Auto merge of #5120 - JohnTitor:split-up-drop-forget-ref, r=flip1995

Split up `drop_forget_ref` ui test

Part of #2038

changelog: none

Author: bors

tests/ui/drop_forget_ref.stderr

@@ -1,37 +1,27 @@
-#![warn(clippy::drop_ref, clippy::forget_ref)]
-#![allow(clippy::toplevel_ref_arg, clippy::similar_names, clippy::needless_pass_by_value)]
+#![warn(clippy::drop_ref)]
+#![allow(clippy::toplevel_ref_arg)]
 
-use std::mem::{drop, forget};
+use std::mem::drop;
 
 struct SomeStruct;
 
 fn main() {
     drop(&SomeStruct);
-    forget(&SomeStruct);
 
     let mut owned1 = SomeStruct;
     drop(&owned1);
     drop(&&owned1);
     drop(&mut owned1);
     drop(owned1); //OK
-    let mut owned2 = SomeStruct;
-    forget(&owned2);
-    forget(&&owned2);
-    forget(&mut owned2);
-    forget(owned2); //OK
 
     let reference1 = &SomeStruct;
     drop(reference1);
-    forget(&*reference1);
 
     let reference2 = &mut SomeStruct;
     drop(reference2);
-    let reference3 = &mut SomeStruct;
-    forget(reference3);
 
-    let ref reference4 = SomeStruct;
-    drop(reference4);
-    forget(reference4);
+    let ref reference3 = SomeStruct;
+    drop(reference3);
 }
 
 #[allow(dead_code)]
@@ -40,20 +30,11 @@ fn test_generic_fn_drop<T>(val: T) {
     drop(val); //OK
 }
 
-#[allow(dead_code)]
-fn test_generic_fn_forget<T>(val: T) {
-    forget(&val);
-    forget(val); //OK
-}
-
 #[allow(dead_code)]
 fn test_similarly_named_function() {
     fn drop<T>(_val: T) {}
     drop(&SomeStruct); //OK; call to unrelated function which happens to have the same name
     std::mem::drop(&SomeStruct);
-    fn forget<T>(_val: T) {}
-    forget(&SomeStruct); //OK; call to unrelated function which happens to have the same name
-    std::mem::forget(&SomeStruct);
 }
 
 #[derive(Copy, Clone)]

tests/ui/drop_forget_ref.rs tests/ui/drop_ref.rs

@@ -0,0 +1,111 @@
+error: calls to `std::mem::drop` with a reference instead of an owned value. Dropping a reference does nothing.
+  --> $DIR/drop_ref.rs:9:5
+   |
+LL |     drop(&SomeStruct);
+   |     ^^^^^^^^^^^^^^^^^
+   |
+   = note: `-D clippy::drop-ref` implied by `-D warnings`
+note: argument has type `&SomeStruct`
+  --> $DIR/drop_ref.rs:9:10
+   |
+LL |     drop(&SomeStruct);
+   |          ^^^^^^^^^^^
+
+error: calls to `std::mem::drop` with a reference instead of an owned value. Dropping a reference does nothing.
+  --> $DIR/drop_ref.rs:12:5
+   |
+LL |     drop(&owned1);
+   |     ^^^^^^^^^^^^^
+   |
+note: argument has type `&SomeStruct`
+  --> $DIR/drop_ref.rs:12:10
+   |
+LL |     drop(&owned1);
+   |          ^^^^^^^
+
+error: calls to `std::mem::drop` with a reference instead of an owned value. Dropping a reference does nothing.
+  --> $DIR/drop_ref.rs:13:5
+   |
+LL |     drop(&&owned1);
+   |     ^^^^^^^^^^^^^^
+   |
+note: argument has type `&&SomeStruct`
+  --> $DIR/drop_ref.rs:13:10
+   |
+LL |     drop(&&owned1);
+   |          ^^^^^^^^
+
+error: calls to `std::mem::drop` with a reference instead of an owned value. Dropping a reference does nothing.
+  --> $DIR/drop_ref.rs:14:5
+   |
+LL |     drop(&mut owned1);
+   |     ^^^^^^^^^^^^^^^^^
+   |
+note: argument has type `&mut SomeStruct`
+  --> $DIR/drop_ref.rs:14:10
+   |
+LL |     drop(&mut owned1);
+   |          ^^^^^^^^^^^
+
+error: calls to `std::mem::drop` with a reference instead of an owned value. Dropping a reference does nothing.
+  --> $DIR/drop_ref.rs:18:5
+   |
+LL |     drop(reference1);
+   |     ^^^^^^^^^^^^^^^^
+   |
+note: argument has type `&SomeStruct`
+  --> $DIR/drop_ref.rs:18:10
+   |
+LL |     drop(reference1);
+   |          ^^^^^^^^^^
+
+error: calls to `std::mem::drop` with a reference instead of an owned value. Dropping a reference does nothing.
+  --> $DIR/drop_ref.rs:21:5
+   |
+LL |     drop(reference2);
+   |     ^^^^^^^^^^^^^^^^
+   |
+note: argument has type `&mut SomeStruct`
+  --> $DIR/drop_ref.rs:21:10
+   |
+LL |     drop(reference2);
+   |          ^^^^^^^^^^
+
+error: calls to `std::mem::drop` with a reference instead of an owned value. Dropping a reference does nothing.
+  --> $DIR/drop_ref.rs:24:5
+   |
+LL |     drop(reference3);
+   |     ^^^^^^^^^^^^^^^^
+   |
+note: argument has type `&SomeStruct`
+  --> $DIR/drop_ref.rs:24:10
+   |
+LL |     drop(reference3);
+   |          ^^^^^^^^^^
+
+error: calls to `std::mem::drop` with a reference instead of an owned value. Dropping a reference does nothing.
+  --> $DIR/drop_ref.rs:29:5
+   |
+LL |     drop(&val);
+   |     ^^^^^^^^^^
+   |
+note: argument has type `&T`
+  --> $DIR/drop_ref.rs:29:10
+   |
+LL |     drop(&val);
+   |          ^^^^
+
+error: calls to `std::mem::drop` with a reference instead of an owned value. Dropping a reference does nothing.
+  --> $DIR/drop_ref.rs:37:5
+   |
+LL |     std::mem::drop(&SomeStruct);
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+note: argument has type `&SomeStruct`
+  --> $DIR/drop_ref.rs:37:20
+   |
+LL |     std::mem::drop(&SomeStruct);
+   |                    ^^^^^^^^^^^
+
+error: aborting due to 9 previous errors
+