Expose a non-Symbol way to access current rustc version string

Author: dtolnay

Diff for: compiler/rustc_attr/src/builtin.rs

@@ -24,8 +24,10 @@ use crate::session_diagnostics::{self, IncorrectReprFormatGenericCause};
 /// For more, see [this pull request](https://github.com/rust-lang/rust/pull/100591).
 pub const VERSION_PLACEHOLDER: &str = "CURRENT_RUSTC_VERSION";
 
+pub const CURRENT_RUSTC_VERSION: &str = env!("CFG_RELEASE");
+
 pub fn rust_version_symbol() -> Symbol {
-    Symbol::intern(env!("CFG_RELEASE"))
+    Symbol::intern(CURRENT_RUSTC_VERSION)
 }
 
 pub fn is_builtin_attr(attr: &Attribute) -> bool {
@@ -629,7 +631,7 @@ pub fn eval_condition(
                 sess.emit_warning(session_diagnostics::UnknownVersionLiteral { span: *span });
                 return false;
             };
-            let rustc_version = parse_version(env!("CFG_RELEASE"), true).unwrap();
+            let rustc_version = parse_version(CURRENT_RUSTC_VERSION, true).unwrap();
 
             // See https://github.com/rust-lang/rust/issues/64796#issuecomment-640851454 for details
             if sess.assume_incomplete_release {

Diff for: src/librustdoc/html/render/mod.rs

@@ -48,7 +48,7 @@ use std::str;
 use std::string::ToString;
 
 use askama::Template;
-use rustc_attr::{rust_version_symbol, ConstStability, Deprecation, Since, StabilityLevel};
+use rustc_attr::{ConstStability, Deprecation, Since, StabilityLevel, CURRENT_RUSTC_VERSION};
 use rustc_data_structures::captures::Captures;
 use rustc_data_structures::fx::{FxHashMap, FxHashSet};
 use rustc_hir::def_id::{DefId, DefIdSet};
@@ -979,7 +979,7 @@ fn render_stability_since_raw_with_extra(
 fn since_to_string(since: &Since) -> Option<String> {
     match since {
         Since::Version(since) => Some(since.to_string()),
-        Since::Current => Some(rust_version_symbol().to_string()),
+        Since::Current => Some(CURRENT_RUSTC_VERSION.to_owned()),
         Since::Err => None,
     }
 }

Diff for: src/tools/clippy/clippy_utils/src/qualify_min_const_fn.rs

@@ -5,7 +5,7 @@
 
 use crate::msrvs::Msrv;
 use hir::LangItem;
-use rustc_attr::{rust_version_symbol, Since};
+use rustc_attr::{Since, CURRENT_RUSTC_VERSION};
 use rustc_const_eval::transform::check_consts::ConstCx;
 use rustc_hir as hir;
 use rustc_hir::def_id::DefId;
@@ -380,10 +380,9 @@ fn is_const_fn(tcx: TyCtxt<'_>, def_id: DefId, msrv: &Msrv) -> bool {
                     Since::Current => {
                         // HACK(nilstrieb): CURRENT_RUSTC_VERSION can return versions like 1.66.0-dev.
                         // `rustc-semver` doesn't accept the `-dev` version number so we have to strip it off.
-                        let current_rustc_version = rust_version_symbol();
-                        let short_version = current_rustc_version.as_str().split('-').next().unwrap();
+                        let short_version = CURRENT_RUSTC_VERSION.split('-').next().unwrap();
                         RustcVersion::parse(short_version).unwrap_or_else(|err| {
-                            panic!("`rustc_attr::StabilityLevel::Stable::since` is ill-formatted: `{current_rustc_version}`, {err:?}")
+                            panic!("`rustc_attr::StabilityLevel::Stable::since` is ill-formatted: `{CURRENT_RUSTC_VERSION}`, {err:?}")
                         })
                     },
                     Since::Err => return false,