Only suggest .copied() for Option right now

Manishearth · Manishearth · commit 38b3bf17f140 · 2019-04-15T14:54:04.000-07:00
diff --git a/clippy_lints/src/map_clone.rs b/clippy_lints/src/map_clone.rs
@@ -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
@@ -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<i8> = vec![5_i8; 6].iter().copied().collect();
+    let _: Vec<i8> = vec![5_i8; 6].iter().cloned().collect();
     let _: Vec<String> = vec![String::new()].iter().cloned().collect();
-    let _: Vec<u32> = vec![42, 43].iter().copied().collect();
+    let _: Vec<u32> = vec![42, 43].iter().cloned().collect();
     let _: Option<u64> = Some(Box::new(16)).map(|b| *b);
-    let _: Vec<u8> = vec![1; 6].iter().copied().collect();
+    let _: Option<u64> = Some(&16).copied();
+    let _: Option<u8> = 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
@@ -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<i8> = vec![5_i8; 6].iter().map(|x| *x).collect();
     let _: Vec<String> = vec![String::new()].iter().map(|x| x.clone()).collect();
     let _: Vec<u32> = vec![42, 43].iter().map(|&x| x).collect();
     let _: Option<u64> = Some(Box::new(16)).map(|b| *b);
-    let _: Vec<u8> = vec![1; 6].iter().map(|x| x.clone()).collect();
+    let _: Option<u64> = Some(&16).map(|b| *b);
+    let _: Option<u8> = 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
@@ -1,34 +1,40 @@
-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<i8> = 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<String> = 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<u32> = 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<u64> = 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<u8> = vec![1; 6].iter().map(|x| x.clone()).collect();
-   |                      ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: Consider calling the dedicated `copied` method: `vec![1; 6].iter().copied()`
+LL |     let _: Option<u8> = 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
    |
 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
 
