addresss reviews

Author: tesuji

alloc/Cargo.toml

@@ -43,9 +43,12 @@ optimize_for_size = ["core/optimize_for_size"]
 
 [lints.rust.unexpected_cfgs]
 level = "warn"
+# x.py uses beta cargo, so `check-cfg` entries do not yet take effect
+# for rust-lang/rust. But for users of `-Zbuild-std` it does.
+# The unused warning is waiting for rust-lang/cargo#13925 to reach beta.
 check-cfg = [
-    'cfg(no_global_oom_handling)',
     'cfg(bootstrap)',
+    'cfg(no_global_oom_handling)',
     'cfg(no_rc)',
     'cfg(no_sync)',
 ]

core/Cargo.toml

@@ -39,9 +39,13 @@ debug_refcell = []
 
 [lints.rust.unexpected_cfgs]
 level = "warn"
+# x.py uses beta cargo, so `check-cfg` entries do not yet take effect
+# for rust-lang/rust. But for users of `-Zbuild-std` it does.
+# The unused warning is waiting for rust-lang/cargo#13925 to reach beta.
 check-cfg = [
     'cfg(no_fp_fmt_parse)',
     'cfg(bootstrap)',
     'cfg(stdarch_intel_sde)',
-    'cfg(feature, values("all_lane_counts"))',
+    # This matches `EXTRA_CHECK_CFGS` in `src/bootstrap/src/lib.rs`.
+    'cfg(feature, values(any()))',
 ]