diff --git a/clippy_lints/src/map_clone.rs b/clippy_lints/src/map_clone.rs index 4a3092640962..1a9334ae4889 100644 --- a/clippy_lints/src/map_clone.rs +++ b/clippy_lints/src/map_clone.rs @@ -1,6 +1,6 @@ use crate::utils::paths; use crate::utils::{ - in_macro, match_trait_method, match_type, remove_blocks, snippet_with_applicability, span_lint_and_sugg, + in_macro, is_copy, match_trait_method, match_type, remove_blocks, snippet_with_applicability, span_lint_and_sugg, }; use if_chain::if_chain; use rustc::hir; @@ -63,7 +63,8 @@ impl<'a, 'tcx> LateLintPass<'a, 'tcx> for Pass { if args.len() == 2; if method.ident.as_str() == "map"; let ty = cx.tables.expr_ty(&args[0]); - if match_type(cx, ty, &paths::OPTION) || match_trait_method(cx, e, &paths::ITERATOR); + let is_option = match_type(cx, ty, &paths::OPTION); + if is_option || match_trait_method(cx, e, &paths::ITERATOR); if let hir::ExprKind::Closure(_, _, body_id, _, _) = args[1].node; let closure_body = cx.tcx.hir().body(body_id); let closure_expr = remove_blocks(&closure_body.value); @@ -73,14 +74,16 @@ impl<'a, 'tcx> LateLintPass<'a, 'tcx> for Pass { hir::BindingAnnotation::Unannotated, .., name, None ) = inner.node { if ident_eq(name, closure_expr) { - lint(cx, e.span, args[0].span); + // FIXME When Iterator::copied() stabilizes we can remove is_option + // from here and the other lint() calls + lint(cx, e.span, args[0].span, is_option); } }, hir::PatKind::Binding(hir::BindingAnnotation::Unannotated, .., name, None) => { match closure_expr.node { hir::ExprKind::Unary(hir::UnOp::UnDeref, ref inner) => { if ident_eq(name, inner) && !cx.tables.expr_ty(inner).is_box() { - lint(cx, e.span, args[0].span); + lint(cx, e.span, args[0].span, is_option); } }, hir::ExprKind::MethodCall(ref method, _, ref obj) => { @@ -88,8 +91,9 @@ impl<'a, 'tcx> LateLintPass<'a, 'tcx> for Pass { && match_trait_method(cx, closure_expr, &paths::CLONE_TRAIT) { let obj_ty = cx.tables.expr_ty(&obj[0]); - if let ty::Ref(..) = obj_ty.sty { - lint(cx, e.span, args[0].span); + if let ty::Ref(_, ty, _) = obj_ty.sty { + let copy = is_copy(cx, ty); + lint(cx, e.span, args[0].span, is_option && copy); } else { lint_needless_cloning(cx, e.span, args[0].span); } @@ -125,18 +129,33 @@ fn lint_needless_cloning(cx: &LateContext<'_, '_>, root: Span, receiver: Span) { ) } -fn lint(cx: &LateContext<'_, '_>, replace: Span, root: Span) { +fn lint(cx: &LateContext<'_, '_>, replace: Span, root: Span, copied: bool) { let mut applicability = Applicability::MachineApplicable; - span_lint_and_sugg( - cx, - MAP_CLONE, - replace, - "You are using an explicit closure for cloning elements", - "Consider calling the dedicated `cloned` method", - format!( - "{}.cloned()", - snippet_with_applicability(cx, root, "..", &mut applicability) - ), - applicability, - ) + if copied { + span_lint_and_sugg( + cx, + MAP_CLONE, + replace, + "You are using an explicit closure for copying elements", + "Consider calling the dedicated `copied` method", + format!( + "{}.copied()", + snippet_with_applicability(cx, root, "..", &mut applicability) + ), + applicability, + ) + } else { + span_lint_and_sugg( + cx, + MAP_CLONE, + replace, + "You are using an explicit closure for cloning elements", + "Consider calling the dedicated `cloned` method", + format!( + "{}.cloned()", + snippet_with_applicability(cx, root, "..", &mut applicability) + ), + applicability, + ) + } } diff --git a/tests/ui/map_clone.fixed b/tests/ui/map_clone.fixed index d804e838d5a6..7ba4ac7d5a38 100644 --- a/tests/ui/map_clone.fixed +++ b/tests/ui/map_clone.fixed @@ -10,6 +10,8 @@ fn main() { let _: Vec = vec![String::new()].iter().cloned().collect(); let _: Vec = vec![42, 43].iter().cloned().collect(); let _: Option = Some(Box::new(16)).map(|b| *b); + let _: Option = Some(&16).copied(); + let _: Option = Some(&1).copied(); // Don't lint these let v = vec![5_i8; 6]; diff --git a/tests/ui/map_clone.rs b/tests/ui/map_clone.rs index d98cd939d8cc..9a7be3da2067 100644 --- a/tests/ui/map_clone.rs +++ b/tests/ui/map_clone.rs @@ -10,6 +10,8 @@ fn main() { let _: Vec = vec![String::new()].iter().map(|x| x.clone()).collect(); let _: Vec = vec![42, 43].iter().map(|&x| x).collect(); let _: Option = Some(Box::new(16)).map(|b| *b); + let _: Option = Some(&16).map(|b| *b); + let _: Option = Some(&1).map(|x| x.clone()); // Don't lint these let v = vec![5_i8; 6]; diff --git a/tests/ui/map_clone.stderr b/tests/ui/map_clone.stderr index db7fa4f52fce..fb0c636d3ba0 100644 --- a/tests/ui/map_clone.stderr +++ b/tests/ui/map_clone.stderr @@ -18,11 +18,23 @@ error: You are using an explicit closure for cloning elements LL | let _: Vec = vec![42, 43].iter().map(|&x| x).collect(); | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: Consider calling the dedicated `cloned` method: `vec![42, 43].iter().cloned()` +error: You are using an explicit closure for copying elements + --> $DIR/map_clone.rs:13:26 + | +LL | let _: Option = Some(&16).map(|b| *b); + | ^^^^^^^^^^^^^^^^^^^^^ help: Consider calling the dedicated `copied` method: `Some(&16).copied()` + +error: You are using an explicit closure for copying elements + --> $DIR/map_clone.rs:14:25 + | +LL | let _: Option = Some(&1).map(|x| x.clone()); + | ^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: Consider calling the dedicated `copied` method: `Some(&1).copied()` + error: You are needlessly cloning iterator elements - --> $DIR/map_clone.rs:23:29 + --> $DIR/map_clone.rs:25:29 | LL | let _ = std::env::args().map(|v| v.clone()); | ^^^^^^^^^^^^^^^^^^^ help: Remove the map call -error: aborting due to 4 previous errors +error: aborting due to 6 previous errors