Descriptive variant name deprecation versions outside the standard library

compiler/rustc_attr/src/builtin.rs

@@ -737,7 +737,7 @@ pub enum DeprecatedSince {
     Future,
     /// `feature(staged_api)` is off. Deprecation versions outside the standard
     /// library are allowed to be arbitrary strings, for better or worse.
-    Symbol(Symbol),
+    NonStandard(Symbol),
     /// Deprecation version is unspecified but optional.
     Unspecified,
     /// Failed to parse a deprecation version, or the deprecation version is
@@ -754,7 +754,7 @@ impl Deprecation {
             DeprecatedSince::RustcVersion(since) => since <= RustcVersion::CURRENT,
             DeprecatedSince::Future => false,
             // The `since` field doesn't have semantic purpose without `#![staged_api]`.
-            DeprecatedSince::Symbol(_) => true,
+            DeprecatedSince::NonStandard(_) => true,
             // Assume deprecation is in effect if "since" field is absent or invalid.
             DeprecatedSince::Unspecified | DeprecatedSince::Err => true,
         }
@@ -871,7 +871,7 @@ pub fn find_deprecation(
             if since.as_str() == "TBD" {
                 DeprecatedSince::Future
             } else if !is_rustc {
-                DeprecatedSince::Symbol(since)
+                DeprecatedSince::NonStandard(since)
             } else if let Some(version) = parse_version(since) {
                 DeprecatedSince::RustcVersion(version)
             } else {

compiler/rustc_middle/src/middle/stability.rs

@@ -162,7 +162,9 @@ fn deprecation_message(
             DeprecatedSince::Future => {
                 format!("use of {kind} `{path}` that will be deprecated in a future Rust version")
             }
-            DeprecatedSince::Symbol(_) | DeprecatedSince::Unspecified | DeprecatedSince::Err => {
+            DeprecatedSince::NonStandard(_)
+            | DeprecatedSince::Unspecified
+            | DeprecatedSince::Err => {
                 unreachable!("this deprecation is always in effect; {since:?}")
             }
         }

src/librustdoc/html/render/mod.rs

@@ -628,7 +628,7 @@ fn short_item_info(
                 }
             }
             DeprecatedSince::Future => String::from("Deprecating in a future Rust version"),
-            DeprecatedSince::Symbol(since) => {
+            DeprecatedSince::NonStandard(since) => {
                 format!("Deprecated since {}", Escape(since.as_str()))
             }
             DeprecatedSince::Unspecified | DeprecatedSince::Err => String::from("Deprecated"),

src/librustdoc/json/conversions.rs

@@ -143,7 +143,7 @@ pub(crate) fn from_deprecation(deprecation: rustc_attr::Deprecation) -> Deprecat
     let since = match since {
         DeprecatedSince::RustcVersion(version) => Some(version.to_string()),
         DeprecatedSince::Future => Some("TBD".to_owned()),
-        DeprecatedSince::Symbol(since) => Some(since.to_string()),
+        DeprecatedSince::NonStandard(since) => Some(since.to_string()),
         DeprecatedSince::Unspecified | DeprecatedSince::Err => None,
     };
     Deprecation { since, note: note.map(|s| s.to_string()) }