diff --git a/cpp2rust/converter/rules/rules_loader.cpp b/cpp2rust/converter/rules/rules_loader.cpp
index d1b69f724..6460f1cc9 100644
--- a/cpp2rust/converter/rules/rules_loader.cpp
+++ b/cpp2rust/converter/rules/rules_loader.cpp
@@ -524,7 +524,7 @@ std::string TypeKey(clang::QualType type) {
     type = typeof_type->getUnderlyingExpr()->getType();
   }
   if (auto alias = type->getAs<clang::TypedefType>();
-      alias && type.getCanonicalType()->isBuiltinType()) {
+      alias && !type.getCanonicalType()->getAsTagDecl()) {
     return DeclKey(alias->getDecl());
   }
   if (auto sugar = type->getAs<clang::PredefinedSugarType>()) {
diff --git a/cpp2rust/rule_preprocessing/cpp_rule_indexer.cpp b/cpp2rust/rule_preprocessing/cpp_rule_indexer.cpp
index 240daa824..e3f3fda4a 100644
--- a/cpp2rust/rule_preprocessing/cpp_rule_indexer.cpp
+++ b/cpp2rust/rule_preprocessing/cpp_rule_indexer.cpp
@@ -215,6 +215,9 @@ std::string ExprKey(clang::ASTContext &ctx, const clang::Decl *rule) {
 
 std::string TypeKey(const clang::TypedefNameDecl *rule) {
   auto type = rule->getUnderlyingType();
+  if (auto key = RulesLoader::TypeKey(type); !key.empty()) {
+    return key;
+  }
   while (type->isPointerType() || type->isReferenceType()) {
     type = type->getPointeeType();
   }
diff --git a/rules/signal/src.c b/rules/signal/src.c
index 516ab7fb2..1601cc42c 100644
--- a/rules/signal/src.c
+++ b/rules/signal/src.c
@@ -5,6 +5,8 @@
 #define _GNU_SOURCE
 #include <signal.h>
 
+typedef sig_t t1;
+
 int f1(int signum, const struct sigaction *act, struct sigaction *oldact) {
   return sigaction(signum, act, oldact);
 }
diff --git a/rules/signal/tgt_refcount.rs b/rules/signal/tgt_refcount.rs
new file mode 100644
index 000000000..865c1652e
--- /dev/null
+++ b/rules/signal/tgt_refcount.rs
@@ -0,0 +1,8 @@
+// Copyright (c) 2022-present INESC-ID.
+// Distributed under the MIT license that can be found in the LICENSE file.
+
+use libcc2rs::*;
+
+fn t1() -> FnPtr<fn(i32)> {
+    FnPtr::null()
+}
diff --git a/rules/signal/tgt_unsafe.rs b/rules/signal/tgt_unsafe.rs
index dfa56f892..9908c19a2 100644
--- a/rules/signal/tgt_unsafe.rs
+++ b/rules/signal/tgt_unsafe.rs
@@ -1,6 +1,10 @@
 // Copyright (c) 2022-present INESC-ID.
 // Distributed under the MIT license that can be found in the LICENSE file.
 
+fn t1() -> Option<unsafe fn(i32)> {
+    None
+}
+
 unsafe fn f1(a0: i32, a1: *const ::libc::sigaction, a2: *mut ::libc::sigaction) -> i32 {
     libc::sigaction(a0, a1, a2)
 }
diff --git a/tests/unit/fn_ptr.cpp b/tests/unit/fn_ptr.cpp
index 25269cadb..cfe3d2a6e 100644
--- a/tests/unit/fn_ptr.cpp
+++ b/tests/unit/fn_ptr.cpp
@@ -1,5 +1,6 @@
 #include <assert.h>
 #include <cstddef>
+#include <signal.h>
 #include <stddef.h>
 
 typedef int (*foo_t)(void *);
@@ -28,6 +29,10 @@ template <class H> struct HashHolder {
   HashHolder(const H &h) : h(h) {}
 };
 
+static int total = 0;
+
+void add_to_total(int x) { total += x; }
+
 int main() {
   foo_t fn = nullptr;
   assert(fn == nullptr);
@@ -55,5 +60,10 @@ int main() {
 
   HashHolder<std::size_t (*)(bool)> hh(identity_hash<bool>);
   assert(hh.h(true) == 1);
+
+  sig_t handler = add_to_total;
+  handler(2);
+  handler(3);
+  assert(total == 5);
   return 0;
 }
diff --git a/tests/unit/out/refcount/fn_ptr.rs b/tests/unit/out/refcount/fn_ptr.rs
index 3f9112232..885ca183f 100644
--- a/tests/unit/out/refcount/fn_ptr.rs
+++ b/tests/unit/out/refcount/fn_ptr.rs
@@ -40,6 +40,12 @@ impl HashHolder_unsigned_long__ptr__bool__ {
         Self { h: (h.read()) }
     }
 }
+thread_local!(
+    pub static total_7: Value<i32> = Rc::new(RefCell::new(0));
+);
+pub fn add_to_total_8(mut x: i32) {
+    total_7.with(|rc| *rc.borrow_mut() += x);
+}
 pub fn main() {
     __cpp2rust_init_globals();
     std::process::exit(main_0());
@@ -71,6 +77,12 @@ fn main_0() -> i32 {
         HashHolder_unsigned_long__ptr__bool__::new({ __tmp_0.as_pointer() })
     };
     assert!((({ hh.h.call(true,) }) == 1_u64));
+    let mut handler: FnPtr<fn(i32)> = FnPtr::<fn(i32)>::new(add_to_total_8);
+    ({ handler.call(2) });
+    ({ handler.call(3) });
+    assert!((total_7.with(|rc| *rc.borrow()) == 5));
     return 0;
 }
-pub fn __cpp2rust_init_globals() {}
+pub fn __cpp2rust_init_globals() {
+    let _ = total_7.with(|_| ());
+}
diff --git a/tests/unit/out/unsafe/fn_ptr.rs b/tests/unit/out/unsafe/fn_ptr.rs
index 3d6032e46..b1c1ecf33 100644
--- a/tests/unit/out/unsafe/fn_ptr.rs
+++ b/tests/unit/out/unsafe/fn_ptr.rs
@@ -42,6 +42,10 @@ impl HashHolder_unsigned_long__ptr__bool__ {
         this
     }
 }
+pub static mut total_7: std::cell::LazyCell<i32> = std::cell::LazyCell::new(|| unsafe { 0 });
+pub unsafe fn add_to_total_8(mut x: i32) {
+    (*std::cell::LazyCell::force_mut(&mut *&raw mut total_7)) += x;
+}
 pub fn main() {
     unsafe {
         __cpp2rust_init_globals();
@@ -76,6 +80,12 @@ unsafe fn main_0() -> i32 {
         HashHolder_unsigned_long__ptr__bool__::new({ &mut __tmp_0 })
     };
     assert!(((unsafe { (hh.h).unwrap()(true,) }) == (1_u64)));
+    let mut handler: Option<unsafe fn(i32)> = Some(add_to_total_8);
+    (unsafe { (handler).unwrap()(2) });
+    (unsafe { (handler).unwrap()(3) });
+    assert!(((*std::cell::LazyCell::force_mut(&mut *&raw mut total_7)) == (5)));
     return 0;
 }
-pub unsafe fn __cpp2rust_init_globals() {}
+pub unsafe fn __cpp2rust_init_globals() {
+    std::cell::LazyCell::force(&*&raw const total_7);
+}