dbg_macro: feature gate + move semantics test.

Author: Centril

src/test/ui/rfc-2361-dbg-macro/dbg-macro-feature-gate.rs

@@ -0,0 +1,5 @@
+// Feature gate test for `dbg!(..)`.
+
+fn main() {
+    dbg!(1);
+}

src/test/ui/rfc-2361-dbg-macro/dbg-macro-feature-gate.stderr

@@ -0,0 +1,11 @@
+error[E0658]: macro dbg! is unstable (see issue #54306)
+  --> $DIR/dbg-macro-feature-gate.rs:4:5
+   |
+LL |     dbg!(1);
+   |     ^^^^^^^^
+   |
+   = help: add #![feature(dbg_macro)] to the crate attributes to enable
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0658`.

src/test/ui/rfc-2361-dbg-macro/dbg-macro-move-semantics.nll.stderr

@@ -0,0 +1,36 @@
+error[E0382]: use of moved value: `a`
+  --> $DIR/dbg-macro-move-semantics.rs:11:18
+   |
+LL |     let _ = dbg!(a);
+   |             ------- value moved here
+LL |     let _ = dbg!(a);
+   |                  ^ value used here after move
+   |
+   = note: move occurs because `a` has type `NoCopy`, which does not implement the `Copy` trait
+   = note: this error originates in a macro outside of the current crate (in Nightly builds, run with -Z external-macro-backtrace for more info)
+
+error[E0382]: borrow of moved value: `a`
+  --> $DIR/dbg-macro-move-semantics.rs:11:18
+   |
+LL |     let _ = dbg!(a);
+   |             ------- value moved here
+LL |     let _ = dbg!(a);
+   |                  ^ value borrowed here after move
+   |
+   = note: move occurs because `a` has type `NoCopy`, which does not implement the `Copy` trait
+   = note: this error originates in a macro outside of the current crate (in Nightly builds, run with -Z external-macro-backtrace for more info)
+
+error[E0382]: use of moved value: `a`
+  --> $DIR/dbg-macro-move-semantics.rs:11:13
+   |
+LL |     let _ = dbg!(a);
+   |             ------- value moved here
+LL |     let _ = dbg!(a);
+   |             ^^^^^^^ value used here after move
+   |
+   = note: move occurs because `a` has type `NoCopy`, which does not implement the `Copy` trait
+   = note: this error originates in a macro outside of the current crate (in Nightly builds, run with -Z external-macro-backtrace for more info)
+
+error: aborting due to 3 previous errors
+
+For more information about this error, try `rustc --explain E0382`.

src/test/ui/rfc-2361-dbg-macro/dbg-macro-move-semantics.rs

@@ -0,0 +1,12 @@
+// Test ensuring that `dbg!(expr)` will take ownership of the argument.
+
+#![feature(dbg_macro)]
+
+#[derive(Debug)]
+struct NoCopy(usize);
+
+fn main() {
+    let a = NoCopy(0);
+    let _ = dbg!(a);
+    let _ = dbg!(a);
+}

src/test/ui/rfc-2361-dbg-macro/dbg-macro-move-semantics.stderr

@@ -0,0 +1,25 @@
+error[E0382]: use of moved value: `a`
+  --> $DIR/dbg-macro-move-semantics.rs:11:18
+   |
+LL |     let _ = dbg!(a);
+   |             ------- value moved here
+LL |     let _ = dbg!(a);
+   |                  ^ value used here after move
+   |
+   = note: move occurs because `a` has type `NoCopy`, which does not implement the `Copy` trait
+   = note: this error originates in a macro outside of the current crate (in Nightly builds, run with -Z external-macro-backtrace for more info)
+
+error[E0382]: use of moved value: `a`
+  --> $DIR/dbg-macro-move-semantics.rs:11:13
+   |
+LL |     let _ = dbg!(a);
+   |             ------- value moved here
+LL |     let _ = dbg!(a);
+   |             ^^^^^^^ value used here after move
+   |
+   = note: move occurs because `a` has type `NoCopy`, which does not implement the `Copy` trait
+   = note: this error originates in a macro outside of the current crate (in Nightly builds, run with -Z external-macro-backtrace for more info)
+
+error: aborting due to 2 previous errors
+
+For more information about this error, try `rustc --explain E0382`.