Move compile-fail/unsized-locals under ui as per #44844.

src/test/ui/unsized-locals/by-value-trait-object-safety.stderr

@@ -0,0 +1,8 @@
+error: the `foo` method cannot be invoked on a trait object
+  --> $DIR/by-value-trait-object-safety.rs:28:7
+   |
+LL |     x.foo();
+   |       ^^^
+
+error: aborting due to previous error
+

src/test/ui/unsized-locals/unsized-exprs.stderr

@@ -0,0 +1,25 @@
+error[E0277]: the size for values of type `[u8]` cannot be known at compilation time
+  --> $DIR/unsized-exprs.rs:32:26
+   |
+LL |     udrop::<(i32, [u8])>((42, *foo()));
+   |                          ^^^^^^^^^^^^ doesn't have a size known at compile-time
+   |
+   = help: within `({integer}, [u8])`, the trait `std::marker::Sized` is not implemented for `[u8]`
+   = note: to learn more, visit <https://doc.rust-lang.org/book/second-edition/ch19-04-advanced-types.html#dynamically-sized-types-and-the-sized-trait>
+   = note: required because it appears within the type `({integer}, [u8])`
+   = note: tuples must have a statically known size to be initialized
+
+error[E0277]: the size for values of type `[u8]` cannot be known at compilation time
+  --> $DIR/unsized-exprs.rs:34:22
+   |
+LL |     udrop::<A<[u8]>>(A { 0: *foo() });
+   |                      ^^^^^^^^^^^^^^^ doesn't have a size known at compile-time
+   |
+   = help: within `A<[u8]>`, the trait `std::marker::Sized` is not implemented for `[u8]`
+   = note: to learn more, visit <https://doc.rust-lang.org/book/second-edition/ch19-04-advanced-types.html#dynamically-sized-types-and-the-sized-trait>
+   = note: required because it appears within the type `A<[u8]>`
+   = note: structs must have a statically known size to be initialized
+
+error: aborting due to 2 previous errors
+
+For more information about this error, try `rustc --explain E0277`.

src/test/ui/unsized-locals/unsized-exprs2.nll.stderr

@@ -0,0 +1,19 @@
+error[E0508]: cannot move out of type `[u8]`, a non-copy slice
+  --> $DIR/unsized-exprs2.rs:32:19
+   |
+LL |     udrop::<[u8]>(foo()[..]);
+   |                   ^^^^^^^^^ cannot move out of here
+
+error[E0507]: cannot move out of data in a `&` reference
+  --> $DIR/unsized-exprs2.rs:32:19
+   |
+LL |     udrop::<[u8]>(foo()[..]);
+   |                   ^^^^^^^^^
+   |                   |
+   |                   cannot move out of data in a `&` reference
+   |                   cannot move
+
+error: aborting due to 2 previous errors
+
+Some errors occurred: E0507, E0508.
+For more information about an error, try `rustc --explain E0507`.

src/test/ui/unsized-locals/unsized-exprs2.stderr

@@ -0,0 +1,9 @@
+error[E0507]: cannot move out of indexed content
+  --> $DIR/unsized-exprs2.rs:32:19
+   |
+LL |     udrop::<[u8]>(foo()[..]);
+   |                   ^^^^^^^^^ cannot move out of indexed content
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0507`.