copy_on_clone - add machine applicability

clippy_lints/src/methods/mod.rs

@@ -2041,7 +2041,7 @@ fn lint_clone_on_copy(cx: &LateContext<'_, '_>, expr: &hir::Expr<'_>, arg: &hir:
         }
         span_lint_and_then(cx, CLONE_ON_COPY, expr.span, "using `clone` on a `Copy` type", |diag| {
             if let Some((text, snip)) = snip {
-                diag.span_suggestion(expr.span, text, snip, Applicability::Unspecified);
+                diag.span_suggestion(expr.span, text, snip, Applicability::MachineApplicable);
             }
         });
     }

tests/ui/clone_on_copy.fixed

@@ -0,0 +1,40 @@
+// run-rustfix
+
+#![allow(
+    unused,
+    clippy::redundant_clone,
+    clippy::deref_addrof,
+    clippy::no_effect,
+    clippy::unnecessary_operation
+)]
+
+use std::cell::RefCell;
+use std::rc::{self, Rc};
+use std::sync::{self, Arc};
+
+fn main() {}
+
+fn is_ascii(ch: char) -> bool {
+    ch.is_ascii()
+}
+
+fn clone_on_copy() {
+    42;
+
+    vec![1].clone(); // ok, not a Copy type
+    Some(vec![1]).clone(); // ok, not a Copy type
+    *(&42);
+
+    let rc = RefCell::new(0);
+    *rc.borrow();
+
+    // Issue #4348
+    let mut x = 43;
+    let _ = &x.clone(); // ok, getting a ref
+    'a'.clone().make_ascii_uppercase(); // ok, clone and then mutate
+    is_ascii('z');
+
+    // Issue #5436
+    let mut vec = Vec::new();
+    vec.push(42);
+}

tests/ui/clone_on_copy.rs

@@ -0,0 +1,40 @@
+// run-rustfix
+
+#![allow(
+    unused,
+    clippy::redundant_clone,
+    clippy::deref_addrof,
+    clippy::no_effect,
+    clippy::unnecessary_operation
+)]
+
+use std::cell::RefCell;
+use std::rc::{self, Rc};
+use std::sync::{self, Arc};
+
+fn main() {}
+
+fn is_ascii(ch: char) -> bool {
+    ch.is_ascii()
+}
+
+fn clone_on_copy() {
+    42.clone();
+
+    vec![1].clone(); // ok, not a Copy type
+    Some(vec![1]).clone(); // ok, not a Copy type
+    (&42).clone();
+
+    let rc = RefCell::new(0);
+    rc.borrow().clone();
+
+    // Issue #4348
+    let mut x = 43;
+    let _ = &x.clone(); // ok, getting a ref
+    'a'.clone().make_ascii_uppercase(); // ok, clone and then mutate
+    is_ascii('z'.clone());
+
+    // Issue #5436
+    let mut vec = Vec::new();
+    vec.push(42.clone());
+}

tests/ui/clone_on_copy.stderr

@@ -0,0 +1,34 @@
+error: using `clone` on a `Copy` type
+  --> $DIR/clone_on_copy.rs:22:5
+   |
+LL |     42.clone();
+   |     ^^^^^^^^^^ help: try removing the `clone` call: `42`
+   |
+   = note: `-D clippy::clone-on-copy` implied by `-D warnings`
+
+error: using `clone` on a `Copy` type
+  --> $DIR/clone_on_copy.rs:26:5
+   |
+LL |     (&42).clone();
+   |     ^^^^^^^^^^^^^ help: try dereferencing it: `*(&42)`
+
+error: using `clone` on a `Copy` type
+  --> $DIR/clone_on_copy.rs:29:5
+   |
+LL |     rc.borrow().clone();
+   |     ^^^^^^^^^^^^^^^^^^^ help: try dereferencing it: `*rc.borrow()`
+
+error: using `clone` on a `Copy` type
+  --> $DIR/clone_on_copy.rs:35:14
+   |
+LL |     is_ascii('z'.clone());
+   |              ^^^^^^^^^^^ help: try removing the `clone` call: `'z'`
+
+error: using `clone` on a `Copy` type
+  --> $DIR/clone_on_copy.rs:39:14
+   |
+LL |     vec.push(42.clone());
+   |              ^^^^^^^^^^ help: try removing the `clone` call: `42`
+
+error: aborting due to 5 previous errors
+

tests/ui/unnecessary_clone.rs

@@ -13,31 +13,6 @@ impl SomeTrait for SomeImpl {}
 
 fn main() {}
 
-fn is_ascii(ch: char) -> bool {
-    ch.is_ascii()
-}
-
-fn clone_on_copy() {
-    42.clone();
-
-    vec![1].clone(); // ok, not a Copy type
-    Some(vec![1]).clone(); // ok, not a Copy type
-    (&42).clone();
-
-    let rc = RefCell::new(0);
-    rc.borrow().clone();
-
-    // Issue #4348
-    let mut x = 43;
-    let _ = &x.clone(); // ok, getting a ref
-    'a'.clone().make_ascii_uppercase(); // ok, clone and then mutate
-    is_ascii('z'.clone());
-
-    // Issue #5436
-    let mut vec = Vec::new();
-    vec.push(42.clone());
-}
-
 fn clone_on_ref_ptr() {
     let rc = Rc::new(true);
     let arc = Arc::new(true);

tests/ui/unnecessary_clone.stderr

@@ -1,37 +1,5 @@
-error: using `clone` on a `Copy` type
-  --> $DIR/unnecessary_clone.rs:21:5
-   |
-LL |     42.clone();
-   |     ^^^^^^^^^^ help: try removing the `clone` call: `42`
-   |
-   = note: `-D clippy::clone-on-copy` implied by `-D warnings`
-
-error: using `clone` on a `Copy` type
-  --> $DIR/unnecessary_clone.rs:25:5
-   |
-LL |     (&42).clone();
-   |     ^^^^^^^^^^^^^ help: try dereferencing it: `*(&42)`
-
-error: using `clone` on a `Copy` type
-  --> $DIR/unnecessary_clone.rs:28:5
-   |
-LL |     rc.borrow().clone();
-   |     ^^^^^^^^^^^^^^^^^^^ help: try dereferencing it: `*rc.borrow()`
-
-error: using `clone` on a `Copy` type
-  --> $DIR/unnecessary_clone.rs:34:14
-   |
-LL |     is_ascii('z'.clone());
-   |              ^^^^^^^^^^^ help: try removing the `clone` call: `'z'`
-
-error: using `clone` on a `Copy` type
-  --> $DIR/unnecessary_clone.rs:38:14
-   |
-LL |     vec.push(42.clone());
-   |              ^^^^^^^^^^ help: try removing the `clone` call: `42`
-
 error: using `.clone()` on a ref-counted pointer
-  --> $DIR/unnecessary_clone.rs:48:5
+  --> $DIR/unnecessary_clone.rs:23:5
    |
 LL |     rc.clone();
    |     ^^^^^^^^^^ help: try this: `Rc::<bool>::clone(&rc)`
@@ -39,43 +7,45 @@ LL |     rc.clone();
    = note: `-D clippy::clone-on-ref-ptr` implied by `-D warnings`
 
 error: using `.clone()` on a ref-counted pointer
-  --> $DIR/unnecessary_clone.rs:51:5
+  --> $DIR/unnecessary_clone.rs:26:5
    |
 LL |     arc.clone();
    |     ^^^^^^^^^^^ help: try this: `Arc::<bool>::clone(&arc)`
 
 error: using `.clone()` on a ref-counted pointer
-  --> $DIR/unnecessary_clone.rs:54:5
+  --> $DIR/unnecessary_clone.rs:29:5
    |
 LL |     rcweak.clone();
    |     ^^^^^^^^^^^^^^ help: try this: `Weak::<bool>::clone(&rcweak)`
 
 error: using `.clone()` on a ref-counted pointer
-  --> $DIR/unnecessary_clone.rs:57:5
+  --> $DIR/unnecessary_clone.rs:32:5
    |
 LL |     arc_weak.clone();
    |     ^^^^^^^^^^^^^^^^ help: try this: `Weak::<bool>::clone(&arc_weak)`
 
 error: using `.clone()` on a ref-counted pointer
-  --> $DIR/unnecessary_clone.rs:61:33
+  --> $DIR/unnecessary_clone.rs:36:33
    |
 LL |     let _: Arc<dyn SomeTrait> = x.clone();
    |                                 ^^^^^^^^^ help: try this: `Arc::<SomeImpl>::clone(&x)`
 
 error: using `clone` on a `Copy` type
-  --> $DIR/unnecessary_clone.rs:65:5
+  --> $DIR/unnecessary_clone.rs:40:5
    |
 LL |     t.clone();
    |     ^^^^^^^^^ help: try removing the `clone` call: `t`
+   |
+   = note: `-D clippy::clone-on-copy` implied by `-D warnings`
 
 error: using `clone` on a `Copy` type
-  --> $DIR/unnecessary_clone.rs:67:5
+  --> $DIR/unnecessary_clone.rs:42:5
    |
 LL |     Some(t).clone();
    |     ^^^^^^^^^^^^^^^ help: try removing the `clone` call: `Some(t)`
 
 error: using `clone` on a double-reference; this will copy the reference instead of cloning the inner type
-  --> $DIR/unnecessary_clone.rs:73:22
+  --> $DIR/unnecessary_clone.rs:48:22
    |
 LL |     let z: &Vec<_> = y.clone();
    |                      ^^^^^^^^^
@@ -91,13 +61,13 @@ LL |     let z: &Vec<_> = <&std::vec::Vec<i32>>::clone(y);
    |                      ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
 error: using `clone` on a `Copy` type
-  --> $DIR/unnecessary_clone.rs:109:20
+  --> $DIR/unnecessary_clone.rs:84:20
    |
 LL |         let _: E = a.clone();
    |                    ^^^^^^^^^ help: try dereferencing it: `*****a`
 
 error: using `clone` on a double-reference; this will copy the reference instead of cloning the inner type
-  --> $DIR/unnecessary_clone.rs:114:22
+  --> $DIR/unnecessary_clone.rs:89:22
    |
 LL |         let _ = &mut encoded.clone();
    |                      ^^^^^^^^^^^^^^^
@@ -112,7 +82,7 @@ LL |         let _ = &mut <&[u8]>::clone(encoded);
    |                      ^^^^^^^^^^^^^^^^^^^^^^^
 
 error: using `clone` on a double-reference; this will copy the reference instead of cloning the inner type
-  --> $DIR/unnecessary_clone.rs:115:18
+  --> $DIR/unnecessary_clone.rs:90:18
    |
 LL |         let _ = &encoded.clone();
    |                  ^^^^^^^^^^^^^^^
@@ -126,5 +96,5 @@ help: or try being explicit if you are sure, that you want to clone a reference
 LL |         let _ = &<&[u8]>::clone(encoded);
    |                  ^^^^^^^^^^^^^^^^^^^^^^^
 
-error: aborting due to 16 previous errors
+error: aborting due to 11 previous errors