From b3631e1174e222bf1dadf1549cfd0f717ebf6d64 Mon Sep 17 00:00:00 2001
From: Jana Dönszelmann <jana@donsz.nl>
Date: Tue, 16 Sep 2025 11:52:17 -0700
Subject: improve empty attribute diagnostic

---
 tests/ui/attributes/empty-repr.stderr         | 1 +
 tests/ui/empty/empty-attributes.stderr        | 4 ++++
 tests/ui/macros/macro-use-all-and-none.stderr | 3 ++-
 tests/ui/repr/repr-empty-packed.stderr        | 1 +
 4 files changed, 8 insertions(+), 1 deletion(-)

(limited to 'tests/ui')

diff --git a/tests/ui/attributes/empty-repr.stderr b/tests/ui/attributes/empty-repr.stderr
index 92901fa170c..6dfa2df75b7 100644
--- a/tests/ui/attributes/empty-repr.stderr
+++ b/tests/ui/attributes/empty-repr.stderr
@@ -4,6 +4,7 @@ error: unused attribute
 LL | #[repr()]
    | ^^^^^^^^^ help: remove this attribute
    |
+   = note: using `repr` with an empty list has no effect
 note: the lint level is defined here
   --> $DIR/empty-repr.rs:4:9
    |
diff --git a/tests/ui/empty/empty-attributes.stderr b/tests/ui/empty/empty-attributes.stderr
index f0be56ddc6a..41dc790737d 100644
--- a/tests/ui/empty/empty-attributes.stderr
+++ b/tests/ui/empty/empty-attributes.stderr
@@ -56,12 +56,16 @@ error: unused attribute
    |
 LL | #[repr()]
    | ^^^^^^^^^ help: remove this attribute
+   |
+   = note: using `repr` with an empty list has no effect
 
 error: unused attribute
   --> $DIR/empty-attributes.rs:12:1
    |
 LL | #[target_feature()]
    | ^^^^^^^^^^^^^^^^^^^ help: remove this attribute
+   |
+   = note: using `target_feature` with an empty list has no effect
 
 error: aborting due to 8 previous errors
 
diff --git a/tests/ui/macros/macro-use-all-and-none.stderr b/tests/ui/macros/macro-use-all-and-none.stderr
index a5efb065a21..b4c05adcb33 100644
--- a/tests/ui/macros/macro-use-all-and-none.stderr
+++ b/tests/ui/macros/macro-use-all-and-none.stderr
@@ -2,8 +2,9 @@ warning: unused attribute
   --> $DIR/macro-use-all-and-none.rs:7:12
    |
 LL | #[macro_use()]
-   |            ^^ help: remove this attribute
+   |            ^^ help: remove these parentheses
    |
+   = note: using `macro_use` with an empty list is equivalent to not using a list at all
 note: the lint level is defined here
   --> $DIR/macro-use-all-and-none.rs:4:9
    |
diff --git a/tests/ui/repr/repr-empty-packed.stderr b/tests/ui/repr/repr-empty-packed.stderr
index 6565b2e8c1d..adf32c95529 100644
--- a/tests/ui/repr/repr-empty-packed.stderr
+++ b/tests/ui/repr/repr-empty-packed.stderr
@@ -15,6 +15,7 @@ error: unused attribute
 LL | #[repr()]
    | ^^^^^^^^^ help: remove this attribute
    |
+   = note: using `repr` with an empty list has no effect
 note: the lint level is defined here
   --> $DIR/repr-empty-packed.rs:2:9
    |
-- 
cgit 1.4.1-3-g733a5