diff --git a/compiler/rustc_interface/src/tests.rs b/compiler/rustc_interface/src/tests.rs
index 316e2e29cd8b3..a3b9891ee64e9 100644
--- a/compiler/rustc_interface/src/tests.rs
+++ b/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 {
@@ -754,7 +754,7 @@ fn test_unstable_options_tracking_hash() {
     tracked!(mir_enable_passes, vec![("DestProp".to_string(), false)]);
     tracked!(mir_opt_level, Some(4));
     tracked!(move_size_limit, Some(4096));
-    tracked!(mutable_noalias, Some(true));
+    tracked!(mutable_noalias, false);
     tracked!(no_generate_arange_section, true);
     tracked!(no_jump_tables, true);
     tracked!(no_link, true);
diff --git a/compiler/rustc_session/src/options.rs b/compiler/rustc_session/src/options.rs
index 043a60a1c5310..994be8d5f85fe 100644
--- a/compiler/rustc_session/src/options.rs
+++ b/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"),
@@ -1437,7 +1437,7 @@ options! {
         "use line numbers relative to the function in mir pretty printing"),
     move_size_limit: Option<usize> = (None, parse_opt_number, [TRACKED],
         "the size at which the `large_assignments` lint starts to be emitted"),
-    mutable_noalias: Option<bool> = (None, parse_opt_bool, [TRACKED],
+    mutable_noalias: bool = (true, parse_bool, [TRACKED],
         "emit noalias metadata for mutable references (default: yes)"),
     nll_facts: bool = (false, parse_bool, [UNTRACKED],
         "dump facts from NLL analysis into side files (default: no)"),
diff --git a/compiler/rustc_ty_utils/src/abi.rs b/compiler/rustc_ty_utils/src/abi.rs
index f8a5691f29de0..d1197774fe96c 100644
--- a/compiler/rustc_ty_utils/src/abi.rs
+++ b/compiler/rustc_ty_utils/src/abi.rs
@@ -254,12 +254,12 @@ 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
             // versions at all anymore. We still support turning it off using -Zmutable-noalias.
-            let noalias_mut_ref = cx.tcx.sess.opts.unstable_opts.mutable_noalias.unwrap_or(true);
+            let noalias_mut_ref = cx.tcx.sess.opts.unstable_opts.mutable_noalias;
 
             // `&mut` pointer parameters never alias other parameters,
             // or mutable global data