clean-up tests, first pass

- remove unused attributes
- add `warn`s for _all_ the lints tested
- remove `fn main` from the no-std test, so that it's considered a lib
  and thus doesn't need the no-std boilerplate
- use shorthand error patterns
diff --git a/tests/ui/mem_replace.fixed b/tests/ui/mem_replace.fixed
index 26aa7aa..df2d36a 100644
--- a/tests/ui/mem_replace.fixed
+++ b/tests/ui/mem_replace.fixed
@@ -1,7 +1,6 @@
-#![allow(unused, clippy::needless_lifetimes)]
 #![warn(
-    clippy::style,
     clippy::mem_replace_option_with_none,
+    clippy::mem_replace_option_with_some,
     clippy::mem_replace_with_default
 )]
 
@@ -142,14 +141,13 @@
         val: String::from("bar"),
     };
 
-    // replace option with none
     let _ = f.0.take();
     //~^ mem_replace_option_with_none
     let _ = (*f).take();
     //~^ mem_replace_option_with_none
     let _ = b.opt.take();
     //~^ mem_replace_option_with_none
-    // replace with default
+
     let _ = std::mem::take(&mut b.val);
     //~^ mem_replace_with_default
 }
@@ -158,16 +156,16 @@
 fn mem_replace_option_with_some() {
     let mut an_option = Some(0);
     let replaced = an_option.replace(1);
-    //~^ ERROR: replacing an `Option` with `Some(..)`
+    //~^ mem_replace_option_with_some
 
     let mut an_option = &mut Some(0);
     let replaced = an_option.replace(1);
-    //~^ ERROR: replacing an `Option` with `Some(..)`
+    //~^ mem_replace_option_with_some
 
     let (mut opt1, mut opt2) = (Some(0), Some(0));
     let b = true;
     let replaced = (if b { &mut opt1 } else { &mut opt2 }).replace(1);
-    //~^ ERROR: replacing an `Option` with `Some(..)`
+    //~^ mem_replace_option_with_some
 }
 
 #[clippy::msrv = "1.30"]
diff --git a/tests/ui/mem_replace.rs b/tests/ui/mem_replace.rs
index cd675f5..970bd61 100644
--- a/tests/ui/mem_replace.rs
+++ b/tests/ui/mem_replace.rs
@@ -1,7 +1,6 @@
-#![allow(unused, clippy::needless_lifetimes)]
 #![warn(
-    clippy::style,
     clippy::mem_replace_option_with_none,
+    clippy::mem_replace_option_with_some,
     clippy::mem_replace_with_default
 )]
 
@@ -142,14 +141,13 @@
         val: String::from("bar"),
     };
 
-    // replace option with none
     let _ = std::mem::replace(&mut f.0, None);
     //~^ mem_replace_option_with_none
     let _ = std::mem::replace(&mut *f, None);
     //~^ mem_replace_option_with_none
     let _ = std::mem::replace(&mut b.opt, None);
     //~^ mem_replace_option_with_none
-    // replace with default
+
     let _ = std::mem::replace(&mut b.val, String::default());
     //~^ mem_replace_with_default
 }
@@ -158,16 +156,16 @@
 fn mem_replace_option_with_some() {
     let mut an_option = Some(0);
     let replaced = mem::replace(&mut an_option, Some(1));
-    //~^ ERROR: replacing an `Option` with `Some(..)`
+    //~^ mem_replace_option_with_some
 
     let mut an_option = &mut Some(0);
     let replaced = mem::replace(an_option, Some(1));
-    //~^ ERROR: replacing an `Option` with `Some(..)`
+    //~^ mem_replace_option_with_some
 
     let (mut opt1, mut opt2) = (Some(0), Some(0));
     let b = true;
     let replaced = mem::replace(if b { &mut opt1 } else { &mut opt2 }, Some(1));
-    //~^ ERROR: replacing an `Option` with `Some(..)`
+    //~^ mem_replace_option_with_some
 }
 
 #[clippy::msrv = "1.30"]
diff --git a/tests/ui/mem_replace.stderr b/tests/ui/mem_replace.stderr
index 9424c32..04dcd04 100644
--- a/tests/ui/mem_replace.stderr
+++ b/tests/ui/mem_replace.stderr
@@ -1,5 +1,5 @@
 error: replacing an `Option` with `None`
-  --> tests/ui/mem_replace.rs:13:13
+  --> tests/ui/mem_replace.rs:12:13
    |
 LL |     let _ = mem::replace(&mut an_option, None);
    |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider using `Option::take()` instead: `an_option.take()`
@@ -8,13 +8,13 @@
    = help: to override `-D warnings` add `#[allow(clippy::mem_replace_option_with_none)]`
 
 error: replacing an `Option` with `None`
-  --> tests/ui/mem_replace.rs:16:13
+  --> tests/ui/mem_replace.rs:15:13
    |
 LL |     let _ = mem::replace(an_option, None);
    |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider using `Option::take()` instead: `an_option.take()`
 
 error: replacing a value of type `T` with `T::default()`
-  --> tests/ui/mem_replace.rs:22:13
+  --> tests/ui/mem_replace.rs:21:13
    |
 LL |     let _ = std::mem::replace(&mut s, String::default());
    |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider using `std::mem::take` instead: `std::mem::take(&mut s)`
@@ -23,145 +23,145 @@
    = help: to override `-D warnings` add `#[allow(clippy::mem_replace_with_default)]`
 
 error: replacing a value of type `T` with `T::default()`
-  --> tests/ui/mem_replace.rs:24:13
+  --> tests/ui/mem_replace.rs:23:13
    |
 LL |     let _ = std::mem::replace(&mut s, String::new());
    |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider using `std::mem::take` instead: `std::mem::take(&mut s)`
 
 error: replacing a value of type `T` with `T::default()`
-  --> tests/ui/mem_replace.rs:28:13
+  --> tests/ui/mem_replace.rs:27:13
    |
 LL |     let _ = std::mem::replace(s, String::default());
    |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider using `std::mem::take` instead: `std::mem::take(s)`
 
 error: replacing a value of type `T` with `T::default()`
-  --> tests/ui/mem_replace.rs:30:13
+  --> tests/ui/mem_replace.rs:29:13
    |
 LL |     let _ = std::mem::replace(s, String::new());
    |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider using `std::mem::take` instead: `std::mem::take(s)`
 
 error: replacing a value of type `T` with `T::default()`
-  --> tests/ui/mem_replace.rs:32:13
+  --> tests/ui/mem_replace.rs:31:13
    |
 LL |     let _ = std::mem::replace(s, Default::default());
    |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider using `std::mem::take` instead: `std::mem::take(s)`
 
 error: replacing a value of type `T` with `T::default()`
-  --> tests/ui/mem_replace.rs:36:13
+  --> tests/ui/mem_replace.rs:35:13
    |
 LL |     let _ = std::mem::replace(&mut v, Vec::default());
    |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider using `std::mem::take` instead: `std::mem::take(&mut v)`
 
 error: replacing a value of type `T` with `T::default()`
-  --> tests/ui/mem_replace.rs:38:13
+  --> tests/ui/mem_replace.rs:37:13
    |
 LL |     let _ = std::mem::replace(&mut v, Default::default());
    |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider using `std::mem::take` instead: `std::mem::take(&mut v)`
 
 error: replacing a value of type `T` with `T::default()`
-  --> tests/ui/mem_replace.rs:40:13
+  --> tests/ui/mem_replace.rs:39:13
    |
 LL |     let _ = std::mem::replace(&mut v, Vec::new());
    |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider using `std::mem::take` instead: `std::mem::take(&mut v)`
 
 error: replacing a value of type `T` with `T::default()`
-  --> tests/ui/mem_replace.rs:42:13
+  --> tests/ui/mem_replace.rs:41:13
    |
 LL |     let _ = std::mem::replace(&mut v, vec![]);
    |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider using `std::mem::take` instead: `std::mem::take(&mut v)`
 
 error: replacing a value of type `T` with `T::default()`
-  --> tests/ui/mem_replace.rs:46:13
+  --> tests/ui/mem_replace.rs:45:13
    |
 LL |     let _ = std::mem::replace(&mut hash_map, HashMap::new());
    |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider using `std::mem::take` instead: `std::mem::take(&mut hash_map)`
 
 error: replacing a value of type `T` with `T::default()`
-  --> tests/ui/mem_replace.rs:50:13
+  --> tests/ui/mem_replace.rs:49:13
    |
 LL |     let _ = std::mem::replace(&mut btree_map, BTreeMap::new());
    |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider using `std::mem::take` instead: `std::mem::take(&mut btree_map)`
 
 error: replacing a value of type `T` with `T::default()`
-  --> tests/ui/mem_replace.rs:54:13
+  --> tests/ui/mem_replace.rs:53:13
    |
 LL |     let _ = std::mem::replace(&mut vd, VecDeque::new());
    |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider using `std::mem::take` instead: `std::mem::take(&mut vd)`
 
 error: replacing a value of type `T` with `T::default()`
-  --> tests/ui/mem_replace.rs:58:13
+  --> tests/ui/mem_replace.rs:57:13
    |
 LL |     let _ = std::mem::replace(&mut hash_set, HashSet::new());
    |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider using `std::mem::take` instead: `std::mem::take(&mut hash_set)`
 
 error: replacing a value of type `T` with `T::default()`
-  --> tests/ui/mem_replace.rs:62:13
+  --> tests/ui/mem_replace.rs:61:13
    |
 LL |     let _ = std::mem::replace(&mut btree_set, BTreeSet::new());
    |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider using `std::mem::take` instead: `std::mem::take(&mut btree_set)`
 
 error: replacing a value of type `T` with `T::default()`
-  --> tests/ui/mem_replace.rs:66:13
+  --> tests/ui/mem_replace.rs:65:13
    |
 LL |     let _ = std::mem::replace(&mut list, LinkedList::new());
    |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider using `std::mem::take` instead: `std::mem::take(&mut list)`
 
 error: replacing a value of type `T` with `T::default()`
-  --> tests/ui/mem_replace.rs:70:13
+  --> tests/ui/mem_replace.rs:69:13
    |
 LL |     let _ = std::mem::replace(&mut binary_heap, BinaryHeap::new());
    |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider using `std::mem::take` instead: `std::mem::take(&mut binary_heap)`
 
 error: replacing a value of type `T` with `T::default()`
-  --> tests/ui/mem_replace.rs:74:13
+  --> tests/ui/mem_replace.rs:73:13
    |
 LL |     let _ = std::mem::replace(&mut tuple, (vec![], BinaryHeap::new()));
    |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider using `std::mem::take` instead: `std::mem::take(&mut tuple)`
 
 error: replacing a value of type `T` with `T::default()`
-  --> tests/ui/mem_replace.rs:78:13
+  --> tests/ui/mem_replace.rs:77:13
    |
 LL |     let _ = std::mem::replace(&mut refstr, "");
    |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider using `std::mem::take` instead: `std::mem::take(&mut refstr)`
 
 error: replacing a value of type `T` with `T::default()`
-  --> tests/ui/mem_replace.rs:82:13
+  --> tests/ui/mem_replace.rs:81:13
    |
 LL |     let _ = std::mem::replace(&mut slice, &[]);
    |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider using `std::mem::take` instead: `std::mem::take(&mut slice)`
 
 error: replacing a value of type `T` with `T::default()`
-  --> tests/ui/mem_replace.rs:115:13
+  --> tests/ui/mem_replace.rs:114:13
    |
 LL |     let _ = std::mem::replace(&mut s, String::default());
    |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider using `std::mem::take` instead: `std::mem::take(&mut s)`
 
 error: replacing an `Option` with `None`
-  --> tests/ui/mem_replace.rs:146:13
+  --> tests/ui/mem_replace.rs:144:13
    |
 LL |     let _ = std::mem::replace(&mut f.0, None);
    |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider using `Option::take()` instead: `f.0.take()`
 
 error: replacing an `Option` with `None`
-  --> tests/ui/mem_replace.rs:148:13
+  --> tests/ui/mem_replace.rs:146:13
    |
 LL |     let _ = std::mem::replace(&mut *f, None);
    |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider using `Option::take()` instead: `(*f).take()`
 
 error: replacing an `Option` with `None`
-  --> tests/ui/mem_replace.rs:150:13
+  --> tests/ui/mem_replace.rs:148:13
    |
 LL |     let _ = std::mem::replace(&mut b.opt, None);
    |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider using `Option::take()` instead: `b.opt.take()`
 
 error: replacing a value of type `T` with `T::default()`
-  --> tests/ui/mem_replace.rs:153:13
+  --> tests/ui/mem_replace.rs:151:13
    |
 LL |     let _ = std::mem::replace(&mut b.val, String::default());
    |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider using `std::mem::take` instead: `std::mem::take(&mut b.val)`
 
 error: replacing an `Option` with `Some(..)`
-  --> tests/ui/mem_replace.rs:160:20
+  --> tests/ui/mem_replace.rs:158:20
    |
 LL |     let replaced = mem::replace(&mut an_option, Some(1));
    |                    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider using `Option::replace()` instead: `an_option.replace(1)`
@@ -170,19 +170,19 @@
    = help: to override `-D warnings` add `#[allow(clippy::mem_replace_option_with_some)]`
 
 error: replacing an `Option` with `Some(..)`
-  --> tests/ui/mem_replace.rs:164:20
+  --> tests/ui/mem_replace.rs:162:20
    |
 LL |     let replaced = mem::replace(an_option, Some(1));
    |                    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider using `Option::replace()` instead: `an_option.replace(1)`
 
 error: replacing an `Option` with `Some(..)`
-  --> tests/ui/mem_replace.rs:169:20
+  --> tests/ui/mem_replace.rs:167:20
    |
 LL |     let replaced = mem::replace(if b { &mut opt1 } else { &mut opt2 }, Some(1));
    |                    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider using `Option::replace()` instead: `(if b { &mut opt1 } else { &mut opt2 }).replace(1)`
 
 error: replacing a value of type `T` with `T::default()`
-  --> tests/ui/mem_replace.rs:181:20
+  --> tests/ui/mem_replace.rs:179:20
    |
 LL |     let replaced = std::mem::replace(dbg!(&mut text), String::default());
    |                    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider using `std::mem::take` instead: `std::mem::take(dbg!(&mut text))`
diff --git a/tests/ui/mem_replace_no_std.fixed b/tests/ui/mem_replace_no_std.fixed
index 4e2d413..3cb22ad 100644
--- a/tests/ui/mem_replace_no_std.fixed
+++ b/tests/ui/mem_replace_no_std.fixed
@@ -1,22 +1,11 @@
-#![allow(unused, clippy::needless_lifetimes)]
 #![warn(
-    clippy::style,
     clippy::mem_replace_option_with_none,
+    clippy::mem_replace_option_with_some,
     clippy::mem_replace_with_default
 )]
-#![feature(lang_items)]
 #![no_std]
 
 use core::mem;
-use core::panic::PanicInfo;
-
-#[lang = "eh_personality"]
-extern "C" fn eh_personality() {}
-
-#[panic_handler]
-fn panic(info: &PanicInfo) -> ! {
-    loop {}
-}
 
 fn replace_option_with_none() {
     let mut an_option = Some(1);
@@ -47,8 +36,6 @@
     let _ = mem::replace(&mut pint, 0);
 }
 
-fn main() {}
-
 fn issue9824() {
     struct Foo<'a>(Option<&'a str>);
     impl<'a> core::ops::Deref for Foo<'a> {
diff --git a/tests/ui/mem_replace_no_std.rs b/tests/ui/mem_replace_no_std.rs
index c089230..75f2472 100644
--- a/tests/ui/mem_replace_no_std.rs
+++ b/tests/ui/mem_replace_no_std.rs
@@ -1,22 +1,11 @@
-#![allow(unused, clippy::needless_lifetimes)]
 #![warn(
-    clippy::style,
     clippy::mem_replace_option_with_none,
+    clippy::mem_replace_option_with_some,
     clippy::mem_replace_with_default
 )]
-#![feature(lang_items)]
 #![no_std]
 
 use core::mem;
-use core::panic::PanicInfo;
-
-#[lang = "eh_personality"]
-extern "C" fn eh_personality() {}
-
-#[panic_handler]
-fn panic(info: &PanicInfo) -> ! {
-    loop {}
-}
 
 fn replace_option_with_none() {
     let mut an_option = Some(1);
@@ -47,8 +36,6 @@
     let _ = mem::replace(&mut pint, 0);
 }
 
-fn main() {}
-
 fn issue9824() {
     struct Foo<'a>(Option<&'a str>);
     impl<'a> core::ops::Deref for Foo<'a> {
diff --git a/tests/ui/mem_replace_no_std.stderr b/tests/ui/mem_replace_no_std.stderr
index ae4f4a7..bbb5fb9 100644
--- a/tests/ui/mem_replace_no_std.stderr
+++ b/tests/ui/mem_replace_no_std.stderr
@@ -1,5 +1,5 @@
 error: replacing an `Option` with `None`
-  --> tests/ui/mem_replace_no_std.rs:23:13
+  --> tests/ui/mem_replace_no_std.rs:12:13
    |
 LL |     let _ = mem::replace(&mut an_option, None);
    |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider using `Option::take()` instead: `an_option.take()`
@@ -8,13 +8,13 @@
    = help: to override `-D warnings` add `#[allow(clippy::mem_replace_option_with_none)]`
 
 error: replacing an `Option` with `None`
-  --> tests/ui/mem_replace_no_std.rs:26:13
+  --> tests/ui/mem_replace_no_std.rs:15:13
    |
 LL |     let _ = mem::replace(an_option, None);
    |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider using `Option::take()` instead: `an_option.take()`
 
 error: replacing a value of type `T` with `T::default()`
-  --> tests/ui/mem_replace_no_std.rs:32:13
+  --> tests/ui/mem_replace_no_std.rs:21:13
    |
 LL |     let _ = mem::replace(&mut refstr, "");
    |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider using `core::mem::take` instead: `core::mem::take(&mut refstr)`
@@ -23,25 +23,25 @@
    = help: to override `-D warnings` add `#[allow(clippy::mem_replace_with_default)]`
 
 error: replacing a value of type `T` with `T::default()`
-  --> tests/ui/mem_replace_no_std.rs:36:13
+  --> tests/ui/mem_replace_no_std.rs:25:13
    |
 LL |     let _ = mem::replace(&mut slice, &[]);
    |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider using `core::mem::take` instead: `core::mem::take(&mut slice)`
 
 error: replacing an `Option` with `None`
-  --> tests/ui/mem_replace_no_std.rs:76:13
+  --> tests/ui/mem_replace_no_std.rs:63:13
    |
 LL |     let _ = mem::replace(&mut f.0, None);
    |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider using `Option::take()` instead: `f.0.take()`
 
 error: replacing an `Option` with `None`
-  --> tests/ui/mem_replace_no_std.rs:78:13
+  --> tests/ui/mem_replace_no_std.rs:65:13
    |
 LL |     let _ = mem::replace(&mut *f, None);
    |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider using `Option::take()` instead: `(*f).take()`
 
 error: replacing an `Option` with `None`
-  --> tests/ui/mem_replace_no_std.rs:80:13
+  --> tests/ui/mem_replace_no_std.rs:67:13
    |
 LL |     let _ = mem::replace(&mut b.opt, None);
    |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider using `Option::take()` instead: `b.opt.take()`