Auto merge of #90437 - matthiaskrgr:rollup-vd8uqm6, r=matthiaskrgr

Rollup of 4 pull requests

Successful merges:

 - #89068 (Restructure std::rt (part 2))
 - #89786 (Add #[must_use] to len and is_empty)
 - #90430 (Add #[must_use] to remaining std functions (A-N))
 - #90431 (Add #[must_use] to remaining std functions (O-Z))

Failed merges:

r? `@ghost`
`@rustbot` modify labels: rollup

9 files changed, 54 insertions, 52 deletions

diff --git a/src/test/ui/rt-explody-panic-payloads.rs b/src/test/ui/rt-explody-panic-payloads.rs
index 1d3a2ff8284..dc193582c6a 100644
--- a/src/test/ui/rt-explody-panic-payloads.rs
+++ b/src/test/ui/rt-explody-panic-payloads.rs
@@ -25,6 +25,6 @@ fn main() {
     println!("{:#?}", output);
     let stderr = std::str::from_utf8(&output.stderr);
     assert!(stderr.map(|v| {
-        v.ends_with("drop of the panic payload panicked")
+        v.ends_with("fatal runtime error: drop of the panic payload panicked\n")
     }).unwrap_or(false));
 }
diff --git a/src/test/ui/rust-2018/uniform-paths/redundant.rs b/src/test/ui/rust-2018/uniform-paths/redundant.rs
index 2d306eb920c..fd7fc7fbd41 100644
--- a/src/test/ui/rust-2018/uniform-paths/redundant.rs
+++ b/src/test/ui/rust-2018/uniform-paths/redundant.rs
@@ -13,8 +13,8 @@ mod bar {
 }
 
 fn main() {
-    io::stdout();
-    self::std::io::stdout();
-    foo::my_std::io::stdout();
-    bar::std::io::stdout();
+    let _ = io::stdout();
+    let _ = self::std::io::stdout();
+    let _ = foo::my_std::io::stdout();
+    let _ = bar::std::io::stdout();
 }
diff --git a/src/test/ui/uniform-paths/basic-nested.rs b/src/test/ui/uniform-paths/basic-nested.rs
index e4e8b32c70e..dcf0eb646f3 100644
--- a/src/test/ui/uniform-paths/basic-nested.rs
+++ b/src/test/ui/uniform-paths/basic-nested.rs
@@ -44,10 +44,10 @@ mod bar {
 
 fn main() {
     foo::Foo(());
-    foo::std_io::stdout();
+    let _ = foo::std_io::stdout();
     foo::local_io(());
-    io::stdout();
-    bar::io::stdout();
+    let _ = io::stdout();
+    let _ = bar::io::stdout();
     bar::std();
     bar::std!();
 
@@ -56,6 +56,6 @@ fn main() {
         // scope is allowed, when both resolve to the same definition.
         use std::io;
         use io::stdout;
-        stdout();
+        let _ = stdout();
     }
 }
diff --git a/src/test/ui/uniform-paths/basic.rs b/src/test/ui/uniform-paths/basic.rs
index 4e2e2dedef6..ce611a7cacf 100644
--- a/src/test/ui/uniform-paths/basic.rs
+++ b/src/test/ui/uniform-paths/basic.rs
@@ -20,7 +20,7 @@ use self::std::io as local_io;
 
 fn main() {
     Foo(());
-    std_io::stdout();
+    let _ = std_io::stdout();
     local_io(());
 
     {
@@ -28,6 +28,6 @@ fn main() {
         // scope is allowed, when both resolve to the same definition.
         use ::std::io as std_io;
         use std_io::stdout;
-        stdout();
+        let _ = stdout();
     }
 }
diff --git a/src/test/ui/uniform-paths/macros-nested.rs b/src/test/ui/uniform-paths/macros-nested.rs
index a62a28bb94d..175ccd34e98 100644
--- a/src/test/ui/uniform-paths/macros-nested.rs
+++ b/src/test/ui/uniform-paths/macros-nested.rs
@@ -46,8 +46,8 @@ mod bar {
 
 fn main() {
     foo::Foo(());
-    foo::std_io::stdout();
+    let _ = foo::std_io::stdout();
     foo::local_io(());
-    io::stdout();
-    bar::io::stdout();
+    let _ = io::stdout();
+    let _ = bar::io::stdout();
 }
diff --git a/src/test/ui/uniform-paths/macros.rs b/src/test/ui/uniform-paths/macros.rs
index 31b809f0cfd..bf512b30560 100644
--- a/src/test/ui/uniform-paths/macros.rs
+++ b/src/test/ui/uniform-paths/macros.rs
@@ -31,6 +31,6 @@ m2!();
 
 fn main() {
     Foo(());
-    std_io::stdout();
+    let _ = std_io::stdout();
     local_io(());
 }
diff --git a/src/tools/clippy/tests/ui/iter_count.fixed b/src/tools/clippy/tests/ui/iter_count.fixed
index 97c5929783d..90a6eef7526 100644
--- a/src/tools/clippy/tests/ui/iter_count.fixed
+++ b/src/tools/clippy/tests/ui/iter_count.fixed
@@ -33,6 +33,7 @@ impl HasIter {
     }
 }
 
+#[allow(unused_must_use)]
 fn main() {
     let mut vec = vec![0, 1, 2, 3];
     let mut boxed_slice: Box<[u8]> = Box::new([0, 1, 2, 3]);
@@ -50,7 +51,7 @@ fn main() {
     linked_list.push_back(1);
     binary_heap.push(1);
 
-    let _ = &vec[..].len();
+    &vec[..].len();
     vec.len();
     boxed_slice.len();
     vec_deque.len();
@@ -62,13 +63,13 @@ fn main() {
     binary_heap.len();
 
     vec.len();
-    let _ = &vec[..].len();
+    &vec[..].len();
     vec_deque.len();
     hash_map.len();
     b_tree_map.len();
     linked_list.len();
 
-    let _ = &vec[..].len();
+    &vec[..].len();
     vec.len();
     vec_deque.len();
     hash_set.len();
diff --git a/src/tools/clippy/tests/ui/iter_count.rs b/src/tools/clippy/tests/ui/iter_count.rs
index 70bb734763f..6681a480a28 100644
--- a/src/tools/clippy/tests/ui/iter_count.rs
+++ b/src/tools/clippy/tests/ui/iter_count.rs
@@ -33,6 +33,7 @@ impl HasIter {
     }
 }
 
+#[allow(unused_must_use)]
 fn main() {
     let mut vec = vec![0, 1, 2, 3];
     let mut boxed_slice: Box<[u8]> = Box::new([0, 1, 2, 3]);
@@ -50,7 +51,7 @@ fn main() {
     linked_list.push_back(1);
     binary_heap.push(1);
 
-    let _ = &vec[..].iter().count();
+    &vec[..].iter().count();
     vec.iter().count();
     boxed_slice.iter().count();
     vec_deque.iter().count();
@@ -62,13 +63,13 @@ fn main() {
     binary_heap.iter().count();
 
     vec.iter_mut().count();
-    let _ = &vec[..].iter_mut().count();
+    &vec[..].iter_mut().count();
     vec_deque.iter_mut().count();
     hash_map.iter_mut().count();
     b_tree_map.iter_mut().count();
     linked_list.iter_mut().count();
 
-    let _ = &vec[..].into_iter().count();
+    &vec[..].into_iter().count();
     vec.into_iter().count();
     vec_deque.into_iter().count();
     hash_set.into_iter().count();
diff --git a/src/tools/clippy/tests/ui/iter_count.stderr b/src/tools/clippy/tests/ui/iter_count.stderr
index 1d2c22f9dfa..2e3d7fc35de 100644
--- a/src/tools/clippy/tests/ui/iter_count.stderr
+++ b/src/tools/clippy/tests/ui/iter_count.stderr
@@ -1,151 +1,151 @@
 error: called `.iter().count()` on a `slice`
-  --> $DIR/iter_count.rs:53:14
+  --> $DIR/iter_count.rs:54:6
    |
-LL |     let _ = &vec[..].iter().count();
-   |              ^^^^^^^^^^^^^^^^^^^^^^ help: try: `vec[..].len()`
+LL |     &vec[..].iter().count();
+   |      ^^^^^^^^^^^^^^^^^^^^^^ help: try: `vec[..].len()`
    |
    = note: `-D clippy::iter-count` implied by `-D warnings`
 
 error: called `.iter().count()` on a `Vec`
-  --> $DIR/iter_count.rs:54:5
+  --> $DIR/iter_count.rs:55:5
    |
 LL |     vec.iter().count();
    |     ^^^^^^^^^^^^^^^^^^ help: try: `vec.len()`
 
 error: called `.iter().count()` on a `slice`
-  --> $DIR/iter_count.rs:55:5
+  --> $DIR/iter_count.rs:56:5
    |
 LL |     boxed_slice.iter().count();
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `boxed_slice.len()`
 
 error: called `.iter().count()` on a `VecDeque`
-  --> $DIR/iter_count.rs:56:5
+  --> $DIR/iter_count.rs:57:5
    |
 LL |     vec_deque.iter().count();
    |     ^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `vec_deque.len()`
 
 error: called `.iter().count()` on a `HashSet`
-  --> $DIR/iter_count.rs:57:5
+  --> $DIR/iter_count.rs:58:5
    |
 LL |     hash_set.iter().count();
    |     ^^^^^^^^^^^^^^^^^^^^^^^ help: try: `hash_set.len()`
 
 error: called `.iter().count()` on a `HashMap`
-  --> $DIR/iter_count.rs:58:5
+  --> $DIR/iter_count.rs:59:5
    |
 LL |     hash_map.iter().count();
    |     ^^^^^^^^^^^^^^^^^^^^^^^ help: try: `hash_map.len()`
 
 error: called `.iter().count()` on a `BTreeMap`
-  --> $DIR/iter_count.rs:59:5
+  --> $DIR/iter_count.rs:60:5
    |
 LL |     b_tree_map.iter().count();
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `b_tree_map.len()`
 
 error: called `.iter().count()` on a `BTreeSet`
-  --> $DIR/iter_count.rs:60:5
+  --> $DIR/iter_count.rs:61:5
    |
 LL |     b_tree_set.iter().count();
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `b_tree_set.len()`
 
 error: called `.iter().count()` on a `LinkedList`
-  --> $DIR/iter_count.rs:61:5
+  --> $DIR/iter_count.rs:62:5
    |
 LL |     linked_list.iter().count();
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `linked_list.len()`
 
 error: called `.iter().count()` on a `BinaryHeap`
-  --> $DIR/iter_count.rs:62:5
+  --> $DIR/iter_count.rs:63:5
    |
 LL |     binary_heap.iter().count();
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `binary_heap.len()`
 
 error: called `.iter_mut().count()` on a `Vec`
-  --> $DIR/iter_count.rs:64:5
+  --> $DIR/iter_count.rs:65:5
    |
 LL |     vec.iter_mut().count();
    |     ^^^^^^^^^^^^^^^^^^^^^^ help: try: `vec.len()`
 
 error: called `.iter_mut().count()` on a `slice`
-  --> $DIR/iter_count.rs:65:14
+  --> $DIR/iter_count.rs:66:6
    |
-LL |     let _ = &vec[..].iter_mut().count();
-   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `vec[..].len()`
+LL |     &vec[..].iter_mut().count();
+   |      ^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `vec[..].len()`
 
 error: called `.iter_mut().count()` on a `VecDeque`
-  --> $DIR/iter_count.rs:66:5
+  --> $DIR/iter_count.rs:67:5
    |
 LL |     vec_deque.iter_mut().count();
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `vec_deque.len()`
 
 error: called `.iter_mut().count()` on a `HashMap`
-  --> $DIR/iter_count.rs:67:5
+  --> $DIR/iter_count.rs:68:5
    |
 LL |     hash_map.iter_mut().count();
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `hash_map.len()`
 
 error: called `.iter_mut().count()` on a `BTreeMap`
-  --> $DIR/iter_count.rs:68:5
+  --> $DIR/iter_count.rs:69:5
    |
 LL |     b_tree_map.iter_mut().count();
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `b_tree_map.len()`
 
 error: called `.iter_mut().count()` on a `LinkedList`
-  --> $DIR/iter_count.rs:69:5
+  --> $DIR/iter_count.rs:70:5
    |
 LL |     linked_list.iter_mut().count();
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `linked_list.len()`
 
 error: called `.into_iter().count()` on a `slice`
-  --> $DIR/iter_count.rs:71:14
+  --> $DIR/iter_count.rs:72:6
    |
-LL |     let _ = &vec[..].into_iter().count();
-   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `vec[..].len()`
+LL |     &vec[..].into_iter().count();
+   |      ^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `vec[..].len()`
 
 error: called `.into_iter().count()` on a `Vec`
-  --> $DIR/iter_count.rs:72:5
+  --> $DIR/iter_count.rs:73:5
    |
 LL |     vec.into_iter().count();
    |     ^^^^^^^^^^^^^^^^^^^^^^^ help: try: `vec.len()`
 
 error: called `.into_iter().count()` on a `VecDeque`
-  --> $DIR/iter_count.rs:73:5
+  --> $DIR/iter_count.rs:74:5
    |
 LL |     vec_deque.into_iter().count();
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `vec_deque.len()`
 
 error: called `.into_iter().count()` on a `HashSet`
-  --> $DIR/iter_count.rs:74:5
+  --> $DIR/iter_count.rs:75:5
    |
 LL |     hash_set.into_iter().count();
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `hash_set.len()`
 
 error: called `.into_iter().count()` on a `HashMap`
-  --> $DIR/iter_count.rs:75:5
+  --> $DIR/iter_count.rs:76:5
    |
 LL |     hash_map.into_iter().count();
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `hash_map.len()`
 
 error: called `.into_iter().count()` on a `BTreeMap`
-  --> $DIR/iter_count.rs:76:5
+  --> $DIR/iter_count.rs:77:5
    |
 LL |     b_tree_map.into_iter().count();
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `b_tree_map.len()`
 
 error: called `.into_iter().count()` on a `BTreeSet`
-  --> $DIR/iter_count.rs:77:5
+  --> $DIR/iter_count.rs:78:5
    |
 LL |     b_tree_set.into_iter().count();
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `b_tree_set.len()`
 
 error: called `.into_iter().count()` on a `LinkedList`
-  --> $DIR/iter_count.rs:78:5
+  --> $DIR/iter_count.rs:79:5
    |
 LL |     linked_list.into_iter().count();
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `linked_list.len()`
 
 error: called `.into_iter().count()` on a `BinaryHeap`
-  --> $DIR/iter_count.rs:79:5
+  --> $DIR/iter_count.rs:80:5
    |
 LL |     binary_heap.into_iter().count();
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `binary_heap.len()`