diff options
Diffstat (limited to 'src/tools/clippy/clippy_lints/src/swap.rs')
-rw-r--r-- | src/tools/clippy/clippy_lints/src/swap.rs | 107 |
1 files changed, 64 insertions, 43 deletions
diff --git a/src/tools/clippy/clippy_lints/src/swap.rs b/src/tools/clippy/clippy_lints/src/swap.rs index 17e9cc5f6..0f062cecf 100644 --- a/src/tools/clippy/clippy_lints/src/swap.rs +++ b/src/tools/clippy/clippy_lints/src/swap.rs @@ -10,7 +10,7 @@ use rustc_lint::{LateContext, LateLintPass}; use rustc_middle::ty; use rustc_session::{declare_lint_pass, declare_tool_lint}; use rustc_span::source_map::Spanned; -use rustc_span::{sym, Span}; +use rustc_span::{sym, symbol::Ident, Span}; declare_clippy_lint! { /// ### What it does @@ -174,53 +174,74 @@ fn check_manual_swap(cx: &LateContext<'_>, block: &Block<'_>) { /// Implementation of the `ALMOST_SWAPPED` lint. fn check_suspicious_swap(cx: &LateContext<'_>, block: &Block<'_>) { - for w in block.stmts.windows(2) { - if_chain! { - if let StmtKind::Semi(first) = w[0].kind; - if let StmtKind::Semi(second) = w[1].kind; - if first.span.ctxt() == second.span.ctxt(); - if let ExprKind::Assign(lhs0, rhs0, _) = first.kind; - if let ExprKind::Assign(lhs1, rhs1, _) = second.kind; - if eq_expr_value(cx, lhs0, rhs1); - if eq_expr_value(cx, lhs1, rhs0); - then { - let lhs0 = Sugg::hir_opt(cx, lhs0); - let rhs0 = Sugg::hir_opt(cx, rhs0); - let (what, lhs, rhs) = if let (Some(first), Some(second)) = (lhs0, rhs0) { - ( - format!(" `{first}` and `{second}`"), - first.mut_addr().to_string(), - second.mut_addr().to_string(), - ) - } else { - (String::new(), String::new(), String::new()) - }; + for [first, second] in block.stmts.array_windows() { + if let Some((lhs0, rhs0)) = parse(first) + && let Some((lhs1, rhs1)) = parse(second) + && first.span.eq_ctxt(second.span) + && is_same(cx, lhs0, rhs1) + && is_same(cx, lhs1, rhs0) + && let Some(lhs_sugg) = match &lhs0 { + ExprOrIdent::Expr(expr) => Sugg::hir_opt(cx, expr), + ExprOrIdent::Ident(ident) => Some(Sugg::NonParen(ident.as_str().into())), + } + && let Some(rhs_sugg) = Sugg::hir_opt(cx, rhs0) + { + let span = first.span.to(rhs1.span); + let Some(sugg) = std_or_core(cx) else { return }; + span_lint_and_then( + cx, + ALMOST_SWAPPED, + span, + &format!("this looks like you are trying to swap `{lhs_sugg}` and `{rhs_sugg}`"), + |diag| { + diag.span_suggestion( + span, + "try", + format!("{sugg}::mem::swap({}, {})", lhs_sugg.mut_addr(), rhs_sugg.mut_addr()), + Applicability::MaybeIncorrect, + ); + diag.note(format!("or maybe you should use `{sugg}::mem::replace`?")); + }, + ); + } + } +} + +fn is_same(cx: &LateContext<'_>, lhs: ExprOrIdent<'_>, rhs: &Expr<'_>) -> bool { + match lhs { + ExprOrIdent::Expr(expr) => eq_expr_value(cx, expr, rhs), + ExprOrIdent::Ident(ident) => { + if let ExprKind::Path(QPath::Resolved(None, path)) = rhs.kind + && let [segment] = &path.segments + && segment.ident == ident + { + true + } else { + false + } + } + } +} - let span = first.span.to(second.span); - let Some(sugg) = std_or_core(cx) else { return }; +#[derive(Debug, Clone, Copy)] +enum ExprOrIdent<'a> { + Expr(&'a Expr<'a>), + Ident(Ident), +} - span_lint_and_then(cx, - ALMOST_SWAPPED, - span, - &format!("this looks like you are trying to swap{what}"), - |diag| { - if !what.is_empty() { - diag.span_suggestion( - span, - "try", - format!( - "{sugg}::mem::swap({lhs}, {rhs})", - ), - Applicability::MaybeIncorrect, - ); - diag.note( - format!("or maybe you should use `{sugg}::mem::replace`?") - ); - } - }); +fn parse<'a, 'hir>(stmt: &'a Stmt<'hir>) -> Option<(ExprOrIdent<'hir>, &'a Expr<'hir>)> { + if let StmtKind::Semi(expr) = stmt.kind { + if let ExprKind::Assign(lhs, rhs, _) = expr.kind { + return Some((ExprOrIdent::Expr(lhs), rhs)); + } + } else if let StmtKind::Local(expr) = stmt.kind { + if let Some(rhs) = expr.init { + if let PatKind::Binding(_, _, ident_l, _) = expr.pat.kind { + return Some((ExprOrIdent::Ident(ident_l), rhs)); } } } + None } /// Implementation of the xor case for `MANUAL_SWAP` lint. |