From a3ea65c2d9bc52f308745ae488435388fce753a2 Mon Sep 17 00:00:00 2001 From: Dániel Buga Date: Mon, 15 Jun 2020 11:21:56 +0200 Subject: Implement new lint --- CHANGELOG.md | 1 + clippy_lints/src/lib.rs | 3 + clippy_lints/src/methods/mod.rs | 130 +++++++++++++++++++++++++++++- src/lintlist/mod.rs | 7 ++ tests/ui/unnecessary_lazy_eval.fixed | 105 +++++++++++++++++++++++++ tests/ui/unnecessary_lazy_eval.rs | 105 +++++++++++++++++++++++++ tests/ui/unnecessary_lazy_eval.stderr | 144 ++++++++++++++++++++++++++++++++++ 7 files changed, 494 insertions(+), 1 deletion(-) create mode 100644 tests/ui/unnecessary_lazy_eval.fixed create mode 100644 tests/ui/unnecessary_lazy_eval.rs create mode 100644 tests/ui/unnecessary_lazy_eval.stderr diff --git a/CHANGELOG.md b/CHANGELOG.md index 50fe7612909..c21190e9b9c 100644 --- a/CHANGELOG.md +++ b/CHANGELOG.md @@ -1646,6 +1646,7 @@ Released 2018-09-13 [`option_map_or_none`]: https://rust-lang.github.io/rust-clippy/master/index.html#option_map_or_none [`option_map_unit_fn`]: https://rust-lang.github.io/rust-clippy/master/index.html#option_map_unit_fn [`option_option`]: https://rust-lang.github.io/rust-clippy/master/index.html#option_option +[`option_unwrap_or_else`]: https://rust-lang.github.io/rust-clippy/master/index.html#option_unwrap_or_else [`or_fun_call`]: https://rust-lang.github.io/rust-clippy/master/index.html#or_fun_call [`out_of_bounds_indexing`]: https://rust-lang.github.io/rust-clippy/master/index.html#out_of_bounds_indexing [`overflow_check_conditional`]: https://rust-lang.github.io/rust-clippy/master/index.html#overflow_check_conditional diff --git a/clippy_lints/src/lib.rs b/clippy_lints/src/lib.rs index 986e9d9bee4..cb29f71387b 100644 --- a/clippy_lints/src/lib.rs +++ b/clippy_lints/src/lib.rs @@ -672,6 +672,7 @@ pub fn register_plugins(store: &mut rustc_lint::LintStore, sess: &Session, conf: &methods::OK_EXPECT, &methods::OPTION_AS_REF_DEREF, &methods::OPTION_MAP_OR_NONE, + &methods::UNNECESSARY_LAZY_EVALUATION, &methods::OR_FUN_CALL, &methods::RESULT_MAP_OR_INTO_OPTION, &methods::SEARCH_IS_SOME, @@ -1360,6 +1361,7 @@ pub fn register_plugins(store: &mut rustc_lint::LintStore, sess: &Session, conf: LintId::of(&methods::UNINIT_ASSUMED_INIT), LintId::of(&methods::UNNECESSARY_FILTER_MAP), LintId::of(&methods::UNNECESSARY_FOLD), + LintId::of(&methods::UNNECESSARY_LAZY_EVALUATION), LintId::of(&methods::USELESS_ASREF), LintId::of(&methods::WRONG_SELF_CONVENTION), LintId::of(&methods::ZST_OFFSET), @@ -1610,6 +1612,7 @@ pub fn register_plugins(store: &mut rustc_lint::LintStore, sess: &Session, conf: LintId::of(&methods::FILTER_NEXT), LintId::of(&methods::FLAT_MAP_IDENTITY), LintId::of(&methods::OPTION_AS_REF_DEREF), + LintId::of(&methods::UNNECESSARY_LAZY_EVALUATION), LintId::of(&methods::SEARCH_IS_SOME), LintId::of(&methods::SKIP_WHILE_NEXT), LintId::of(&methods::SUSPICIOUS_MAP), diff --git a/clippy_lints/src/methods/mod.rs b/clippy_lints/src/methods/mod.rs index 2330978e67f..61b7f2647ee 100644 --- a/clippy_lints/src/methods/mod.rs +++ b/clippy_lints/src/methods/mod.rs @@ -1329,6 +1329,32 @@ declare_clippy_lint! { "`push_str()` used with a single-character string literal as parameter" } +declare_clippy_lint! { + /// **What it does:** Looks for unnecessary lazily evaluated closures on `Option` and `Result`. + /// + /// **Why is this bad?** Using eager evaluation is shorter and simpler in some cases. + /// + /// **Known problems:** None. + /// + /// **Example:** + /// + /// ```rust + /// // example code where clippy issues a warning + /// let opt: Option = None; + /// + /// opt.unwrap_or_else(|| 42); + /// ``` + /// Use instead: + /// ```rust + /// let opt: Option = None; + /// + /// opt.unwrap_or(42); + /// ``` + pub UNNECESSARY_LAZY_EVALUATION, + style, + "using unnecessary lazy evaluation, which can be replaced with simpler eager evaluation" +} + declare_lint_pass!(Methods => [ UNWRAP_USED, EXPECT_USED, @@ -1378,6 +1404,7 @@ declare_lint_pass!(Methods => [ ZST_OFFSET, FILETYPE_IS_FILE, OPTION_AS_REF_DEREF, + UNNECESSARY_LAZY_EVALUATION, ]); impl<'tcx> LateLintPass<'tcx> for Methods { @@ -1398,13 +1425,18 @@ impl<'tcx> LateLintPass<'tcx> for Methods { ["expect", "ok"] => lint_ok_expect(cx, expr, arg_lists[1]), ["expect", ..] => lint_expect(cx, expr, arg_lists[0]), ["unwrap_or", "map"] => option_map_unwrap_or::lint(cx, expr, arg_lists[1], arg_lists[0], method_spans[1]), - ["unwrap_or_else", "map"] => lint_map_unwrap_or_else(cx, expr, arg_lists[1], arg_lists[0]), + ["unwrap_or_else", "map"] => { + lint_lazy_eval(cx, expr, arg_lists[0], true, "unwrap_or"); + lint_map_unwrap_or_else(cx, expr, arg_lists[1], arg_lists[0]); + }, ["map_or", ..] => lint_map_or_none(cx, expr, arg_lists[0]), ["and_then", ..] => { + lint_lazy_eval(cx, expr, arg_lists[0], false, "and"); bind_instead_of_map::OptionAndThenSome::lint(cx, expr, arg_lists[0]); bind_instead_of_map::ResultAndThenOk::lint(cx, expr, arg_lists[0]); }, ["or_else", ..] => { + lint_lazy_eval(cx, expr, arg_lists[0], false, "or"); bind_instead_of_map::ResultOrElseErrInfo::lint(cx, expr, arg_lists[0]); }, ["next", "filter"] => lint_filter_next(cx, expr, arg_lists[1]), @@ -1448,6 +1480,9 @@ impl<'tcx> LateLintPass<'tcx> for Methods { ["is_file", ..] => lint_filetype_is_file(cx, expr, arg_lists[0]), ["map", "as_ref"] => lint_option_as_ref_deref(cx, expr, arg_lists[1], arg_lists[0], false), ["map", "as_mut"] => lint_option_as_ref_deref(cx, expr, arg_lists[1], arg_lists[0], true), + ["unwrap_or_else", ..] => lint_lazy_eval(cx, expr, arg_lists[0], true, "unwrap_or"), + ["get_or_insert_with", ..] => lint_lazy_eval(cx, expr, arg_lists[0], true, "get_or_insert"), + ["ok_or_else", ..] => lint_lazy_eval(cx, expr, arg_lists[0], true, "ok_or"), _ => {}, } @@ -2663,6 +2698,99 @@ fn lint_map_flatten<'tcx>(cx: &LateContext<'tcx>, expr: &'tcx hir::Expr<'_>, map } } +/// lint use of `_else(simple closure)` for `Option`s and `Result`s that can be +/// replaced with `(return value of simple closure)` +fn lint_lazy_eval<'a, 'tcx>( + cx: &LateContext<'a, 'tcx>, + expr: &'tcx hir::Expr<'_>, + args: &'tcx [hir::Expr<'_>], + allow_variant_calls: bool, + simplify_using: &str, +) { + let is_option = is_type_diagnostic_item(cx, cx.tables.expr_ty(&args[0]), sym!(option_type)); + let is_result = is_type_diagnostic_item(cx, cx.tables.expr_ty(&args[0]), sym!(result_type)); + + if !is_option && !is_result { + return; + } + + // Return true if the expression is an accessor of any of the arguments + fn expr_uses_argument(expr: &hir::Expr<'_>, params: &[hir::Param<'_>]) -> bool { + params.iter().any(|arg| { + if_chain! { + if let hir::PatKind::Binding(_, _, ident, _) = arg.pat.kind; + if let hir::ExprKind::Path(hir::QPath::Resolved(_, ref path)) = expr.kind; + if let [p, ..] = path.segments; + then { + ident.name == p.ident.name + } else { + false + } + } + }) + } + + fn match_any_qpath(path: &hir::QPath<'_>, paths: &[&[&str]]) -> bool { + paths.iter().any(|candidate| match_qpath(path, candidate)) + } + + if let hir::ExprKind::Closure(_, _, eid, _, _) = args[1].kind { + let body = cx.tcx.hir().body(eid); + let ex = &body.value; + let params = &body.params; + + let simplify = match ex.kind { + // Closures returning literals can be unconditionally simplified + hir::ExprKind::Lit(_) => true, + + // Reading fields can be simplified if the object is not an argument of the closure + hir::ExprKind::Field(ref object, _) => !expr_uses_argument(object, params), + + // Paths can be simplified if the root is not the argument, this also covers None + hir::ExprKind::Path(_) => !expr_uses_argument(ex, params), + + // Calls to Some, Ok, Err can be considered literals if they don't derive an argument + hir::ExprKind::Call(ref func, ref args) => if_chain! { + if allow_variant_calls; // Disable lint when rules conflict with bind_instead_of_map + if let hir::ExprKind::Path(ref path) = func.kind; + if match_any_qpath(path, &[&["Some"], &["Ok"], &["Err"]]); + then { + !args.iter().any(|arg| expr_uses_argument(arg, params)) + } else { + false + } + }, + + // For anything more complex than the above, a closure is probably the right solution, + // or the case is handled by an other lint + _ => false, + }; + + if simplify { + let msg = if is_option { + "unnecessary closure used to substitute value for `Option::None`" + } else { + "unnecessary closure used to substitute value for `Result::Err`" + }; + + span_lint_and_sugg( + cx, + UNNECESSARY_LAZY_EVALUATION, + expr.span, + msg, + &format!("Use `{}` instead", simplify_using), + format!( + "{0}.{1}({2})", + snippet(cx, args[0].span, ".."), + simplify_using, + snippet(cx, ex.span, ".."), + ), + Applicability::MachineApplicable, + ); + } + } +} + /// lint use of `map().unwrap_or_else()` for `Option`s and `Result`s fn lint_map_unwrap_or_else<'tcx>( cx: &LateContext<'tcx>, diff --git a/src/lintlist/mod.rs b/src/lintlist/mod.rs index 233f95deedd..1e76163f946 100644 --- a/src/lintlist/mod.rs +++ b/src/lintlist/mod.rs @@ -2383,6 +2383,13 @@ pub static ref ALL_LINTS: Vec = vec![ deprecation: None, module: "methods", }, + Lint { + name: "unnecessary_lazy_eval", + group: "style", + desc: "using unnecessary lazy evaluation, which can be replaced with simpler eager evaluation", + deprecation: None, + module: "methods", + }, Lint { name: "unnecessary_mut_passed", group: "style", diff --git a/tests/ui/unnecessary_lazy_eval.fixed b/tests/ui/unnecessary_lazy_eval.fixed new file mode 100644 index 00000000000..fcfa6dfe12d --- /dev/null +++ b/tests/ui/unnecessary_lazy_eval.fixed @@ -0,0 +1,105 @@ +// run-rustfix +#![warn(clippy::unnecessary_lazy_evaluation)] +#![allow(clippy::redundant_closure)] +#![allow(clippy::bind_instead_of_map)] + +struct Deep(Option); + +#[derive(Copy, Clone)] +struct SomeStruct { + some_field: u32, +} + +impl SomeStruct { + fn return_some_field(&self) -> u32 { + self.some_field + } +} + +fn some_call() -> T { + T::default() +} + +fn main() { + let astronomers_pi = 10; + let ext_str = SomeStruct { some_field: 10 }; + + // Should lint - Option + let mut opt = Some(42); + let ext_opt = Some(42); + let _ = opt.unwrap_or(2); + let _ = opt.unwrap_or(astronomers_pi); + let _ = opt.unwrap_or(ext_str.some_field); + let _ = opt.and(ext_opt); + let _ = opt.or(ext_opt); + let _ = opt.or(None); + let _ = opt.get_or_insert(2); + let _ = opt.ok_or(2); + + // Cases when unwrap is not called on a simple variable + let _ = Some(10).unwrap_or(2); + let _ = Some(10).and(ext_opt); + let _: Option = None.or(ext_opt); + let _ = None.get_or_insert(2); + let _: Result = None.ok_or(2); + let _: Option = None.or(None); + + let mut deep = Deep(Some(42)); + let _ = deep.0.unwrap_or(2); + let _ = deep.0.and(ext_opt); + let _ = deep.0.or(None); + let _ = deep.0.get_or_insert(2); + let _ = deep.0.ok_or(2); + + // Should not lint - Option + let _ = opt.unwrap_or_else(|| ext_str.return_some_field()); + let _ = opt.or_else(some_call); + let _ = opt.or_else(|| some_call()); + let _: Result = opt.ok_or_else(|| some_call()); + let _: Result = opt.ok_or_else(some_call); + let _ = deep.0.get_or_insert_with(|| some_call()); + let _ = deep.0.or_else(some_call); + let _ = deep.0.or_else(|| some_call()); + + // These are handled by bind_instead_of_map + let _: Option = None.or_else(|| Some(3)); + let _ = deep.0.or_else(|| Some(3)); + let _ = opt.or_else(|| Some(3)); + + // Should lint - Result + let res: Result = Err(5); + let res2: Result = Err(SomeStruct { some_field: 5 }); + + let _ = res2.unwrap_or(2); + let _ = res2.unwrap_or(astronomers_pi); + let _ = res2.unwrap_or(ext_str.some_field); + + // Should not lint - Result + let _ = res.unwrap_or_else(|err| err); + let _ = res2.unwrap_or_else(|err| err.some_field); + let _ = res2.unwrap_or_else(|err| err.return_some_field()); + let _ = res2.unwrap_or_else(|_| ext_str.return_some_field()); + + let _: Result = res.and_then(|x| Ok(x)); + let _: Result = res.and_then(|x| Err(x)); + + let _: Result = res.or_else(|err| Ok(err)); + let _: Result = res.or_else(|err| Err(err)); + + // These are handled by bind_instead_of_map + let _: Result = res.and_then(|_| Ok(2)); + let _: Result = res.and_then(|_| Ok(astronomers_pi)); + let _: Result = res.and_then(|_| Ok(ext_str.some_field)); + + let _: Result = res.and_then(|_| Err(2)); + let _: Result = res.and_then(|_| Err(astronomers_pi)); + let _: Result = res.and_then(|_| Err(ext_str.some_field)); + + let _: Result = res.or_else(|_| Ok(2)); + let _: Result = res.or_else(|_| Ok(astronomers_pi)); + let _: Result = res.or_else(|_| Ok(ext_str.some_field)); + + let _: Result = res.or_else(|_| Err(2)); + let _: Result = res.or_else(|_| Err(astronomers_pi)); + let _: Result = res.or_else(|_| Err(ext_str.some_field)); +} diff --git a/tests/ui/unnecessary_lazy_eval.rs b/tests/ui/unnecessary_lazy_eval.rs new file mode 100644 index 00000000000..04b3c8ae1e2 --- /dev/null +++ b/tests/ui/unnecessary_lazy_eval.rs @@ -0,0 +1,105 @@ +// run-rustfix +#![warn(clippy::unnecessary_lazy_eval)] +#![allow(clippy::redundant_closure)] +#![allow(clippy::bind_instead_of_map)] + +struct Deep(Option); + +#[derive(Copy, Clone)] +struct SomeStruct { + some_field: u32, +} + +impl SomeStruct { + fn return_some_field(&self) -> u32 { + self.some_field + } +} + +fn some_call() -> T { + T::default() +} + +fn main() { + let astronomers_pi = 10; + let ext_str = SomeStruct { some_field: 10 }; + + // Should lint - Option + let mut opt = Some(42); + let ext_opt = Some(42); + let _ = opt.unwrap_or_else(|| 2); + let _ = opt.unwrap_or_else(|| astronomers_pi); + let _ = opt.unwrap_or_else(|| ext_str.some_field); + let _ = opt.and_then(|_| ext_opt); + let _ = opt.or_else(|| ext_opt); + let _ = opt.or_else(|| None); + let _ = opt.get_or_insert_with(|| 2); + let _ = opt.ok_or_else(|| 2); + + // Cases when unwrap is not called on a simple variable + let _ = Some(10).unwrap_or_else(|| 2); + let _ = Some(10).and_then(|_| ext_opt); + let _: Option = None.or_else(|| ext_opt); + let _ = None.get_or_insert_with(|| 2); + let _: Result = None.ok_or_else(|| 2); + let _: Option = None.or_else(|| None); + + let mut deep = Deep(Some(42)); + let _ = deep.0.unwrap_or_else(|| 2); + let _ = deep.0.and_then(|_| ext_opt); + let _ = deep.0.or_else(|| None); + let _ = deep.0.get_or_insert_with(|| 2); + let _ = deep.0.ok_or_else(|| 2); + + // Should not lint - Option + let _ = opt.unwrap_or_else(|| ext_str.return_some_field()); + let _ = opt.or_else(some_call); + let _ = opt.or_else(|| some_call()); + let _: Result = opt.ok_or_else(|| some_call()); + let _: Result = opt.ok_or_else(some_call); + let _ = deep.0.get_or_insert_with(|| some_call()); + let _ = deep.0.or_else(some_call); + let _ = deep.0.or_else(|| some_call()); + + // These are handled by bind_instead_of_map + let _: Option = None.or_else(|| Some(3)); + let _ = deep.0.or_else(|| Some(3)); + let _ = opt.or_else(|| Some(3)); + + // Should lint - Result + let res: Result = Err(5); + let res2: Result = Err(SomeStruct { some_field: 5 }); + + let _ = res2.unwrap_or_else(|_| 2); + let _ = res2.unwrap_or_else(|_| astronomers_pi); + let _ = res2.unwrap_or_else(|_| ext_str.some_field); + + // Should not lint - Result + let _ = res.unwrap_or_else(|err| err); + let _ = res2.unwrap_or_else(|err| err.some_field); + let _ = res2.unwrap_or_else(|err| err.return_some_field()); + let _ = res2.unwrap_or_else(|_| ext_str.return_some_field()); + + let _: Result = res.and_then(|x| Ok(x)); + let _: Result = res.and_then(|x| Err(x)); + + let _: Result = res.or_else(|err| Ok(err)); + let _: Result = res.or_else(|err| Err(err)); + + // These are handled by bind_instead_of_map + let _: Result = res.and_then(|_| Ok(2)); + let _: Result = res.and_then(|_| Ok(astronomers_pi)); + let _: Result = res.and_then(|_| Ok(ext_str.some_field)); + + let _: Result = res.and_then(|_| Err(2)); + let _: Result = res.and_then(|_| Err(astronomers_pi)); + let _: Result = res.and_then(|_| Err(ext_str.some_field)); + + let _: Result = res.or_else(|_| Ok(2)); + let _: Result = res.or_else(|_| Ok(astronomers_pi)); + let _: Result = res.or_else(|_| Ok(ext_str.some_field)); + + let _: Result = res.or_else(|_| Err(2)); + let _: Result = res.or_else(|_| Err(astronomers_pi)); + let _: Result = res.or_else(|_| Err(ext_str.some_field)); +} diff --git a/tests/ui/unnecessary_lazy_eval.stderr b/tests/ui/unnecessary_lazy_eval.stderr new file mode 100644 index 00000000000..b941bf84246 --- /dev/null +++ b/tests/ui/unnecessary_lazy_eval.stderr @@ -0,0 +1,144 @@ +error: unnecessary closure used to substitute value for `Option::None` + --> $DIR/unnecessary_lazy_eval.rs:30:13 + | +LL | let _ = opt.unwrap_or_else(|| 2); + | ^^^^^^^^^^^^^^^^^^^^^^^^ help: Use `unwrap_or` instead: `opt.unwrap_or(2)` + | + = note: `-D clippy::unnecessary-lazy-evaluation` implied by `-D warnings` + +error: unnecessary closure used to substitute value for `Option::None` + --> $DIR/unnecessary_lazy_eval.rs:31:13 + | +LL | let _ = opt.unwrap_or_else(|| astronomers_pi); + | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: Use `unwrap_or` instead: `opt.unwrap_or(astronomers_pi)` + +error: unnecessary closure used to substitute value for `Option::None` + --> $DIR/unnecessary_lazy_eval.rs:32:13 + | +LL | let _ = opt.unwrap_or_else(|| ext_str.some_field); + | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: Use `unwrap_or` instead: `opt.unwrap_or(ext_str.some_field)` + +error: unnecessary closure used to substitute value for `Option::None` + --> $DIR/unnecessary_lazy_eval.rs:33:13 + | +LL | let _ = opt.and_then(|_| ext_opt); + | ^^^^^^^^^^^^^^^^^^^^^^^^^ help: Use `and` instead: `opt.and(ext_opt)` + +error: unnecessary closure used to substitute value for `Option::None` + --> $DIR/unnecessary_lazy_eval.rs:34:13 + | +LL | let _ = opt.or_else(|| ext_opt); + | ^^^^^^^^^^^^^^^^^^^^^^^ help: Use `or` instead: `opt.or(ext_opt)` + +error: unnecessary closure used to substitute value for `Option::None` + --> $DIR/unnecessary_lazy_eval.rs:35:13 + | +LL | let _ = opt.or_else(|| None); + | ^^^^^^^^^^^^^^^^^^^^ help: Use `or` instead: `opt.or(None)` + +error: unnecessary closure used to substitute value for `Option::None` + --> $DIR/unnecessary_lazy_eval.rs:36:13 + | +LL | let _ = opt.get_or_insert_with(|| 2); + | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: Use `get_or_insert` instead: `opt.get_or_insert(2)` + +error: unnecessary closure used to substitute value for `Option::None` + --> $DIR/unnecessary_lazy_eval.rs:37:13 + | +LL | let _ = opt.ok_or_else(|| 2); + | ^^^^^^^^^^^^^^^^^^^^ help: Use `ok_or` instead: `opt.ok_or(2)` + +error: unnecessary closure used to substitute value for `Option::None` + --> $DIR/unnecessary_lazy_eval.rs:40:13 + | +LL | let _ = Some(10).unwrap_or_else(|| 2); + | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: Use `unwrap_or` instead: `Some(10).unwrap_or(2)` + +error: unnecessary closure used to substitute value for `Option::None` + --> $DIR/unnecessary_lazy_eval.rs:41:13 + | +LL | let _ = Some(10).and_then(|_| ext_opt); + | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: Use `and` instead: `Some(10).and(ext_opt)` + +error: unnecessary closure used to substitute value for `Option::None` + --> $DIR/unnecessary_lazy_eval.rs:42:26 + | +LL | let _: Option = None.or_else(|| ext_opt); + | ^^^^^^^^^^^^^^^^^^^^^^^^ help: Use `or` instead: `None.or(ext_opt)` + +error: unnecessary closure used to substitute value for `Option::None` + --> $DIR/unnecessary_lazy_eval.rs:43:13 + | +LL | let _ = None.get_or_insert_with(|| 2); + | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: Use `get_or_insert` instead: `None.get_or_insert(2)` + +error: unnecessary closure used to substitute value for `Option::None` + --> $DIR/unnecessary_lazy_eval.rs:44:31 + | +LL | let _: Result = None.ok_or_else(|| 2); + | ^^^^^^^^^^^^^^^^^^^^^ help: Use `ok_or` instead: `None.ok_or(2)` + +error: unnecessary closure used to substitute value for `Option::None` + --> $DIR/unnecessary_lazy_eval.rs:45:26 + | +LL | let _: Option = None.or_else(|| None); + | ^^^^^^^^^^^^^^^^^^^^^ help: Use `or` instead: `None.or(None)` + +error: unnecessary closure used to substitute value for `Option::None` + --> $DIR/unnecessary_lazy_eval.rs:48:13 + | +LL | let _ = deep.0.unwrap_or_else(|| 2); + | ^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: Use `unwrap_or` instead: `deep.0.unwrap_or(2)` + +error: unnecessary closure used to substitute value for `Option::None` + --> $DIR/unnecessary_lazy_eval.rs:49:13 + | +LL | let _ = deep.0.and_then(|_| ext_opt); + | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: Use `and` instead: `deep.0.and(ext_opt)` + +error: unnecessary closure used to substitute value for `Option::None` + --> $DIR/unnecessary_lazy_eval.rs:50:13 + | +LL | let _ = deep.0.or_else(|| None); + | ^^^^^^^^^^^^^^^^^^^^^^^ help: Use `or` instead: `deep.0.or(None)` + +error: unnecessary closure used to substitute value for `Option::None` + --> $DIR/unnecessary_lazy_eval.rs:51:13 + | +LL | let _ = deep.0.get_or_insert_with(|| 2); + | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: Use `get_or_insert` instead: `deep.0.get_or_insert(2)` + +error: unnecessary closure used to substitute value for `Option::None` + --> $DIR/unnecessary_lazy_eval.rs:52:13 + | +LL | let _ = deep.0.ok_or_else(|| 2); + | ^^^^^^^^^^^^^^^^^^^^^^^ help: Use `ok_or` instead: `deep.0.ok_or(2)` + +error: unnecessary closure used to substitute value for `Result::Err` + --> $DIR/unnecessary_lazy_eval.rs:73:13 + | +LL | let _ = res2.unwrap_or_else(|_| 2); + | ^^^^^^^^^^^^^^^^^^^^^^^^^^ help: Use `unwrap_or` instead: `res2.unwrap_or(2)` + +error: unnecessary closure used to substitute value for `Result::Err` + --> $DIR/unnecessary_lazy_eval.rs:74:13 + | +LL | let _ = res2.unwrap_or_else(|_| astronomers_pi); + | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: Use `unwrap_or` instead: `res2.unwrap_or(astronomers_pi)` + +error: unnecessary closure used to substitute value for `Result::Err` + --> $DIR/unnecessary_lazy_eval.rs:75:13 + | +LL | let _ = res2.unwrap_or_else(|_| ext_str.some_field); + | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: Use `unwrap_or` instead: `res2.unwrap_or(ext_str.some_field)` + +error: unknown clippy lint: clippy::unnecessary_lazy_eval + --> $DIR/unnecessary_lazy_eval.rs:2:9 + | +LL | #![warn(clippy::unnecessary_lazy_eval)] + | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: did you mean: `clippy::unnecessary_lazy_evaluation` + | + = note: `-D clippy::unknown-clippy-lints` implied by `-D warnings` + +error: aborting due to 23 previous errors + -- cgit 1.4.1-3-g733a5 From 923d61222cc9de9e662e90570e4725ef00f48d71 Mon Sep 17 00:00:00 2001 From: Dániel Buga Date: Mon, 15 Jun 2020 11:48:14 +0200 Subject: Rename the changelog footnote as well --- CHANGELOG.md | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/CHANGELOG.md b/CHANGELOG.md index c21190e9b9c..54489751014 100644 --- a/CHANGELOG.md +++ b/CHANGELOG.md @@ -1646,7 +1646,6 @@ Released 2018-09-13 [`option_map_or_none`]: https://rust-lang.github.io/rust-clippy/master/index.html#option_map_or_none [`option_map_unit_fn`]: https://rust-lang.github.io/rust-clippy/master/index.html#option_map_unit_fn [`option_option`]: https://rust-lang.github.io/rust-clippy/master/index.html#option_option -[`option_unwrap_or_else`]: https://rust-lang.github.io/rust-clippy/master/index.html#option_unwrap_or_else [`or_fun_call`]: https://rust-lang.github.io/rust-clippy/master/index.html#or_fun_call [`out_of_bounds_indexing`]: https://rust-lang.github.io/rust-clippy/master/index.html#out_of_bounds_indexing [`overflow_check_conditional`]: https://rust-lang.github.io/rust-clippy/master/index.html#overflow_check_conditional @@ -1755,6 +1754,7 @@ Released 2018-09-13 [`unnecessary_cast`]: https://rust-lang.github.io/rust-clippy/master/index.html#unnecessary_cast [`unnecessary_filter_map`]: https://rust-lang.github.io/rust-clippy/master/index.html#unnecessary_filter_map [`unnecessary_fold`]: https://rust-lang.github.io/rust-clippy/master/index.html#unnecessary_fold +[`unnecessary_lazy_eval`]: https://rust-lang.github.io/rust-clippy/master/index.html#unnecessary_lazy_eval [`unnecessary_mut_passed`]: https://rust-lang.github.io/rust-clippy/master/index.html#unnecessary_mut_passed [`unnecessary_operation`]: https://rust-lang.github.io/rust-clippy/master/index.html#unnecessary_operation [`unnecessary_sort_by`]: https://rust-lang.github.io/rust-clippy/master/index.html#unnecessary_sort_by -- cgit 1.4.1-3-g733a5 From 848af393103d769458a206547ea4506fd0229304 Mon Sep 17 00:00:00 2001 From: Dániel Buga Date: Mon, 15 Jun 2020 14:55:23 +0200 Subject: Add note to `or_fun_call`, list checked methods --- clippy_lints/src/methods/mod.rs | 14 ++++++++++++-- 1 file changed, 12 insertions(+), 2 deletions(-) diff --git a/clippy_lints/src/methods/mod.rs b/clippy_lints/src/methods/mod.rs index 61b7f2647ee..c672ca41dec 100644 --- a/clippy_lints/src/methods/mod.rs +++ b/clippy_lints/src/methods/mod.rs @@ -1330,11 +1330,21 @@ declare_clippy_lint! { } declare_clippy_lint! { - /// **What it does:** Looks for unnecessary lazily evaluated closures on `Option` and `Result`. + /// **What it does:** As the counterpart to `or_fun_call`, this lint looks for unnecessary + /// lazily evaluated closures on `Option` and `Result`. + /// + /// This lint suggests changing the following functions, when eager evaluation results in + /// simpler code: + /// - `unwrap_or_else` to `unwrap_or` + /// - `and_then` to `and` + /// - `or_else` to `or` + /// - `get_or_insert_with` to `get_or_insert` + /// - `ok_or_else` to `ok_or` /// /// **Why is this bad?** Using eager evaluation is shorter and simpler in some cases. /// - /// **Known problems:** None. + /// **Known problems:** It is possible, but not recommended for `Deref` and `Index` to have + /// side effects. Eagerly evaluating them can change the semantics of the program. /// /// **Example:** /// -- cgit 1.4.1-3-g733a5 From a7cc5d40683b9351c35a627b05886f43fdec684f Mon Sep 17 00:00:00 2001 From: Dániel Buga Date: Mon, 15 Jun 2020 15:26:02 +0200 Subject: Also simplify if the closure body is an index expression --- clippy_lints/src/methods/mod.rs | 10 ++++++ tests/ui/unnecessary_lazy_eval.fixed | 60 +++++++++++++++++-------------- tests/ui/unnecessary_lazy_eval.rs | 60 +++++++++++++++++-------------- tests/ui/unnecessary_lazy_eval.stderr | 68 ++++++++++++++++++++--------------- 4 files changed, 116 insertions(+), 82 deletions(-) diff --git a/clippy_lints/src/methods/mod.rs b/clippy_lints/src/methods/mod.rs index c672ca41dec..ed8eaba75d1 100644 --- a/clippy_lints/src/methods/mod.rs +++ b/clippy_lints/src/methods/mod.rs @@ -2753,6 +2753,16 @@ fn lint_lazy_eval<'a, 'tcx>( // Closures returning literals can be unconditionally simplified hir::ExprKind::Lit(_) => true, + hir::ExprKind::Index(ref object, ref index) => { + // arguments are not being indexed into + if !expr_uses_argument(object, params) { + // arguments are not used as index + !expr_uses_argument(index, params) + } else { + false + } + }, + // Reading fields can be simplified if the object is not an argument of the closure hir::ExprKind::Field(ref object, _) => !expr_uses_argument(object, params), diff --git a/tests/ui/unnecessary_lazy_eval.fixed b/tests/ui/unnecessary_lazy_eval.fixed index fcfa6dfe12d..c806cf8dce4 100644 --- a/tests/ui/unnecessary_lazy_eval.fixed +++ b/tests/ui/unnecessary_lazy_eval.fixed @@ -3,15 +3,15 @@ #![allow(clippy::redundant_closure)] #![allow(clippy::bind_instead_of_map)] -struct Deep(Option); +struct Deep(Option); #[derive(Copy, Clone)] struct SomeStruct { - some_field: u32, + some_field: usize, } impl SomeStruct { - fn return_some_field(&self) -> u32 { + fn return_some_field(&self) -> usize { self.some_field } } @@ -22,6 +22,7 @@ fn some_call() -> T { fn main() { let astronomers_pi = 10; + let ext_arr: [usize; 1] = [2]; let ext_str = SomeStruct { some_field: 10 }; // Should lint - Option @@ -30,19 +31,21 @@ fn main() { let _ = opt.unwrap_or(2); let _ = opt.unwrap_or(astronomers_pi); let _ = opt.unwrap_or(ext_str.some_field); + let _ = opt.unwrap_or(ext_arr[0]); let _ = opt.and(ext_opt); let _ = opt.or(ext_opt); let _ = opt.or(None); let _ = opt.get_or_insert(2); let _ = opt.ok_or(2); + let _ = opt.ok_or(ext_arr[0]); // Cases when unwrap is not called on a simple variable let _ = Some(10).unwrap_or(2); let _ = Some(10).and(ext_opt); - let _: Option = None.or(ext_opt); + let _: Option = None.or(ext_opt); let _ = None.get_or_insert(2); - let _: Result = None.ok_or(2); - let _: Option = None.or(None); + let _: Result = None.ok_or(2); + let _: Option = None.or(None); let mut deep = Deep(Some(42)); let _ = deep.0.unwrap_or(2); @@ -55,20 +58,22 @@ fn main() { let _ = opt.unwrap_or_else(|| ext_str.return_some_field()); let _ = opt.or_else(some_call); let _ = opt.or_else(|| some_call()); - let _: Result = opt.ok_or_else(|| some_call()); - let _: Result = opt.ok_or_else(some_call); + let _: Result = opt.ok_or_else(|| some_call()); + let _: Result = opt.ok_or_else(some_call); let _ = deep.0.get_or_insert_with(|| some_call()); let _ = deep.0.or_else(some_call); let _ = deep.0.or_else(|| some_call()); // These are handled by bind_instead_of_map - let _: Option = None.or_else(|| Some(3)); + let _ = Some(10).and_then(|idx| Some(ext_arr[idx])); + let _ = Some(10).and_then(|idx| Some(idx)); + let _: Option = None.or_else(|| Some(3)); let _ = deep.0.or_else(|| Some(3)); let _ = opt.or_else(|| Some(3)); // Should lint - Result - let res: Result = Err(5); - let res2: Result = Err(SomeStruct { some_field: 5 }); + let res: Result = Err(5); + let res2: Result = Err(SomeStruct { some_field: 5 }); let _ = res2.unwrap_or(2); let _ = res2.unwrap_or(astronomers_pi); @@ -76,30 +81,31 @@ fn main() { // Should not lint - Result let _ = res.unwrap_or_else(|err| err); + let _ = res.unwrap_or_else(|err| ext_arr[err]); let _ = res2.unwrap_or_else(|err| err.some_field); let _ = res2.unwrap_or_else(|err| err.return_some_field()); let _ = res2.unwrap_or_else(|_| ext_str.return_some_field()); - let _: Result = res.and_then(|x| Ok(x)); - let _: Result = res.and_then(|x| Err(x)); + let _: Result = res.and_then(|x| Ok(x)); + let _: Result = res.and_then(|x| Err(x)); - let _: Result = res.or_else(|err| Ok(err)); - let _: Result = res.or_else(|err| Err(err)); + let _: Result = res.or_else(|err| Ok(err)); + let _: Result = res.or_else(|err| Err(err)); // These are handled by bind_instead_of_map - let _: Result = res.and_then(|_| Ok(2)); - let _: Result = res.and_then(|_| Ok(astronomers_pi)); - let _: Result = res.and_then(|_| Ok(ext_str.some_field)); + let _: Result = res.and_then(|_| Ok(2)); + let _: Result = res.and_then(|_| Ok(astronomers_pi)); + let _: Result = res.and_then(|_| Ok(ext_str.some_field)); - let _: Result = res.and_then(|_| Err(2)); - let _: Result = res.and_then(|_| Err(astronomers_pi)); - let _: Result = res.and_then(|_| Err(ext_str.some_field)); + let _: Result = res.and_then(|_| Err(2)); + let _: Result = res.and_then(|_| Err(astronomers_pi)); + let _: Result = res.and_then(|_| Err(ext_str.some_field)); - let _: Result = res.or_else(|_| Ok(2)); - let _: Result = res.or_else(|_| Ok(astronomers_pi)); - let _: Result = res.or_else(|_| Ok(ext_str.some_field)); + let _: Result = res.or_else(|_| Ok(2)); + let _: Result = res.or_else(|_| Ok(astronomers_pi)); + let _: Result = res.or_else(|_| Ok(ext_str.some_field)); - let _: Result = res.or_else(|_| Err(2)); - let _: Result = res.or_else(|_| Err(astronomers_pi)); - let _: Result = res.or_else(|_| Err(ext_str.some_field)); + let _: Result = res.or_else(|_| Err(2)); + let _: Result = res.or_else(|_| Err(astronomers_pi)); + let _: Result = res.or_else(|_| Err(ext_str.some_field)); } diff --git a/tests/ui/unnecessary_lazy_eval.rs b/tests/ui/unnecessary_lazy_eval.rs index 04b3c8ae1e2..dfc6d3ba573 100644 --- a/tests/ui/unnecessary_lazy_eval.rs +++ b/tests/ui/unnecessary_lazy_eval.rs @@ -3,15 +3,15 @@ #![allow(clippy::redundant_closure)] #![allow(clippy::bind_instead_of_map)] -struct Deep(Option); +struct Deep(Option); #[derive(Copy, Clone)] struct SomeStruct { - some_field: u32, + some_field: usize, } impl SomeStruct { - fn return_some_field(&self) -> u32 { + fn return_some_field(&self) -> usize { self.some_field } } @@ -22,6 +22,7 @@ fn some_call() -> T { fn main() { let astronomers_pi = 10; + let ext_arr: [usize; 1] = [2]; let ext_str = SomeStruct { some_field: 10 }; // Should lint - Option @@ -30,19 +31,21 @@ fn main() { let _ = opt.unwrap_or_else(|| 2); let _ = opt.unwrap_or_else(|| astronomers_pi); let _ = opt.unwrap_or_else(|| ext_str.some_field); + let _ = opt.unwrap_or_else(|| ext_arr[0]); let _ = opt.and_then(|_| ext_opt); let _ = opt.or_else(|| ext_opt); let _ = opt.or_else(|| None); let _ = opt.get_or_insert_with(|| 2); let _ = opt.ok_or_else(|| 2); + let _ = opt.ok_or_else(|| ext_arr[0]); // Cases when unwrap is not called on a simple variable let _ = Some(10).unwrap_or_else(|| 2); let _ = Some(10).and_then(|_| ext_opt); - let _: Option = None.or_else(|| ext_opt); + let _: Option = None.or_else(|| ext_opt); let _ = None.get_or_insert_with(|| 2); - let _: Result = None.ok_or_else(|| 2); - let _: Option = None.or_else(|| None); + let _: Result = None.ok_or_else(|| 2); + let _: Option = None.or_else(|| None); let mut deep = Deep(Some(42)); let _ = deep.0.unwrap_or_else(|| 2); @@ -55,20 +58,22 @@ fn main() { let _ = opt.unwrap_or_else(|| ext_str.return_some_field()); let _ = opt.or_else(some_call); let _ = opt.or_else(|| some_call()); - let _: Result = opt.ok_or_else(|| some_call()); - let _: Result = opt.ok_or_else(some_call); + let _: Result = opt.ok_or_else(|| some_call()); + let _: Result = opt.ok_or_else(some_call); let _ = deep.0.get_or_insert_with(|| some_call()); let _ = deep.0.or_else(some_call); let _ = deep.0.or_else(|| some_call()); // These are handled by bind_instead_of_map - let _: Option = None.or_else(|| Some(3)); + let _ = Some(10).and_then(|idx| Some(ext_arr[idx])); + let _ = Some(10).and_then(|idx| Some(idx)); + let _: Option = None.or_else(|| Some(3)); let _ = deep.0.or_else(|| Some(3)); let _ = opt.or_else(|| Some(3)); // Should lint - Result - let res: Result = Err(5); - let res2: Result = Err(SomeStruct { some_field: 5 }); + let res: Result = Err(5); + let res2: Result = Err(SomeStruct { some_field: 5 }); let _ = res2.unwrap_or_else(|_| 2); let _ = res2.unwrap_or_else(|_| astronomers_pi); @@ -76,30 +81,31 @@ fn main() { // Should not lint - Result let _ = res.unwrap_or_else(|err| err); + let _ = res.unwrap_or_else(|err| ext_arr[err]); let _ = res2.unwrap_or_else(|err| err.some_field); let _ = res2.unwrap_or_else(|err| err.return_some_field()); let _ = res2.unwrap_or_else(|_| ext_str.return_some_field()); - let _: Result = res.and_then(|x| Ok(x)); - let _: Result = res.and_then(|x| Err(x)); + let _: Result = res.and_then(|x| Ok(x)); + let _: Result = res.and_then(|x| Err(x)); - let _: Result = res.or_else(|err| Ok(err)); - let _: Result = res.or_else(|err| Err(err)); + let _: Result = res.or_else(|err| Ok(err)); + let _: Result = res.or_else(|err| Err(err)); // These are handled by bind_instead_of_map - let _: Result = res.and_then(|_| Ok(2)); - let _: Result = res.and_then(|_| Ok(astronomers_pi)); - let _: Result = res.and_then(|_| Ok(ext_str.some_field)); + let _: Result = res.and_then(|_| Ok(2)); + let _: Result = res.and_then(|_| Ok(astronomers_pi)); + let _: Result = res.and_then(|_| Ok(ext_str.some_field)); - let _: Result = res.and_then(|_| Err(2)); - let _: Result = res.and_then(|_| Err(astronomers_pi)); - let _: Result = res.and_then(|_| Err(ext_str.some_field)); + let _: Result = res.and_then(|_| Err(2)); + let _: Result = res.and_then(|_| Err(astronomers_pi)); + let _: Result = res.and_then(|_| Err(ext_str.some_field)); - let _: Result = res.or_else(|_| Ok(2)); - let _: Result = res.or_else(|_| Ok(astronomers_pi)); - let _: Result = res.or_else(|_| Ok(ext_str.some_field)); + let _: Result = res.or_else(|_| Ok(2)); + let _: Result = res.or_else(|_| Ok(astronomers_pi)); + let _: Result = res.or_else(|_| Ok(ext_str.some_field)); - let _: Result = res.or_else(|_| Err(2)); - let _: Result = res.or_else(|_| Err(astronomers_pi)); - let _: Result = res.or_else(|_| Err(ext_str.some_field)); + let _: Result = res.or_else(|_| Err(2)); + let _: Result = res.or_else(|_| Err(astronomers_pi)); + let _: Result = res.or_else(|_| Err(ext_str.some_field)); } diff --git a/tests/ui/unnecessary_lazy_eval.stderr b/tests/ui/unnecessary_lazy_eval.stderr index b941bf84246..15591817540 100644 --- a/tests/ui/unnecessary_lazy_eval.stderr +++ b/tests/ui/unnecessary_lazy_eval.stderr @@ -1,5 +1,5 @@ error: unnecessary closure used to substitute value for `Option::None` - --> $DIR/unnecessary_lazy_eval.rs:30:13 + --> $DIR/unnecessary_lazy_eval.rs:31:13 | LL | let _ = opt.unwrap_or_else(|| 2); | ^^^^^^^^^^^^^^^^^^^^^^^^ help: Use `unwrap_or` instead: `opt.unwrap_or(2)` @@ -7,43 +7,49 @@ LL | let _ = opt.unwrap_or_else(|| 2); = note: `-D clippy::unnecessary-lazy-evaluation` implied by `-D warnings` error: unnecessary closure used to substitute value for `Option::None` - --> $DIR/unnecessary_lazy_eval.rs:31:13 + --> $DIR/unnecessary_lazy_eval.rs:32:13 | LL | let _ = opt.unwrap_or_else(|| astronomers_pi); | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: Use `unwrap_or` instead: `opt.unwrap_or(astronomers_pi)` error: unnecessary closure used to substitute value for `Option::None` - --> $DIR/unnecessary_lazy_eval.rs:32:13 + --> $DIR/unnecessary_lazy_eval.rs:33:13 | LL | let _ = opt.unwrap_or_else(|| ext_str.some_field); | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: Use `unwrap_or` instead: `opt.unwrap_or(ext_str.some_field)` error: unnecessary closure used to substitute value for `Option::None` - --> $DIR/unnecessary_lazy_eval.rs:33:13 + --> $DIR/unnecessary_lazy_eval.rs:34:13 + | +LL | let _ = opt.unwrap_or_else(|| ext_arr[0]); + | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: Use `unwrap_or` instead: `opt.unwrap_or(ext_arr[0])` + +error: unnecessary closure used to substitute value for `Option::None` + --> $DIR/unnecessary_lazy_eval.rs:35:13 | LL | let _ = opt.and_then(|_| ext_opt); | ^^^^^^^^^^^^^^^^^^^^^^^^^ help: Use `and` instead: `opt.and(ext_opt)` error: unnecessary closure used to substitute value for `Option::None` - --> $DIR/unnecessary_lazy_eval.rs:34:13 + --> $DIR/unnecessary_lazy_eval.rs:36:13 | LL | let _ = opt.or_else(|| ext_opt); | ^^^^^^^^^^^^^^^^^^^^^^^ help: Use `or` instead: `opt.or(ext_opt)` error: unnecessary closure used to substitute value for `Option::None` - --> $DIR/unnecessary_lazy_eval.rs:35:13 + --> $DIR/unnecessary_lazy_eval.rs:37:13 | LL | let _ = opt.or_else(|| None); | ^^^^^^^^^^^^^^^^^^^^ help: Use `or` instead: `opt.or(None)` error: unnecessary closure used to substitute value for `Option::None` - --> $DIR/unnecessary_lazy_eval.rs:36:13 + --> $DIR/unnecessary_lazy_eval.rs:38:13 | LL | let _ = opt.get_or_insert_with(|| 2); | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: Use `get_or_insert` instead: `opt.get_or_insert(2)` error: unnecessary closure used to substitute value for `Option::None` - --> $DIR/unnecessary_lazy_eval.rs:37:13 + --> $DIR/unnecessary_lazy_eval.rs:39:13 | LL | let _ = opt.ok_or_else(|| 2); | ^^^^^^^^^^^^^^^^^^^^ help: Use `ok_or` instead: `opt.ok_or(2)` @@ -51,83 +57,89 @@ LL | let _ = opt.ok_or_else(|| 2); error: unnecessary closure used to substitute value for `Option::None` --> $DIR/unnecessary_lazy_eval.rs:40:13 | +LL | let _ = opt.ok_or_else(|| ext_arr[0]); + | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: Use `ok_or` instead: `opt.ok_or(ext_arr[0])` + +error: unnecessary closure used to substitute value for `Option::None` + --> $DIR/unnecessary_lazy_eval.rs:43:13 + | LL | let _ = Some(10).unwrap_or_else(|| 2); | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: Use `unwrap_or` instead: `Some(10).unwrap_or(2)` error: unnecessary closure used to substitute value for `Option::None` - --> $DIR/unnecessary_lazy_eval.rs:41:13 + --> $DIR/unnecessary_lazy_eval.rs:44:13 | LL | let _ = Some(10).and_then(|_| ext_opt); | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: Use `and` instead: `Some(10).and(ext_opt)` error: unnecessary closure used to substitute value for `Option::None` - --> $DIR/unnecessary_lazy_eval.rs:42:26 + --> $DIR/unnecessary_lazy_eval.rs:45:28 | -LL | let _: Option = None.or_else(|| ext_opt); - | ^^^^^^^^^^^^^^^^^^^^^^^^ help: Use `or` instead: `None.or(ext_opt)` +LL | let _: Option = None.or_else(|| ext_opt); + | ^^^^^^^^^^^^^^^^^^^^^^^^ help: Use `or` instead: `None.or(ext_opt)` error: unnecessary closure used to substitute value for `Option::None` - --> $DIR/unnecessary_lazy_eval.rs:43:13 + --> $DIR/unnecessary_lazy_eval.rs:46:13 | LL | let _ = None.get_or_insert_with(|| 2); | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: Use `get_or_insert` instead: `None.get_or_insert(2)` error: unnecessary closure used to substitute value for `Option::None` - --> $DIR/unnecessary_lazy_eval.rs:44:31 + --> $DIR/unnecessary_lazy_eval.rs:47:35 | -LL | let _: Result = None.ok_or_else(|| 2); - | ^^^^^^^^^^^^^^^^^^^^^ help: Use `ok_or` instead: `None.ok_or(2)` +LL | let _: Result = None.ok_or_else(|| 2); + | ^^^^^^^^^^^^^^^^^^^^^ help: Use `ok_or` instead: `None.ok_or(2)` error: unnecessary closure used to substitute value for `Option::None` - --> $DIR/unnecessary_lazy_eval.rs:45:26 + --> $DIR/unnecessary_lazy_eval.rs:48:28 | -LL | let _: Option = None.or_else(|| None); - | ^^^^^^^^^^^^^^^^^^^^^ help: Use `or` instead: `None.or(None)` +LL | let _: Option = None.or_else(|| None); + | ^^^^^^^^^^^^^^^^^^^^^ help: Use `or` instead: `None.or(None)` error: unnecessary closure used to substitute value for `Option::None` - --> $DIR/unnecessary_lazy_eval.rs:48:13 + --> $DIR/unnecessary_lazy_eval.rs:51:13 | LL | let _ = deep.0.unwrap_or_else(|| 2); | ^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: Use `unwrap_or` instead: `deep.0.unwrap_or(2)` error: unnecessary closure used to substitute value for `Option::None` - --> $DIR/unnecessary_lazy_eval.rs:49:13 + --> $DIR/unnecessary_lazy_eval.rs:52:13 | LL | let _ = deep.0.and_then(|_| ext_opt); | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: Use `and` instead: `deep.0.and(ext_opt)` error: unnecessary closure used to substitute value for `Option::None` - --> $DIR/unnecessary_lazy_eval.rs:50:13 + --> $DIR/unnecessary_lazy_eval.rs:53:13 | LL | let _ = deep.0.or_else(|| None); | ^^^^^^^^^^^^^^^^^^^^^^^ help: Use `or` instead: `deep.0.or(None)` error: unnecessary closure used to substitute value for `Option::None` - --> $DIR/unnecessary_lazy_eval.rs:51:13 + --> $DIR/unnecessary_lazy_eval.rs:54:13 | LL | let _ = deep.0.get_or_insert_with(|| 2); | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: Use `get_or_insert` instead: `deep.0.get_or_insert(2)` error: unnecessary closure used to substitute value for `Option::None` - --> $DIR/unnecessary_lazy_eval.rs:52:13 + --> $DIR/unnecessary_lazy_eval.rs:55:13 | LL | let _ = deep.0.ok_or_else(|| 2); | ^^^^^^^^^^^^^^^^^^^^^^^ help: Use `ok_or` instead: `deep.0.ok_or(2)` error: unnecessary closure used to substitute value for `Result::Err` - --> $DIR/unnecessary_lazy_eval.rs:73:13 + --> $DIR/unnecessary_lazy_eval.rs:78:13 | LL | let _ = res2.unwrap_or_else(|_| 2); | ^^^^^^^^^^^^^^^^^^^^^^^^^^ help: Use `unwrap_or` instead: `res2.unwrap_or(2)` error: unnecessary closure used to substitute value for `Result::Err` - --> $DIR/unnecessary_lazy_eval.rs:74:13 + --> $DIR/unnecessary_lazy_eval.rs:79:13 | LL | let _ = res2.unwrap_or_else(|_| astronomers_pi); | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: Use `unwrap_or` instead: `res2.unwrap_or(astronomers_pi)` error: unnecessary closure used to substitute value for `Result::Err` - --> $DIR/unnecessary_lazy_eval.rs:75:13 + --> $DIR/unnecessary_lazy_eval.rs:80:13 | LL | let _ = res2.unwrap_or_else(|_| ext_str.some_field); | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: Use `unwrap_or` instead: `res2.unwrap_or(ext_str.some_field)` @@ -140,5 +152,5 @@ LL | #![warn(clippy::unnecessary_lazy_eval)] | = note: `-D clippy::unknown-clippy-lints` implied by `-D warnings` -error: aborting due to 23 previous errors +error: aborting due to 25 previous errors -- cgit 1.4.1-3-g733a5 From d7220dbd9143422a5b3a1ebf4dd46b708f83f1d3 Mon Sep 17 00:00:00 2001 From: Dániel Buga Date: Mon, 15 Jun 2020 15:22:22 +0200 Subject: Run cargo dev update_lints --- CHANGELOG.md | 2 +- clippy_lints/src/lib.rs | 4 ++-- src/lintlist/mod.rs | 2 +- 3 files changed, 4 insertions(+), 4 deletions(-) diff --git a/CHANGELOG.md b/CHANGELOG.md index 54489751014..675dfd420a7 100644 --- a/CHANGELOG.md +++ b/CHANGELOG.md @@ -1754,7 +1754,7 @@ Released 2018-09-13 [`unnecessary_cast`]: https://rust-lang.github.io/rust-clippy/master/index.html#unnecessary_cast [`unnecessary_filter_map`]: https://rust-lang.github.io/rust-clippy/master/index.html#unnecessary_filter_map [`unnecessary_fold`]: https://rust-lang.github.io/rust-clippy/master/index.html#unnecessary_fold -[`unnecessary_lazy_eval`]: https://rust-lang.github.io/rust-clippy/master/index.html#unnecessary_lazy_eval +[`unnecessary_lazy_evaluation`]: https://rust-lang.github.io/rust-clippy/master/index.html#unnecessary_lazy_evaluation [`unnecessary_mut_passed`]: https://rust-lang.github.io/rust-clippy/master/index.html#unnecessary_mut_passed [`unnecessary_operation`]: https://rust-lang.github.io/rust-clippy/master/index.html#unnecessary_operation [`unnecessary_sort_by`]: https://rust-lang.github.io/rust-clippy/master/index.html#unnecessary_sort_by diff --git a/clippy_lints/src/lib.rs b/clippy_lints/src/lib.rs index cb29f71387b..ae7045884f7 100644 --- a/clippy_lints/src/lib.rs +++ b/clippy_lints/src/lib.rs @@ -672,7 +672,6 @@ pub fn register_plugins(store: &mut rustc_lint::LintStore, sess: &Session, conf: &methods::OK_EXPECT, &methods::OPTION_AS_REF_DEREF, &methods::OPTION_MAP_OR_NONE, - &methods::UNNECESSARY_LAZY_EVALUATION, &methods::OR_FUN_CALL, &methods::RESULT_MAP_OR_INTO_OPTION, &methods::SEARCH_IS_SOME, @@ -686,6 +685,7 @@ pub fn register_plugins(store: &mut rustc_lint::LintStore, sess: &Session, conf: &methods::UNINIT_ASSUMED_INIT, &methods::UNNECESSARY_FILTER_MAP, &methods::UNNECESSARY_FOLD, + &methods::UNNECESSARY_LAZY_EVALUATION, &methods::UNWRAP_USED, &methods::USELESS_ASREF, &methods::WRONG_PUB_SELF_CONVENTION, @@ -1542,6 +1542,7 @@ pub fn register_plugins(store: &mut rustc_lint::LintStore, sess: &Session, conf: LintId::of(&methods::SINGLE_CHAR_PUSH_STR), LintId::of(&methods::STRING_EXTEND_CHARS), LintId::of(&methods::UNNECESSARY_FOLD), + LintId::of(&methods::UNNECESSARY_LAZY_EVALUATION), LintId::of(&methods::WRONG_SELF_CONVENTION), LintId::of(&misc::TOPLEVEL_REF_ARG), LintId::of(&misc::ZERO_PTR), @@ -1612,7 +1613,6 @@ pub fn register_plugins(store: &mut rustc_lint::LintStore, sess: &Session, conf: LintId::of(&methods::FILTER_NEXT), LintId::of(&methods::FLAT_MAP_IDENTITY), LintId::of(&methods::OPTION_AS_REF_DEREF), - LintId::of(&methods::UNNECESSARY_LAZY_EVALUATION), LintId::of(&methods::SEARCH_IS_SOME), LintId::of(&methods::SKIP_WHILE_NEXT), LintId::of(&methods::SUSPICIOUS_MAP), diff --git a/src/lintlist/mod.rs b/src/lintlist/mod.rs index 1e76163f946..2a66d3495ed 100644 --- a/src/lintlist/mod.rs +++ b/src/lintlist/mod.rs @@ -2384,7 +2384,7 @@ pub static ref ALL_LINTS: Vec = vec![ module: "methods", }, Lint { - name: "unnecessary_lazy_eval", + name: "unnecessary_lazy_evaluation", group: "style", desc: "using unnecessary lazy evaluation, which can be replaced with simpler eager evaluation", deprecation: None, -- cgit 1.4.1-3-g733a5 From 75637c1edac6db37b3c8aa17ef6b5a91db699a00 Mon Sep 17 00:00:00 2001 From: Dániel Buga Date: Mon, 15 Jun 2020 20:01:18 +0200 Subject: Catch function calls in argument lists, add tests that tuples don't get linted --- clippy_lints/src/methods/mod.rs | 25 ++++++++++-------- tests/ui/unnecessary_lazy_eval.fixed | 8 +++++- tests/ui/unnecessary_lazy_eval.rs | 8 +++++- tests/ui/unnecessary_lazy_eval.stderr | 48 +++++++++++++++++------------------ 4 files changed, 52 insertions(+), 37 deletions(-) diff --git a/clippy_lints/src/methods/mod.rs b/clippy_lints/src/methods/mod.rs index ed8eaba75d1..463ef48f62c 100644 --- a/clippy_lints/src/methods/mod.rs +++ b/clippy_lints/src/methods/mod.rs @@ -2744,12 +2744,8 @@ fn lint_lazy_eval<'a, 'tcx>( paths.iter().any(|candidate| match_qpath(path, candidate)) } - if let hir::ExprKind::Closure(_, _, eid, _, _) = args[1].kind { - let body = cx.tcx.hir().body(eid); - let ex = &body.value; - let params = &body.params; - - let simplify = match ex.kind { + fn can_simplify(expr: &hir::Expr<'_>, params: &[hir::Param<'_>], variant_calls: bool) -> bool { + match expr.kind { // Closures returning literals can be unconditionally simplified hir::ExprKind::Lit(_) => true, @@ -2767,15 +2763,16 @@ fn lint_lazy_eval<'a, 'tcx>( hir::ExprKind::Field(ref object, _) => !expr_uses_argument(object, params), // Paths can be simplified if the root is not the argument, this also covers None - hir::ExprKind::Path(_) => !expr_uses_argument(ex, params), + hir::ExprKind::Path(_) => !expr_uses_argument(expr, params), // Calls to Some, Ok, Err can be considered literals if they don't derive an argument hir::ExprKind::Call(ref func, ref args) => if_chain! { - if allow_variant_calls; // Disable lint when rules conflict with bind_instead_of_map + if variant_calls; // Disable lint when rules conflict with bind_instead_of_map if let hir::ExprKind::Path(ref path) = func.kind; if match_any_qpath(path, &[&["Some"], &["Ok"], &["Err"]]); then { - !args.iter().any(|arg| expr_uses_argument(arg, params)) + // Recursively check all arguments + args.iter().all(|arg| can_simplify(arg, params, variant_calls)) } else { false } @@ -2784,9 +2781,15 @@ fn lint_lazy_eval<'a, 'tcx>( // For anything more complex than the above, a closure is probably the right solution, // or the case is handled by an other lint _ => false, - }; + } + } + + if let hir::ExprKind::Closure(_, _, eid, _, _) = args[1].kind { + let body = cx.tcx.hir().body(eid); + let ex = &body.value; + let params = &body.params; - if simplify { + if can_simplify(ex, params, allow_variant_calls) { let msg = if is_option { "unnecessary closure used to substitute value for `Option::None`" } else { diff --git a/tests/ui/unnecessary_lazy_eval.fixed b/tests/ui/unnecessary_lazy_eval.fixed index c806cf8dce4..7f9d90a8569 100644 --- a/tests/ui/unnecessary_lazy_eval.fixed +++ b/tests/ui/unnecessary_lazy_eval.fixed @@ -25,9 +25,12 @@ fn main() { let ext_arr: [usize; 1] = [2]; let ext_str = SomeStruct { some_field: 10 }; - // Should lint - Option let mut opt = Some(42); let ext_opt = Some(42); + let nested_opt = Some(Some(42)); + let nested_tuple_opt = Some(Some((42, 43))); + + // Should lint - Option let _ = opt.unwrap_or(2); let _ = opt.unwrap_or(astronomers_pi); let _ = opt.unwrap_or(ext_str.some_field); @@ -56,6 +59,9 @@ fn main() { // Should not lint - Option let _ = opt.unwrap_or_else(|| ext_str.return_some_field()); + let _ = nested_opt.unwrap_or_else(|| Some(some_call())); + let _ = nested_tuple_opt.unwrap_or_else(|| Some((1, 2))); + let _ = nested_tuple_opt.unwrap_or_else(|| Some((some_call(), some_call()))); let _ = opt.or_else(some_call); let _ = opt.or_else(|| some_call()); let _: Result = opt.ok_or_else(|| some_call()); diff --git a/tests/ui/unnecessary_lazy_eval.rs b/tests/ui/unnecessary_lazy_eval.rs index dfc6d3ba573..ca8238d6dcf 100644 --- a/tests/ui/unnecessary_lazy_eval.rs +++ b/tests/ui/unnecessary_lazy_eval.rs @@ -25,9 +25,12 @@ fn main() { let ext_arr: [usize; 1] = [2]; let ext_str = SomeStruct { some_field: 10 }; - // Should lint - Option let mut opt = Some(42); let ext_opt = Some(42); + let nested_opt = Some(Some(42)); + let nested_tuple_opt = Some(Some((42, 43))); + + // Should lint - Option let _ = opt.unwrap_or_else(|| 2); let _ = opt.unwrap_or_else(|| astronomers_pi); let _ = opt.unwrap_or_else(|| ext_str.some_field); @@ -56,6 +59,9 @@ fn main() { // Should not lint - Option let _ = opt.unwrap_or_else(|| ext_str.return_some_field()); + let _ = nested_opt.unwrap_or_else(|| Some(some_call())); + let _ = nested_tuple_opt.unwrap_or_else(|| Some((1, 2))); + let _ = nested_tuple_opt.unwrap_or_else(|| Some((some_call(), some_call()))); let _ = opt.or_else(some_call); let _ = opt.or_else(|| some_call()); let _: Result = opt.ok_or_else(|| some_call()); diff --git a/tests/ui/unnecessary_lazy_eval.stderr b/tests/ui/unnecessary_lazy_eval.stderr index 15591817540..b8ec654e5c7 100644 --- a/tests/ui/unnecessary_lazy_eval.stderr +++ b/tests/ui/unnecessary_lazy_eval.stderr @@ -1,5 +1,5 @@ error: unnecessary closure used to substitute value for `Option::None` - --> $DIR/unnecessary_lazy_eval.rs:31:13 + --> $DIR/unnecessary_lazy_eval.rs:34:13 | LL | let _ = opt.unwrap_or_else(|| 2); | ^^^^^^^^^^^^^^^^^^^^^^^^ help: Use `unwrap_or` instead: `opt.unwrap_or(2)` @@ -7,139 +7,139 @@ LL | let _ = opt.unwrap_or_else(|| 2); = note: `-D clippy::unnecessary-lazy-evaluation` implied by `-D warnings` error: unnecessary closure used to substitute value for `Option::None` - --> $DIR/unnecessary_lazy_eval.rs:32:13 + --> $DIR/unnecessary_lazy_eval.rs:35:13 | LL | let _ = opt.unwrap_or_else(|| astronomers_pi); | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: Use `unwrap_or` instead: `opt.unwrap_or(astronomers_pi)` error: unnecessary closure used to substitute value for `Option::None` - --> $DIR/unnecessary_lazy_eval.rs:33:13 + --> $DIR/unnecessary_lazy_eval.rs:36:13 | LL | let _ = opt.unwrap_or_else(|| ext_str.some_field); | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: Use `unwrap_or` instead: `opt.unwrap_or(ext_str.some_field)` error: unnecessary closure used to substitute value for `Option::None` - --> $DIR/unnecessary_lazy_eval.rs:34:13 + --> $DIR/unnecessary_lazy_eval.rs:37:13 | LL | let _ = opt.unwrap_or_else(|| ext_arr[0]); | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: Use `unwrap_or` instead: `opt.unwrap_or(ext_arr[0])` error: unnecessary closure used to substitute value for `Option::None` - --> $DIR/unnecessary_lazy_eval.rs:35:13 + --> $DIR/unnecessary_lazy_eval.rs:38:13 | LL | let _ = opt.and_then(|_| ext_opt); | ^^^^^^^^^^^^^^^^^^^^^^^^^ help: Use `and` instead: `opt.and(ext_opt)` error: unnecessary closure used to substitute value for `Option::None` - --> $DIR/unnecessary_lazy_eval.rs:36:13 + --> $DIR/unnecessary_lazy_eval.rs:39:13 | LL | let _ = opt.or_else(|| ext_opt); | ^^^^^^^^^^^^^^^^^^^^^^^ help: Use `or` instead: `opt.or(ext_opt)` error: unnecessary closure used to substitute value for `Option::None` - --> $DIR/unnecessary_lazy_eval.rs:37:13 + --> $DIR/unnecessary_lazy_eval.rs:40:13 | LL | let _ = opt.or_else(|| None); | ^^^^^^^^^^^^^^^^^^^^ help: Use `or` instead: `opt.or(None)` error: unnecessary closure used to substitute value for `Option::None` - --> $DIR/unnecessary_lazy_eval.rs:38:13 + --> $DIR/unnecessary_lazy_eval.rs:41:13 | LL | let _ = opt.get_or_insert_with(|| 2); | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: Use `get_or_insert` instead: `opt.get_or_insert(2)` error: unnecessary closure used to substitute value for `Option::None` - --> $DIR/unnecessary_lazy_eval.rs:39:13 + --> $DIR/unnecessary_lazy_eval.rs:42:13 | LL | let _ = opt.ok_or_else(|| 2); | ^^^^^^^^^^^^^^^^^^^^ help: Use `ok_or` instead: `opt.ok_or(2)` error: unnecessary closure used to substitute value for `Option::None` - --> $DIR/unnecessary_lazy_eval.rs:40:13 + --> $DIR/unnecessary_lazy_eval.rs:43:13 | LL | let _ = opt.ok_or_else(|| ext_arr[0]); | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: Use `ok_or` instead: `opt.ok_or(ext_arr[0])` error: unnecessary closure used to substitute value for `Option::None` - --> $DIR/unnecessary_lazy_eval.rs:43:13 + --> $DIR/unnecessary_lazy_eval.rs:46:13 | LL | let _ = Some(10).unwrap_or_else(|| 2); | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: Use `unwrap_or` instead: `Some(10).unwrap_or(2)` error: unnecessary closure used to substitute value for `Option::None` - --> $DIR/unnecessary_lazy_eval.rs:44:13 + --> $DIR/unnecessary_lazy_eval.rs:47:13 | LL | let _ = Some(10).and_then(|_| ext_opt); | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: Use `and` instead: `Some(10).and(ext_opt)` error: unnecessary closure used to substitute value for `Option::None` - --> $DIR/unnecessary_lazy_eval.rs:45:28 + --> $DIR/unnecessary_lazy_eval.rs:48:28 | LL | let _: Option = None.or_else(|| ext_opt); | ^^^^^^^^^^^^^^^^^^^^^^^^ help: Use `or` instead: `None.or(ext_opt)` error: unnecessary closure used to substitute value for `Option::None` - --> $DIR/unnecessary_lazy_eval.rs:46:13 + --> $DIR/unnecessary_lazy_eval.rs:49:13 | LL | let _ = None.get_or_insert_with(|| 2); | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: Use `get_or_insert` instead: `None.get_or_insert(2)` error: unnecessary closure used to substitute value for `Option::None` - --> $DIR/unnecessary_lazy_eval.rs:47:35 + --> $DIR/unnecessary_lazy_eval.rs:50:35 | LL | let _: Result = None.ok_or_else(|| 2); | ^^^^^^^^^^^^^^^^^^^^^ help: Use `ok_or` instead: `None.ok_or(2)` error: unnecessary closure used to substitute value for `Option::None` - --> $DIR/unnecessary_lazy_eval.rs:48:28 + --> $DIR/unnecessary_lazy_eval.rs:51:28 | LL | let _: Option = None.or_else(|| None); | ^^^^^^^^^^^^^^^^^^^^^ help: Use `or` instead: `None.or(None)` error: unnecessary closure used to substitute value for `Option::None` - --> $DIR/unnecessary_lazy_eval.rs:51:13 + --> $DIR/unnecessary_lazy_eval.rs:54:13 | LL | let _ = deep.0.unwrap_or_else(|| 2); | ^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: Use `unwrap_or` instead: `deep.0.unwrap_or(2)` error: unnecessary closure used to substitute value for `Option::None` - --> $DIR/unnecessary_lazy_eval.rs:52:13 + --> $DIR/unnecessary_lazy_eval.rs:55:13 | LL | let _ = deep.0.and_then(|_| ext_opt); | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: Use `and` instead: `deep.0.and(ext_opt)` error: unnecessary closure used to substitute value for `Option::None` - --> $DIR/unnecessary_lazy_eval.rs:53:13 + --> $DIR/unnecessary_lazy_eval.rs:56:13 | LL | let _ = deep.0.or_else(|| None); | ^^^^^^^^^^^^^^^^^^^^^^^ help: Use `or` instead: `deep.0.or(None)` error: unnecessary closure used to substitute value for `Option::None` - --> $DIR/unnecessary_lazy_eval.rs:54:13 + --> $DIR/unnecessary_lazy_eval.rs:57:13 | LL | let _ = deep.0.get_or_insert_with(|| 2); | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: Use `get_or_insert` instead: `deep.0.get_or_insert(2)` error: unnecessary closure used to substitute value for `Option::None` - --> $DIR/unnecessary_lazy_eval.rs:55:13 + --> $DIR/unnecessary_lazy_eval.rs:58:13 | LL | let _ = deep.0.ok_or_else(|| 2); | ^^^^^^^^^^^^^^^^^^^^^^^ help: Use `ok_or` instead: `deep.0.ok_or(2)` error: unnecessary closure used to substitute value for `Result::Err` - --> $DIR/unnecessary_lazy_eval.rs:78:13 + --> $DIR/unnecessary_lazy_eval.rs:84:13 | LL | let _ = res2.unwrap_or_else(|_| 2); | ^^^^^^^^^^^^^^^^^^^^^^^^^^ help: Use `unwrap_or` instead: `res2.unwrap_or(2)` error: unnecessary closure used to substitute value for `Result::Err` - --> $DIR/unnecessary_lazy_eval.rs:79:13 + --> $DIR/unnecessary_lazy_eval.rs:85:13 | LL | let _ = res2.unwrap_or_else(|_| astronomers_pi); | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: Use `unwrap_or` instead: `res2.unwrap_or(astronomers_pi)` error: unnecessary closure used to substitute value for `Result::Err` - --> $DIR/unnecessary_lazy_eval.rs:80:13 + --> $DIR/unnecessary_lazy_eval.rs:86:13 | LL | let _ = res2.unwrap_or_else(|_| ext_str.some_field); | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: Use `unwrap_or` instead: `res2.unwrap_or(ext_str.some_field)` -- cgit 1.4.1-3-g733a5 From a7083eea1c8821ff187218f55a1ac17b0f2c0fcb Mon Sep 17 00:00:00 2001 From: Dániel Buga Date: Sun, 26 Jul 2020 20:18:12 +0200 Subject: Removed the extra lifetime parameter --- clippy_lints/src/methods/mod.rs | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/clippy_lints/src/methods/mod.rs b/clippy_lints/src/methods/mod.rs index 463ef48f62c..6693c358a02 100644 --- a/clippy_lints/src/methods/mod.rs +++ b/clippy_lints/src/methods/mod.rs @@ -2710,8 +2710,8 @@ fn lint_map_flatten<'tcx>(cx: &LateContext<'tcx>, expr: &'tcx hir::Expr<'_>, map /// lint use of `_else(simple closure)` for `Option`s and `Result`s that can be /// replaced with `(return value of simple closure)` -fn lint_lazy_eval<'a, 'tcx>( - cx: &LateContext<'a, 'tcx>, +fn lint_lazy_eval<'tcx>( + cx: &LateContext<'tcx>, expr: &'tcx hir::Expr<'_>, args: &'tcx [hir::Expr<'_>], allow_variant_calls: bool, -- cgit 1.4.1-3-g733a5 From 94cf90e5a56bbd9adbf6d6181d046ede9b96a7d8 Mon Sep 17 00:00:00 2001 From: Dániel Buga Date: Sun, 26 Jul 2020 20:52:00 +0200 Subject: Apply suggested change Co-authored-by: Philipp Krones --- clippy_lints/src/methods/mod.rs | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/clippy_lints/src/methods/mod.rs b/clippy_lints/src/methods/mod.rs index 6693c358a02..4578c228107 100644 --- a/clippy_lints/src/methods/mod.rs +++ b/clippy_lints/src/methods/mod.rs @@ -2717,8 +2717,8 @@ fn lint_lazy_eval<'tcx>( allow_variant_calls: bool, simplify_using: &str, ) { - let is_option = is_type_diagnostic_item(cx, cx.tables.expr_ty(&args[0]), sym!(option_type)); - let is_result = is_type_diagnostic_item(cx, cx.tables.expr_ty(&args[0]), sym!(result_type)); + let is_option = is_type_diagnostic_item(cx, cx.tables().expr_ty(&args[0]), sym!(option_type)); + let is_result = is_type_diagnostic_item(cx, cx.tables().expr_ty(&args[0]), sym!(result_type)); if !is_option && !is_result { return; -- cgit 1.4.1-3-g733a5 From 9c41822d34c69dbfded4d9d8b4b8962564be80f1 Mon Sep 17 00:00:00 2001 From: Dániel Buga Date: Sun, 26 Jul 2020 21:08:07 +0200 Subject: Apply suggested change Co-authored-by: Philipp Krones --- clippy_lints/src/methods/mod.rs | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/clippy_lints/src/methods/mod.rs b/clippy_lints/src/methods/mod.rs index 4578c228107..70a6b1f5021 100644 --- a/clippy_lints/src/methods/mod.rs +++ b/clippy_lints/src/methods/mod.rs @@ -2717,8 +2717,8 @@ fn lint_lazy_eval<'tcx>( allow_variant_calls: bool, simplify_using: &str, ) { - let is_option = is_type_diagnostic_item(cx, cx.tables().expr_ty(&args[0]), sym!(option_type)); - let is_result = is_type_diagnostic_item(cx, cx.tables().expr_ty(&args[0]), sym!(result_type)); + let is_option = is_type_diagnostic_item(cx, cx.typeck_results().expr_ty(&args[0]), sym!(option_type)); + let is_result = is_type_diagnostic_item(cx, cx.typeck_results().expr_ty(&args[0]), sym!(result_type)); if !is_option && !is_result { return; -- cgit 1.4.1-3-g733a5 From d71b418ac511ee604af9320e401a7ff3fd115482 Mon Sep 17 00:00:00 2001 From: Dániel Buga Date: Sun, 16 Aug 2020 20:47:50 +0200 Subject: Moved to submodule, don't trigger if map_unwrap_or does --- clippy_lints/src/methods/mod.rs | 136 +++------------------- clippy_lints/src/methods/unnecessary_lazy_eval.rs | 113 ++++++++++++++++++ 2 files changed, 132 insertions(+), 117 deletions(-) create mode 100644 clippy_lints/src/methods/unnecessary_lazy_eval.rs diff --git a/clippy_lints/src/methods/mod.rs b/clippy_lints/src/methods/mod.rs index 70a6b1f5021..bfc89a74742 100644 --- a/clippy_lints/src/methods/mod.rs +++ b/clippy_lints/src/methods/mod.rs @@ -3,6 +3,7 @@ mod inefficient_to_string; mod manual_saturating_arithmetic; mod option_map_unwrap_or; mod unnecessary_filter_map; +mod unnecessary_lazy_eval; use std::borrow::Cow; use std::fmt; @@ -1436,17 +1437,18 @@ impl<'tcx> LateLintPass<'tcx> for Methods { ["expect", ..] => lint_expect(cx, expr, arg_lists[0]), ["unwrap_or", "map"] => option_map_unwrap_or::lint(cx, expr, arg_lists[1], arg_lists[0], method_spans[1]), ["unwrap_or_else", "map"] => { - lint_lazy_eval(cx, expr, arg_lists[0], true, "unwrap_or"); - lint_map_unwrap_or_else(cx, expr, arg_lists[1], arg_lists[0]); + if !lint_map_unwrap_or_else(cx, expr, arg_lists[1], arg_lists[0]) { + unnecessary_lazy_eval::lint(cx, expr, arg_lists[0], true, "unwrap_or"); + } }, ["map_or", ..] => lint_map_or_none(cx, expr, arg_lists[0]), ["and_then", ..] => { - lint_lazy_eval(cx, expr, arg_lists[0], false, "and"); + unnecessary_lazy_eval::lint(cx, expr, arg_lists[0], false, "and"); bind_instead_of_map::OptionAndThenSome::lint(cx, expr, arg_lists[0]); bind_instead_of_map::ResultAndThenOk::lint(cx, expr, arg_lists[0]); }, ["or_else", ..] => { - lint_lazy_eval(cx, expr, arg_lists[0], false, "or"); + unnecessary_lazy_eval::lint(cx, expr, arg_lists[0], false, "or"); bind_instead_of_map::ResultOrElseErrInfo::lint(cx, expr, arg_lists[0]); }, ["next", "filter"] => lint_filter_next(cx, expr, arg_lists[1]), @@ -1490,9 +1492,9 @@ impl<'tcx> LateLintPass<'tcx> for Methods { ["is_file", ..] => lint_filetype_is_file(cx, expr, arg_lists[0]), ["map", "as_ref"] => lint_option_as_ref_deref(cx, expr, arg_lists[1], arg_lists[0], false), ["map", "as_mut"] => lint_option_as_ref_deref(cx, expr, arg_lists[1], arg_lists[0], true), - ["unwrap_or_else", ..] => lint_lazy_eval(cx, expr, arg_lists[0], true, "unwrap_or"), - ["get_or_insert_with", ..] => lint_lazy_eval(cx, expr, arg_lists[0], true, "get_or_insert"), - ["ok_or_else", ..] => lint_lazy_eval(cx, expr, arg_lists[0], true, "ok_or"), + ["unwrap_or_else", ..] => unnecessary_lazy_eval::lint(cx, expr, arg_lists[0], true, "unwrap_or"), + ["get_or_insert_with", ..] => unnecessary_lazy_eval::lint(cx, expr, arg_lists[0], true, "get_or_insert"), + ["ok_or_else", ..] => unnecessary_lazy_eval::lint(cx, expr, arg_lists[0], true, "ok_or"), _ => {}, } @@ -2708,119 +2710,13 @@ fn lint_map_flatten<'tcx>(cx: &LateContext<'tcx>, expr: &'tcx hir::Expr<'_>, map } } -/// lint use of `_else(simple closure)` for `Option`s and `Result`s that can be -/// replaced with `(return value of simple closure)` -fn lint_lazy_eval<'tcx>( - cx: &LateContext<'tcx>, - expr: &'tcx hir::Expr<'_>, - args: &'tcx [hir::Expr<'_>], - allow_variant_calls: bool, - simplify_using: &str, -) { - let is_option = is_type_diagnostic_item(cx, cx.typeck_results().expr_ty(&args[0]), sym!(option_type)); - let is_result = is_type_diagnostic_item(cx, cx.typeck_results().expr_ty(&args[0]), sym!(result_type)); - - if !is_option && !is_result { - return; - } - - // Return true if the expression is an accessor of any of the arguments - fn expr_uses_argument(expr: &hir::Expr<'_>, params: &[hir::Param<'_>]) -> bool { - params.iter().any(|arg| { - if_chain! { - if let hir::PatKind::Binding(_, _, ident, _) = arg.pat.kind; - if let hir::ExprKind::Path(hir::QPath::Resolved(_, ref path)) = expr.kind; - if let [p, ..] = path.segments; - then { - ident.name == p.ident.name - } else { - false - } - } - }) - } - - fn match_any_qpath(path: &hir::QPath<'_>, paths: &[&[&str]]) -> bool { - paths.iter().any(|candidate| match_qpath(path, candidate)) - } - - fn can_simplify(expr: &hir::Expr<'_>, params: &[hir::Param<'_>], variant_calls: bool) -> bool { - match expr.kind { - // Closures returning literals can be unconditionally simplified - hir::ExprKind::Lit(_) => true, - - hir::ExprKind::Index(ref object, ref index) => { - // arguments are not being indexed into - if !expr_uses_argument(object, params) { - // arguments are not used as index - !expr_uses_argument(index, params) - } else { - false - } - }, - - // Reading fields can be simplified if the object is not an argument of the closure - hir::ExprKind::Field(ref object, _) => !expr_uses_argument(object, params), - - // Paths can be simplified if the root is not the argument, this also covers None - hir::ExprKind::Path(_) => !expr_uses_argument(expr, params), - - // Calls to Some, Ok, Err can be considered literals if they don't derive an argument - hir::ExprKind::Call(ref func, ref args) => if_chain! { - if variant_calls; // Disable lint when rules conflict with bind_instead_of_map - if let hir::ExprKind::Path(ref path) = func.kind; - if match_any_qpath(path, &[&["Some"], &["Ok"], &["Err"]]); - then { - // Recursively check all arguments - args.iter().all(|arg| can_simplify(arg, params, variant_calls)) - } else { - false - } - }, - - // For anything more complex than the above, a closure is probably the right solution, - // or the case is handled by an other lint - _ => false, - } - } - - if let hir::ExprKind::Closure(_, _, eid, _, _) = args[1].kind { - let body = cx.tcx.hir().body(eid); - let ex = &body.value; - let params = &body.params; - - if can_simplify(ex, params, allow_variant_calls) { - let msg = if is_option { - "unnecessary closure used to substitute value for `Option::None`" - } else { - "unnecessary closure used to substitute value for `Result::Err`" - }; - - span_lint_and_sugg( - cx, - UNNECESSARY_LAZY_EVALUATION, - expr.span, - msg, - &format!("Use `{}` instead", simplify_using), - format!( - "{0}.{1}({2})", - snippet(cx, args[0].span, ".."), - simplify_using, - snippet(cx, ex.span, ".."), - ), - Applicability::MachineApplicable, - ); - } - } -} - /// lint use of `map().unwrap_or_else()` for `Option`s and `Result`s fn lint_map_unwrap_or_else<'tcx>( cx: &LateContext<'tcx>, expr: &'tcx hir::Expr<'_>, map_args: &'tcx [hir::Expr<'_>], unwrap_args: &'tcx [hir::Expr<'_>], -) { +) -> bool { // lint if the caller of `map()` is an `Option` let is_option = is_type_diagnostic_item(cx, cx.typeck_results().expr_ty(&map_args[0]), sym!(option_type)); let is_result = is_type_diagnostic_item(cx, cx.typeck_results().expr_ty(&map_args[0]), sym!(result_type)); @@ -2832,10 +2728,10 @@ fn lint_map_unwrap_or_else<'tcx>( let unwrap_mutated_vars = mutated_variables(&unwrap_args[1], cx); if let (Some(map_mutated_vars), Some(unwrap_mutated_vars)) = (map_mutated_vars, unwrap_mutated_vars) { if map_mutated_vars.intersection(&unwrap_mutated_vars).next().is_some() { - return; + return false; } } else { - return; + return false; } // lint message @@ -2865,9 +2761,15 @@ fn lint_map_unwrap_or_else<'tcx>( map_snippet, unwrap_snippet, ), ); + true } else if same_span && multiline { span_lint(cx, MAP_UNWRAP_OR, expr.span, msg); - }; + true + } else { + false + } + } else { + false } } diff --git a/clippy_lints/src/methods/unnecessary_lazy_eval.rs b/clippy_lints/src/methods/unnecessary_lazy_eval.rs new file mode 100644 index 00000000000..0dbedc4919c --- /dev/null +++ b/clippy_lints/src/methods/unnecessary_lazy_eval.rs @@ -0,0 +1,113 @@ +use crate::utils::{match_qpath, span_lint_and_sugg, snippet, is_type_diagnostic_item}; +use if_chain::if_chain; +use rustc_errors::Applicability; +use rustc_hir as hir; +use rustc_lint::LateContext; + +use super::UNNECESSARY_LAZY_EVALUATION; + +/// lint use of `_else(simple closure)` for `Option`s and `Result`s that can be +/// replaced with `(return value of simple closure)` +pub(super) fn lint<'tcx>( + cx: &LateContext<'tcx>, + expr: &'tcx hir::Expr<'_>, + args: &'tcx [hir::Expr<'_>], + allow_variant_calls: bool, + simplify_using: &str, +) { + let is_option = is_type_diagnostic_item(cx, cx.typeck_results().expr_ty(&args[0]), sym!(option_type)); + let is_result = is_type_diagnostic_item(cx, cx.typeck_results().expr_ty(&args[0]), sym!(result_type)); + + if !is_option && !is_result { + return; + } + + // Return true if the expression is an accessor of any of the arguments + fn expr_uses_argument(expr: &hir::Expr<'_>, params: &[hir::Param<'_>]) -> bool { + params.iter().any(|arg| { + if_chain! { + if let hir::PatKind::Binding(_, _, ident, _) = arg.pat.kind; + if let hir::ExprKind::Path(hir::QPath::Resolved(_, ref path)) = expr.kind; + if let [p, ..] = path.segments; + then { + ident.name == p.ident.name + } else { + false + } + } + }) + } + + fn match_any_qpath(path: &hir::QPath<'_>, paths: &[&[&str]]) -> bool { + paths.iter().any(|candidate| match_qpath(path, candidate)) + } + + fn can_simplify(expr: &hir::Expr<'_>, params: &[hir::Param<'_>], variant_calls: bool) -> bool { + match expr.kind { + // Closures returning literals can be unconditionally simplified + hir::ExprKind::Lit(_) => true, + + hir::ExprKind::Index(ref object, ref index) => { + // arguments are not being indexed into + if !expr_uses_argument(object, params) { + // arguments are not used as index + !expr_uses_argument(index, params) + } else { + false + } + }, + + // Reading fields can be simplified if the object is not an argument of the closure + hir::ExprKind::Field(ref object, _) => !expr_uses_argument(object, params), + + // Paths can be simplified if the root is not the argument, this also covers None + hir::ExprKind::Path(_) => !expr_uses_argument(expr, params), + + // Calls to Some, Ok, Err can be considered literals if they don't derive an argument + hir::ExprKind::Call(ref func, ref args) => if_chain! { + if variant_calls; // Disable lint when rules conflict with bind_instead_of_map + if let hir::ExprKind::Path(ref path) = func.kind; + if match_any_qpath(path, &[&["Some"], &["Ok"], &["Err"]]); + then { + // Recursively check all arguments + args.iter().all(|arg| can_simplify(arg, params, variant_calls)) + } else { + false + } + }, + + // For anything more complex than the above, a closure is probably the right solution, + // or the case is handled by an other lint + _ => false, + } + } + + if let hir::ExprKind::Closure(_, _, eid, _, _) = args[1].kind { + let body = cx.tcx.hir().body(eid); + let ex = &body.value; + let params = &body.params; + + if can_simplify(ex, params, allow_variant_calls) { + let msg = if is_option { + "unnecessary closure used to substitute value for `Option::None`" + } else { + "unnecessary closure used to substitute value for `Result::Err`" + }; + + span_lint_and_sugg( + cx, + UNNECESSARY_LAZY_EVALUATION, + expr.span, + msg, + &format!("Use `{}` instead", simplify_using), + format!( + "{0}.{1}({2})", + snippet(cx, args[0].span, ".."), + simplify_using, + snippet(cx, ex.span, ".."), + ), + Applicability::MachineApplicable, + ); + } + } +} -- cgit 1.4.1-3-g733a5 From 8a14c115369f163e7f96544df48b26376a06a3fb Mon Sep 17 00:00:00 2001 From: Dániel Buga Date: Sun, 16 Aug 2020 20:50:30 +0200 Subject: Cleanup, explain return value --- clippy_lints/src/methods/mod.rs | 11 +++++------ 1 file changed, 5 insertions(+), 6 deletions(-) diff --git a/clippy_lints/src/methods/mod.rs b/clippy_lints/src/methods/mod.rs index bfc89a74742..c2b2cb98012 100644 --- a/clippy_lints/src/methods/mod.rs +++ b/clippy_lints/src/methods/mod.rs @@ -2711,6 +2711,7 @@ fn lint_map_flatten<'tcx>(cx: &LateContext<'tcx>, expr: &'tcx hir::Expr<'_>, map } /// lint use of `map().unwrap_or_else()` for `Option`s and `Result`s +/// Return true if lint triggered fn lint_map_unwrap_or_else<'tcx>( cx: &LateContext<'tcx>, expr: &'tcx hir::Expr<'_>, @@ -2761,16 +2762,14 @@ fn lint_map_unwrap_or_else<'tcx>( map_snippet, unwrap_snippet, ), ); - true + return true; } else if same_span && multiline { span_lint(cx, MAP_UNWRAP_OR, expr.span, msg); - true - } else { - false + return true; } - } else { - false } + + false } /// lint use of `_.map_or(None, _)` for `Option`s and `Result`s -- cgit 1.4.1-3-g733a5 From 3b52d7f780f2023d6596fe73c0a71f663b26bc33 Mon Sep 17 00:00:00 2001 From: Dániel Buga Date: Sun, 16 Aug 2020 20:51:16 +0200 Subject: run cargo dev fmt --- clippy_lints/src/methods/unnecessary_lazy_eval.rs | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/clippy_lints/src/methods/unnecessary_lazy_eval.rs b/clippy_lints/src/methods/unnecessary_lazy_eval.rs index 0dbedc4919c..b44089f7bfc 100644 --- a/clippy_lints/src/methods/unnecessary_lazy_eval.rs +++ b/clippy_lints/src/methods/unnecessary_lazy_eval.rs @@ -1,4 +1,4 @@ -use crate::utils::{match_qpath, span_lint_and_sugg, snippet, is_type_diagnostic_item}; +use crate::utils::{is_type_diagnostic_item, match_qpath, snippet, span_lint_and_sugg}; use if_chain::if_chain; use rustc_errors::Applicability; use rustc_hir as hir; -- cgit 1.4.1-3-g733a5 From b7ee8685ac83e0f3f32ac5ab5d597d5451d07057 Mon Sep 17 00:00:00 2001 From: Dániel Buga Date: Sun, 16 Aug 2020 21:04:02 +0200 Subject: Fix dogfooding test errors --- clippy_lints/src/methods/unnecessary_lazy_eval.rs | 172 +++++++++++----------- 1 file changed, 85 insertions(+), 87 deletions(-) diff --git a/clippy_lints/src/methods/unnecessary_lazy_eval.rs b/clippy_lints/src/methods/unnecessary_lazy_eval.rs index b44089f7bfc..a3e7e9971f8 100644 --- a/clippy_lints/src/methods/unnecessary_lazy_eval.rs +++ b/clippy_lints/src/methods/unnecessary_lazy_eval.rs @@ -6,6 +6,66 @@ use rustc_lint::LateContext; use super::UNNECESSARY_LAZY_EVALUATION; +// Return true if the expression is an accessor of any of the arguments +fn expr_uses_argument(expr: &hir::Expr<'_>, params: &[hir::Param<'_>]) -> bool { + params.iter().any(|arg| { + if_chain! { + if let hir::PatKind::Binding(_, _, ident, _) = arg.pat.kind; + if let hir::ExprKind::Path(hir::QPath::Resolved(_, ref path)) = expr.kind; + if let [p, ..] = path.segments; + then { + ident.name == p.ident.name + } else { + false + } + } + }) +} + +fn match_any_qpath(path: &hir::QPath<'_>, paths: &[&[&str]]) -> bool { + paths.iter().any(|candidate| match_qpath(path, candidate)) +} + +fn can_simplify(expr: &hir::Expr<'_>, params: &[hir::Param<'_>], variant_calls: bool) -> bool { + match expr.kind { + // Closures returning literals can be unconditionally simplified + hir::ExprKind::Lit(_) => true, + + hir::ExprKind::Index(ref object, ref index) => { + // arguments are not being indexed into + if expr_uses_argument(object, params) { + false + } else { + // arguments are not used as index + !expr_uses_argument(index, params) + } + }, + + // Reading fields can be simplified if the object is not an argument of the closure + hir::ExprKind::Field(ref object, _) => !expr_uses_argument(object, params), + + // Paths can be simplified if the root is not the argument, this also covers None + hir::ExprKind::Path(_) => !expr_uses_argument(expr, params), + + // Calls to Some, Ok, Err can be considered literals if they don't derive an argument + hir::ExprKind::Call(ref func, ref args) => if_chain! { + if variant_calls; // Disable lint when rules conflict with bind_instead_of_map + if let hir::ExprKind::Path(ref path) = func.kind; + if match_any_qpath(path, &[&["Some"], &["Ok"], &["Err"]]); + then { + // Recursively check all arguments + args.iter().all(|arg| can_simplify(arg, params, variant_calls)) + } else { + false + } + }, + + // For anything more complex than the above, a closure is probably the right solution, + // or the case is handled by an other lint + _ => false, + } +} + /// lint use of `_else(simple closure)` for `Option`s and `Result`s that can be /// replaced with `(return value of simple closure)` pub(super) fn lint<'tcx>( @@ -18,96 +78,34 @@ pub(super) fn lint<'tcx>( let is_option = is_type_diagnostic_item(cx, cx.typeck_results().expr_ty(&args[0]), sym!(option_type)); let is_result = is_type_diagnostic_item(cx, cx.typeck_results().expr_ty(&args[0]), sym!(result_type)); - if !is_option && !is_result { - return; - } - - // Return true if the expression is an accessor of any of the arguments - fn expr_uses_argument(expr: &hir::Expr<'_>, params: &[hir::Param<'_>]) -> bool { - params.iter().any(|arg| { - if_chain! { - if let hir::PatKind::Binding(_, _, ident, _) = arg.pat.kind; - if let hir::ExprKind::Path(hir::QPath::Resolved(_, ref path)) = expr.kind; - if let [p, ..] = path.segments; - then { - ident.name == p.ident.name - } else { - false - } - } - }) - } + if is_option || is_result { + if let hir::ExprKind::Closure(_, _, eid, _, _) = args[1].kind { + let body = cx.tcx.hir().body(eid); + let ex = &body.value; + let params = &body.params; - fn match_any_qpath(path: &hir::QPath<'_>, paths: &[&[&str]]) -> bool { - paths.iter().any(|candidate| match_qpath(path, candidate)) - } - - fn can_simplify(expr: &hir::Expr<'_>, params: &[hir::Param<'_>], variant_calls: bool) -> bool { - match expr.kind { - // Closures returning literals can be unconditionally simplified - hir::ExprKind::Lit(_) => true, - - hir::ExprKind::Index(ref object, ref index) => { - // arguments are not being indexed into - if !expr_uses_argument(object, params) { - // arguments are not used as index - !expr_uses_argument(index, params) + if can_simplify(ex, params, allow_variant_calls) { + let msg = if is_option { + "unnecessary closure used to substitute value for `Option::None`" } else { - false - } - }, - - // Reading fields can be simplified if the object is not an argument of the closure - hir::ExprKind::Field(ref object, _) => !expr_uses_argument(object, params), - - // Paths can be simplified if the root is not the argument, this also covers None - hir::ExprKind::Path(_) => !expr_uses_argument(expr, params), + "unnecessary closure used to substitute value for `Result::Err`" + }; - // Calls to Some, Ok, Err can be considered literals if they don't derive an argument - hir::ExprKind::Call(ref func, ref args) => if_chain! { - if variant_calls; // Disable lint when rules conflict with bind_instead_of_map - if let hir::ExprKind::Path(ref path) = func.kind; - if match_any_qpath(path, &[&["Some"], &["Ok"], &["Err"]]); - then { - // Recursively check all arguments - args.iter().all(|arg| can_simplify(arg, params, variant_calls)) - } else { - false - } - }, - - // For anything more complex than the above, a closure is probably the right solution, - // or the case is handled by an other lint - _ => false, - } - } - - if let hir::ExprKind::Closure(_, _, eid, _, _) = args[1].kind { - let body = cx.tcx.hir().body(eid); - let ex = &body.value; - let params = &body.params; - - if can_simplify(ex, params, allow_variant_calls) { - let msg = if is_option { - "unnecessary closure used to substitute value for `Option::None`" - } else { - "unnecessary closure used to substitute value for `Result::Err`" - }; - - span_lint_and_sugg( - cx, - UNNECESSARY_LAZY_EVALUATION, - expr.span, - msg, - &format!("Use `{}` instead", simplify_using), - format!( - "{0}.{1}({2})", - snippet(cx, args[0].span, ".."), - simplify_using, - snippet(cx, ex.span, ".."), - ), - Applicability::MachineApplicable, - ); + span_lint_and_sugg( + cx, + UNNECESSARY_LAZY_EVALUATION, + expr.span, + msg, + &format!("Use `{}` instead", simplify_using), + format!( + "{0}.{1}({2})", + snippet(cx, args[0].span, ".."), + simplify_using, + snippet(cx, ex.span, ".."), + ), + Applicability::MachineApplicable, + ); + } } } } -- cgit 1.4.1-3-g733a5 From b175642a85f5d1507b35b8ef269ecbdaef9aa27d Mon Sep 17 00:00:00 2001 From: Dániel Buga Date: Sun, 16 Aug 2020 21:33:29 +0200 Subject: Fix missed rename --- tests/ui/unnecessary_lazy_eval.rs | 2 +- tests/ui/unnecessary_lazy_eval.stderr | 10 +--------- 2 files changed, 2 insertions(+), 10 deletions(-) diff --git a/tests/ui/unnecessary_lazy_eval.rs b/tests/ui/unnecessary_lazy_eval.rs index ca8238d6dcf..fd8f8ed0329 100644 --- a/tests/ui/unnecessary_lazy_eval.rs +++ b/tests/ui/unnecessary_lazy_eval.rs @@ -1,5 +1,5 @@ // run-rustfix -#![warn(clippy::unnecessary_lazy_eval)] +#![warn(clippy::unnecessary_lazy_evaluation)] #![allow(clippy::redundant_closure)] #![allow(clippy::bind_instead_of_map)] diff --git a/tests/ui/unnecessary_lazy_eval.stderr b/tests/ui/unnecessary_lazy_eval.stderr index b8ec654e5c7..e86b7ed6253 100644 --- a/tests/ui/unnecessary_lazy_eval.stderr +++ b/tests/ui/unnecessary_lazy_eval.stderr @@ -144,13 +144,5 @@ error: unnecessary closure used to substitute value for `Result::Err` LL | let _ = res2.unwrap_or_else(|_| ext_str.some_field); | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: Use `unwrap_or` instead: `res2.unwrap_or(ext_str.some_field)` -error: unknown clippy lint: clippy::unnecessary_lazy_eval - --> $DIR/unnecessary_lazy_eval.rs:2:9 - | -LL | #![warn(clippy::unnecessary_lazy_eval)] - | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: did you mean: `clippy::unnecessary_lazy_evaluation` - | - = note: `-D clippy::unknown-clippy-lints` implied by `-D warnings` - -error: aborting due to 25 previous errors +error: aborting due to 24 previous errors -- cgit 1.4.1-3-g733a5 From fc1e07e0c1803edb3ade2db2f46034cf227642c9 Mon Sep 17 00:00:00 2001 From: Dániel Buga Date: Sun, 16 Aug 2020 22:16:39 +0200 Subject: Rename lint to use plural form --- CHANGELOG.md | 2 +- clippy_lints/src/lib.rs | 6 +++--- clippy_lints/src/methods/mod.rs | 4 ++-- clippy_lints/src/methods/unnecessary_lazy_eval.rs | 4 ++-- src/lintlist/mod.rs | 2 +- tests/ui/unnecessary_lazy_eval.fixed | 2 +- tests/ui/unnecessary_lazy_eval.rs | 2 +- tests/ui/unnecessary_lazy_eval.stderr | 2 +- 8 files changed, 12 insertions(+), 12 deletions(-) diff --git a/CHANGELOG.md b/CHANGELOG.md index 675dfd420a7..f662de122f9 100644 --- a/CHANGELOG.md +++ b/CHANGELOG.md @@ -1754,7 +1754,7 @@ Released 2018-09-13 [`unnecessary_cast`]: https://rust-lang.github.io/rust-clippy/master/index.html#unnecessary_cast [`unnecessary_filter_map`]: https://rust-lang.github.io/rust-clippy/master/index.html#unnecessary_filter_map [`unnecessary_fold`]: https://rust-lang.github.io/rust-clippy/master/index.html#unnecessary_fold -[`unnecessary_lazy_evaluation`]: https://rust-lang.github.io/rust-clippy/master/index.html#unnecessary_lazy_evaluation +[`unnecessary_lazy_evaluations`]: https://rust-lang.github.io/rust-clippy/master/index.html#unnecessary_lazy_evaluations [`unnecessary_mut_passed`]: https://rust-lang.github.io/rust-clippy/master/index.html#unnecessary_mut_passed [`unnecessary_operation`]: https://rust-lang.github.io/rust-clippy/master/index.html#unnecessary_operation [`unnecessary_sort_by`]: https://rust-lang.github.io/rust-clippy/master/index.html#unnecessary_sort_by diff --git a/clippy_lints/src/lib.rs b/clippy_lints/src/lib.rs index ae7045884f7..17501e8e6da 100644 --- a/clippy_lints/src/lib.rs +++ b/clippy_lints/src/lib.rs @@ -685,7 +685,7 @@ pub fn register_plugins(store: &mut rustc_lint::LintStore, sess: &Session, conf: &methods::UNINIT_ASSUMED_INIT, &methods::UNNECESSARY_FILTER_MAP, &methods::UNNECESSARY_FOLD, - &methods::UNNECESSARY_LAZY_EVALUATION, + &methods::UNNECESSARY_LAZY_EVALUATIONS, &methods::UNWRAP_USED, &methods::USELESS_ASREF, &methods::WRONG_PUB_SELF_CONVENTION, @@ -1361,7 +1361,7 @@ pub fn register_plugins(store: &mut rustc_lint::LintStore, sess: &Session, conf: LintId::of(&methods::UNINIT_ASSUMED_INIT), LintId::of(&methods::UNNECESSARY_FILTER_MAP), LintId::of(&methods::UNNECESSARY_FOLD), - LintId::of(&methods::UNNECESSARY_LAZY_EVALUATION), + LintId::of(&methods::UNNECESSARY_LAZY_EVALUATIONS), LintId::of(&methods::USELESS_ASREF), LintId::of(&methods::WRONG_SELF_CONVENTION), LintId::of(&methods::ZST_OFFSET), @@ -1542,7 +1542,7 @@ pub fn register_plugins(store: &mut rustc_lint::LintStore, sess: &Session, conf: LintId::of(&methods::SINGLE_CHAR_PUSH_STR), LintId::of(&methods::STRING_EXTEND_CHARS), LintId::of(&methods::UNNECESSARY_FOLD), - LintId::of(&methods::UNNECESSARY_LAZY_EVALUATION), + LintId::of(&methods::UNNECESSARY_LAZY_EVALUATIONS), LintId::of(&methods::WRONG_SELF_CONVENTION), LintId::of(&misc::TOPLEVEL_REF_ARG), LintId::of(&misc::ZERO_PTR), diff --git a/clippy_lints/src/methods/mod.rs b/clippy_lints/src/methods/mod.rs index c2b2cb98012..0f50a4c813a 100644 --- a/clippy_lints/src/methods/mod.rs +++ b/clippy_lints/src/methods/mod.rs @@ -1361,7 +1361,7 @@ declare_clippy_lint! { /// /// opt.unwrap_or(42); /// ``` - pub UNNECESSARY_LAZY_EVALUATION, + pub UNNECESSARY_LAZY_EVALUATIONS, style, "using unnecessary lazy evaluation, which can be replaced with simpler eager evaluation" } @@ -1415,7 +1415,7 @@ declare_lint_pass!(Methods => [ ZST_OFFSET, FILETYPE_IS_FILE, OPTION_AS_REF_DEREF, - UNNECESSARY_LAZY_EVALUATION, + UNNECESSARY_LAZY_EVALUATIONS, ]); impl<'tcx> LateLintPass<'tcx> for Methods { diff --git a/clippy_lints/src/methods/unnecessary_lazy_eval.rs b/clippy_lints/src/methods/unnecessary_lazy_eval.rs index a3e7e9971f8..31517659c34 100644 --- a/clippy_lints/src/methods/unnecessary_lazy_eval.rs +++ b/clippy_lints/src/methods/unnecessary_lazy_eval.rs @@ -4,7 +4,7 @@ use rustc_errors::Applicability; use rustc_hir as hir; use rustc_lint::LateContext; -use super::UNNECESSARY_LAZY_EVALUATION; +use super::UNNECESSARY_LAZY_EVALUATIONS; // Return true if the expression is an accessor of any of the arguments fn expr_uses_argument(expr: &hir::Expr<'_>, params: &[hir::Param<'_>]) -> bool { @@ -93,7 +93,7 @@ pub(super) fn lint<'tcx>( span_lint_and_sugg( cx, - UNNECESSARY_LAZY_EVALUATION, + UNNECESSARY_LAZY_EVALUATIONS, expr.span, msg, &format!("Use `{}` instead", simplify_using), diff --git a/src/lintlist/mod.rs b/src/lintlist/mod.rs index 2a66d3495ed..3229c8da507 100644 --- a/src/lintlist/mod.rs +++ b/src/lintlist/mod.rs @@ -2384,7 +2384,7 @@ pub static ref ALL_LINTS: Vec = vec![ module: "methods", }, Lint { - name: "unnecessary_lazy_evaluation", + name: "unnecessary_lazy_evaluations", group: "style", desc: "using unnecessary lazy evaluation, which can be replaced with simpler eager evaluation", deprecation: None, diff --git a/tests/ui/unnecessary_lazy_eval.fixed b/tests/ui/unnecessary_lazy_eval.fixed index 7f9d90a8569..fa66e68794e 100644 --- a/tests/ui/unnecessary_lazy_eval.fixed +++ b/tests/ui/unnecessary_lazy_eval.fixed @@ -1,5 +1,5 @@ // run-rustfix -#![warn(clippy::unnecessary_lazy_evaluation)] +#![warn(clippy::unnecessary_lazy_evaluations)] #![allow(clippy::redundant_closure)] #![allow(clippy::bind_instead_of_map)] diff --git a/tests/ui/unnecessary_lazy_eval.rs b/tests/ui/unnecessary_lazy_eval.rs index fd8f8ed0329..04f47d1aa29 100644 --- a/tests/ui/unnecessary_lazy_eval.rs +++ b/tests/ui/unnecessary_lazy_eval.rs @@ -1,5 +1,5 @@ // run-rustfix -#![warn(clippy::unnecessary_lazy_evaluation)] +#![warn(clippy::unnecessary_lazy_evaluations)] #![allow(clippy::redundant_closure)] #![allow(clippy::bind_instead_of_map)] diff --git a/tests/ui/unnecessary_lazy_eval.stderr b/tests/ui/unnecessary_lazy_eval.stderr index e86b7ed6253..5c1b2eb1f14 100644 --- a/tests/ui/unnecessary_lazy_eval.stderr +++ b/tests/ui/unnecessary_lazy_eval.stderr @@ -4,7 +4,7 @@ error: unnecessary closure used to substitute value for `Option::None` LL | let _ = opt.unwrap_or_else(|| 2); | ^^^^^^^^^^^^^^^^^^^^^^^^ help: Use `unwrap_or` instead: `opt.unwrap_or(2)` | - = note: `-D clippy::unnecessary-lazy-evaluation` implied by `-D warnings` + = note: `-D clippy::unnecessary-lazy-evaluations` implied by `-D warnings` error: unnecessary closure used to substitute value for `Option::None` --> $DIR/unnecessary_lazy_eval.rs:35:13 -- cgit 1.4.1-3-g733a5