diff --git a/example/issue-72793.rs b/example/issue-72793.rs
index 2e08fbca8ef2..95d58b90e798 100644
--- a/example/issue-72793.rs
+++ b/example/issue-72793.rs
@@ -2,23 +2,21 @@
 
 #![feature(type_alias_impl_trait)]
 
-mod helper {
-    pub trait T {
-        type Item;
-    }
-
-    pub type Alias<'a> = impl T<Item = &'a ()>;
-
-    struct S;
-    impl<'a> T for &'a S {
-        type Item = &'a ();
-    }
-
-    pub fn filter_positive<'a>() -> Alias<'a> {
-        &S
-    }
+pub trait T {
+    type Item;
+}
+
+pub type Alias<'a> = impl T<Item = &'a ()>;
+
+struct S;
+impl<'a> T for &'a S {
+    type Item = &'a ();
+}
+
+#[define_opaque(Alias)]
+pub fn filter_positive<'a>() -> Alias<'a> {
+    &S
 }
-use helper::*;
 
 fn with_positive(fun: impl Fn(Alias<'_>)) {
     fun(filter_positive());
diff --git a/patches/0029-stdlib-Disable-f16-and-f128-in-compiler-builtins.patch b/patches/0029-stdlib-Disable-f16-and-f128-in-compiler-builtins.patch
index d8db7d63f2dd..754025ff49db 100644
--- a/patches/0029-stdlib-Disable-f16-and-f128-in-compiler-builtins.patch
+++ b/patches/0029-stdlib-Disable-f16-and-f128-in-compiler-builtins.patch
@@ -12,15 +12,15 @@ index 7165c3e48af..968552ad435 100644
 --- a/library/alloc/Cargo.toml
 +++ b/library/alloc/Cargo.toml
 @@ -11,7 +11,7 @@ test = { path = "../test" }
- edition = "2021"
+ bench = false
  
  [dependencies]
  core = { path = "../core", public = true }
--compiler_builtins = { version = "=0.1.150", features = ['rustc-dep-of-std'] }
-+compiler_builtins = { version = "=0.1.150", features = ['rustc-dep-of-std', 'no-f16-f128'] }
+-compiler_builtins = { version = "=0.1.151", features = ['rustc-dep-of-std'] }
++compiler_builtins = { version = "=0.1.151", features = ['rustc-dep-of-std', 'no-f16-f128'] }
  
- [dev-dependencies]
- rand = { version = "0.8.5", default-features = false, features = ["alloc"] }
+ [features]
+ compiler-builtins-mem = ['compiler_builtins/mem']
 -- 
 2.34.1
 
diff --git a/src/lib.rs b/src/lib.rs
index 4d97c3ae6048..caaa06967ed8 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -175,13 +175,9 @@ impl CodegenBackend for CraneliftCodegenBackend {
         }
     }
 
-    fn target_features_cfg(
-        &self,
-        sess: &Session,
-        _allow_unstable: bool,
-    ) -> Vec<rustc_span::Symbol> {
+    fn target_features_cfg(&self, sess: &Session) -> (Vec<Symbol>, Vec<Symbol>) {
         // FIXME return the actually used target features. this is necessary for #[cfg(target_feature)]
-        if sess.target.arch == "x86_64" && sess.target.os != "none" {
+        let target_features = if sess.target.arch == "x86_64" && sess.target.os != "none" {
             // x86_64 mandates SSE2 support and rustc requires the x87 feature to be enabled
             vec![sym::fsxr, sym::sse, sym::sse2, Symbol::intern("x87")]
         } else if sess.target.arch == "aarch64" {
@@ -195,7 +191,10 @@ impl CodegenBackend for CraneliftCodegenBackend {
             }
         } else {
             vec![]
-        }
+        };
+        // FIXME do `unstable_target_features` properly
+        let unstable_target_features = target_features.clone();
+        (target_features, unstable_target_features)
     }
 
     fn print_version(&self) {