Stop dbg! macro yapping about format modifiers

4 files changed, 25 insertions, 9 deletions

diff --git a/tests/ui/modules/issue-107649.stderr b/tests/ui/modules/issue-107649.stderr
index f0353282d28..802ac669a10 100644
--- a/tests/ui/modules/issue-107649.stderr
+++ b/tests/ui/modules/issue-107649.stderr
@@ -2,12 +2,10 @@ error[E0277]: `Dummy` doesn't implement `Debug`
    --> $DIR/issue-107649.rs:105:5
     |
 105 |     dbg!(lib::Dummy);
-    |     ^^^^^^^^^^^^^^^^ `Dummy` cannot be formatted using `{:?}` because it doesn't implement `Debug`
+    |     ^^^^^^^^^^^^^^^^ the trait `Debug` is not implemented for `Dummy`
     |
-    = help: the trait `Debug` is not implemented for `Dummy`
     = note: add `#[derive(Debug)]` to `Dummy` or manually `impl Debug for Dummy`
-    = note: required for `&Dummy` to implement `Debug`
-    = note: this error originates in the macro `$crate::format_args_nl` which comes from the expansion of the macro `dbg` (in Nightly builds, run with -Z macro-backtrace for more info)
+    = note: this error originates in 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
     |
diff --git a/tests/ui/rfcs/rfc-2361-dbg-macro/dbg-macro-ref-impl.rs b/tests/ui/rfcs/rfc-2361-dbg-macro/dbg-macro-ref-impl.rs
new file mode 100644
index 00000000000..c6e38c0758d
--- /dev/null
+++ b/tests/ui/rfcs/rfc-2361-dbg-macro/dbg-macro-ref-impl.rs
@@ -0,0 +1,17 @@
+/// Check that only `&X: Debug` is required, not `X: Debug`
+//@check-pass
+
+use std::fmt::Debug;
+use std::fmt::Formatter;
+
+struct X;
+
+impl Debug for &X {
+    fn fmt(&self, f: &mut Formatter<'_>) -> Result<(), std::fmt::Error> {
+        f.write_str("X")
+    }
+}
+
+fn main() {
+    dbg!(X);
+}
diff --git a/tests/ui/rfcs/rfc-2361-dbg-macro/dbg-macro-requires-debug.rs b/tests/ui/rfcs/rfc-2361-dbg-macro/dbg-macro-requires-debug.rs
index f2fb62d76f3..fe71f106fdf 100644
--- a/tests/ui/rfcs/rfc-2361-dbg-macro/dbg-macro-requires-debug.rs
+++ b/tests/ui/rfcs/rfc-2361-dbg-macro/dbg-macro-requires-debug.rs
@@ -1,4 +1,7 @@
 // Test ensuring that `dbg!(expr)` requires the passed type to implement `Debug`.
+//
+// `dbg!` shouldn't tell the user about format literal syntax; the user didn't write one.
+//@ forbid-output: cannot be formatted using
 
 struct NotDebug;
 
diff --git a/tests/ui/rfcs/rfc-2361-dbg-macro/dbg-macro-requires-debug.stderr b/tests/ui/rfcs/rfc-2361-dbg-macro/dbg-macro-requires-debug.stderr
index 190db042994..4e0ae918415 100644
--- a/tests/ui/rfcs/rfc-2361-dbg-macro/dbg-macro-requires-debug.stderr
+++ b/tests/ui/rfcs/rfc-2361-dbg-macro/dbg-macro-requires-debug.stderr
@@ -1,13 +1,11 @@
 error[E0277]: `NotDebug` doesn't implement `Debug`
-  --> $DIR/dbg-macro-requires-debug.rs:6:23
+  --> $DIR/dbg-macro-requires-debug.rs:9:23
    |
 LL |     let _: NotDebug = dbg!(NotDebug);
-   |                       ^^^^^^^^^^^^^^ `NotDebug` cannot be formatted using `{:?}` because it doesn't implement `Debug`
+   |                       ^^^^^^^^^^^^^^ the trait `Debug` is not implemented for `NotDebug`
    |
-   = help: the trait `Debug` is not implemented for `NotDebug`
    = note: add `#[derive(Debug)]` to `NotDebug` or manually `impl Debug for NotDebug`
-   = note: required for `&NotDebug` to implement `Debug`
-   = note: this error originates in the macro `$crate::format_args_nl` which comes from the expansion of the macro `dbg` (in Nightly builds, run with -Z macro-backtrace for more info)
+   = note: this error originates in the macro `dbg` (in Nightly builds, run with -Z macro-backtrace for more info)
 help: consider annotating `NotDebug` with `#[derive(Debug)]`
    |
 LL + #[derive(Debug)]