(3); +327 | let bad_slice = &some_vec[..].iter().nth(3); | ^^^^^^^^^^^^^^^^^^^^^^^^^^ error: called `.iter().nth()` on a slice. Calling `.get()` is both faster and more readable - --> $DIR/methods.rs:318:31 + --> $DIR/methods.rs:328:31 | -318 | let bad_boxed_slice = boxed_slice.iter().nth(3); +328 | let bad_boxed_slice = boxed_slice.iter().nth(3); | ^^^^^^^^^^^^^^^^^^^^^^^^^ error: called `.iter().nth()` on a VecDeque. Calling `.get()` is both faster and more readable - --> $DIR/methods.rs:319:29 + --> $DIR/methods.rs:329:29 | -319 | let bad_vec_deque = some_vec_deque.iter().nth(3); +329 | let bad_vec_deque = some_vec_deque.iter().nth(3); | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ error: called `.iter_mut().nth()` on a Vec. Calling `.get_mut()` is both faster and more readable - --> $DIR/methods.rs:324:23 + --> $DIR/methods.rs:334:23 | -324 | let bad_vec = some_vec.iter_mut().nth(3); +334 | let bad_vec = some_vec.iter_mut().nth(3); | ^^^^^^^^^^^^^^^^^^^^^^^^^^ error: called `.iter_mut().nth()` on a slice. Calling `.get_mut()` is both faster and more readable - --> $DIR/methods.rs:327:26 + --> $DIR/methods.rs:337:26 | -327 | let bad_slice = &some_vec[..].iter_mut().nth(3); +337 | let bad_slice = &some_vec[..].iter_mut().nth(3); | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ error: called `.iter_mut().nth()` on a VecDeque. Calling `.get_mut()` is both faster and more readable - --> $DIR/methods.rs:330:29 + --> $DIR/methods.rs:340:29 | -330 | let bad_vec_deque = some_vec_deque.iter_mut().nth(3); +340 | let bad_vec_deque = some_vec_deque.iter_mut().nth(3); | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ error: called `skip(x).next()` on an iterator. This is more succinctly expressed by calling `nth(x)` - --> $DIR/methods.rs:342:13 + --> $DIR/methods.rs:352:13 | -342 | let _ = some_vec.iter().skip(42).next(); +352 | let _ = some_vec.iter().skip(42).next(); | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ | = note: `-D iter-skip-next` implied by `-D warnings` error: called `skip(x).next()` on an iterator. This is more succinctly expressed by calling `nth(x)` - --> $DIR/methods.rs:343:13 + --> $DIR/methods.rs:353:13 | -343 | let _ = some_vec.iter().cycle().skip(42).next(); +353 | let _ = some_vec.iter().cycle().skip(42).next(); | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ error: called `skip(x).next()` on an iterator. This is more succinctly expressed by calling `nth(x)` - --> $DIR/methods.rs:344:13 + --> $DIR/methods.rs:354:13 | -344 | let _ = (1..10).skip(10).next(); +354 | let _ = (1..10).skip(10).next(); | ^^^^^^^^^^^^^^^^^^^^^^^ error: called `skip(x).next()` on an iterator. This is more succinctly expressed by calling `nth(x)` - --> $DIR/methods.rs:345:14 + --> $DIR/methods.rs:355:14 | -345 | let _ = &some_vec[..].iter().skip(3).next(); +355 | let _ = &some_vec[..].iter().skip(3).next(); | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ error: called `.get().unwrap()` on a slice. Using `[]` is more clear and more concise - --> $DIR/methods.rs:371:17 + --> $DIR/methods.rs:381:17 | -371 | let _ = boxed_slice.get(1).unwrap(); +381 | let _ = boxed_slice.get(1).unwrap(); | ^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try this: `&boxed_slice[1]` | = note: `-D get-unwrap` implied by `-D warnings` error: called `.get().unwrap()` on a slice. Using `[]` is more clear and more concise - --> $DIR/methods.rs:372:17 + --> $DIR/methods.rs:382:17 | -372 | let _ = some_slice.get(0).unwrap(); +382 | let _ = some_slice.get(0).unwrap(); | ^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try this: `&some_slice[0]` error: called `.get().unwrap()` on a Vec. Using `[]` is more clear and more concise - --> $DIR/methods.rs:373:17 + --> $DIR/methods.rs:383:17 | -373 | let _ = some_vec.get(0).unwrap(); +383 | let _ = some_vec.get(0).unwrap(); | ^^^^^^^^^^^^^^^^^^^^^^^^ help: try this: `&some_vec[0]` error: called `.get().unwrap()` on a VecDeque. Using `[]` is more clear and more concise - --> $DIR/methods.rs:374:17 + --> $DIR/methods.rs:384:17 | -374 | let _ = some_vecdeque.get(0).unwrap(); +384 | let _ = some_vecdeque.get(0).unwrap(); | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try this: `&some_vecdeque[0]` error: called `.get().unwrap()` on a HashMap. Using `[]` is more clear and more concise - --> $DIR/methods.rs:375:17 + --> $DIR/methods.rs:385:17 | -375 | let _ = some_hashmap.get(&1).unwrap(); +385 | let _ = some_hashmap.get(&1).unwrap(); | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try this: `&some_hashmap[&1]` error: called `.get().unwrap()` on a BTreeMap. Using `[]` is more clear and more concise - --> $DIR/methods.rs:376:17 + --> $DIR/methods.rs:386:17 | -376 | let _ = some_btreemap.get(&1).unwrap(); +386 | let _ = some_btreemap.get(&1).unwrap(); | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try this: `&some_btreemap[&1]` error: called `.get_mut().unwrap()` on a slice. Using `[]` is more clear and more concise - --> $DIR/methods.rs:381:10 + --> $DIR/methods.rs:391:10 | -381 | *boxed_slice.get_mut(0).unwrap() = 1; +391 | *boxed_slice.get_mut(0).unwrap() = 1; | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try this: `&mut boxed_slice[0]` error: called `.get_mut().unwrap()` on a slice. Using `[]` is more clear and more concise - --> $DIR/methods.rs:382:10 + --> $DIR/methods.rs:392:10 | -382 | *some_slice.get_mut(0).unwrap() = 1; +392 | *some_slice.get_mut(0).unwrap() = 1; | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try this: `&mut some_slice[0]` error: called `.get_mut().unwrap()` on a Vec. Using `[]` is more clear and more concise - --> $DIR/methods.rs:383:10 + --> $DIR/methods.rs:393:10 | -383 | *some_vec.get_mut(0).unwrap() = 1; +393 | *some_vec.get_mut(0).unwrap() = 1; | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try this: `&mut some_vec[0]` error: called `.get_mut().unwrap()` on a VecDeque. Using `[]` is more clear and more concise - --> $DIR/methods.rs:384:10 + --> $DIR/methods.rs:394:10 | -384 | *some_vecdeque.get_mut(0).unwrap() = 1; +394 | *some_vecdeque.get_mut(0).unwrap() = 1; | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try this: `&mut some_vecdeque[0]` error: used unwrap() on an Option value. If you don't want to handle the None case gracefully, consider using expect() to provide a better panic message - --> $DIR/methods.rs:398:13 + --> $DIR/methods.rs:408:13 | -398 | let _ = opt.unwrap(); +408 | let _ = opt.unwrap(); | ^^^^^^^^^^^^ | = note: `-D option-unwrap-used` implied by `-D warnings` error: used unwrap() on a Result value. If you don't want to handle the Err case gracefully, consider using expect() to provide a better panic message - --> $DIR/methods.rs:401:13 + --> $DIR/methods.rs:411:13 | -401 | let _ = res.unwrap(); +411 | let _ = res.unwrap(); | ^^^^^^^^^^^^ | = note: `-D result-unwrap-used` implied by `-D warnings` error: called `ok().expect()` on a Result value. You can call `expect` directly on the `Result` - --> $DIR/methods.rs:403:5 + --> $DIR/methods.rs:413:5 | -403 | res.ok().expect("disaster!"); +413 | res.ok().expect("disaster!"); | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ | = note: `-D ok-expect` implied by `-D warnings` error: called `ok().expect()` on a Result value. You can call `expect` directly on the `Result` - --> $DIR/methods.rs:409:5 + --> $DIR/methods.rs:419:5 | -409 | res3.ok().expect("whoof"); +419 | res3.ok().expect("whoof"); | ^^^^^^^^^^^^^^^^^^^^^^^^^ error: called `ok().expect()` on a Result value. You can call `expect` directly on the `Result` - --> $DIR/methods.rs:411:5 + --> $DIR/methods.rs:421:5 | -411 | res4.ok().expect("argh"); +421 | res4.ok().expect("argh"); | ^^^^^^^^^^^^^^^^^^^^^^^^ error: called `ok().expect()` on a Result value. You can call `expect` directly on the `Result` - --> $DIR/methods.rs:413:5 + --> $DIR/methods.rs:423:5 | -413 | res5.ok().expect("oops"); +423 | res5.ok().expect("oops"); | ^^^^^^^^^^^^^^^^^^^^^^^^ error: called `ok().expect()` on a Result value. You can call `expect` directly on the `Result` - --> $DIR/methods.rs:415:5 + --> $DIR/methods.rs:425:5 | -415 | res6.ok().expect("meh"); +425 | res6.ok().expect("meh"); | ^^^^^^^^^^^^^^^^^^^^^^^ error: you should use the `starts_with` method - --> $DIR/methods.rs:427:5 + --> $DIR/methods.rs:437:5 | -427 | "".chars().next() == Some(' '); +437 | "".chars().next() == Some(' '); | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: like this: `"".starts_with(' ')` | = note: `-D chars-next-cmp` implied by `-D warnings` error: you should use the `starts_with` method - --> $DIR/methods.rs:428:5 + --> $DIR/methods.rs:438:5 | -428 | Some(' ') != "".chars().next(); +438 | Some(' ') != "".chars().next(); | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: like this: `!"".starts_with(' ')` error: calling `.extend(_.chars())` - --> $DIR/methods.rs:437:5 + --> $DIR/methods.rs:447:5 | -437 | s.extend(abc.chars()); +447 | s.extend(abc.chars()); | ^^^^^^^^^^^^^^^^^^^^^ help: try this: `s.push_str(abc)` | = note: `-D string-extend-chars` implied by `-D warnings` error: calling `.extend(_.chars())` - --> $DIR/methods.rs:440:5 + --> $DIR/methods.rs:450:5 | -440 | s.extend("abc".chars()); +450 | s.extend("abc".chars()); | ^^^^^^^^^^^^^^^^^^^^^^^ help: try this: `s.push_str("abc")` error: calling `.extend(_.chars())` - --> $DIR/methods.rs:443:5 + --> $DIR/methods.rs:453:5 | -443 | s.extend(def.chars()); +453 | s.extend(def.chars()); | ^^^^^^^^^^^^^^^^^^^^^ help: try this: `s.push_str(&def)` error: using `clone` on a `Copy` type - --> $DIR/methods.rs:454:5 + --> $DIR/methods.rs:464:5 | -454 | 42.clone(); +464 | 42.clone(); | ^^^^^^^^^^ help: try removing the `clone` call: `42` | = note: `-D clone-on-copy` implied by `-D warnings` error: using `clone` on a `Copy` type - --> $DIR/methods.rs:458:5 + --> $DIR/methods.rs:468:5 | -458 | (&42).clone(); +468 | (&42).clone(); | ^^^^^^^^^^^^^ help: try dereferencing it: `*(&42)` error: using '.clone()' on a ref-counted pointer - --> $DIR/methods.rs:468:5 + --> $DIR/methods.rs:478:5 | -468 | rc.clone(); +478 | rc.clone(); | ^^^^^^^^^^ help: try this: `Rc::clone(&rc)` | = note: `-D clone-on-ref-ptr` implied by `-D warnings` error: using '.clone()' on a ref-counted pointer - --> $DIR/methods.rs:471:5 + --> $DIR/methods.rs:481:5 | -471 | arc.clone(); +481 | arc.clone(); | ^^^^^^^^^^^ help: try this: `Arc::clone(&arc)` error: using '.clone()' on a ref-counted pointer - --> $DIR/methods.rs:474:5 + --> $DIR/methods.rs:484:5 | -474 | rcweak.clone(); +484 | rcweak.clone(); | ^^^^^^^^^^^^^^ help: try this: `Weak::clone(&rcweak)` error: using '.clone()' on a ref-counted pointer - --> $DIR/methods.rs:477:5 + --> $DIR/methods.rs:487:5 | -477 | arc_weak.clone(); +487 | arc_weak.clone(); | ^^^^^^^^^^^^^^^^ help: try this: `Weak::clone(&arc_weak)` error: using `clone` on a `Copy` type - --> $DIR/methods.rs:484:5 + --> $DIR/methods.rs:494:5 | -484 | t.clone(); +494 | t.clone(); | ^^^^^^^^^ help: try removing the `clone` call: `t` error: using `clone` on a `Copy` type - --> $DIR/methods.rs:486:5 + --> $DIR/methods.rs:496:5 | -486 | Some(t).clone(); +496 | Some(t).clone(); | ^^^^^^^^^^^^^^^ help: try removing the `clone` call: `Some(t)` error: using `clone` on a double-reference; this will copy the reference instead of cloning the inner type - --> $DIR/methods.rs:492:22 + --> $DIR/methods.rs:502:22 | -492 | let z: &Vec<_> = y.clone(); +502 | let z: &Vec<_> = y.clone(); | ^^^^^^^^^ help: try dereferencing it: `(*y).clone()` | = note: `-D clone-double-ref` implied by `-D warnings` error: single-character string constant used as pattern - --> $DIR/methods.rs:499:13 + --> $DIR/methods.rs:509:13 | -499 | x.split("x"); +509 | x.split("x"); | --------^^^- help: try using a char instead: `x.split('x')` | = note: `-D single-char-pattern` implied by `-D warnings` error: single-character string constant used as pattern - --> $DIR/methods.rs:516:16 + --> $DIR/methods.rs:526:16 | -516 | x.contains("x"); +526 | x.contains("x"); | -----------^^^- help: try using a char instead: `x.contains('x')` error: single-character string constant used as pattern - --> $DIR/methods.rs:517:19 + --> $DIR/methods.rs:527:19 | -517 | x.starts_with("x"); +527 | x.starts_with("x"); | --------------^^^- help: try using a char instead: `x.starts_with('x')` error: single-character string constant used as pattern - --> $DIR/methods.rs:518:17 + --> $DIR/methods.rs:528:17 | -518 | x.ends_with("x"); +528 | x.ends_with("x"); | ------------^^^- help: try using a char instead: `x.ends_with('x')` error: single-character string constant used as pattern - --> $DIR/methods.rs:519:12 + --> $DIR/methods.rs:529:12 | -519 | x.find("x"); +529 | x.find("x"); | -------^^^- help: try using a char instead: `x.find('x')` error: single-character string constant used as pattern - --> $DIR/methods.rs:520:13 + --> $DIR/methods.rs:530:13 | -520 | x.rfind("x"); +530 | x.rfind("x"); | --------^^^- help: try using a char instead: `x.rfind('x')` error: single-character string constant used as pattern - --> $DIR/methods.rs:521:14 + --> $DIR/methods.rs:531:14 | -521 | x.rsplit("x"); +531 | x.rsplit("x"); | ---------^^^- help: try using a char instead: `x.rsplit('x')` error: single-character string constant used as pattern - --> $DIR/methods.rs:522:24 + --> $DIR/methods.rs:532:24 | -522 | x.split_terminator("x"); +532 | x.split_terminator("x"); | -------------------^^^- help: try using a char instead: `x.split_terminator('x')` error: single-character string constant used as pattern - --> $DIR/methods.rs:523:25 + --> $DIR/methods.rs:533:25 | -523 | x.rsplit_terminator("x"); +533 | x.rsplit_terminator("x"); | --------------------^^^- help: try using a char instead: `x.rsplit_terminator('x')` error: single-character string constant used as pattern - --> $DIR/methods.rs:524:17 + --> $DIR/methods.rs:534:17 | -524 | x.splitn(0, "x"); +534 | x.splitn(0, "x"); | ------------^^^- help: try using a char instead: `x.splitn(0, 'x')` error: single-character string constant used as pattern - --> $DIR/methods.rs:525:18 + --> $DIR/methods.rs:535:18 | -525 | x.rsplitn(0, "x"); +535 | x.rsplitn(0, "x"); | -------------^^^- help: try using a char instead: `x.rsplitn(0, 'x')` error: single-character string constant used as pattern - --> $DIR/methods.rs:526:15 + --> $DIR/methods.rs:536:15 | -526 | x.matches("x"); +536 | x.matches("x"); | ----------^^^- help: try using a char instead: `x.matches('x')` error: single-character string constant used as pattern - --> $DIR/methods.rs:527:16 + --> $DIR/methods.rs:537:16 | -527 | x.rmatches("x"); +537 | x.rmatches("x"); | -----------^^^- help: try using a char instead: `x.rmatches('x')` error: single-character string constant used as pattern - --> $DIR/methods.rs:528:21 + --> $DIR/methods.rs:538:21 | -528 | x.match_indices("x"); +538 | x.match_indices("x"); | ----------------^^^- help: try using a char instead: `x.match_indices('x')` error: single-character string constant used as pattern - --> $DIR/methods.rs:529:22 + --> $DIR/methods.rs:539:22 | -529 | x.rmatch_indices("x"); +539 | x.rmatch_indices("x"); | -----------------^^^- help: try using a char instead: `x.rmatch_indices('x')` error: single-character string constant used as pattern - --> $DIR/methods.rs:530:25 + --> $DIR/methods.rs:540:25 | -530 | x.trim_left_matches("x"); +540 | x.trim_left_matches("x"); | --------------------^^^- help: try using a char instead: `x.trim_left_matches('x')` error: single-character string constant used as pattern - --> $DIR/methods.rs:531:26 + --> $DIR/methods.rs:541:26 | -531 | x.trim_right_matches("x"); +541 | x.trim_right_matches("x"); | ---------------------^^^- help: try using a char instead: `x.trim_right_matches('x')` error: you are getting the inner pointer of a temporary `CString` - --> $DIR/methods.rs:541:5 + --> $DIR/methods.rs:551:5 | -541 | CString::new("foo").unwrap().as_ptr(); +551 | CString::new("foo").unwrap().as_ptr(); | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ | = note: `-D temporary-cstring-as-ptr` implied by `-D warnings` = note: that pointer will be invalid outside this expression help: assign the `CString` to a variable to extend its lifetime - --> $DIR/methods.rs:541:5 + --> $DIR/methods.rs:551:5 | -541 | CString::new("foo").unwrap().as_ptr(); +551 | CString::new("foo").unwrap().as_ptr(); | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ error: called `cloned().collect()` on a slice to create a `Vec`. Calling `to_vec()` is both faster and more readable - --> $DIR/methods.rs:546:27 + --> $DIR/methods.rs:556:27 | -546 | let v2 : Vec = v.iter().cloned().collect(); +556 | let v2 : Vec = v.iter().cloned().collect(); | ^^^^^^^^^^^^^^^^^^^^^^^^^^^ | = note: `-D iter-cloned-collect` implied by `-D warnings` error: you should use the `starts_with` method - --> $DIR/methods.rs:553:8 + --> $DIR/methods.rs:563:8 | -553 | if s.chars().next().unwrap() == 'f' { // s.starts_with('f') +563 | if s.chars().next().unwrap() == 'f' { // s.starts_with('f') | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: like this: `s.starts_with('f')` error: used unwrap() on an Option value. If you don't want to handle the None case gracefully, consider using expect() to provide a better panic message - --> $DIR/methods.rs:553:8 + --> $DIR/methods.rs:563:8 | -553 | if s.chars().next().unwrap() == 'f' { // s.starts_with('f') +563 | if s.chars().next().unwrap() == 'f' { // s.starts_with('f') | ^^^^^^^^^^^^^^^^^^^^^^^^^ error: you should use the `ends_with` method - --> $DIR/methods.rs:556:8 + --> $DIR/methods.rs:566:8 | -556 | if s.chars().next_back().unwrap() == 'o' { // s.ends_with('o') +566 | if s.chars().next_back().unwrap() == 'o' { // s.ends_with('o') | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: like this: `s.ends_with('o')` | = note: `-D chars-last-cmp` implied by `-D warnings` error: used unwrap() on an Option value. If you don't want to handle the None case gracefully, consider using expect() to provide a better panic message - --> $DIR/methods.rs:556:8 + --> $DIR/methods.rs:566:8 | -556 | if s.chars().next_back().unwrap() == 'o' { // s.ends_with('o') +566 | if s.chars().next_back().unwrap() == 'o' { // s.ends_with('o') | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ error: you should use the `ends_with` method - --> $DIR/methods.rs:559:8 + --> $DIR/methods.rs:569:8 | -559 | if s.chars().last().unwrap() == 'o' { // s.ends_with('o') +569 | if s.chars().last().unwrap() == 'o' { // s.ends_with('o') | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: like this: `s.ends_with('o')` error: used unwrap() on an Option value. If you don't want to handle the None case gracefully, consider using expect() to provide a better panic message - --> $DIR/methods.rs:559:8 + --> $DIR/methods.rs:569:8 | -559 | if s.chars().last().unwrap() == 'o' { // s.ends_with('o') +569 | if s.chars().last().unwrap() == 'o' { // s.ends_with('o') | ^^^^^^^^^^^^^^^^^^^^^^^^^ error: you should use the `starts_with` method - --> $DIR/methods.rs:562:8 + --> $DIR/methods.rs:572:8 | -562 | if s.chars().next().unwrap() != 'f' { // !s.starts_with('f') +572 | if s.chars().next().unwrap() != 'f' { // !s.starts_with('f') | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: like this: `!s.starts_with('f')` error: used unwrap() on an Option value. If you don't want to handle the None case gracefully, consider using expect() to provide a better panic message - --> $DIR/methods.rs:562:8 + --> $DIR/methods.rs:572:8 | -562 | if s.chars().next().unwrap() != 'f' { // !s.starts_with('f') +572 | if s.chars().next().unwrap() != 'f' { // !s.starts_with('f') | ^^^^^^^^^^^^^^^^^^^^^^^^^ error: you should use the `ends_with` method - --> $DIR/methods.rs:565:8 + --> $DIR/methods.rs:575:8 | -565 | if s.chars().next_back().unwrap() != 'o' { // !s.ends_with('o') +575 | if s.chars().next_back().unwrap() != 'o' { // !s.ends_with('o') | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: like this: `!s.ends_with('o')` error: used unwrap() on an Option value. If you don't want to handle the None case gracefully, consider using expect() to provide a better panic message - --> $DIR/methods.rs:565:8 + --> $DIR/methods.rs:575:8 | -565 | if s.chars().next_back().unwrap() != 'o' { // !s.ends_with('o') +575 | if s.chars().next_back().unwrap() != 'o' { // !s.ends_with('o') | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ error: you should use the `ends_with` method - --> $DIR/methods.rs:568:8 + --> $DIR/methods.rs:578:8 | -568 | if s.chars().last().unwrap() != 'o' { // !s.ends_with('o') +578 | if s.chars().last().unwrap() != 'o' { // !s.ends_with('o') | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: like this: `!s.ends_with('o')` error: used unwrap() on an Option value. If you don't want to handle the None case gracefully, consider using expect() to provide a better panic message - --> $DIR/methods.rs:568:8 + --> $DIR/methods.rs:578:8 | -568 | if s.chars().last().unwrap() != 'o' { // !s.ends_with('o') +578 | if s.chars().last().unwrap() != 'o' { // !s.ends_with('o') | ^^^^^^^^^^^^^^^^^^^^^^^^^ error: you should use the `ends_with` method - --> $DIR/methods.rs:575:5 + --> $DIR/methods.rs:585:5 | -575 | "".chars().last() == Some(' '); +585 | "".chars().last() == Some(' '); | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: like this: `"".ends_with(' ')` error: you should use the `ends_with` method - --> $DIR/methods.rs:576:5 + --> $DIR/methods.rs:586:5 | -576 | Some(' ') != "".chars().last(); +586 | Some(' ') != "".chars().last(); | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: like this: `!"".ends_with(' ')` error: you should use the `ends_with` method - --> $DIR/methods.rs:577:5 + --> $DIR/methods.rs:587:5 | -577 | "".chars().next_back() == Some(' '); +587 | "".chars().next_back() == Some(' '); | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: like this: `"".ends_with(' ')` error: you should use the `ends_with` method - --> $DIR/methods.rs:578:5 + --> $DIR/methods.rs:588:5 | -578 | Some(' ') != "".chars().next_back(); +588 | Some(' ') != "".chars().next_back(); | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: like this: `!"".ends_with(' ')`