diff options
Diffstat (limited to 'src/libstd/error.rs')
| -rw-r--r-- | src/libstd/error.rs | 12 |
1 files changed, 10 insertions, 2 deletions
diff --git a/src/libstd/error.rs b/src/libstd/error.rs index 7cb830e751a..d2aa2195a35 100644 --- a/src/libstd/error.rs +++ b/src/libstd/error.rs @@ -201,11 +201,19 @@ pub trait Error: Debug + Display { #[unstable(feature = "error_type_id", reason = "this is memory unsafe to override in user code", issue = "60784")] - fn type_id(&self) -> TypeId where Self: 'static { + 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`]. @@ -575,7 +583,7 @@ impl dyn Error + 'static { 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 |