diff options
| -rw-r--r-- | clippy_lints/src/methods/mod.rs | 22 | ||||
| -rw-r--r-- | clippy_lints/src/methods/str_splitn.rs | 223 | ||||
| -rw-r--r-- | tests/ui/manual_split_once.fixed | 96 | ||||
| -rw-r--r-- | tests/ui/manual_split_once.rs | 96 | ||||
| -rw-r--r-- | tests/ui/manual_split_once.stderr | 129 |
5 files changed, 527 insertions, 39 deletions
diff --git a/clippy_lints/src/methods/mod.rs b/clippy_lints/src/methods/mod.rs index 23266739645..7a1bf36489a 100644 --- a/clippy_lints/src/methods/mod.rs +++ b/clippy_lints/src/methods/mod.rs @@ -2009,13 +2009,27 @@ declare_clippy_lint! { /// ### Example /// ```rust,ignore /// // Bad - /// let (key, value) = _.splitn(2, '=').next_tuple()?; - /// let value = _.splitn(2, '=').nth(1)?; + /// let s = "key=value=add"; + /// let (key, value) = s.splitn(2, '=').next_tuple()?; + /// let value = s.splitn(2, '=').nth(1)?; /// + /// let mut parts = s.splitn(2, '='); + /// let key = parts.next()?; + /// let value = parts.next()?; + /// ``` + /// Use instead: + /// ```rust,ignore /// // Good - /// let (key, value) = _.split_once('=')?; - /// let value = _.split_once('=')?.1; + /// let s = "key=value=add"; + /// let (key, value) = s.split_once('=')?; + /// let value = s.split_once('=')?.1; + /// + /// let (key, value) = s.split_once('=')?; /// ``` + /// + /// ### Limitations + /// The multiple statement variant currently only detects `iter.next()?`/`iter.next().unwrap()` + /// in two separate `let` statements that immediately follow the `splitn()` #[clippy::version = "1.57.0"] pub MANUAL_SPLIT_ONCE, complexity, diff --git a/clippy_lints/src/methods/str_splitn.rs b/clippy_lints/src/methods/str_splitn.rs index 6eaa9eb2ef0..52891eeed06 100644 --- a/clippy_lints/src/methods/str_splitn.rs +++ b/clippy_lints/src/methods/str_splitn.rs @@ -1,14 +1,19 @@ use clippy_utils::consts::{constant, Constant}; -use clippy_utils::diagnostics::span_lint_and_sugg; +use clippy_utils::diagnostics::{span_lint_and_sugg, span_lint_and_then}; use clippy_utils::source::snippet_with_context; -use clippy_utils::{is_diag_item_method, match_def_path, meets_msrv, msrvs, paths}; +use clippy_utils::usage::local_used_after_expr; +use clippy_utils::visitors::expr_visitor; +use clippy_utils::{is_diag_item_method, match_def_path, meets_msrv, msrvs, path_to_local_id, paths}; use if_chain::if_chain; use rustc_errors::Applicability; -use rustc_hir::{Expr, ExprKind, HirId, LangItem, Node, QPath}; +use rustc_hir::intravisit::Visitor; +use rustc_hir::{ + BindingAnnotation, Expr, ExprKind, HirId, LangItem, Local, MatchSource, Node, Pat, PatKind, QPath, Stmt, StmtKind, +}; use rustc_lint::LateContext; use rustc_middle::ty; use rustc_semver::RustcVersion; -use rustc_span::{symbol::sym, Span, SyntaxContext}; +use rustc_span::{sym, Span, Symbol, SyntaxContext}; use super::{MANUAL_SPLIT_ONCE, NEEDLESS_SPLITN}; @@ -25,40 +30,41 @@ pub(super) fn check( return; } - let ctxt = expr.span.ctxt(); - let Some(usage) = parse_iter_usage(cx, ctxt, cx.tcx.hir().parent_iter(expr.hir_id)) else { return }; - - let needless = match usage.kind { + let needless = |usage_kind| match usage_kind { IterUsageKind::Nth(n) => count > n + 1, IterUsageKind::NextTuple => count > 2, }; + let manual = count == 2 && meets_msrv(msrv, &msrvs::STR_SPLIT_ONCE); - if needless { - let mut app = Applicability::MachineApplicable; - let (r, message) = if method_name == "splitn" { - ("", "unnecessary use of `splitn`") - } else { - ("r", "unnecessary use of `rsplitn`") - }; - - span_lint_and_sugg( - cx, - NEEDLESS_SPLITN, - expr.span, - message, - "try this", - format!( - "{}.{r}split({})", - snippet_with_context(cx, self_arg.span, ctxt, "..", &mut app).0, - snippet_with_context(cx, pat_arg.span, ctxt, "..", &mut app).0, - ), - app, - ); - } else if count == 2 && meets_msrv(msrv, &msrvs::STR_SPLIT_ONCE) { - check_manual_split_once(cx, method_name, expr, self_arg, pat_arg, &usage); + match parse_iter_usage(cx, expr.span.ctxt(), cx.tcx.hir().parent_iter(expr.hir_id)) { + Some(usage) if needless(usage.kind) => lint_needless(cx, method_name, expr, self_arg, pat_arg), + Some(usage) if manual => check_manual_split_once(cx, method_name, expr, self_arg, pat_arg, &usage), + None if manual => { + check_manual_split_once_indirect(cx, method_name, expr, self_arg, pat_arg); + }, + _ => {}, } } +fn lint_needless(cx: &LateContext<'_>, method_name: &str, expr: &Expr<'_>, self_arg: &Expr<'_>, pat_arg: &Expr<'_>) { + let mut app = Applicability::MachineApplicable; + let r = if method_name == "splitn" { "" } else { "r" }; + + span_lint_and_sugg( + cx, + NEEDLESS_SPLITN, + expr.span, + &format!("unnecessary use of `{r}splitn`"), + "try this", + format!( + "{}.{r}split({})", + snippet_with_context(cx, self_arg.span, expr.span.ctxt(), "..", &mut app).0, + snippet_with_context(cx, pat_arg.span, expr.span.ctxt(), "..", &mut app).0, + ), + app, + ); +} + fn check_manual_split_once( cx: &LateContext<'_>, method_name: &str, @@ -107,16 +113,171 @@ fn check_manual_split_once( span_lint_and_sugg(cx, MANUAL_SPLIT_ONCE, usage.span, msg, "try this", sugg, app); } +/// checks for +/// +/// ``` +/// let mut iter = "a.b.c".splitn(2, '.'); +/// let a = iter.next(); +/// let b = iter.next(); +/// ``` +fn check_manual_split_once_indirect( + cx: &LateContext<'_>, + method_name: &str, + expr: &Expr<'_>, + self_arg: &Expr<'_>, + pat_arg: &Expr<'_>, +) -> Option<()> { + let ctxt = expr.span.ctxt(); + let mut parents = cx.tcx.hir().parent_iter(expr.hir_id); + if let (_, Node::Local(local)) = parents.next()? + && let PatKind::Binding(BindingAnnotation::Mutable, iter_binding_id, iter_ident, None) = local.pat.kind + && let (iter_stmt_id, Node::Stmt(_)) = parents.next()? + && let (_, Node::Block(enclosing_block)) = parents.next()? + + && let mut stmts = enclosing_block + .stmts + .iter() + .skip_while(|stmt| stmt.hir_id != iter_stmt_id) + .skip(1) + + && let first = indirect_usage(cx, stmts.next()?, iter_binding_id, ctxt)? + && let second = indirect_usage(cx, stmts.next()?, iter_binding_id, ctxt)? + && first.unwrap_kind == second.unwrap_kind + && first.name != second.name + && !local_used_after_expr(cx, iter_binding_id, second.init_expr) + { + let (r, lhs, rhs) = if method_name == "splitn" { + ("", first.name, second.name) + } else { + ("r", second.name, first.name) + }; + let msg = format!("manual implementation of `{r}split_once`"); + + let mut app = Applicability::MachineApplicable; + let self_snip = snippet_with_context(cx, self_arg.span, ctxt, "..", &mut app).0; + let pat_snip = snippet_with_context(cx, pat_arg.span, ctxt, "..", &mut app).0; + + span_lint_and_then(cx, MANUAL_SPLIT_ONCE, local.span, &msg, |diag| { + diag.span_label(first.span, "first usage here"); + diag.span_label(second.span, "second usage here"); + + let unwrap = match first.unwrap_kind { + UnwrapKind::Unwrap => ".unwrap()", + UnwrapKind::QuestionMark => "?", + }; + diag.span_suggestion_verbose( + local.span, + &format!("try `{r}split_once`"), + format!("let ({lhs}, {rhs}) = {self_snip}.{r}split_once({pat_snip}){unwrap};"), + app, + ); + + let remove_msg = format!("remove the `{iter_ident}` usages"); + diag.span_suggestion( + first.span, + &remove_msg, + String::new(), + app, + ); + diag.span_suggestion( + second.span, + &remove_msg, + String::new(), + app, + ); + }); + } + + Some(()) +} + +#[derive(Debug)] +struct IndirectUsage<'a> { + name: Symbol, + span: Span, + init_expr: &'a Expr<'a>, + unwrap_kind: UnwrapKind, +} + +/// returns `Some(IndirectUsage)` for e.g. +/// +/// ```ignore +/// let name = binding.next()?; +/// let name = binding.next().unwrap(); +/// ``` +fn indirect_usage<'tcx>( + cx: &LateContext<'tcx>, + stmt: &Stmt<'tcx>, + binding: HirId, + ctxt: SyntaxContext, +) -> Option<IndirectUsage<'tcx>> { + if let StmtKind::Local(Local { + pat: + Pat { + kind: PatKind::Binding(BindingAnnotation::Unannotated, _, ident, None), + .. + }, + init: Some(init_expr), + hir_id: local_hir_id, + .. + }) = stmt.kind + { + let mut path_to_binding = None; + expr_visitor(cx, |expr| { + if path_to_local_id(expr, binding) { + path_to_binding = Some(expr); + } + + path_to_binding.is_none() + }) + .visit_expr(init_expr); + + let mut parents = cx.tcx.hir().parent_iter(path_to_binding?.hir_id); + let iter_usage = parse_iter_usage(cx, ctxt, &mut parents)?; + + let (parent_id, _) = parents.find(|(_, node)| { + !matches!( + node, + Node::Expr(Expr { + kind: ExprKind::Match(.., MatchSource::TryDesugar), + .. + }) + ) + })?; + + if let IterUsage { + kind: IterUsageKind::Nth(0), + unwrap_kind: Some(unwrap_kind), + .. + } = iter_usage + { + if parent_id == *local_hir_id { + return Some(IndirectUsage { + name: ident.name, + span: stmt.span, + init_expr, + unwrap_kind, + }); + } + } + } + + None +} + +#[derive(Debug, Clone, Copy)] enum IterUsageKind { Nth(u128), NextTuple, } +#[derive(Debug, PartialEq)] enum UnwrapKind { Unwrap, QuestionMark, } +#[derive(Debug)] struct IterUsage { kind: IterUsageKind, unwrap_kind: Option<UnwrapKind>, diff --git a/tests/ui/manual_split_once.fixed b/tests/ui/manual_split_once.fixed index bffc7b9b631..c7ca770434a 100644 --- a/tests/ui/manual_split_once.fixed +++ b/tests/ui/manual_split_once.fixed @@ -2,7 +2,7 @@ #![feature(custom_inner_attributes)] #![warn(clippy::manual_split_once)] -#![allow(clippy::iter_skip_next, clippy::iter_nth_zero)] +#![allow(unused, clippy::iter_skip_next, clippy::iter_nth_zero)] extern crate itertools; @@ -41,13 +41,107 @@ fn main() { let _ = s.rsplit_once('=').map(|x| x.0); } +fn indirect() -> Option<()> { + let (l, r) = "a.b.c".split_once('.').unwrap(); + + + + let (l, r) = "a.b.c".split_once('.')?; + + + + let (l, r) = "a.b.c".rsplit_once('.').unwrap(); + + + + let (l, r) = "a.b.c".rsplit_once('.')?; + + + + // could lint, currently doesn't + + let mut iter = "a.b.c".splitn(2, '.'); + let other = 1; + let l = iter.next()?; + let r = iter.next()?; + + let mut iter = "a.b.c".splitn(2, '.'); + let mut mut_binding = iter.next()?; + let r = iter.next()?; + + let mut iter = "a.b.c".splitn(2, '.'); + let tuple = (iter.next()?, iter.next()?); + + // should not lint + + let mut missing_unwrap = "a.b.c".splitn(2, '.'); + let l = missing_unwrap.next(); + let r = missing_unwrap.next(); + + let mut mixed_unrap = "a.b.c".splitn(2, '.'); + let unwrap = mixed_unrap.next().unwrap(); + let question_mark = mixed_unrap.next()?; + + let mut iter = "a.b.c".splitn(2, '.'); + let same_name = iter.next()?; + let same_name = iter.next()?; + + let mut iter = "a.b.c".splitn(2, '.'); + let shadows_existing = "d"; + let shadows_existing = iter.next()?; + let r = iter.next()?; + + let mut iter = "a.b.c".splitn(2, '.'); + let becomes_shadowed = iter.next()?; + let becomes_shadowed = "d"; + let r = iter.next()?; + + let mut iter = "a.b.c".splitn(2, '.'); + let l = iter.next()?; + let r = iter.next()?; + let third_usage = iter.next()?; + + let mut n_three = "a.b.c".splitn(3, '.'); + let l = n_three.next()?; + let r = n_three.next()?; + + let mut iter = "a.b.c".splitn(2, '.'); + { + let in_block = iter.next()?; + } + let r = iter.next()?; + + let mut lacks_binding = "a.b.c".splitn(2, '.'); + let _ = lacks_binding.next()?; + let r = lacks_binding.next()?; + + let mut mapped = "a.b.c".splitn(2, '.').map(|_| "~"); + let l = iter.next()?; + let r = iter.next()?; + + let mut assigned = ""; + let mut iter = "a.b.c".splitn(2, '.'); + let l = iter.next()?; + assigned = iter.next()?; + + None +} + fn _msrv_1_51() { #![clippy::msrv = "1.51"] // `str::split_once` was stabilized in 1.52. Do not lint this let _ = "key=value".splitn(2, '=').nth(1).unwrap(); + + let mut iter = "a.b.c".splitn(2, '.'); + let a = iter.next().unwrap(); + let b = iter.next().unwrap(); } fn _msrv_1_52() { #![clippy::msrv = "1.52"] let _ = "key=value".split_once('=').unwrap().1; + + let (a, b) = "a.b.c".split_once('.').unwrap(); + + } diff --git a/tests/ui/manual_split_once.rs b/tests/ui/manual_split_once.rs index 147be7c7ab1..ee2848a251e 100644 --- a/tests/ui/manual_split_once.rs +++ b/tests/ui/manual_split_once.rs @@ -2,7 +2,7 @@ #![feature(custom_inner_attributes)] #![warn(clippy::manual_split_once)] -#![allow(clippy::iter_skip_next, clippy::iter_nth_zero)] +#![allow(unused, clippy::iter_skip_next, clippy::iter_nth_zero)] extern crate itertools; @@ -41,13 +41,107 @@ fn main() { let _ = s.rsplitn(2, '=').nth(1); } +fn indirect() -> Option<()> { + let mut iter = "a.b.c".splitn(2, '.'); + let l = iter.next().unwrap(); + let r = iter.next().unwrap(); + + let mut iter = "a.b.c".splitn(2, '.'); + let l = iter.next()?; + let r = iter.next()?; + + let mut iter = "a.b.c".rsplitn(2, '.'); + let r = iter.next().unwrap(); + let l = iter.next().unwrap(); + + let mut iter = "a.b.c".rsplitn(2, '.'); + let r = iter.next()?; + let l = iter.next()?; + + // could lint, currently doesn't + + let mut iter = "a.b.c".splitn(2, '.'); + let other = 1; + let l = iter.next()?; + let r = iter.next()?; + + let mut iter = "a.b.c".splitn(2, '.'); + let mut mut_binding = iter.next()?; + let r = iter.next()?; + + let mut iter = "a.b.c".splitn(2, '.'); + let tuple = (iter.next()?, iter.next()?); + + // should not lint + + let mut missing_unwrap = "a.b.c".splitn(2, '.'); + let l = missing_unwrap.next(); + let r = missing_unwrap.next(); + + let mut mixed_unrap = "a.b.c".splitn(2, '.'); + let unwrap = mixed_unrap.next().unwrap(); + let question_mark = mixed_unrap.next()?; + + let mut iter = "a.b.c".splitn(2, '.'); + let same_name = iter.next()?; + let same_name = iter.next()?; + + let mut iter = "a.b.c".splitn(2, '.'); + let shadows_existing = "d"; + let shadows_existing = iter.next()?; + let r = iter.next()?; + + let mut iter = "a.b.c".splitn(2, '.'); + let becomes_shadowed = iter.next()?; + let becomes_shadowed = "d"; + let r = iter.next()?; + + let mut iter = "a.b.c".splitn(2, '.'); + let l = iter.next()?; + let r = iter.next()?; + let third_usage = iter.next()?; + + let mut n_three = "a.b.c".splitn(3, '.'); + let l = n_three.next()?; + let r = n_three.next()?; + + let mut iter = "a.b.c".splitn(2, '.'); + { + let in_block = iter.next()?; + } + let r = iter.next()?; + + let mut lacks_binding = "a.b.c".splitn(2, '.'); + let _ = lacks_binding.next()?; + let r = lacks_binding.next()?; + + let mut mapped = "a.b.c".splitn(2, '.').map(|_| "~"); + let l = iter.next()?; + let r = iter.next()?; + + let mut assigned = ""; + let mut iter = "a.b.c".splitn(2, '.'); + let l = iter.next()?; + assigned = iter.next()?; + + None +} + fn _msrv_1_51() { #![clippy::msrv = "1.51"] // `str::split_once` was stabilized in 1.52. Do not lint this let _ = "key=value".splitn(2, '=').nth(1).unwrap(); + + let mut iter = "a.b.c".splitn(2, '.'); + let a = iter.next().unwrap(); + let b = iter.next().unwrap(); } fn _msrv_1_52() { #![clippy::msrv = "1.52"] let _ = "key=value".splitn(2, '=').nth(1).unwrap(); + + let mut iter = "a.b.c".splitn(2, '.'); + let a = iter.next().unwrap(); + let b = iter.next().unwrap(); } diff --git a/tests/ui/manual_split_once.stderr b/tests/ui/manual_split_once.stderr index 9635e6c5e4b..2563a6904b7 100644 --- a/tests/ui/manual_split_once.stderr +++ b/tests/ui/manual_split_once.stderr @@ -79,10 +79,135 @@ LL | let _ = s.rsplitn(2, '=').nth(1); | ^^^^^^^^^^^^^^^^^^^^^^^^ help: try this: `s.rsplit_once('=').map(|x| x.0)` error: manual implementation of `split_once` - --> $DIR/manual_split_once.rs:52:13 + --> $DIR/manual_split_once.rs:45:5 + | +LL | let mut iter = "a.b.c".splitn(2, '.'); + | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ +LL | let l = iter.next().unwrap(); + | ----------------------------- first usage here +LL | let r = iter.next().unwrap(); + | ----------------------------- second usage here + | +help: try `split_once` + | +LL | let (l, r) = "a.b.c".split_once('.').unwrap(); + | +help: remove the `iter` usages + | +LL - let l = iter.next().unwrap(); +LL + + | +help: remove the `iter` usages + | +LL - let r = iter.next().unwrap(); +LL + + | + +error: manual implementation of `split_once` + --> $DIR/manual_split_once.rs:49:5 + | +LL | let mut iter = "a.b.c".splitn(2, '.'); + | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ +LL | let l = iter.next()?; + | --------------------- first usage here +LL | let r = iter.next()?; + | --------------------- second usage here + | +help: try `split_once` + | +LL | let (l, r) = "a.b.c".split_once('.')?; + | +help: remove the `iter` usages + | +LL - let l = iter.next()?; +LL + + | +help: remove the `iter` usages + | +LL - let r = iter.next()?; +LL + + | + +error: manual implementation of `rsplit_once` + --> $DIR/manual_split_once.rs:53:5 + | +LL | let mut iter = "a.b.c".rsplitn(2, '.'); + | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ +LL | let r = iter.next().unwrap(); + | ----------------------------- first usage here +LL | let l = iter.next().unwrap(); + | ----------------------------- second usage here + | +help: try `rsplit_once` + | +LL | let (l, r) = "a.b.c".rsplit_once('.').unwrap(); + | +help: remove the `iter` usages + | +LL - let r = iter.next().unwrap(); +LL + + | +help: remove the `iter` usages + | +LL - let l = iter.next().unwrap(); +LL + + | + +error: manual implementation of `rsplit_once` + --> $DIR/manual_split_once.rs:57:5 + | +LL | let mut iter = "a.b.c".rsplitn(2, '.'); + | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ +LL | let r = iter.next()?; + | --------------------- first usage here +LL | let l = iter.next()?; + | --------------------- second usage here + | +help: try `rsplit_once` + | +LL | let (l, r) = "a.b.c".rsplit_once('.')?; + | +help: remove the `iter` usages + | +LL - let r = iter.next()?; +LL + + | +help: remove the `iter` usages + | +LL - let l = iter.next()?; +LL + + | + +error: manual implementation of `split_once` + --> $DIR/manual_split_once.rs:142:13 | LL | let _ = "key=value".splitn(2, '=').nth(1).unwrap(); | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try this: `"key=value".split_once('=').unwrap().1` -error: aborting due to 14 previous errors +error: manual implementation of `split_once` + --> $DIR/manual_split_once.rs:144:5 + | +LL | let mut iter = "a.b.c".splitn(2, '.'); + | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ +LL | let a = iter.next().unwrap(); + | ----------------------------- first usage here +LL | let b = iter.next().unwrap(); + | ----------------------------- second usage here + | +help: try `split_once` + | +LL | let (a, b) = "a.b.c".split_once('.').unwrap(); + | +help: remove the `iter` usages + | +LL - let a = iter.next().unwrap(); +LL + + | +help: remove the `iter` usages + | +LL - let b = iter.next().unwrap(); +LL + + | + +error: aborting due to 19 previous errors |