2 files changed, 124 insertions, 0 deletions
diff --git a/tests/ui/modules/issue-107649.rs b/tests/ui/modules/issue-107649.rs
new file mode 100644
index 00000000000..71b84cd30d6
--- /dev/null
+++ b/tests/ui/modules/issue-107649.rs
@@ -0,0 +1,106 @@
+// compile-flags: -Z ui-testing=no
+#[path = "auxiliary/dummy_lib.rs"]
+mod lib;
+
+/// The function needs to be long enough to
+/// ensure `max_line_num_len` to be large enough
+/// for no-ui-testing
+fn main() {
+    ();
+    ();
+    ();
+    ();
+    ();
+    ();
+    ();
+    ();
+    ();
+    ();
+    ();
+    ();
+    ();
+    ();
+    ();
+    ();
+    ();
+    ();
+    ();
+    ();
+    ();
+    ();
+    ();
+    ();
+    ();
+    ();
+    ();
+    ();
+    ();
+    ();
+    ();
+    ();
+    ();
+    ();
+    ();
+    ();
+    ();
+    ();
+    ();
+    ();
+    ();
+    ();
+    ();
+    ();
+    ();
+    ();
+    ();
+    ();
+    ();
+    ();
+    ();
+    ();
+    ();
+    ();
+    ();
+    ();
+    ();
+    ();
+    ();
+    ();
+    ();
+    ();
+    ();
+    ();
+    ();
+    ();
+    ();
+    ();
+    ();
+    ();
+    ();
+    ();
+    ();
+    ();
+    ();
+    ();
+    ();
+    ();
+    ();
+    ();
+    ();
+    ();
+    ();
+    ();
+    ();
+    ();
+    ();
+    ();
+    ();
+    ();
+    ();
+    ();
+    ();
+    ();
+    ();
+    ();
+    dbg!(lib::Dummy); //~ Error: `Dummy` doesn't implement `Debug`
+}
diff --git a/tests/ui/modules/issue-107649.stderr b/tests/ui/modules/issue-107649.stderr
new file mode 100644
index 00000000000..1cea71f2829
--- /dev/null
+++ b/tests/ui/modules/issue-107649.stderr
@@ -0,0 +1,18 @@
+error[E0277]: `Dummy` doesn't implement `Debug`
+   --> $DIR/issue-107649.rs:105:5
+    |
+105 |     dbg!(lib::Dummy);
+    |     ^^^^^^^^^^^^^^^^ `Dummy` cannot be formatted using `{:?}`
+    |
+    = help: the trait `Debug` is not implemented for `Dummy`
+    = note: add `#[derive(Debug)]` to `Dummy` or manually `impl Debug for Dummy`
+    = note: this error originates in the macro `$crate::format_args_nl` which comes from the expansion of the macro `dbg` (in Nightly builds, run with -Z macro-backtrace for more info)
+help: consider annotating `Dummy` with `#[derive(Debug)]`
+   --> $DIR/auxiliary/dummy_lib.rs:2:1
+    |
+2   | #[derive(Debug)]
+    |
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0277`.