Add extended error message for E0523

Adds the extended error documentation for E0523 to indicate that the
error is no longer produced by the compiler.

Update the E0464 documentation to include example code that produces the
error.

Remove the error message E0523 from the compiler and replace it with an
internal compiler error.

1 files changed, 6 insertions, 1 deletions

diff --git a/compiler/rustc_metadata/src/creader.rs b/compiler/rustc_metadata/src/creader.rs
index 21652063b47..bf8b8aa2ce4 100644
--- a/compiler/rustc_metadata/src/creader.rs
+++ b/compiler/rustc_metadata/src/creader.rs
@@ -356,7 +356,12 @@ impl<'a> CrateLoader<'a> {
         for (_, other) in self.cstore.iter_crate_data() {
             // Same stable crate id but different SVH
             if other.stable_crate_id() == root.stable_crate_id() && other.hash() != root.hash() {
-                return Err(CrateError::SymbolConflictsOthers(root.name()));
+                bug!(
+                    "Previously returned E0523 here. \
+                     See https://github.com/rust-lang/rust/pull/100599 for additional discussion.\
+                     root.name() = {}.",
+                    root.name()
+                );
             }
         }