Move `finish` out of the `Encoder` trait.

This simplifies things, but requires making `CacheEncoder` non-generic.

(This was previously merged as commit 4 in #94732 and then was reverted
in #97905 because it caused a perf regression.)

1 files changed, 1 insertions, 8 deletions

diff --git a/compiler/rustc_metadata/src/rmeta/encoder.rs b/compiler/rustc_metadata/src/rmeta/encoder.rs
index 91ca4ecf3e1..2db0800190a 100644
--- a/compiler/rustc_metadata/src/rmeta/encoder.rs
+++ b/compiler/rustc_metadata/src/rmeta/encoder.rs
@@ -94,9 +94,6 @@ macro_rules! encoder_methods {
 }
 
 impl<'a, 'tcx> Encoder for EncodeContext<'a, 'tcx> {
-    type Ok = <MemEncoder as Encoder>::Ok;
-    type Err = <MemEncoder as Encoder>::Err;
-
     encoder_methods! {
         emit_usize(usize);
         emit_u128(u128);
@@ -119,10 +116,6 @@ impl<'a, 'tcx> Encoder for EncodeContext<'a, 'tcx> {
         emit_str(&str);
         emit_raw_bytes(&[u8]);
     }
-
-    fn finish(self) -> Result<Self::Ok, Self::Err> {
-        self.opaque.finish()
-    }
 }
 
 impl<'a, 'tcx, T> Encodable<EncodeContext<'a, 'tcx>> for LazyValue<T> {
@@ -2216,7 +2209,7 @@ fn encode_metadata_impl(tcx: TyCtxt<'_>) -> EncodedMetadata {
     // culminating in the `CrateRoot` which points to all of it.
     let root = ecx.encode_crate_root();
 
-    let mut result = ecx.opaque.finish().unwrap();
+    let mut result = ecx.opaque.finish();
 
     // Encode the root position.
     let header = METADATA_HEADER.len();