Add tracking issue number

Author: ehuss

Diff for: src/bin/cargo/commands/clean.rs

@@ -176,10 +176,12 @@ pub fn exec(config: &mut Config, args: &ArgMatches) -> CliResult {
     }
 
     let unstable_gc = |opt| {
-        // TODO: issue number
-        config
-            .cli_unstable()
-            .fail_if_stable_opt_custom_z(opt, 0, "gc", config.cli_unstable().gc)
+        config.cli_unstable().fail_if_stable_opt_custom_z(
+            opt,
+            12633,
+            "gc",
+            config.cli_unstable().gc,
+        )
     };
     let unstable_cache_opt = |opt| -> CargoResult<Option<&str>> {
         let arg = args.get_one::<String>(opt).map(String::as_str);

Diff for: tests/testsuite/clean.rs

@@ -685,7 +685,7 @@ fn clean_dry_run_gated() {
         .with_stderr("\
 error: the `dry-run` flag is unstable, and only available on the nightly channel of Cargo, but this is the `stable` channel
 See https://doc.rust-lang.org/book/appendix-07-nightly-rust.html for more information about Rust release channels.
-See https://github.com/rust-lang/cargo/issues/0 for more information about the `dry-run` flag.
+See https://github.com/rust-lang/cargo/issues/12633 for more information about the `dry-run` flag.
 ")
         .run();
 }