diff --git a/clippy_lints/src/types.rs b/clippy_lints/src/types.rs index 51d7d9b3ab71..6866635b904b 100644 --- a/clippy_lints/src/types.rs +++ b/clippy_lints/src/types.rs @@ -779,89 +779,22 @@ impl<'a, 'tcx> LateLintPass<'a, 'tcx> for UnitArg { match expr.kind { ExprKind::Call(_, args) | ExprKind::MethodCall(_, _, args) => { - let mut args_to_recover = vec![]; - for arg in args { - if is_unit(cx.tables.expr_ty(arg)) && !is_unit_literal(arg) { - if let ExprKind::Match(.., match_source) = &arg.kind { - if *match_source == MatchSource::TryDesugar { - continue; + let args_to_recover = args + .iter() + .filter(|arg| { + if is_unit(cx.tables.expr_ty(arg)) && !is_unit_literal(arg) { + if let ExprKind::Match(.., MatchSource::TryDesugar) = &arg.kind { + false + } else { + true } + } else { + false } - - args_to_recover.push(arg); - } - } + }) + .collect::>(); if !args_to_recover.is_empty() { - let mut applicability = Applicability::MachineApplicable; - span_lint_and_then(cx, UNIT_ARG, expr.span, "passing a unit value to a function", |db| { - let mut or = ""; - args_to_recover - .iter() - .filter_map(|arg| { - if_chain! { - if let ExprKind::Block(block, _) = arg.kind; - if block.expr.is_none(); - if let Some(last_stmt) = block.stmts.iter().last(); - if let StmtKind::Semi(last_expr) = last_stmt.kind; - if let Some(snip) = snippet_opt(cx, last_expr.span); - then { - Some(( - last_stmt.span, - snip, - )) - } - else { - None - } - } - }) - .for_each(|(span, sugg)| { - db.span_suggestion( - span, - "remove the semicolon from the last statement in the block", - sugg, - Applicability::MaybeIncorrect, - ); - or = "or "; - }); - let sugg = args_to_recover - .iter() - .enumerate() - .map(|(i, arg)| { - let indent = if i == 0 { - 0 - } else { - indent_of(cx, expr.span).unwrap_or(0) - }; - format!( - "{}{};", - " ".repeat(indent), - snippet_block_with_applicability( - cx, - arg.span, - "..", - Some(expr.span), - &mut applicability - ) - ) - }) - .collect::>() - .join("\n"); - db.span_suggestion( - expr.span.with_hi(expr.span.lo()), - &format!("{}move the expressions in front of the call...", or), - format!("{}\n", sugg), - applicability, - ); - db.multipart_suggestion( - "...and use unit literals instead", - args_to_recover - .iter() - .map(|arg| (arg.span, "()".to_string())) - .collect::>(), - applicability, - ); - }); + lint_unit_args(cx, expr, &args_to_recover); } }, _ => (), @@ -869,6 +802,84 @@ impl<'a, 'tcx> LateLintPass<'a, 'tcx> for UnitArg { } } +fn lint_unit_args(cx: &LateContext<'_, '_>, expr: &Expr<'_>, args_to_recover: &[&Expr<'_>]) { + let mut applicability = Applicability::MachineApplicable; + let (singular, plural) = if args_to_recover.len() > 1 { + ("", "s") + } else { + ("a ", "") + }; + span_lint_and_then( + cx, + UNIT_ARG, + expr.span, + &format!("passing {}unit value{} to a function", singular, plural), + |db| { + let mut or = ""; + args_to_recover + .iter() + .filter_map(|arg| { + if_chain! { + if let ExprKind::Block(block, _) = arg.kind; + if block.expr.is_none(); + if let Some(last_stmt) = block.stmts.iter().last(); + if let StmtKind::Semi(last_expr) = last_stmt.kind; + if let Some(snip) = snippet_opt(cx, last_expr.span); + then { + Some(( + last_stmt.span, + snip, + )) + } + else { + None + } + } + }) + .for_each(|(span, sugg)| { + db.span_suggestion( + span, + "remove the semicolon from the last statement in the block", + sugg, + Applicability::MaybeIncorrect, + ); + or = "or "; + }); + let sugg = args_to_recover + .iter() + .enumerate() + .map(|(i, arg)| { + let indent = if i == 0 { + 0 + } else { + indent_of(cx, expr.span).unwrap_or(0) + }; + format!( + "{}{};", + " ".repeat(indent), + snippet_block_with_applicability(cx, arg.span, "..", Some(expr.span), &mut applicability) + ) + }) + .collect::>() + .join("\n"); + db.span_suggestion( + expr.span.with_hi(expr.span.lo()), + &format!("{}move the expression{} in front of the call...", or, plural), + format!("{}\n", sugg), + applicability, + ); + db.multipart_suggestion( + &format!("...and use {}unit literal{} instead", singular, plural), + args_to_recover + .iter() + .map(|arg| (arg.span, "()".to_string())) + .collect::>(), + applicability, + ); + }, + ); +} + fn is_questionmark_desugar_marked_call(expr: &Expr<'_>) -> bool { use rustc_span::hygiene::DesugaringKind; if let ExprKind::Call(ref callee, _) = expr.kind {