diff --git a/clippy_lints/src/functions/not_unsafe_ptr_arg_deref.rs b/clippy_lints/src/functions/not_unsafe_ptr_arg_deref.rs
index 6d829a18b2e..834f6d2425e 100644
--- a/clippy_lints/src/functions/not_unsafe_ptr_arg_deref.rs
+++ b/clippy_lints/src/functions/not_unsafe_ptr_arg_deref.rs
@@ -42,8 +42,7 @@ fn check_raw_ptr<'tcx>(
     let expr = &body.value;
     if unsafety == hir::Unsafety::Normal && cx.access_levels.is_exported(def_id) {
         let raw_ptrs = iter_input_pats(decl, body)
-            .zip(decl.inputs.iter())
-            .filter_map(|(arg, ty)| raw_ptr_arg(arg, ty))
+            .filter_map(|arg| raw_ptr_arg(cx, arg))
             .collect::<HirIdSet>();
 
         if !raw_ptrs.is_empty() {
@@ -59,8 +58,12 @@ fn check_raw_ptr<'tcx>(
     }
 }
 
-fn raw_ptr_arg(arg: &hir::Param<'_>, ty: &hir::Ty<'_>) -> Option<hir::HirId> {
-    if let (&hir::PatKind::Binding(_, id, _, _), &hir::TyKind::Ptr(_)) = (&arg.pat.kind, &ty.kind) {
+fn raw_ptr_arg(cx: &LateContext<'_>, arg: &hir::Param<'_>) -> Option<hir::HirId> {
+    if let (&hir::PatKind::Binding(_, id, _, _), Some(&ty::RawPtr(_))) = (
+        &arg.pat.kind,
+        cx.maybe_typeck_results()
+            .map(|typeck_results| typeck_results.pat_ty(arg.pat).kind()),
+    ) {
         Some(id)
     } else {
         None
diff --git a/tests/ui/functions.rs b/tests/ui/functions.rs
index 271754cb06e..5521870eaec 100644
--- a/tests/ui/functions.rs
+++ b/tests/ui/functions.rs
@@ -78,6 +78,14 @@ pub fn public(p: *const u8) {
     unsafe { std::ptr::read(p) };
 }
 
+type Alias = *const u8;
+
+pub fn type_alias(p: Alias) {
+    println!("{}", unsafe { *p });
+    println!("{:?}", unsafe { p.as_ref() });
+    unsafe { std::ptr::read(p) };
+}
+
 impl Bar {
     fn private(self, p: *const u8) {
         println!("{}", unsafe { *p });
diff --git a/tests/ui/functions.stderr b/tests/ui/functions.stderr
index a2b8c2a384b..8ebd4997f4f 100644
--- a/tests/ui/functions.stderr
+++ b/tests/ui/functions.stderr
@@ -69,22 +69,40 @@ LL |     unsafe { std::ptr::read(p) };
    |                             ^
 
 error: this public function might dereference a raw pointer but is not marked `unsafe`
-  --> $DIR/functions.rs:87:34
+  --> $DIR/functions.rs:84:30
+   |
+LL |     println!("{}", unsafe { *p });
+   |                              ^
+
+error: this public function might dereference a raw pointer but is not marked `unsafe`
+  --> $DIR/functions.rs:85:31
+   |
+LL |     println!("{:?}", unsafe { p.as_ref() });
+   |                               ^
+
+error: this public function might dereference a raw pointer but is not marked `unsafe`
+  --> $DIR/functions.rs:86:29
+   |
+LL |     unsafe { std::ptr::read(p) };
+   |                             ^
+
+error: this public function might dereference a raw pointer but is not marked `unsafe`
+  --> $DIR/functions.rs:95:34
    |
 LL |         println!("{}", unsafe { *p });
    |                                  ^
 
 error: this public function might dereference a raw pointer but is not marked `unsafe`
-  --> $DIR/functions.rs:88:35
+  --> $DIR/functions.rs:96:35
    |
 LL |         println!("{:?}", unsafe { p.as_ref() });
    |                                   ^
 
 error: this public function might dereference a raw pointer but is not marked `unsafe`
-  --> $DIR/functions.rs:89:33
+  --> $DIR/functions.rs:97:33
    |
 LL |         unsafe { std::ptr::read(p) };
    |                                 ^
 
-error: aborting due to 13 previous errors
+error: aborting due to 16 previous errors