inout: Avoid implicit conversions to error::Unspecified.

src/aead/aes_gcm.rs

@@ -18,6 +18,7 @@ use super::{
 };
 use crate::{
     cpu, error,
+    inout::overlapping::SrcIndexError,
     polyfill::{slice, sliceutil::overwrite_at_start, usize_from_u64_saturated},
 };
 use core::ops::RangeFrom;
@@ -276,7 +277,8 @@ pub(super) fn open(
     src: RangeFrom<usize>,
 ) -> Result<Tag, error::Unspecified> {
     #[cfg(any(target_arch = "aarch64", target_arch = "x86_64"))]
-    let in_out = Overlapping::new(in_out_slice, src.clone())?;
+    let in_out =
+        Overlapping::new(in_out_slice, src.clone()).map_err(error::erase::<SrcIndexError>)?;
 
     let mut ctr = Counter::one(nonce);
     let tag_iv = ctr.increment();
@@ -332,7 +334,8 @@ pub(super) fn open(
             let whole_len = slice::flatten(whole).len();
 
             // Decrypt any remaining whole blocks.
-            let whole = Overlapping::new(&mut in_out[..(src.start + whole_len)], src.clone())?;
+            let whole = Overlapping::new(&mut in_out[..(src.start + whole_len)], src.clone())
+                .map_err(error::erase::<SrcIndexError>)?;
             aes_key.ctr32_encrypt_within(whole, &mut ctr);
 
             let in_out = match in_out.get_mut(whole_len..) {
@@ -452,7 +455,8 @@ fn open_strided<A: aes::EncryptBlock + aes::EncryptCtr32, G: gcm::UpdateBlocks +
             let chunk = Overlapping::new(
                 &mut in_out[output..][..(chunk_len + in_prefix_len)],
                 in_prefix_len..,
-            )?;
+            )
+            .map_err(error::erase::<SrcIndexError>)?;
             aes_key.ctr32_encrypt_within(chunk, &mut ctr);
             output += chunk_len;
             input += chunk_len;

src/inout/overlapping/mod.rs

@@ -12,6 +12,6 @@
 // OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
 // CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 
-pub use self::overlapping::Overlapping;
+pub use self::overlapping::{Overlapping, SrcIndexError};
 
 mod overlapping;

src/inout/overlapping/overlapping.rs

@@ -12,7 +12,6 @@
 // OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
 // CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 
-use crate::error;
 use core::ops::RangeFrom;
 
 pub struct Overlapping<'o, T> {
@@ -63,9 +62,3 @@ impl SrcIndexError {
         Self(src)
     }
 }
-
-impl From<SrcIndexError> for error::Unspecified {
-    fn from(_: SrcIndexError) -> Self {
-        Self
-    }
-}