Add test cases for replace with Default::default()

Author: krishna-veerareddy

tests/ui/mem_replace.fixed

@@ -30,6 +30,7 @@ fn replace_with_default() {
     let _ = std::mem::take(&mut s);
     let s = &mut String::from("foo");
     let _ = std::mem::take(s);
+    let _ = std::mem::take(s);
 }
 
 fn main() {

tests/ui/mem_replace.rs

@@ -30,6 +30,7 @@ fn replace_with_default() {
     let _ = std::mem::replace(&mut s, String::default());
     let s = &mut String::from("foo");
     let _ = std::mem::replace(s, String::default());
+    let _ = std::mem::replace(s, Default::default());
 }
 
 fn main() {

tests/ui/mem_replace.stderr

@@ -26,5 +26,11 @@ error: replacing a value of type `T` with `T::default()` is better expressed usi
 LL |     let _ = std::mem::replace(s, String::default());
    |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider using: `std::mem::take(s)`
 
-error: aborting due to 4 previous errors
+error: replacing a value of type `T` with `T::default()` is better expressed using `std::mem::take`
+  --> $DIR/mem_replace.rs:33:13
+   |
+LL |     let _ = std::mem::replace(s, Default::default());
+   |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider using: `std::mem::take(s)`
+
+error: aborting due to 5 previous errors