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| author | Manish Goregaokar <manishsmail@gmail.com> | 2019-05-17 11:34:13 -0700 |
|---|---|---|
| committer | GitHub <noreply@github.com> | 2019-05-17 11:34:13 -0700 |
| commit | f48f37b052bd2683ff89037001d794f5ffac9e5b (patch) | |
| tree | 4fb7f1a6229a9d360d01861a3c90eff426a2f910 | |
| parent | ba0e2518c852f844a8975c2e4b1d5814dd2d11c8 (diff) | |
| parent | 686a611b9e19b487a70fccc960ea0e16e71de988 (diff) | |
| download | rust-f48f37b052bd2683ff89037001d794f5ffac9e5b.tar.gz rust-f48f37b052bd2683ff89037001d794f5ffac9e5b.zip | |
Rollup merge of #60902 - sfackler:fix-error-soudness, r=alexcrichton
Prevent Error::type_id overrides type_id now takes an argument that can't be named outside of the std::error module, which prevents any implementations from overriding it. It's a pretty grody solution, and there's no way we can stabilize the method with this API, but it avoids the soudness issue! Closes #60784 r? @alexcrichton
| -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..62282006a40 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 |