diff --git a/clippy_lints/src/methods/unnecessary_fold.rs b/clippy_lints/src/methods/unnecessary_fold.rs index e545abd8ba8..8ec15a1c1b7 100644 --- a/clippy_lints/src/methods/unnecessary_fold.rs +++ b/clippy_lints/src/methods/unnecessary_fold.rs @@ -52,6 +52,68 @@ struct Replacement { has_generic_return: bool, } +fn check_fold_with_op( + cx: &LateContext<'_>, + expr: &hir::Expr<'_>, + acc: &hir::Expr<'_>, + fold_span: Span, + op: hir::BinOpKind, + replacement: Replacement, +) { + if_chain! { + // Extract the body of the closure passed to fold + if let hir::ExprKind::Closure(&hir::Closure { body, .. }) = acc.kind; + let closure_body = cx.tcx.hir().body(body); + let closure_expr = peel_blocks(closure_body.value); + + // Check if the closure body is of the form `acc some_expr(x)` + if let hir::ExprKind::Binary(ref bin_op, left_expr, right_expr) = closure_expr.kind; + if bin_op.node == op; + + // Extract the names of the two arguments to the closure + if let [param_a, param_b] = closure_body.params; + if let PatKind::Binding(_, first_arg_id, ..) = strip_pat_refs(param_a.pat).kind; + if let PatKind::Binding(_, second_arg_id, second_arg_ident, _) = strip_pat_refs(param_b.pat).kind; + + if path_to_local_id(left_expr, first_arg_id); + if replacement.has_args || path_to_local_id(right_expr, second_arg_id); + + then { + let mut applicability = Applicability::MachineApplicable; + + let turbofish = if replacement.has_generic_return { + format!("::<{}>", cx.typeck_results().expr_ty_adjusted(right_expr).peel_refs()) + } else { + String::new() + }; + + let sugg = if replacement.has_args { + format!( + "{method}{turbofish}(|{second_arg_ident}| {r})", + method = replacement.method_name, + r = snippet_with_applicability(cx, right_expr.span, "EXPR", &mut applicability), + ) + } else { + format!( + "{method}{turbofish}()", + method = replacement.method_name, + ) + }; + + span_lint_and_sugg( + cx, + UNNECESSARY_FOLD, + fold_span.with_hi(expr.span.hi()), + // TODO #2371 don't suggest e.g., .any(|x| f(x)) if we can suggest .any(f) + "this `.fold` can be written more succinctly using another method", + "try", + sugg, + applicability, + ); + } + } +} + pub(super) fn check( cx: &LateContext<'_>, expr: &hir::Expr<'_>, @@ -59,68 +121,6 @@ pub(super) fn check( acc: &hir::Expr<'_>, fold_span: Span, ) { - fn check_fold_with_op( - cx: &LateContext<'_>, - expr: &hir::Expr<'_>, - acc: &hir::Expr<'_>, - fold_span: Span, - op: hir::BinOpKind, - replacement: Replacement, - ) { - if_chain! { - // Extract the body of the closure passed to fold - if let hir::ExprKind::Closure(&hir::Closure { body, .. }) = acc.kind; - let closure_body = cx.tcx.hir().body(body); - let closure_expr = peel_blocks(closure_body.value); - - // Check if the closure body is of the form `acc some_expr(x)` - if let hir::ExprKind::Binary(ref bin_op, left_expr, right_expr) = closure_expr.kind; - if bin_op.node == op; - - // Extract the names of the two arguments to the closure - if let [param_a, param_b] = closure_body.params; - if let PatKind::Binding(_, first_arg_id, ..) = strip_pat_refs(param_a.pat).kind; - if let PatKind::Binding(_, second_arg_id, second_arg_ident, _) = strip_pat_refs(param_b.pat).kind; - - if path_to_local_id(left_expr, first_arg_id); - if replacement.has_args || path_to_local_id(right_expr, second_arg_id); - - then { - let mut applicability = Applicability::MachineApplicable; - - let turbofish = if replacement.has_generic_return { - format!("::<{}>", cx.typeck_results().expr_ty_adjusted(right_expr).peel_refs()) - } else { - String::new() - }; - - let sugg = if replacement.has_args { - format!( - "{method}{turbofish}(|{second_arg_ident}| {r})", - method = replacement.method_name, - r = snippet_with_applicability(cx, right_expr.span, "EXPR", &mut applicability), - ) - } else { - format!( - "{method}{turbofish}()", - method = replacement.method_name, - ) - }; - - span_lint_and_sugg( - cx, - UNNECESSARY_FOLD, - fold_span.with_hi(expr.span.hi()), - // TODO #2371 don't suggest e.g., .any(|x| f(x)) if we can suggest .any(f) - "this `.fold` can be written more succinctly using another method", - "try", - sugg, - applicability, - ); - } - } - } - // Check that this is a call to Iterator::fold rather than just some function called fold if !is_trait_method(cx, expr, sym::Iterator) { return;