diff --git a/compiler/rustc_symbol_mangling/src/typeid/typeid_itanium_cxx_abi.rs b/compiler/rustc_symbol_mangling/src/typeid/typeid_itanium_cxx_abi.rs
index da8a16dee8a..da3dafedd9b 100644
--- a/compiler/rustc_symbol_mangling/src/typeid/typeid_itanium_cxx_abi.rs
+++ b/compiler/rustc_symbol_mangling/src/typeid/typeid_itanium_cxx_abi.rs
@@ -608,9 +608,7 @@ fn encode_ty<'tcx>(
         }
 
         // Function types
-        ty::FnDef(def_id, substs)
-        | ty::Closure(def_id, substs)
-        | ty::Generator(def_id, substs, ..) => {
+        ty::FnDef(def_id, substs) | ty::Closure(def_id, substs) => {
             // u<length><name>[I<element-type1..element-typeN>E], where <element-type> is <subst>,
             // as vendor extended type.
             let mut s = String::new();
@@ -621,6 +619,23 @@ fn encode_ty<'tcx>(
             typeid.push_str(&s);
         }
 
+        ty::Generator(def_id, substs, ..) => {
+            // u<length><name>[I<element-type1..element-typeN>E], where <element-type> is <subst>,
+            // as vendor extended type.
+            let mut s = String::new();
+            let name = encode_ty_name(tcx, *def_id);
+            let _ = write!(s, "u{}{}", name.len(), &name);
+            // Encode parent substs only
+            s.push_str(&encode_substs(
+                tcx,
+                tcx.mk_substs(substs.as_generator().parent_substs()),
+                dict,
+                options,
+            ));
+            compress(dict, DictKey::Ty(ty, TyQ::None), &mut s);
+            typeid.push_str(&s);
+        }
+
         // Pointer types
         ty::Ref(region, ty0, ..) => {
             // [U3mut]u3refI<element-type>E as vendor extended type qualifier and type
@@ -739,7 +754,12 @@ fn transform_ty<'tcx>(tcx: TyCtxt<'tcx>, ty: Ty<'tcx>, options: TransformTyOptio
     let mut ty = ty;
 
     match ty.kind() {
-        ty::Float(..) | ty::Char | ty::Str | ty::Never | ty::Foreign(..) => {}
+        ty::Float(..)
+        | ty::Char
+        | ty::Str
+        | ty::Never
+        | ty::Foreign(..)
+        | ty::GeneratorWitness(..) => {}
 
         ty::Bool => {
             if options.contains(EncodeTyOptions::NORMALIZE_INTEGERS) {
@@ -922,7 +942,6 @@ fn transform_ty<'tcx>(tcx: TyCtxt<'tcx>, ty: Ty<'tcx>, options: TransformTyOptio
 
         ty::Bound(..)
         | ty::Error(..)
-        | ty::GeneratorWitness(..)
         | ty::GeneratorWitnessMIR(..)
         | ty::Infer(..)
         | ty::Alias(..)
diff --git a/tests/ui/sanitize/issue-111184-generator-witness.rs b/tests/ui/sanitize/issue-111184-generator-witness.rs
new file mode 100644
index 00000000000..8f4118057ce
--- /dev/null
+++ b/tests/ui/sanitize/issue-111184-generator-witness.rs
@@ -0,0 +1,17 @@
+// Regression test for issue 111184, where ty::GeneratorWitness were not expected to occur in
+// encode_ty and caused the compiler to ICE.
+//
+// needs-sanitizer-cfi
+// compile-flags: -Clto -Ctarget-feature=-crt-static -Zsanitizer=cfi --edition=2021
+// no-prefer-dynamic
+// only-x86_64-unknown-linux-gnu
+// run-pass
+
+use std::future::Future;
+
+async fn foo() {}
+fn bar<T>(_: impl Future<Output = T>) {}
+
+fn main() {
+    bar(foo());
+}