diff options
Diffstat (limited to '')
-rw-r--r-- | src/tools/clippy/clippy_lints/src/len_zero.rs | 26 |
1 files changed, 17 insertions, 9 deletions
diff --git a/src/tools/clippy/clippy_lints/src/len_zero.rs b/src/tools/clippy/clippy_lints/src/len_zero.rs index 4c133c06a..3c70c9cf1 100644 --- a/src/tools/clippy/clippy_lints/src/len_zero.rs +++ b/src/tools/clippy/clippy_lints/src/len_zero.rs @@ -1,13 +1,13 @@ use clippy_utils::diagnostics::{span_lint, span_lint_and_sugg, span_lint_and_then}; use clippy_utils::source::snippet_with_applicability; -use clippy_utils::{get_item_name, get_parent_as_impl, is_lint_allowed}; +use clippy_utils::{get_item_name, get_parent_as_impl, is_lint_allowed, peel_ref_operators}; use if_chain::if_chain; use rustc_ast::ast::LitKind; use rustc_errors::Applicability; use rustc_hir::def_id::DefIdSet; use rustc_hir::{ def_id::DefId, AssocItemKind, BinOpKind, Expr, ExprKind, FnRetTy, ImplItem, ImplItemKind, ImplicitSelfKind, Item, - ItemKind, Mutability, Node, TraitItemRef, TyKind, + ItemKind, Mutability, Node, TraitItemRef, TyKind, UnOp, }; use rustc_lint::{LateContext, LateLintPass}; use rustc_middle::ty::{self, AssocKind, FnSig, Ty}; @@ -16,6 +16,7 @@ use rustc_span::{ source_map::{Span, Spanned, Symbol}, symbol::sym, }; +use std::borrow::Cow; declare_clippy_lint! { /// ### What it does @@ -218,7 +219,7 @@ fn check_trait_items(cx: &LateContext<'_>, visited_trait: &Item<'_>, trait_items let is_empty = sym!(is_empty); let is_empty_method_found = current_and_super_traits - .iter() + .items() .flat_map(|&i| cx.tcx.associated_items(i).filter_by_name_unhygienic(is_empty)) .any(|i| { i.kind == ty::AssocKind::Fn @@ -360,7 +361,7 @@ fn check_for_is_empty<'tcx>( db.span_note(span, "`is_empty` defined here"); } if let Some(self_kind) = self_kind { - db.note(&output.expected_sig(self_kind)); + db.note(output.expected_sig(self_kind)); } }); } @@ -428,16 +429,23 @@ fn check_len( fn check_empty_expr(cx: &LateContext<'_>, span: Span, lit1: &Expr<'_>, lit2: &Expr<'_>, op: &str) { if (is_empty_array(lit2) || is_empty_string(lit2)) && has_is_empty(cx, lit1) { let mut applicability = Applicability::MachineApplicable; + + let lit1 = peel_ref_operators(cx, lit1); + let mut lit_str = snippet_with_applicability(cx, lit1.span, "_", &mut applicability); + + // Wrap the expression in parentheses if it's a deref expression. Otherwise operator precedence will + // cause the code to dereference boolean(won't compile). + if let ExprKind::Unary(UnOp::Deref, _) = lit1.kind { + lit_str = Cow::from(format!("({lit_str})")); + } + span_lint_and_sugg( cx, COMPARISON_TO_EMPTY, span, "comparison to empty slice", &format!("using `{op}is_empty` is clearer and more explicit"), - format!( - "{op}{}.is_empty()", - snippet_with_applicability(cx, lit1.span, "_", &mut applicability) - ), + format!("{op}{lit_str}.is_empty()"), applicability, ); } @@ -493,7 +501,7 @@ fn has_is_empty(cx: &LateContext<'_>, expr: &Expr<'_>) -> bool { .filter_by_name_unhygienic(is_empty) .any(|item| is_is_empty(cx, item)) }), - ty::Projection(ref proj) => has_is_empty_impl(cx, proj.item_def_id), + ty::Alias(ty::Projection, ref proj) => has_is_empty_impl(cx, proj.def_id), ty::Adt(id, _) => has_is_empty_impl(cx, id.did()), ty::Array(..) | ty::Slice(..) | ty::Str => true, _ => false, |