From d2f7ae70ae07f039321b35a1f9f48585e8ddc9bd Mon Sep 17 00:00:00 2001 From: Manish Goregaokar Date: Mon, 15 Apr 2019 14:32:39 -0700 Subject: [PATCH 1/3] Suggest .copied() instead of .cloned() in map_clone when dealing with references --- clippy_lints/src/map_clone.rs | 47 +++++++++++++++++++++++------------ tests/ui/map_clone.fixed | 5 ++-- tests/ui/map_clone.rs | 1 + tests/ui/map_clone.stderr | 16 ++++++------ 4 files changed, 43 insertions(+), 26 deletions(-) diff --git a/clippy_lints/src/map_clone.rs b/clippy_lints/src/map_clone.rs index 4a3092640962..27b5a2968b8e 100644 --- a/clippy_lints/src/map_clone.rs +++ b/clippy_lints/src/map_clone.rs @@ -73,14 +73,14 @@ 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); + lint(cx, e.span, args[0].span, true); } }, 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, true); } }, hir::ExprKind::MethodCall(ref method, _, ref obj) => { @@ -89,7 +89,7 @@ impl<'a, 'tcx> LateLintPass<'a, 'tcx> for Pass { let obj_ty = cx.tables.expr_ty(&obj[0]); if let ty::Ref(..) = obj_ty.sty { - lint(cx, e.span, args[0].span); + lint(cx, e.span, args[0].span, false); } else { lint_needless_cloning(cx, e.span, args[0].span); } @@ -125,18 +125,33 @@ 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..14d456b14337 100644 --- a/tests/ui/map_clone.fixed +++ b/tests/ui/map_clone.fixed @@ -4,11 +4,12 @@ #![allow(clippy::clone_on_copy)] #![allow(clippy::missing_docs_in_private_items)] #![allow(clippy::redundant_closure)] +#![feature(iter_copied)] fn main() { - let _: Vec = vec![5_i8; 6].iter().cloned().collect(); + let _: Vec = vec![5_i8; 6].iter().copied().collect(); let _: Vec = vec![String::new()].iter().cloned().collect(); - let _: Vec = vec![42, 43].iter().cloned().collect(); + let _: Vec = vec![42, 43].iter().copied().collect(); let _: Option = Some(Box::new(16)).map(|b| *b); // Don't lint these diff --git a/tests/ui/map_clone.rs b/tests/ui/map_clone.rs index d98cd939d8cc..a0160662ed4f 100644 --- a/tests/ui/map_clone.rs +++ b/tests/ui/map_clone.rs @@ -4,6 +4,7 @@ #![allow(clippy::clone_on_copy)] #![allow(clippy::missing_docs_in_private_items)] #![allow(clippy::redundant_closure)] +#![feature(iter_copied)] fn main() { let _: Vec = vec![5_i8; 6].iter().map(|x| *x).collect(); diff --git a/tests/ui/map_clone.stderr b/tests/ui/map_clone.stderr index db7fa4f52fce..8fe7f05f99f0 100644 --- a/tests/ui/map_clone.stderr +++ b/tests/ui/map_clone.stderr @@ -1,25 +1,25 @@ -error: You are using an explicit closure for cloning elements - --> $DIR/map_clone.rs:9:22 +error: You are using an explicit closure for copying elements + --> $DIR/map_clone.rs:10:22 | LL | let _: Vec = vec![5_i8; 6].iter().map(|x| *x).collect(); - | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: Consider calling the dedicated `cloned` method: `vec![5_i8; 6].iter().cloned()` + | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: Consider calling the dedicated `copied` method: `vec![5_i8; 6].iter().copied()` | = note: `-D clippy::map-clone` implied by `-D warnings` error: You are using an explicit closure for cloning elements - --> $DIR/map_clone.rs:10:26 + --> $DIR/map_clone.rs:11:26 | LL | let _: Vec = vec![String::new()].iter().map(|x| x.clone()).collect(); | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: Consider calling the dedicated `cloned` method: `vec![String::new()].iter().cloned()` -error: You are using an explicit closure for cloning elements - --> $DIR/map_clone.rs:11:23 +error: You are using an explicit closure for copying elements + --> $DIR/map_clone.rs:12:23 | LL | let _: Vec = vec![42, 43].iter().map(|&x| x).collect(); - | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: Consider calling the dedicated `cloned` method: `vec![42, 43].iter().cloned()` + | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: Consider calling the dedicated `copied` method: `vec![42, 43].iter().copied()` error: You are needlessly cloning iterator elements - --> $DIR/map_clone.rs:23:29 + --> $DIR/map_clone.rs:24:29 | LL | let _ = std::env::args().map(|v| v.clone()); | ^^^^^^^^^^^^^^^^^^^ help: Remove the map call From ad2c65bd1bd15b6a941a8d697fd0297e7557d927 Mon Sep 17 00:00:00 2001 From: Manish Goregaokar Date: Mon, 15 Apr 2019 14:39:41 -0700 Subject: [PATCH 2/3] Also suggest .copied() when .clone() is called on a Copy type --- clippy_lints/src/map_clone.rs | 7 ++++--- tests/ui/map_clone.fixed | 1 + tests/ui/map_clone.rs | 1 + tests/ui/map_clone.stderr | 10 ++++++++-- 4 files changed, 14 insertions(+), 5 deletions(-) diff --git a/clippy_lints/src/map_clone.rs b/clippy_lints/src/map_clone.rs index 27b5a2968b8e..cb504e651e47 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, match_trait_method, match_type, remove_blocks, snippet_with_applicability, span_lint_and_sugg, is_copy }; use if_chain::if_chain; use rustc::hir; @@ -88,8 +88,9 @@ 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, false); + if let ty::Ref(_, ty, _) = obj_ty.sty { + let copy = is_copy(cx, ty); + lint(cx, e.span, args[0].span, copy); } else { lint_needless_cloning(cx, e.span, args[0].span); } diff --git a/tests/ui/map_clone.fixed b/tests/ui/map_clone.fixed index 14d456b14337..4991f010547b 100644 --- a/tests/ui/map_clone.fixed +++ b/tests/ui/map_clone.fixed @@ -11,6 +11,7 @@ fn main() { let _: Vec = vec![String::new()].iter().cloned().collect(); let _: Vec = vec![42, 43].iter().copied().collect(); let _: Option = Some(Box::new(16)).map(|b| *b); + let _: Vec = vec![1; 6].iter().copied().collect(); // 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 a0160662ed4f..1f18fcf6398c 100644 --- a/tests/ui/map_clone.rs +++ b/tests/ui/map_clone.rs @@ -11,6 +11,7 @@ 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 _: Vec = vec![1; 6].iter().map(|x| x.clone()).collect(); // 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 8fe7f05f99f0..b1a165a42532 100644 --- a/tests/ui/map_clone.stderr +++ b/tests/ui/map_clone.stderr @@ -18,11 +18,17 @@ error: You are using an explicit closure for copying elements LL | let _: Vec = vec![42, 43].iter().map(|&x| x).collect(); | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: Consider calling the dedicated `copied` method: `vec![42, 43].iter().copied()` +error: You are using an explicit closure for copying elements + --> $DIR/map_clone.rs:14:22 + | +LL | let _: Vec = vec![1; 6].iter().map(|x| x.clone()).collect(); + | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: Consider calling the dedicated `copied` method: `vec![1; 6].iter().copied()` + error: You are needlessly cloning iterator elements - --> $DIR/map_clone.rs:24:29 + --> $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 5 previous errors From e9cde416ba14f97feb8d2fa6a47eb91164369347 Mon Sep 17 00:00:00 2001 From: Manish Goregaokar Date: Mon, 15 Apr 2019 14:48:45 -0700 Subject: [PATCH 3/3] Only suggest .copied() for Option right now --- clippy_lints/src/map_clone.rs | 13 ++++++++----- tests/ui/map_clone.fixed | 8 ++++---- tests/ui/map_clone.rs | 4 ++-- tests/ui/map_clone.stderr | 28 +++++++++++++++++----------- 4 files changed, 31 insertions(+), 22 deletions(-) diff --git a/clippy_lints/src/map_clone.rs b/clippy_lints/src/map_clone.rs index cb504e651e47..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, is_copy + 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, true); + // 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, true); + lint(cx, e.span, args[0].span, is_option); } }, hir::ExprKind::MethodCall(ref method, _, ref obj) => { @@ -90,7 +93,7 @@ impl<'a, 'tcx> LateLintPass<'a, 'tcx> for Pass { let obj_ty = cx.tables.expr_ty(&obj[0]); if let ty::Ref(_, ty, _) = obj_ty.sty { let copy = is_copy(cx, ty); - lint(cx, e.span, args[0].span, copy); + lint(cx, e.span, args[0].span, is_option && copy); } else { lint_needless_cloning(cx, e.span, args[0].span); } diff --git a/tests/ui/map_clone.fixed b/tests/ui/map_clone.fixed index 4991f010547b..7ba4ac7d5a38 100644 --- a/tests/ui/map_clone.fixed +++ b/tests/ui/map_clone.fixed @@ -4,14 +4,14 @@ #![allow(clippy::clone_on_copy)] #![allow(clippy::missing_docs_in_private_items)] #![allow(clippy::redundant_closure)] -#![feature(iter_copied)] fn main() { - let _: Vec = vec![5_i8; 6].iter().copied().collect(); + let _: Vec = vec![5_i8; 6].iter().cloned().collect(); let _: Vec = vec![String::new()].iter().cloned().collect(); - let _: Vec = vec![42, 43].iter().copied().collect(); + let _: Vec = vec![42, 43].iter().cloned().collect(); let _: Option = Some(Box::new(16)).map(|b| *b); - let _: Vec = vec![1; 6].iter().copied().collect(); + 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 1f18fcf6398c..9a7be3da2067 100644 --- a/tests/ui/map_clone.rs +++ b/tests/ui/map_clone.rs @@ -4,14 +4,14 @@ #![allow(clippy::clone_on_copy)] #![allow(clippy::missing_docs_in_private_items)] #![allow(clippy::redundant_closure)] -#![feature(iter_copied)] fn main() { let _: Vec = vec![5_i8; 6].iter().map(|x| *x).collect(); 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 _: Vec = vec![1; 6].iter().map(|x| x.clone()).collect(); + 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 b1a165a42532..fb0c636d3ba0 100644 --- a/tests/ui/map_clone.stderr +++ b/tests/ui/map_clone.stderr @@ -1,28 +1,34 @@ -error: You are using an explicit closure for copying elements - --> $DIR/map_clone.rs:10:22 +error: You are using an explicit closure for cloning elements + --> $DIR/map_clone.rs:9:22 | LL | let _: Vec = vec![5_i8; 6].iter().map(|x| *x).collect(); - | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: Consider calling the dedicated `copied` method: `vec![5_i8; 6].iter().copied()` + | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: Consider calling the dedicated `cloned` method: `vec![5_i8; 6].iter().cloned()` | = note: `-D clippy::map-clone` implied by `-D warnings` error: You are using an explicit closure for cloning elements - --> $DIR/map_clone.rs:11:26 + --> $DIR/map_clone.rs:10:26 | LL | let _: Vec = vec![String::new()].iter().map(|x| x.clone()).collect(); | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: Consider calling the dedicated `cloned` method: `vec![String::new()].iter().cloned()` -error: You are using an explicit closure for copying elements - --> $DIR/map_clone.rs:12:23 +error: You are using an explicit closure for cloning elements + --> $DIR/map_clone.rs:11:23 | LL | let _: Vec = vec![42, 43].iter().map(|&x| x).collect(); - | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: Consider calling the dedicated `copied` method: `vec![42, 43].iter().copied()` + | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ 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:14:22 + --> $DIR/map_clone.rs:14:25 | -LL | let _: Vec = vec![1; 6].iter().map(|x| x.clone()).collect(); - | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: Consider calling the dedicated `copied` method: `vec![1; 6].iter().copied()` +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:25:29 @@ -30,5 +36,5 @@ error: You are needlessly cloning iterator elements LL | let _ = std::env::args().map(|v| v.clone()); | ^^^^^^^^^^^^^^^^^^^ help: Remove the map call -error: aborting due to 5 previous errors +error: aborting due to 6 previous errors