diff options
Diffstat (limited to 'src/tools/clippy/clippy_lints/src/map_clone.rs')
| -rw-r--r-- | src/tools/clippy/clippy_lints/src/map_clone.rs | 167 |
1 files changed, 0 insertions, 167 deletions
diff --git a/src/tools/clippy/clippy_lints/src/map_clone.rs b/src/tools/clippy/clippy_lints/src/map_clone.rs deleted file mode 100644 index 95c312f1f..000000000 --- a/src/tools/clippy/clippy_lints/src/map_clone.rs +++ /dev/null @@ -1,167 +0,0 @@ -use clippy_utils::diagnostics::span_lint_and_sugg; -use clippy_utils::source::snippet_with_applicability; -use clippy_utils::ty::{is_copy, is_type_diagnostic_item}; -use clippy_utils::{is_trait_method, meets_msrv, msrvs, peel_blocks}; -use if_chain::if_chain; -use rustc_errors::Applicability; -use rustc_hir as hir; -use rustc_lint::{LateContext, LateLintPass}; -use rustc_middle::mir::Mutability; -use rustc_middle::ty; -use rustc_middle::ty::adjustment::Adjust; -use rustc_semver::RustcVersion; -use rustc_session::{declare_tool_lint, impl_lint_pass}; -use rustc_span::symbol::Ident; -use rustc_span::{sym, Span}; - -declare_clippy_lint! { - /// ### What it does - /// Checks for usage of `map(|x| x.clone())` or - /// dereferencing closures for `Copy` types, on `Iterator` or `Option`, - /// and suggests `cloned()` or `copied()` instead - /// - /// ### Why is this bad? - /// Readability, this can be written more concisely - /// - /// ### Example - /// ```rust - /// let x = vec![42, 43]; - /// let y = x.iter(); - /// let z = y.map(|i| *i); - /// ``` - /// - /// The correct use would be: - /// - /// ```rust - /// let x = vec![42, 43]; - /// let y = x.iter(); - /// let z = y.cloned(); - /// ``` - #[clippy::version = "pre 1.29.0"] - pub MAP_CLONE, - style, - "using `iterator.map(|x| x.clone())`, or dereferencing closures for `Copy` types" -} - -pub struct MapClone { - msrv: Option<RustcVersion>, -} - -impl_lint_pass!(MapClone => [MAP_CLONE]); - -impl MapClone { - pub fn new(msrv: Option<RustcVersion>) -> Self { - Self { msrv } - } -} - -impl<'tcx> LateLintPass<'tcx> for MapClone { - fn check_expr(&mut self, cx: &LateContext<'_>, e: &hir::Expr<'_>) { - if e.span.from_expansion() { - return; - } - - if_chain! { - if let hir::ExprKind::MethodCall(method, args, _) = e.kind; - if args.len() == 2; - if method.ident.name == sym::map; - let ty = cx.typeck_results().expr_ty(&args[0]); - if is_type_diagnostic_item(cx, ty, sym::Option) || is_trait_method(cx, e, sym::Iterator); - if let hir::ExprKind::Closure(&hir::Closure { body, .. }) = args[1].kind; - then { - let closure_body = cx.tcx.hir().body(body); - let closure_expr = peel_blocks(&closure_body.value); - match closure_body.params[0].pat.kind { - hir::PatKind::Ref(inner, hir::Mutability::Not) => if let hir::PatKind::Binding( - hir::BindingAnnotation::Unannotated, .., name, None - ) = inner.kind { - if ident_eq(name, closure_expr) { - self.lint_explicit_closure(cx, e.span, args[0].span, true); - } - }, - hir::PatKind::Binding(hir::BindingAnnotation::Unannotated, .., name, None) => { - match closure_expr.kind { - hir::ExprKind::Unary(hir::UnOp::Deref, inner) => { - if ident_eq(name, inner) { - if let ty::Ref(.., Mutability::Not) = cx.typeck_results().expr_ty(inner).kind() { - self.lint_explicit_closure(cx, e.span, args[0].span, true); - } - } - }, - hir::ExprKind::MethodCall(method, [obj], _) => if_chain! { - if ident_eq(name, obj) && method.ident.name == sym::clone; - if let Some(fn_id) = cx.typeck_results().type_dependent_def_id(closure_expr.hir_id); - if let Some(trait_id) = cx.tcx.trait_of_item(fn_id); - if cx.tcx.lang_items().clone_trait().map_or(false, |id| id == trait_id); - // no autoderefs - if !cx.typeck_results().expr_adjustments(obj).iter() - .any(|a| matches!(a.kind, Adjust::Deref(Some(..)))); - then { - let obj_ty = cx.typeck_results().expr_ty(obj); - if let ty::Ref(_, ty, mutability) = obj_ty.kind() { - if matches!(mutability, Mutability::Not) { - let copy = is_copy(cx, *ty); - self.lint_explicit_closure(cx, e.span, args[0].span, copy); - } - } else { - lint_needless_cloning(cx, e.span, args[0].span); - } - } - }, - _ => {}, - } - }, - _ => {}, - } - } - } - } - - extract_msrv_attr!(LateContext); -} - -fn ident_eq(name: Ident, path: &hir::Expr<'_>) -> bool { - if let hir::ExprKind::Path(hir::QPath::Resolved(None, path)) = path.kind { - path.segments.len() == 1 && path.segments[0].ident == name - } else { - false - } -} - -fn lint_needless_cloning(cx: &LateContext<'_>, root: Span, receiver: Span) { - span_lint_and_sugg( - cx, - MAP_CLONE, - root.trim_start(receiver).unwrap(), - "you are needlessly cloning iterator elements", - "remove the `map` call", - String::new(), - Applicability::MachineApplicable, - ); -} - -impl MapClone { - fn lint_explicit_closure(&self, cx: &LateContext<'_>, replace: Span, root: Span, is_copy: bool) { - let mut applicability = Applicability::MachineApplicable; - - let (message, sugg_method) = if is_copy && meets_msrv(self.msrv, msrvs::ITERATOR_COPIED) { - ("you are using an explicit closure for copying elements", "copied") - } else { - ("you are using an explicit closure for cloning elements", "cloned") - }; - - span_lint_and_sugg( - cx, - MAP_CLONE, - replace, - message, - &format!("consider calling the dedicated `{}` method", sugg_method), - format!( - "{}.{}()", - snippet_with_applicability(cx, root, "..", &mut applicability), - sugg_method, - ), - applicability, - ); - } -} |