Change type of box_noalias to bool

Author: tmiasko

compiler/rustc_interface/src/tests.rs

@@ -715,7 +715,7 @@ fn test_unstable_options_tracking_hash() {
     tracked!(asm_comments, true);
     tracked!(assume_incomplete_release, true);
     tracked!(binary_dep_depinfo, true);
-    tracked!(box_noalias, Some(false));
+    tracked!(box_noalias, false);
     tracked!(
         branch_protection,
         Some(BranchProtection {

compiler/rustc_session/src/options.rs

@@ -1255,7 +1255,7 @@ options! {
     binary_dep_depinfo: bool = (false, parse_bool, [TRACKED],
         "include artifacts (sysroot, crate dependencies) used during compilation in dep-info \
         (default: no)"),
-    box_noalias: Option<bool> = (None, parse_opt_bool, [TRACKED],
+    box_noalias: bool = (true, parse_bool, [TRACKED],
         "emit noalias metadata for box (default: yes)"),
     branch_protection: Option<BranchProtection> = (None, parse_branch_protection, [TRACKED],
         "set options for branch target identification and pointer authentication on AArch64"),

compiler/rustc_ty_utils/src/abi.rs

@@ -254,7 +254,7 @@ fn adjust_for_rust_scalar<'tcx>(
             // The aliasing rules for `Box<T>` are still not decided, but currently we emit
             // `noalias` for it. This can be turned off using an unstable flag.
             // See https://github.com/rust-lang/unsafe-code-guidelines/issues/326
-            let noalias_for_box = cx.tcx.sess.opts.unstable_opts.box_noalias.unwrap_or(true);
+            let noalias_for_box = cx.tcx.sess.opts.unstable_opts.box_noalias;
 
             // LLVM prior to version 12 had known miscompiles in the presence of noalias attributes
             // (see #54878), so it was conditionally disabled, but we don't support earlier