diff options
| -rw-r--r-- | clippy_lints/src/methods/mod.rs | 24 | ||||
| -rw-r--r-- | tests/ui/useful_asref.rs | 22 |
2 files changed, 39 insertions, 7 deletions
diff --git a/clippy_lints/src/methods/mod.rs b/clippy_lints/src/methods/mod.rs index 06d2f2cb5fc..9763392bfdf 100644 --- a/clippy_lints/src/methods/mod.rs +++ b/clippy_lints/src/methods/mod.rs @@ -19,11 +19,11 @@ use crate::syntax::symbol::LocalInternedString; use crate::utils::paths; use crate::utils::sugg; use crate::utils::{ - get_arg_name, get_trait_def_id, implements_trait, in_macro, is_copy, is_expn_of, is_self, is_self_ty, - iter_input_pats, last_path_segment, match_def_path, match_path, match_qpath, match_trait_method, match_type, - match_var, method_calls, method_chain_args, remove_blocks, return_ty, same_tys, single_segment_path, snippet, - snippet_with_applicability, snippet_with_macro_callsite, span_lint, span_lint_and_sugg, span_lint_and_then, - span_note_and_lint, walk_ptrs_ty, walk_ptrs_ty_depth, SpanlessEq, + get_arg_name, get_parent_expr, get_trait_def_id, implements_trait, in_macro, is_copy, is_expn_of, is_self, + is_self_ty, iter_input_pats, last_path_segment, match_def_path, match_path, match_qpath, match_trait_method, + match_type, match_var, method_calls, method_chain_args, remove_blocks, return_ty, same_tys, single_segment_path, + snippet, snippet_with_applicability, snippet_with_macro_callsite, span_lint, span_lint_and_sugg, + span_lint_and_then, span_note_and_lint, walk_ptrs_ty, walk_ptrs_ty_depth, SpanlessEq, }; use if_chain::if_chain; use matches::matches; @@ -859,8 +859,8 @@ impl<'a, 'tcx> LateLintPass<'a, 'tcx> for Pass { ["nth", "iter_mut"] => lint_iter_nth(cx, expr, arg_lists[1], true), ["next", "skip"] => lint_iter_skip_next(cx, expr), ["collect", "cloned"] => lint_iter_cloned_collect(cx, expr, arg_lists[1]), - ["as_ref", ..] => lint_asref(cx, expr, "as_ref", arg_lists[0]), - ["as_mut", ..] => lint_asref(cx, expr, "as_mut", arg_lists[0]), + ["as_ref"] => lint_asref(cx, expr, "as_ref", arg_lists[0]), + ["as_mut"] => lint_asref(cx, expr, "as_mut", arg_lists[0]), ["fold", ..] => lint_unnecessary_fold(cx, expr, arg_lists[0]), ["filter_map", ..] => unnecessary_filter_map::lint(cx, expr, arg_lists[0]), _ => {}, @@ -2181,6 +2181,16 @@ fn lint_asref(cx: &LateContext<'_, '_>, expr: &hir::Expr, call_name: &str, as_re let (base_res_ty, res_depth) = walk_ptrs_ty_depth(res_ty); let (base_rcv_ty, rcv_depth) = walk_ptrs_ty_depth(rcv_ty); if base_rcv_ty == base_res_ty && rcv_depth >= res_depth { + // allow the `as_ref` or `as_mut` if it is followed by another method call + if_chain! { + if let Some(parent) = get_parent_expr(cx, expr); + if let hir::ExprKind::MethodCall(_, ref span, _) = parent.node; + if span != &expr.span; + then { + return; + } + } + let mut applicability = Applicability::MachineApplicable; span_lint_and_sugg( cx, diff --git a/tests/ui/useful_asref.rs b/tests/ui/useful_asref.rs new file mode 100644 index 00000000000..d7e56af2590 --- /dev/null +++ b/tests/ui/useful_asref.rs @@ -0,0 +1,22 @@ +// Copyright 2014-2018 The Rust Project Developers. See the COPYRIGHT +// file at the top-level directory of this distribution. +// +// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or +// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license +// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your +// option. This file may not be copied, modified, or distributed +// except according to those terms. + +#![deny(clippy::useless_asref)] + +trait Trait { + fn as_ptr(&self); +} + +impl<'a> Trait for &'a [u8] { + fn as_ptr(&self) { + self.as_ref().as_ptr(); + } +} + +fn main() {} |