Step all bootstrap cfgs forward

This also takes care of other bootstrap-related changes.

compiler/rustc_index_macros/src/lib.rs

@@ -31,17 +31,17 @@ mod newtype;
 /// - `#[max = 0xFFFF_FFFD]`: specifies the max value, which allows niche
 ///   optimizations. The default max value is 0xFFFF_FF00.
 /// - `#[gate_rustc_only]`: makes parts of the generated code nightly-only.
-///
-/// `SpecOptionPartialEq` is specialized by this macro, so using it requires enabling
-/// `#![feature(min_specialization)]` for the crate.
 #[proc_macro]
 #[cfg_attr(
     feature = "nightly",
-    allow_internal_unstable(step_trait, rustc_attrs, trusted_step, spec_option_partial_eq)
+    allow_internal_unstable(
+        step_trait,
+        rustc_attrs,
+        trusted_step,
+        spec_option_partial_eq,
+        min_specialization
+    )
 )]
-// FIXME: Remove the above comment about `min_specialization` once bootstrap is bumped,
-// and the corresponding one on SpecOptionPartialEq
-#[cfg_attr(all(feature = "nightly", not(bootstrap)), allow_internal_unstable(min_specialization))]
 pub fn newtype_index(input: TokenStream) -> TokenStream {
     newtype::newtype(input)
 }