Lint explicit_auto_deref in implicit return positions for closures

tests/ui/explicit_auto_deref.fixed

@@ -257,13 +257,13 @@ fn main() {
     let x = S7([0]);
     let _: &[u32] = &*x;
 
-    let c1 = |x: &Vec<&u32>| {};
+    let c1 = |_: &Vec<&u32>| {};
     let x = &&vec![&1u32];
     c1(x);
     let _ = for<'a, 'b> |x: &'a &'a Vec<&'b u32>, b: bool| -> &'a Vec<&'b u32> {
         if b {
             return x;
         }
-        *x
+        x
     };
 }

tests/ui/explicit_auto_deref.rs

@@ -257,7 +257,7 @@ fn main() {
     let x = S7([0]);
     let _: &[u32] = &*x;
 
-    let c1 = |x: &Vec<&u32>| {};
+    let c1 = |_: &Vec<&u32>| {};
     let x = &&vec![&1u32];
     c1(*x);
     let _ = for<'a, 'b> |x: &'a &'a Vec<&'b u32>, b: bool| -> &'a Vec<&'b u32> {

tests/ui/explicit_auto_deref.stderr

@@ -228,5 +228,11 @@ error: deref which would be done by auto-deref
 LL |             return *x;
    |                    ^^ help: try this: `x`
 
-error: aborting due to 38 previous errors
+error: deref which would be done by auto-deref
+  --> $DIR/explicit_auto_deref.rs:267:9
+   |
+LL |         *x
+   |         ^^ help: try this: `x`
+
+error: aborting due to 39 previous errors