Auto merge of #60386 - Goirad:sgx-ignore-tests, r=nikomatsakis

[rust.git] / src / libstd / error.rs

diff --git a/src/libstd/error.rs b/src/libstd/error.rs
index 081fff0562b162c224b66177de7f870b1aae299b..62282006a40248df320c8eedc5c99c37b5b4683c 100644 (file)
--- a/src/libstd/error.rs
+++ b/src/libstd/error.rs
@@ -197,12 +197,23 @@ fn cause(&self) -> Option<&dyn Error> {
     fn source(&self) -> Option<&(dyn Error + 'static)> { None }
 
     /// Gets the `TypeId` of `self`
-    #[stable(feature = "error_type_id", since = "1.34.0")]
-    fn type_id(&self) -> TypeId where Self: 'static {
+    #[doc(hidden)]
+    #[unstable(feature = "error_type_id",
+               reason = "this is memory unsafe to override in user code",
+               issue = "60784")]
+    fn type_id(&self, _: private::Internal) -> TypeId where Self: 'static {
         TypeId::of::<Self>()
     }
 }
 
+mod private {
+    // This is a hack to prevent `type_id` from being overridden by `Error`
+    // implementations, since that can enable unsound downcasting.
+    #[unstable(feature = "error_type_id", issue = "60784")]
+    #[derive(Debug)]
+    pub struct Internal;
+}
+
 #[stable(feature = "rust1", since = "1.0.0")]
 impl<'a, E: Error + 'a> From<E> for Box<dyn Error + 'a> {
     /// Converts a type of [`Error`] into a box of dyn [`Error`].
@@ -572,7 +583,7 @@ pub fn is<T: Error + 'static>(&self) -> bool {
         let t = TypeId::of::<T>();
 
         // Get TypeId of the type in the trait object
-        let boxed = self.type_id();
+        let boxed = self.type_id(private::Internal);
 
         // Compare both TypeIds on equality
         t == boxed