Add test case from rust-lang#10488

Author: schubart

tests/ui/collection_is_never_read.rs

@@ -84,12 +84,18 @@ fn shadowing_2() {
 }
 
 #[allow(clippy::let_unit_value)]
-fn fake_read() {
+fn fake_read_1() {
     let mut x = vec![1, 2, 3]; // WARNING
     x.reverse();
     let _: () = x.clear();
 }
 
+fn fake_read_2() {
+    let mut x = vec![1, 2, 3]; // WARNING
+    x.reverse();
+    println!("{:?}", x.push(5));
+}
+
 fn assignment() {
     let mut x = vec![1, 2, 3]; // WARNING
     let y = vec![4, 5, 6]; // Ok

tests/ui/collection_is_never_read.stderr

@@ -37,34 +37,40 @@ LL |     let mut x = vec![1, 2, 3]; // WARNING
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^
 
 error: collection is never read
-  --> $DIR/collection_is_never_read.rs:101:5
+  --> $DIR/collection_is_never_read.rs:100:5
    |
 LL |     let mut x = vec![1, 2, 3]; // WARNING
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^
 
 error: collection is never read
-  --> $DIR/collection_is_never_read.rs:118:5
+  --> $DIR/collection_is_never_read.rs:107:5
+   |
+LL |     let mut x = vec![1, 2, 3]; // WARNING
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+error: collection is never read
+  --> $DIR/collection_is_never_read.rs:124:5
    |
 LL |     let mut x = HashSet::new(); // WARNING
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
 error: collection is never read
-  --> $DIR/collection_is_never_read.rs:132:5
+  --> $DIR/collection_is_never_read.rs:138:5
    |
 LL |     let x = vec![1, 2, 3]; // WARNING
    |     ^^^^^^^^^^^^^^^^^^^^^^
 
 error: collection is never read
-  --> $DIR/collection_is_never_read.rs:168:5
+  --> $DIR/collection_is_never_read.rs:174:5
    |
 LL |     let mut s = String::new();
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^
 
 error: collection is never read
-  --> $DIR/collection_is_never_read.rs:181:5
+  --> $DIR/collection_is_never_read.rs:187:5
    |
 LL |     let mut s = String::from("Hello, World!");
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
-error: aborting due to 11 previous errors
+error: aborting due to 12 previous errors