From 07f1edf2d43efa0ef53e5b6c56c895bc9738ab94 Mon Sep 17 00:00:00 2001 From: Aleksei Latyshev Date: Sat, 25 Apr 2020 23:33:11 +0300 Subject: [PATCH] improve and generalize `option_and_then_some` lint - rename it to bind_instead_of_map --- CHANGELOG.md | 4 +- clippy_lints/src/lib.rs | 7 +- clippy_lints/src/loops.rs | 2 +- .../src/methods/bind_instead_of_map.rs | 309 ++++++++++++++++++ clippy_lints/src/methods/mod.rs | 100 ++---- clippy_lints/src/types.rs | 2 +- src/lintlist/mod.rs | 14 +- ...n_some.fixed => bind_instead_of_map.fixed} | 4 +- ...nd_then_some.rs => bind_instead_of_map.rs} | 2 +- ...some.stderr => bind_instead_of_map.stderr} | 18 +- tests/ui/bind_instead_of_map_multipart.rs | 61 ++++ tests/ui/bind_instead_of_map_multipart.stderr | 73 +++++ tests/ui/blocks_in_if_conditions.fixed | 4 +- tests/ui/blocks_in_if_conditions.rs | 4 +- tests/ui/option_map_or_none.fixed | 2 +- tests/ui/option_map_or_none.rs | 2 +- 16 files changed, 503 insertions(+), 105 deletions(-) create mode 100644 clippy_lints/src/methods/bind_instead_of_map.rs rename tests/ui/{option_and_then_some.fixed => bind_instead_of_map.fixed} (90%) rename tests/ui/{option_and_then_some.rs => bind_instead_of_map.rs} (94%) rename tests/ui/{option_and_then_some.stderr => bind_instead_of_map.stderr} (50%) create mode 100644 tests/ui/bind_instead_of_map_multipart.rs create mode 100644 tests/ui/bind_instead_of_map_multipart.stderr diff --git a/CHANGELOG.md b/CHANGELOG.md index d05819a973a56..7abefe654241a 100644 --- a/CHANGELOG.md +++ b/CHANGELOG.md @@ -315,7 +315,7 @@ Released 2019-11-07 * [`missing_safety_doc`] [#4535](https://github.com/rust-lang/rust-clippy/pull/4535) * [`mem_replace_with_uninit`] [#4511](https://github.com/rust-lang/rust-clippy/pull/4511) * [`suspicious_map`] [#4394](https://github.com/rust-lang/rust-clippy/pull/4394) - * [`option_and_then_some`] [#4386](https://github.com/rust-lang/rust-clippy/pull/4386) + * `option_and_then_some` [#4386](https://github.com/rust-lang/rust-clippy/pull/4386) * [`manual_saturating_arithmetic`] [#4498](https://github.com/rust-lang/rust-clippy/pull/4498) * Deprecate `unused_collect` lint. This is fully covered by rustc's `#[must_use]` on `collect` [#4348](https://github.com/rust-lang/rust-clippy/pull/4348) * Move `type_repetition_in_bounds` to pedantic group [#4403](https://github.com/rust-lang/rust-clippy/pull/4403) @@ -1273,6 +1273,7 @@ Released 2018-09-13 [`assign_ops`]: https://rust-lang.github.io/rust-clippy/master/index.html#assign_ops [`await_holding_lock`]: https://rust-lang.github.io/rust-clippy/master/index.html#await_holding_lock [`bad_bit_mask`]: https://rust-lang.github.io/rust-clippy/master/index.html#bad_bit_mask +[`bind_instead_of_map`]: https://rust-lang.github.io/rust-clippy/master/index.html#bind_instead_of_map [`blacklisted_name`]: https://rust-lang.github.io/rust-clippy/master/index.html#blacklisted_name [`blocks_in_if_conditions`]: https://rust-lang.github.io/rust-clippy/master/index.html#blocks_in_if_conditions [`bool_comparison`]: https://rust-lang.github.io/rust-clippy/master/index.html#bool_comparison @@ -1494,7 +1495,6 @@ Released 2018-09-13 [`not_unsafe_ptr_arg_deref`]: https://rust-lang.github.io/rust-clippy/master/index.html#not_unsafe_ptr_arg_deref [`ok_expect`]: https://rust-lang.github.io/rust-clippy/master/index.html#ok_expect [`op_ref`]: https://rust-lang.github.io/rust-clippy/master/index.html#op_ref -[`option_and_then_some`]: https://rust-lang.github.io/rust-clippy/master/index.html#option_and_then_some [`option_as_ref_deref`]: https://rust-lang.github.io/rust-clippy/master/index.html#option_as_ref_deref [`option_env_unwrap`]: https://rust-lang.github.io/rust-clippy/master/index.html#option_env_unwrap [`option_map_or_none`]: https://rust-lang.github.io/rust-clippy/master/index.html#option_map_or_none diff --git a/clippy_lints/src/lib.rs b/clippy_lints/src/lib.rs index bda0d5c045891..ec198b684b6ff 100644 --- a/clippy_lints/src/lib.rs +++ b/clippy_lints/src/lib.rs @@ -650,6 +650,7 @@ pub fn register_plugins(store: &mut rustc_lint::LintStore, sess: &Session, conf: &mem_replace::MEM_REPLACE_OPTION_WITH_NONE, &mem_replace::MEM_REPLACE_WITH_DEFAULT, &mem_replace::MEM_REPLACE_WITH_UNINIT, + &methods::BIND_INSTEAD_OF_MAP, &methods::CHARS_LAST_CMP, &methods::CHARS_NEXT_CMP, &methods::CLONE_DOUBLE_REF, @@ -676,7 +677,6 @@ pub fn register_plugins(store: &mut rustc_lint::LintStore, sess: &Session, conf: &methods::MAP_UNWRAP_OR, &methods::NEW_RET_NO_SELF, &methods::OK_EXPECT, - &methods::OPTION_AND_THEN_SOME, &methods::OPTION_AS_REF_DEREF, &methods::OPTION_MAP_OR_NONE, &methods::OR_FUN_CALL, @@ -1291,6 +1291,7 @@ pub fn register_plugins(store: &mut rustc_lint::LintStore, sess: &Session, conf: LintId::of(&mem_replace::MEM_REPLACE_OPTION_WITH_NONE), LintId::of(&mem_replace::MEM_REPLACE_WITH_DEFAULT), LintId::of(&mem_replace::MEM_REPLACE_WITH_UNINIT), + LintId::of(&methods::BIND_INSTEAD_OF_MAP), LintId::of(&methods::CHARS_LAST_CMP), LintId::of(&methods::CHARS_NEXT_CMP), LintId::of(&methods::CLONE_DOUBLE_REF), @@ -1307,7 +1308,6 @@ pub fn register_plugins(store: &mut rustc_lint::LintStore, sess: &Session, conf: LintId::of(&methods::MANUAL_SATURATING_ARITHMETIC), LintId::of(&methods::NEW_RET_NO_SELF), LintId::of(&methods::OK_EXPECT), - LintId::of(&methods::OPTION_AND_THEN_SOME), LintId::of(&methods::OPTION_AS_REF_DEREF), LintId::of(&methods::OPTION_MAP_OR_NONE), LintId::of(&methods::OR_FUN_CALL), @@ -1559,10 +1559,10 @@ pub fn register_plugins(store: &mut rustc_lint::LintStore, sess: &Session, conf: LintId::of(&matches::MATCH_AS_REF), LintId::of(&matches::MATCH_SINGLE_BINDING), LintId::of(&matches::WILDCARD_IN_OR_PATTERNS), + LintId::of(&methods::BIND_INSTEAD_OF_MAP), LintId::of(&methods::CLONE_ON_COPY), LintId::of(&methods::FILTER_NEXT), LintId::of(&methods::FLAT_MAP_IDENTITY), - LintId::of(&methods::OPTION_AND_THEN_SOME), LintId::of(&methods::OPTION_AS_REF_DEREF), LintId::of(&methods::SEARCH_IS_SOME), LintId::of(&methods::SKIP_WHILE_NEXT), @@ -1784,6 +1784,7 @@ pub fn register_renamed(ls: &mut rustc_lint::LintStore) { ls.register_renamed("clippy::new_without_default_derive", "clippy::new_without_default"); ls.register_renamed("clippy::cyclomatic_complexity", "clippy::cognitive_complexity"); ls.register_renamed("clippy::const_static_lifetime", "clippy::redundant_static_lifetimes"); + ls.register_renamed("clippy::option_and_then_some", "clippy::bind_instead_of_map"); ls.register_renamed("clippy::block_in_if_condition_expr", "clippy::blocks_in_if_conditions"); ls.register_renamed("clippy::block_in_if_condition_stmt", "clippy::blocks_in_if_conditions"); ls.register_renamed("clippy::option_map_unwrap_or", "clippy::map_unwrap_or"); diff --git a/clippy_lints/src/loops.rs b/clippy_lints/src/loops.rs index 4a9c411d7c8a3..84e8a010738cf 100644 --- a/clippy_lints/src/loops.rs +++ b/clippy_lints/src/loops.rs @@ -1462,7 +1462,7 @@ fn check_for_loop_over_map_kv<'a, 'tcx>( let map = sugg::Sugg::hir(cx, arg, "map"); multispan_sugg( diag, - "use the corresponding method".into(), + "use the corresponding method", vec![ (pat_span, snippet(cx, new_pat_span, kind).into_owned()), (arg_span, format!("{}.{}s{}()", map.maybe_par(), kind, mutbl)), diff --git a/clippy_lints/src/methods/bind_instead_of_map.rs b/clippy_lints/src/methods/bind_instead_of_map.rs new file mode 100644 index 0000000000000..32e86637569ed --- /dev/null +++ b/clippy_lints/src/methods/bind_instead_of_map.rs @@ -0,0 +1,309 @@ +use super::{contains_return, BIND_INSTEAD_OF_MAP}; +use crate::utils::{ + in_macro, match_qpath, match_type, method_calls, multispan_sugg_with_applicability, paths, remove_blocks, snippet, + snippet_with_macro_callsite, span_lint_and_sugg, span_lint_and_then, +}; +use if_chain::if_chain; +use rustc_errors::Applicability; +use rustc_hir as hir; +use rustc_hir::intravisit::{self, Visitor}; +use rustc_lint::LateContext; +use rustc_middle::hir::map::Map; +use rustc_span::Span; + +pub(crate) struct OptionAndThenSome; +impl BindInsteadOfMap for OptionAndThenSome { + const TYPE_NAME: &'static str = "Option"; + const TYPE_QPATH: &'static [&'static str] = &paths::OPTION; + + const BAD_METHOD_NAME: &'static str = "and_then"; + const BAD_VARIANT_NAME: &'static str = "Some"; + const BAD_VARIANT_QPATH: &'static [&'static str] = &paths::OPTION_SOME; + + const GOOD_METHOD_NAME: &'static str = "map"; +} + +pub(crate) struct ResultAndThenOk; +impl BindInsteadOfMap for ResultAndThenOk { + const TYPE_NAME: &'static str = "Result"; + const TYPE_QPATH: &'static [&'static str] = &paths::RESULT; + + const BAD_METHOD_NAME: &'static str = "and_then"; + const BAD_VARIANT_NAME: &'static str = "Ok"; + const BAD_VARIANT_QPATH: &'static [&'static str] = &paths::RESULT_OK; + + const GOOD_METHOD_NAME: &'static str = "map"; +} + +pub(crate) struct ResultOrElseErrInfo; +impl BindInsteadOfMap for ResultOrElseErrInfo { + const TYPE_NAME: &'static str = "Result"; + const TYPE_QPATH: &'static [&'static str] = &paths::RESULT; + + const BAD_METHOD_NAME: &'static str = "or_else"; + const BAD_VARIANT_NAME: &'static str = "Err"; + const BAD_VARIANT_QPATH: &'static [&'static str] = &paths::RESULT_ERR; + + const GOOD_METHOD_NAME: &'static str = "map_err"; +} + +pub(crate) trait BindInsteadOfMap { + const TYPE_NAME: &'static str; + const TYPE_QPATH: &'static [&'static str]; + + const BAD_METHOD_NAME: &'static str; + const BAD_VARIANT_NAME: &'static str; + const BAD_VARIANT_QPATH: &'static [&'static str]; + + const GOOD_METHOD_NAME: &'static str; + + fn no_op_msg() -> String { + format!( + "using `{}.{}({})`, which is a no-op", + Self::TYPE_NAME, + Self::BAD_METHOD_NAME, + Self::BAD_VARIANT_NAME + ) + } + + fn lint_msg() -> String { + format!( + "using `{}.{}(|x| {}(y))`, which is more succinctly expressed as `{}(|x| y)`", + Self::TYPE_NAME, + Self::BAD_METHOD_NAME, + Self::BAD_VARIANT_NAME, + Self::GOOD_METHOD_NAME + ) + } + + fn lint_closure_autofixable( + cx: &LateContext<'_, '_>, + expr: &hir::Expr<'_>, + args: &[hir::Expr<'_>], + closure_expr: &hir::Expr<'_>, + closure_args_span: Span, + ) -> bool { + if_chain! { + if let hir::ExprKind::Call(ref some_expr, ref some_args) = closure_expr.kind; + if let hir::ExprKind::Path(ref qpath) = some_expr.kind; + if match_qpath(qpath, Self::BAD_VARIANT_QPATH); + if some_args.len() == 1; + then { + let inner_expr = &some_args[0]; + + if contains_return(inner_expr) { + return false; + } + + let some_inner_snip = if inner_expr.span.from_expansion() { + snippet_with_macro_callsite(cx, inner_expr.span, "_") + } else { + snippet(cx, inner_expr.span, "_") + }; + + let closure_args_snip = snippet(cx, closure_args_span, ".."); + let option_snip = snippet(cx, args[0].span, ".."); + let note = format!("{}.{}({} {})", option_snip, Self::GOOD_METHOD_NAME, closure_args_snip, some_inner_snip); + span_lint_and_sugg( + cx, + BIND_INSTEAD_OF_MAP, + expr.span, + Self::lint_msg().as_ref(), + "try this", + note, + Applicability::MachineApplicable, + ); + true + } else { + false + } + } + } + + fn lint_closure(cx: &LateContext<'_, '_>, expr: &hir::Expr<'_>, closure_expr: &hir::Expr<'_>) { + let mut suggs = Vec::new(); + let can_sugg = find_all_ret_expressions(cx, closure_expr, |ret_expr| { + if_chain! { + if !in_macro(ret_expr.span); + if let hir::ExprKind::Call(ref func_path, ref args) = ret_expr.kind; + if let hir::ExprKind::Path(ref qpath) = func_path.kind; + if match_qpath(qpath, Self::BAD_VARIANT_QPATH); + if args.len() == 1; + if !contains_return(&args[0]); + then { + suggs.push((ret_expr.span, args[0].span.source_callsite())); + true + } else { + false + } + } + }); + + if can_sugg { + span_lint_and_then(cx, BIND_INSTEAD_OF_MAP, expr.span, Self::lint_msg().as_ref(), |diag| { + multispan_sugg_with_applicability( + diag, + "try this", + Applicability::MachineApplicable, + std::iter::once((*method_calls(expr, 1).2.get(0).unwrap(), Self::GOOD_METHOD_NAME.into())).chain( + suggs + .into_iter() + .map(|(span1, span2)| (span1, snippet(cx, span2, "_").into())), + ), + ) + }); + } + } + + /// Lint use of `_.and_then(|x| Some(y))` for `Option`s + fn lint(cx: &LateContext<'_, '_>, expr: &hir::Expr<'_>, args: &[hir::Expr<'_>]) { + if !match_type(cx, cx.tables.expr_ty(&args[0]), Self::TYPE_QPATH) { + return; + } + + match args[1].kind { + hir::ExprKind::Closure(_, _, body_id, closure_args_span, _) => { + let closure_body = cx.tcx.hir().body(body_id); + let closure_expr = remove_blocks(&closure_body.value); + + if !Self::lint_closure_autofixable(cx, expr, args, closure_expr, closure_args_span) { + Self::lint_closure(cx, expr, closure_expr); + } + }, + // `_.and_then(Some)` case, which is no-op. + hir::ExprKind::Path(ref qpath) if match_qpath(qpath, Self::BAD_VARIANT_QPATH) => { + span_lint_and_sugg( + cx, + BIND_INSTEAD_OF_MAP, + expr.span, + Self::no_op_msg().as_ref(), + "use the expression directly", + snippet(cx, args[0].span, "..").into(), + Applicability::MachineApplicable, + ); + }, + _ => {}, + } + } +} + +/// returns `true` if expr contains match expr desugared from try +fn contains_try(expr: &hir::Expr<'_>) -> bool { + struct TryFinder { + found: bool, + } + + impl<'hir> intravisit::Visitor<'hir> for TryFinder { + type Map = Map<'hir>; + + fn nested_visit_map(&mut self) -> intravisit::NestedVisitorMap { + intravisit::NestedVisitorMap::None + } + + fn visit_expr(&mut self, expr: &'hir hir::Expr<'hir>) { + if self.found { + return; + } + match expr.kind { + hir::ExprKind::Match(_, _, hir::MatchSource::TryDesugar) => self.found = true, + _ => intravisit::walk_expr(self, expr), + } + } + } + + let mut visitor = TryFinder { found: false }; + visitor.visit_expr(expr); + visitor.found +} + +fn find_all_ret_expressions<'hir, F>(_cx: &LateContext<'_, '_>, expr: &'hir hir::Expr<'hir>, callback: F) -> bool +where + F: FnMut(&'hir hir::Expr<'hir>) -> bool, +{ + struct RetFinder { + in_stmt: bool, + failed: bool, + cb: F, + } + + struct WithStmtGuarg<'a, F> { + val: &'a mut RetFinder, + prev_in_stmt: bool, + } + + impl RetFinder { + fn inside_stmt(&mut self, in_stmt: bool) -> WithStmtGuarg<'_, F> { + let prev_in_stmt = std::mem::replace(&mut self.in_stmt, in_stmt); + WithStmtGuarg { + val: self, + prev_in_stmt, + } + } + } + + impl std::ops::Deref for WithStmtGuarg<'_, F> { + type Target = RetFinder; + + fn deref(&self) -> &Self::Target { + self.val + } + } + + impl std::ops::DerefMut for WithStmtGuarg<'_, F> { + fn deref_mut(&mut self) -> &mut Self::Target { + self.val + } + } + + impl Drop for WithStmtGuarg<'_, F> { + fn drop(&mut self) { + self.val.in_stmt = self.prev_in_stmt; + } + } + + impl<'hir, F: FnMut(&'hir hir::Expr<'hir>) -> bool> intravisit::Visitor<'hir> for RetFinder { + type Map = Map<'hir>; + + fn nested_visit_map(&mut self) -> intravisit::NestedVisitorMap { + intravisit::NestedVisitorMap::None + } + + fn visit_stmt(&mut self, stmt: &'hir hir::Stmt<'_>) { + intravisit::walk_stmt(&mut *self.inside_stmt(true), stmt) + } + + fn visit_expr(&mut self, expr: &'hir hir::Expr<'_>) { + if self.failed { + return; + } + if self.in_stmt { + match expr.kind { + hir::ExprKind::Ret(Some(expr)) => self.inside_stmt(false).visit_expr(expr), + _ => intravisit::walk_expr(self, expr), + } + } else { + match expr.kind { + hir::ExprKind::Match(cond, arms, _) => { + self.inside_stmt(true).visit_expr(cond); + for arm in arms { + self.visit_expr(arm.body); + } + }, + hir::ExprKind::Block(..) => intravisit::walk_expr(self, expr), + hir::ExprKind::Ret(Some(expr)) => self.visit_expr(expr), + _ => self.failed |= !(self.cb)(expr), + } + } + } + } + + !contains_try(expr) && { + let mut ret_finder = RetFinder { + in_stmt: false, + failed: false, + cb: callback, + }; + ret_finder.visit_expr(expr); + !ret_finder.failed + } +} diff --git a/clippy_lints/src/methods/mod.rs b/clippy_lints/src/methods/mod.rs index e6094edc5d704..626427c15ecf5 100644 --- a/clippy_lints/src/methods/mod.rs +++ b/clippy_lints/src/methods/mod.rs @@ -1,3 +1,4 @@ +mod bind_instead_of_map; mod inefficient_to_string; mod manual_saturating_arithmetic; mod option_map_unwrap_or; @@ -7,6 +8,7 @@ use std::borrow::Cow; use std::fmt; use std::iter; +use bind_instead_of_map::BindInsteadOfMap; use if_chain::if_chain; use rustc_ast::ast; use rustc_errors::Applicability; @@ -306,27 +308,34 @@ declare_clippy_lint! { } declare_clippy_lint! { - /// **What it does:** Checks for usage of `_.and_then(|x| Some(y))`. + /// **What it does:** Checks for usage of `_.and_then(|x| Some(y))`, `_.and_then(|x| Ok(y))` or + /// `_.or_else(|x| Err(y))`. /// /// **Why is this bad?** Readability, this can be written more concisely as - /// `_.map(|x| y)`. + /// `_.map(|x| y)` or `_.map_err(|x| y)`. /// /// **Known problems:** None /// /// **Example:** /// /// ```rust - /// let x = Some("foo"); - /// let _ = x.and_then(|s| Some(s.len())); + /// # fn opt() -> Option<&'static str> { Some("42") } + /// # fn res() -> Result<&'static str, &'static str> { Ok("42") } + /// let _ = opt().and_then(|s| Some(s.len())); + /// let _ = res().and_then(|s| if s.len() == 42 { Ok(10) } else { Ok(20) }); + /// let _ = res().or_else(|s| if s.len() == 42 { Err(10) } else { Err(20) }); /// ``` /// /// The correct use would be: /// /// ```rust - /// let x = Some("foo"); - /// let _ = x.map(|s| s.len()); + /// # fn opt() -> Option<&'static str> { Some("42") } + /// # fn res() -> Result<&'static str, &'static str> { Ok("42") } + /// let _ = opt().map(|s| s.len()); + /// let _ = res().map(|s| if s.len() == 42 { 10 } else { 20 }); + /// let _ = res().map_err(|s| if s.len() == 42 { 10 } else { 20 }); /// ``` - pub OPTION_AND_THEN_SOME, + pub BIND_INSTEAD_OF_MAP, complexity, "using `Option.and_then(|x| Some(y))`, which is more succinctly expressed as `map(|x| y)`" } @@ -1243,7 +1252,7 @@ declare_lint_pass!(Methods => [ MAP_UNWRAP_OR, RESULT_MAP_OR_INTO_OPTION, OPTION_MAP_OR_NONE, - OPTION_AND_THEN_SOME, + BIND_INSTEAD_OF_MAP, OR_FUN_CALL, EXPECT_FUN_CALL, CHARS_NEXT_CMP, @@ -1302,7 +1311,13 @@ impl<'a, 'tcx> LateLintPass<'a, 'tcx> for Methods { ["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]), ["map_or", ..] => lint_map_or_none(cx, expr, arg_lists[0]), - ["and_then", ..] => lint_option_and_then_some(cx, expr, arg_lists[0]), + ["and_then", ..] => { + bind_instead_of_map::OptionAndThenSome::lint(cx, expr, arg_lists[0]); + bind_instead_of_map::ResultAndThenOk::lint(cx, expr, arg_lists[0]); + }, + ["or_else", ..] => { + bind_instead_of_map::ResultOrElseErrInfo::lint(cx, expr, arg_lists[0]); + }, ["next", "filter"] => lint_filter_next(cx, expr, arg_lists[1]), ["next", "skip_while"] => lint_skip_while_next(cx, expr, arg_lists[1]), ["map", "filter"] => lint_filter_map(cx, expr, arg_lists[1], arg_lists[0]), @@ -2601,73 +2616,6 @@ fn lint_map_or_none<'a, 'tcx>( ); } -/// Lint use of `_.and_then(|x| Some(y))` for `Option`s -fn lint_option_and_then_some(cx: &LateContext<'_, '_>, expr: &hir::Expr<'_>, args: &[hir::Expr<'_>]) { - const LINT_MSG: &str = "using `Option.and_then(|x| Some(y))`, which is more succinctly expressed as `map(|x| y)`"; - const NO_OP_MSG: &str = "using `Option.and_then(Some)`, which is a no-op"; - - let ty = cx.tables.expr_ty(&args[0]); - if !is_type_diagnostic_item(cx, ty, sym!(option_type)) { - return; - } - - match args[1].kind { - hir::ExprKind::Closure(_, _, body_id, closure_args_span, _) => { - let closure_body = cx.tcx.hir().body(body_id); - let closure_expr = remove_blocks(&closure_body.value); - if_chain! { - if let hir::ExprKind::Call(ref some_expr, ref some_args) = closure_expr.kind; - if let hir::ExprKind::Path(ref qpath) = some_expr.kind; - if match_qpath(qpath, &paths::OPTION_SOME); - if some_args.len() == 1; - then { - let inner_expr = &some_args[0]; - - if contains_return(inner_expr) { - return; - } - - let some_inner_snip = if inner_expr.span.from_expansion() { - snippet_with_macro_callsite(cx, inner_expr.span, "_") - } else { - snippet(cx, inner_expr.span, "_") - }; - - let closure_args_snip = snippet(cx, closure_args_span, ".."); - let option_snip = snippet(cx, args[0].span, ".."); - let note = format!("{}.map({} {})", option_snip, closure_args_snip, some_inner_snip); - span_lint_and_sugg( - cx, - OPTION_AND_THEN_SOME, - expr.span, - LINT_MSG, - "try this", - note, - Applicability::MachineApplicable, - ); - } - } - }, - // `_.and_then(Some)` case, which is no-op. - hir::ExprKind::Path(ref qpath) => { - if match_qpath(qpath, &paths::OPTION_SOME) { - let option_snip = snippet(cx, args[0].span, ".."); - let note = format!("{}", option_snip); - span_lint_and_sugg( - cx, - OPTION_AND_THEN_SOME, - expr.span, - NO_OP_MSG, - "use the expression directly", - note, - Applicability::MachineApplicable, - ); - } - }, - _ => {}, - } -} - /// lint use of `filter().next()` for `Iterators` fn lint_filter_next<'a, 'tcx>( cx: &LateContext<'a, 'tcx>, diff --git a/clippy_lints/src/types.rs b/clippy_lints/src/types.rs index f50adbc48ab36..6ed9ff22e4664 100644 --- a/clippy_lints/src/types.rs +++ b/clippy_lints/src/types.rs @@ -2230,7 +2230,7 @@ impl<'a, 'tcx> LateLintPass<'a, 'tcx> for ImplicitHasher { ); if !vis.suggestions.is_empty() { - multispan_sugg(diag, "...and use generic constructor".into(), vis.suggestions); + multispan_sugg(diag, "...and use generic constructor", vis.suggestions); } } diff --git a/src/lintlist/mod.rs b/src/lintlist/mod.rs index e5e3bf453a08a..5b4e2906b5f67 100644 --- a/src/lintlist/mod.rs +++ b/src/lintlist/mod.rs @@ -66,6 +66,13 @@ pub static ref ALL_LINTS: Vec = vec![ deprecation: None, module: "bit_mask", }, + Lint { + name: "bind_instead_of_map", + group: "complexity", + desc: "using `Option.and_then(|x| Some(y))`, which is more succinctly expressed as `map(|x| y)`", + deprecation: None, + module: "methods", + }, Lint { name: "blacklisted_name", group: "style", @@ -1578,13 +1585,6 @@ pub static ref ALL_LINTS: Vec = vec![ deprecation: None, module: "eq_op", }, - Lint { - name: "option_and_then_some", - group: "complexity", - desc: "using `Option.and_then(|x| Some(y))`, which is more succinctly expressed as `map(|x| y)`", - deprecation: None, - module: "methods", - }, Lint { name: "option_as_ref_deref", group: "complexity", diff --git a/tests/ui/option_and_then_some.fixed b/tests/ui/bind_instead_of_map.fixed similarity index 90% rename from tests/ui/option_and_then_some.fixed rename to tests/ui/bind_instead_of_map.fixed index 035bc1e54656b..5815550d7a6a1 100644 --- a/tests/ui/option_and_then_some.fixed +++ b/tests/ui/bind_instead_of_map.fixed @@ -1,5 +1,5 @@ // run-rustfix -#![deny(clippy::option_and_then_some)] +#![deny(clippy::bind_instead_of_map)] // need a main anyway, use it get rid of unused warnings too pub fn main() { @@ -12,7 +12,7 @@ pub fn main() { // Different type let x: Result = Ok(1); - let _ = x.and_then(Ok); + let _ = x; } pub fn foo() -> Option { diff --git a/tests/ui/option_and_then_some.rs b/tests/ui/bind_instead_of_map.rs similarity index 94% rename from tests/ui/option_and_then_some.rs rename to tests/ui/bind_instead_of_map.rs index d49da7813c6e6..623b100a4ce7e 100644 --- a/tests/ui/option_and_then_some.rs +++ b/tests/ui/bind_instead_of_map.rs @@ -1,5 +1,5 @@ // run-rustfix -#![deny(clippy::option_and_then_some)] +#![deny(clippy::bind_instead_of_map)] // need a main anyway, use it get rid of unused warnings too pub fn main() { diff --git a/tests/ui/option_and_then_some.stderr b/tests/ui/bind_instead_of_map.stderr similarity index 50% rename from tests/ui/option_and_then_some.stderr rename to tests/ui/bind_instead_of_map.stderr index 4782549176566..24c6b7f9ef32b 100644 --- a/tests/ui/option_and_then_some.stderr +++ b/tests/ui/bind_instead_of_map.stderr @@ -1,20 +1,26 @@ error: using `Option.and_then(Some)`, which is a no-op - --> $DIR/option_and_then_some.rs:8:13 + --> $DIR/bind_instead_of_map.rs:8:13 | LL | let _ = x.and_then(Some); | ^^^^^^^^^^^^^^^^ help: use the expression directly: `x` | note: the lint level is defined here - --> $DIR/option_and_then_some.rs:2:9 + --> $DIR/bind_instead_of_map.rs:2:9 | -LL | #![deny(clippy::option_and_then_some)] - | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ +LL | #![deny(clippy::bind_instead_of_map)] + | ^^^^^^^^^^^^^^^^^^^^^^^^^^^ error: using `Option.and_then(|x| Some(y))`, which is more succinctly expressed as `map(|x| y)` - --> $DIR/option_and_then_some.rs:9:13 + --> $DIR/bind_instead_of_map.rs:9:13 | LL | let _ = x.and_then(|o| Some(o + 1)); | ^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try this: `x.map(|o| o + 1)` -error: aborting due to 2 previous errors +error: using `Result.and_then(Ok)`, which is a no-op + --> $DIR/bind_instead_of_map.rs:15:13 + | +LL | let _ = x.and_then(Ok); + | ^^^^^^^^^^^^^^ help: use the expression directly: `x` + +error: aborting due to 3 previous errors diff --git a/tests/ui/bind_instead_of_map_multipart.rs b/tests/ui/bind_instead_of_map_multipart.rs new file mode 100644 index 0000000000000..91d9d11e3c110 --- /dev/null +++ b/tests/ui/bind_instead_of_map_multipart.rs @@ -0,0 +1,61 @@ +#![deny(clippy::bind_instead_of_map)] +#![allow(clippy::blocks_in_if_conditions)] + +pub fn main() { + let _ = Some("42").and_then(|s| if s.len() < 42 { Some(0) } else { Some(s.len()) }); + let _ = Some("42").and_then(|s| if s.len() < 42 { None } else { Some(s.len()) }); + + let _ = Ok::<_, ()>("42").and_then(|s| if s.len() < 42 { Ok(0) } else { Ok(s.len()) }); + let _ = Ok::<_, ()>("42").and_then(|s| if s.len() < 42 { Err(()) } else { Ok(s.len()) }); + + let _ = Err::<(), _>("42").or_else(|s| if s.len() < 42 { Err(s.len() + 20) } else { Err(s.len()) }); + let _ = Err::<(), _>("42").or_else(|s| if s.len() < 42 { Ok(()) } else { Err(s.len()) }); + + hard_example(); + macro_example(); +} + +fn hard_example() { + Some("42").and_then(|s| { + if { + if s == "43" { + return Some(43); + } + s == "42" + } { + return Some(45); + } + match s.len() { + 10 => Some(2), + 20 => { + if foo() { + return { + if foo() { + return Some(20); + } + println!("foo"); + Some(3) + }; + } + Some(20) + }, + 40 => Some(30), + _ => Some(1), + } + }); +} + +fn foo() -> bool { + true +} + +macro_rules! m { + () => { + Some(10) + }; +} + +fn macro_example() { + let _ = Some("").and_then(|s| if s.len() == 20 { m!() } else { Some(20) }); + let _ = Some("").and_then(|s| if s.len() == 20 { Some(m!()) } else { Some(Some(20)) }); +} diff --git a/tests/ui/bind_instead_of_map_multipart.stderr b/tests/ui/bind_instead_of_map_multipart.stderr new file mode 100644 index 0000000000000..50ce2f4051e00 --- /dev/null +++ b/tests/ui/bind_instead_of_map_multipart.stderr @@ -0,0 +1,73 @@ +error: using `Option.and_then(|x| Some(y))`, which is more succinctly expressed as `map(|x| y)` + --> $DIR/bind_instead_of_map_multipart.rs:5:13 + | +LL | let _ = Some("42").and_then(|s| if s.len() < 42 { Some(0) } else { Some(s.len()) }); + | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ + | +note: the lint level is defined here + --> $DIR/bind_instead_of_map_multipart.rs:1:9 + | +LL | #![deny(clippy::bind_instead_of_map)] + | ^^^^^^^^^^^^^^^^^^^^^^^^^^^ +help: try this + | +LL | let _ = Some("42").map(|s| if s.len() < 42 { 0 } else { s.len() }); + | ^^^ ^ ^^^^^^^ + +error: using `Result.and_then(|x| Ok(y))`, which is more succinctly expressed as `map(|x| y)` + --> $DIR/bind_instead_of_map_multipart.rs:8:13 + | +LL | let _ = Ok::<_, ()>("42").and_then(|s| if s.len() < 42 { Ok(0) } else { Ok(s.len()) }); + | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ + | +help: try this + | +LL | let _ = Ok::<_, ()>("42").map(|s| if s.len() < 42 { 0 } else { s.len() }); + | ^^^ ^ ^^^^^^^ + +error: using `Result.or_else(|x| Err(y))`, which is more succinctly expressed as `map_err(|x| y)` + --> $DIR/bind_instead_of_map_multipart.rs:11:13 + | +LL | let _ = Err::<(), _>("42").or_else(|s| if s.len() < 42 { Err(s.len() + 20) } else { Err(s.len()) }); + | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ + | +help: try this + | +LL | let _ = Err::<(), _>("42").map_err(|s| if s.len() < 42 { s.len() + 20 } else { s.len() }); + | ^^^^^^^ ^^^^^^^^^^^^ ^^^^^^^ + +error: using `Option.and_then(|x| Some(y))`, which is more succinctly expressed as `map(|x| y)` + --> $DIR/bind_instead_of_map_multipart.rs:19:5 + | +LL | / Some("42").and_then(|s| { +LL | | if { +LL | | if s == "43" { +LL | | return Some(43); +... | +LL | | } +LL | | }); + | |______^ + | +help: try this + | +LL | Some("42").map(|s| { +LL | if { +LL | if s == "43" { +LL | return 43; +LL | } +LL | s == "42" + ... + +error: using `Option.and_then(|x| Some(y))`, which is more succinctly expressed as `map(|x| y)` + --> $DIR/bind_instead_of_map_multipart.rs:60:13 + | +LL | let _ = Some("").and_then(|s| if s.len() == 20 { Some(m!()) } else { Some(Some(20)) }); + | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ + | +help: try this + | +LL | let _ = Some("").map(|s| if s.len() == 20 { m!() } else { Some(20) }); + | ^^^ ^^^^ ^^^^^^^^ + +error: aborting due to 5 previous errors + diff --git a/tests/ui/blocks_in_if_conditions.fixed b/tests/ui/blocks_in_if_conditions.fixed index 9040552cefc42..14562c4d32c12 100644 --- a/tests/ui/blocks_in_if_conditions.fixed +++ b/tests/ui/blocks_in_if_conditions.fixed @@ -63,10 +63,10 @@ fn block_in_assert() { let opt = Some(42); assert!(opt .as_ref() - .and_then(|val| { + .map(|val| { let mut v = val * 2; v -= 1; - Some(v * 3) + v * 3 }) .is_some()); } diff --git a/tests/ui/blocks_in_if_conditions.rs b/tests/ui/blocks_in_if_conditions.rs index 2fe409b22d31f..bda87650f6da2 100644 --- a/tests/ui/blocks_in_if_conditions.rs +++ b/tests/ui/blocks_in_if_conditions.rs @@ -63,10 +63,10 @@ fn block_in_assert() { let opt = Some(42); assert!(opt .as_ref() - .and_then(|val| { + .map(|val| { let mut v = val * 2; v -= 1; - Some(v * 3) + v * 3 }) .is_some()); } diff --git a/tests/ui/option_map_or_none.fixed b/tests/ui/option_map_or_none.fixed index decbae4e5af9a..d80c3c7c1b722 100644 --- a/tests/ui/option_map_or_none.fixed +++ b/tests/ui/option_map_or_none.fixed @@ -1,6 +1,6 @@ // run-rustfix -#![allow(clippy::option_and_then_some)] +#![allow(clippy::bind_instead_of_map)] fn main() { let opt = Some(1); diff --git a/tests/ui/option_map_or_none.rs b/tests/ui/option_map_or_none.rs index 0f1d2218d5d38..629842419e546 100644 --- a/tests/ui/option_map_or_none.rs +++ b/tests/ui/option_map_or_none.rs @@ -1,6 +1,6 @@ // run-rustfix -#![allow(clippy::option_and_then_some)] +#![allow(clippy::bind_instead_of_map)] fn main() { let opt = Some(1);