about summary refs log tree commit diff
path: root/compiler/rustc_feature/src
diff options
context:
space:
mode:
Diffstat (limited to 'compiler/rustc_feature/src')
-rw-r--r--compiler/rustc_feature/src/builtin_attrs.rs6
1 files changed, 4 insertions, 2 deletions
diff --git a/compiler/rustc_feature/src/builtin_attrs.rs b/compiler/rustc_feature/src/builtin_attrs.rs
index fa5f152132a..efb582fde1b 100644
--- a/compiler/rustc_feature/src/builtin_attrs.rs
+++ b/compiler/rustc_feature/src/builtin_attrs.rs
@@ -859,8 +859,10 @@ pub const BUILTIN_ATTRIBUTES: &[BuiltinAttribute] = &[
     rustc_attr!(
         rustc_nonnull_optimization_guaranteed, Normal, template!(Word), WarnFollowing,
         EncodeCrossCrate::Yes,
-        "the `#[rustc_nonnull_optimization_guaranteed]` attribute is just used to enable \
-        niche optimizations in libcore and libstd and will never be stable",
+        "the `#[rustc_nonnull_optimization_guaranteed]` attribute is just used to document \
+        guaranteed niche optimizations in libcore and libstd and will never be stable\n\
+        (note that the compiler does not even check whether the type indeed is being non-null-optimized; \
+        it is your responsibility to ensure that the attribute is only used on types that are optimized)",
     ),
 
     // ==========================================================================