Auto merge of #62561 - Centril:rollup-5pxj3bo, r=Centril

Rollup of 5 pull requests

Successful merges:

 - #62275 (rustc_mir: treat DropAndReplace as Drop + Assign in qualify_consts.)
 - #62465 (Sometimes generate storage statements for temporaries with type `!`)
 - #62481 (Use `fold` in `Iterator::last` default implementation)
 - #62493 (#62357: doc(ptr): add example for {read,write}_unaligned)
 - #62532 (Some more cleanups to syntax::print)

Failed merges:

r? @ghost

src/test/mir-opt/loop_test.rs

@@ -26,6 +26,7 @@ fn main() {
 //        _1 = ();
 //        StorageDead(_2);
 //        StorageDead(_1);
+//        StorageLive(_4);
 //        goto -> bb5;
 //    }
 //    ...

src/test/ui/borrowck/assign-never-type.rs

@@ -0,0 +1,14 @@
+// Regression test for issue 62165
+
+// check-pass
+
+#![feature(never_type)]
+
+pub fn main() {
+    loop {
+        match None {
+            None => return,
+            Some(val) => val,
+        };
+    };
+}

src/test/ui/consts/const-eval/const_let.rs

@@ -9,10 +9,21 @@ impl Drop for FakeNeedsDrop {
 // ok
 const X: FakeNeedsDrop = { let x = FakeNeedsDrop; x };
 
+// ok (used to incorrectly error, see #62273)
+const X2: FakeNeedsDrop = { let x; x = FakeNeedsDrop; x };
+
 // error
 const Y: FakeNeedsDrop = { let mut x = FakeNeedsDrop; x = FakeNeedsDrop; x };
-//~^ ERROR constant contains unimplemented expression type
+//~^ ERROR destructors cannot be evaluated at compile-time
+
+// error
+const Y2: FakeNeedsDrop = { let mut x; x = FakeNeedsDrop; x = FakeNeedsDrop; x };
+//~^ ERROR destructors cannot be evaluated at compile-time
 
 // error
 const Z: () = { let mut x = None; x = Some(FakeNeedsDrop); };
-//~^ ERROR constant contains unimplemented expression type
+//~^ ERROR destructors cannot be evaluated at compile-time
+
+// error
+const Z2: () = { let mut x; x = None; x = Some(FakeNeedsDrop); };
+//~^ ERROR destructors cannot be evaluated at compile-time

src/test/ui/consts/const-eval/const_let.stderr

@@ -1,15 +1,26 @@
-error[E0019]: constant contains unimplemented expression type
-  --> $DIR/const_let.rs:13:55
+error[E0493]: destructors cannot be evaluated at compile-time
+  --> $DIR/const_let.rs:16:32
    |
 LL | const Y: FakeNeedsDrop = { let mut x = FakeNeedsDrop; x = FakeNeedsDrop; x };
-   |                                                       ^
+   |                                ^^^^^ constants cannot evaluate destructors
 
-error[E0019]: constant contains unimplemented expression type
-  --> $DIR/const_let.rs:17:35
+error[E0493]: destructors cannot be evaluated at compile-time
+  --> $DIR/const_let.rs:20:33
+   |
+LL | const Y2: FakeNeedsDrop = { let mut x; x = FakeNeedsDrop; x = FakeNeedsDrop; x };
+   |                                 ^^^^^ constants cannot evaluate destructors
+
+error[E0493]: destructors cannot be evaluated at compile-time
+  --> $DIR/const_let.rs:24:21
    |
 LL | const Z: () = { let mut x = None; x = Some(FakeNeedsDrop); };
-   |                                   ^
+   |                     ^^^^^ constants cannot evaluate destructors
 
-error: aborting due to 2 previous errors
+error[E0493]: destructors cannot be evaluated at compile-time
+  --> $DIR/const_let.rs:28:22
+   |
+LL | const Z2: () = { let mut x; x = None; x = Some(FakeNeedsDrop); };
+   |                      ^^^^^ constants cannot evaluate destructors
+
+error: aborting due to 4 previous errors
 
-For more information about this error, try `rustc --explain E0019`.