diff options
| -rw-r--r-- | clippy_lints/src/methods/mod.rs | 45 | ||||
| -rw-r--r-- | clippy_lints/src/methods/option_map_unwrap_or.rs | 122 | ||||
| -rw-r--r-- | tests/ui/methods.rs | 7 | ||||
| -rw-r--r-- | tests/ui/methods.stderr | 76 |
4 files changed, 173 insertions, 77 deletions
diff --git a/clippy_lints/src/methods/mod.rs b/clippy_lints/src/methods/mod.rs index dd75c8aff37..8d4bb06e59b 100644 --- a/clippy_lints/src/methods/mod.rs +++ b/clippy_lints/src/methods/mod.rs @@ -22,6 +22,7 @@ use syntax::ast; use syntax::source_map::{BytePos, Span}; use syntax::symbol::LocalInternedString; +mod option_map_unwrap_or; mod unnecessary_filter_map; #[derive(Clone)] @@ -836,7 +837,7 @@ impl<'a, 'tcx> LateLintPass<'a, 'tcx> for Pass { ["unwrap", "get_mut"] => lint_get_unwrap(cx, expr, arg_lists[1], true), ["unwrap", ..] => lint_unwrap(cx, expr, arg_lists[0]), ["expect", "ok"] => lint_ok_expect(cx, expr, arg_lists[1]), - ["unwrap_or", "map"] => lint_map_unwrap_or(cx, expr, arg_lists[1], arg_lists[0]), + ["unwrap_or", "map"] => option_map_unwrap_or::lint(cx, expr, arg_lists[1], arg_lists[0]), ["unwrap_or_else", "map"] => lint_map_unwrap_or_else(cx, expr, arg_lists[1], arg_lists[0]), ["map_or", ..] => lint_map_or_none(cx, expr, arg_lists[0]), ["next", "filter"] => lint_filter_next(cx, expr, arg_lists[1]), @@ -1769,48 +1770,6 @@ fn lint_ok_expect(cx: &LateContext<'_, '_>, expr: &hir::Expr, ok_args: &[hir::Ex } } -/// lint use of `map().unwrap_or()` for `Option`s -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) { - // 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 { - 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); - }; - } -} - /// lint use of `map().flatten()` for `Iterators` fn lint_map_flatten<'a, 'tcx>(cx: &LateContext<'a, 'tcx>, expr: &'tcx hir::Expr, map_args: &'tcx [hir::Expr]) { // lint if caller of `.map().flatten()` is an Iterator diff --git a/clippy_lints/src/methods/option_map_unwrap_or.rs b/clippy_lints/src/methods/option_map_unwrap_or.rs new file mode 100644 index 00000000000..9a8880a7960 --- /dev/null +++ b/clippy_lints/src/methods/option_map_unwrap_or.rs @@ -0,0 +1,122 @@ +use crate::utils::paths; +use crate::utils::{is_copy, match_type, snippet, span_lint, span_note_and_lint}; +use rustc::hir::intravisit::{walk_path, NestedVisitorMap, Visitor}; +use rustc::hir::{self, *}; +use rustc::lint::LateContext; +use rustc_data_structures::fx::FxHashSet; +use syntax::symbol::Symbol; + +use super::OPTION_MAP_UNWRAP_OR; + +/// lint use of `map().unwrap_or()` for `Option`s +pub(super) fn lint<'a, 'tcx>( + cx: &LateContext<'a, 'tcx>, + expr: &hir::Expr, + map_args: &'tcx [hir::Expr], + unwrap_args: &'tcx [hir::Expr], +) { + // lint if the caller of `map()` is an `Option` + if match_type(cx, cx.tables.expr_ty(&map_args[0]), &paths::OPTION) { + if !is_copy(cx, cx.tables.expr_ty(&unwrap_args[1])) { + // Do not lint if the `map` argument uses identifiers in the `map` + // argument that are also used in the `unwrap_or` argument + + let mut unwrap_visitor = UnwrapVisitor { + cx, + identifiers: FxHashSet::default(), + }; + unwrap_visitor.visit_expr(&unwrap_args[1]); + + let mut map_expr_visitor = MapExprVisitor { + cx, + identifiers: unwrap_visitor.identifiers, + found_identifier: false, + }; + map_expr_visitor.visit_expr(&map_args[1]); + + if map_expr_visitor.found_identifier { + return; + } + } + + // 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 { + 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); + }; + } +} + +struct UnwrapVisitor<'a, 'tcx: 'a> { + cx: &'a LateContext<'a, 'tcx>, + identifiers: FxHashSet<Symbol>, +} + +impl<'a, 'tcx: 'a> Visitor<'tcx> for UnwrapVisitor<'a, 'tcx> { + fn visit_path(&mut self, path: &'tcx Path, _id: HirId) { + self.identifiers.insert(ident(path)); + walk_path(self, path); + } + + fn nested_visit_map<'this>(&'this mut self) -> NestedVisitorMap<'this, 'tcx> { + NestedVisitorMap::All(&self.cx.tcx.hir()) + } +} + +struct MapExprVisitor<'a, 'tcx: 'a> { + cx: &'a LateContext<'a, 'tcx>, + identifiers: FxHashSet<Symbol>, + found_identifier: bool, +} + +impl<'a, 'tcx: 'a> Visitor<'tcx> for MapExprVisitor<'a, 'tcx> { + fn visit_path(&mut self, path: &'tcx Path, _id: HirId) { + if self.identifiers.contains(&ident(path)) { + self.found_identifier = true; + return; + } + walk_path(self, path); + } + + fn nested_visit_map<'this>(&'this mut self) -> NestedVisitorMap<'this, 'tcx> { + NestedVisitorMap::All(&self.cx.tcx.hir()) + } +} + +fn ident(path: &Path) -> Symbol { + path.segments + .last() + .expect("segments should be composed of at least 1 element") + .ident + .name +} diff --git a/tests/ui/methods.rs b/tests/ui/methods.rs index 6cda888f17f..b93cd6150d7 100644 --- a/tests/ui/methods.rs +++ b/tests/ui/methods.rs @@ -179,6 +179,13 @@ fn option_methods() { // macro case let _ = opt_map!(opt, |x| x + 1).unwrap_or(0); // should not lint + // Should not lint if not copyable + let id: String = "identifier".to_string(); + let _ = Some("prefix").map(|p| format!("{}.{}", p, id)).unwrap_or(id); + // ...but DO lint if the `unwrap_or` argument is not used in the `map` + let id: String = "identifier".to_string(); + let _ = Some("prefix").map(|p| format!("{}.", p)).unwrap_or(id); + // Check OPTION_MAP_UNWRAP_OR_ELSE // single line case let _ = opt.map(|x| x + 1) diff --git a/tests/ui/methods.stderr b/tests/ui/methods.stderr index 33f51a81f6e..fb617c0cb26 100644 --- a/tests/ui/methods.stderr +++ b/tests/ui/methods.stderr @@ -89,8 +89,16 @@ LL | | .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(a)` on an Option value. This can be done more directly by calling `map_or(a, f)` instead + --> $DIR/methods.rs:187:13 + | +LL | let _ = Some("prefix").map(|p| format!("{}.", p)).unwrap_or(id); + | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ + | + = note: replace `map(|p| format!("{}.", p)).unwrap_or(id)` with `map_or(id, |p| format!("{}.", p))` + 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:184:13 + --> $DIR/methods.rs:191:13 | LL | let _ = opt.map(|x| x + 1) | _____________^ @@ -102,7 +110,7 @@ LL | | .unwrap_or_else(|| 0); // should lint even though this cal = 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:188:13 + --> $DIR/methods.rs:195:13 | LL | let _ = opt.map(|x| { | _____________^ @@ -112,7 +120,7 @@ LL | | ).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:192:13 + --> $DIR/methods.rs:199:13 | LL | let _ = opt.map(|x| x + 1) | _____________^ @@ -122,7 +130,7 @@ LL | | ); | |_________________^ error: called `map_or(None, f)` on an Option value. This can be done more directly by calling `and_then(f)` instead - --> $DIR/methods.rs:201:13 + --> $DIR/methods.rs:208:13 | LL | let _ = opt.map_or(None, |x| Some(x + 1)); | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try using and_then instead: `opt.and_then(|x| Some(x + 1))` @@ -130,7 +138,7 @@ LL | let _ = opt.map_or(None, |x| Some(x + 1)); = note: `-D clippy::option-map-or-none` implied by `-D warnings` error: called `map_or(None, f)` on an Option value. This can be done more directly by calling `and_then(f)` instead - --> $DIR/methods.rs:203:13 + --> $DIR/methods.rs:210:13 | LL | let _ = opt.map_or(None, |x| { | _____________^ @@ -146,7 +154,7 @@ LL | }); | error: called `filter(p).next()` on an `Iterator`. This is more succinctly expressed by calling `.find(p)` instead. - --> $DIR/methods.rs:229:13 + --> $DIR/methods.rs:236:13 | LL | let _ = v.iter().filter(|&x| *x < 0).next(); | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ @@ -155,7 +163,7 @@ LL | let _ = v.iter().filter(|&x| *x < 0).next(); = 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:232:13 + --> $DIR/methods.rs:239:13 | LL | let _ = v.iter().filter(|&x| { | _____________^ @@ -165,7 +173,7 @@ LL | | ).next(); | |___________________________^ error: called `is_some()` after searching an `Iterator` with find. This is more succinctly expressed by calling `any()`. - --> $DIR/methods.rs:248:13 + --> $DIR/methods.rs:255:13 | LL | let _ = v.iter().find(|&x| *x < 0).is_some(); | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ @@ -174,7 +182,7 @@ LL | let _ = v.iter().find(|&x| *x < 0).is_some(); = 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:251:13 + --> $DIR/methods.rs:258:13 | LL | let _ = v.iter().find(|&x| { | _____________^ @@ -184,7 +192,7 @@ LL | | ).is_some(); | |______________________________^ error: called `is_some()` after searching an `Iterator` with position. This is more succinctly expressed by calling `any()`. - --> $DIR/methods.rs:257:13 + --> $DIR/methods.rs:264:13 | LL | let _ = v.iter().position(|&x| x < 0).is_some(); | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ @@ -192,7 +200,7 @@ LL | 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:260:13 + --> $DIR/methods.rs:267:13 | LL | let _ = v.iter().position(|&x| { | _____________^ @@ -202,7 +210,7 @@ LL | | ).is_some(); | |______________________________^ error: called `is_some()` after searching an `Iterator` with rposition. This is more succinctly expressed by calling `any()`. - --> $DIR/methods.rs:266:13 + --> $DIR/methods.rs:273:13 | LL | let _ = v.iter().rposition(|&x| x < 0).is_some(); | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ @@ -210,7 +218,7 @@ LL | 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:269:13 + --> $DIR/methods.rs:276:13 | LL | let _ = v.iter().rposition(|&x| { | _____________^ @@ -220,7 +228,7 @@ LL | | ).is_some(); | |______________________________^ error: use of `unwrap_or` followed by a function call - --> $DIR/methods.rs:306:22 + --> $DIR/methods.rs:313:22 | LL | with_constructor.unwrap_or(make()); | ^^^^^^^^^^^^^^^^^ help: try this: `unwrap_or_else(make)` @@ -228,73 +236,73 @@ LL | with_constructor.unwrap_or(make()); = note: `-D clippy::or-fun-call` implied by `-D warnings` error: use of `unwrap_or` followed by a call to `new` - --> $DIR/methods.rs:309:5 + --> $DIR/methods.rs:316:5 | LL | 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:312:21 + --> $DIR/methods.rs:319:21 | LL | with_const_args.unwrap_or(Vec::with_capacity(12)); | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try this: `unwrap_or_else(|| Vec::with_capacity(12))` error: use of `unwrap_or` followed by a function call - --> $DIR/methods.rs:315:14 + --> $DIR/methods.rs:322:14 | LL | with_err.unwrap_or(make()); | ^^^^^^^^^^^^^^^^^ help: try this: `unwrap_or_else(|_| make())` error: use of `unwrap_or` followed by a function call - --> $DIR/methods.rs:318:19 + --> $DIR/methods.rs:325:19 | LL | with_err_args.unwrap_or(Vec::with_capacity(12)); | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try this: `unwrap_or_else(|_| Vec::with_capacity(12))` error: use of `unwrap_or` followed by a call to `default` - --> $DIR/methods.rs:321:5 + --> $DIR/methods.rs:328:5 | LL | 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:324:5 + --> $DIR/methods.rs:331:5 | LL | 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:327:14 + --> $DIR/methods.rs:334:14 | LL | with_vec.unwrap_or(vec![]); | ^^^^^^^^^^^^^^^^^ help: try this: `unwrap_or_else(|| vec![])` error: use of `unwrap_or` followed by a function call - --> $DIR/methods.rs:332:21 + --> $DIR/methods.rs:339:21 | LL | without_default.unwrap_or(Foo::new()); | ^^^^^^^^^^^^^^^^^^^^^ help: try this: `unwrap_or_else(Foo::new)` error: use of `or_insert` followed by a function call - --> $DIR/methods.rs:335:19 + --> $DIR/methods.rs:342:19 | LL | map.entry(42).or_insert(String::new()); | ^^^^^^^^^^^^^^^^^^^^^^^^ help: try this: `or_insert_with(String::new)` error: use of `or_insert` followed by a function call - --> $DIR/methods.rs:338:21 + --> $DIR/methods.rs:345:21 | LL | btree.entry(42).or_insert(String::new()); | ^^^^^^^^^^^^^^^^^^^^^^^^ help: try this: `or_insert_with(String::new)` error: use of `unwrap_or` followed by a function call - --> $DIR/methods.rs:341:21 + --> $DIR/methods.rs:348:21 | LL | let _ = stringy.unwrap_or("".to_owned()); | ^^^^^^^^^^^^^^^^^^^^^^^^ help: try this: `unwrap_or_else(|| "".to_owned())` error: called `.iter().nth()` on a Vec. Calling `.get()` is both faster and more readable - --> $DIR/methods.rs:352:23 + --> $DIR/methods.rs:359:23 | LL | let bad_vec = some_vec.iter().nth(3); | ^^^^^^^^^^^^^^^^^^^^^^ @@ -302,48 +310,48 @@ LL | let bad_vec = some_vec.iter().nth(3); = note: `-D clippy::iter-nth` implied by `-D warnings` error: called `.iter().nth()` on a slice. Calling `.get()` is both faster and more readable - --> $DIR/methods.rs:353:26 + --> $DIR/methods.rs:360:26 | LL | 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:354:31 + --> $DIR/methods.rs:361:31 | LL | 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:355:29 + --> $DIR/methods.rs:362:29 | LL | 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:360:23 + --> $DIR/methods.rs:367:23 | LL | 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:363:26 + --> $DIR/methods.rs:370:26 | LL | 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:366:29 + --> $DIR/methods.rs:373:29 | LL | let bad_vec_deque = some_vec_deque.iter_mut().nth(3); | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ 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:378:13 + --> $DIR/methods.rs:385:13 | LL | let _ = opt.unwrap(); | ^^^^^^^^^^^^ | = note: `-D clippy::option-unwrap-used` implied by `-D warnings` -error: aborting due to 43 previous errors +error: aborting due to 44 previous errors |