diff --git a/src/lib.rs b/src/lib.rs
index 24eef4c..0f05ed7 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -1309,7 +1309,7 @@ macro_rules! __pin_project_internal {
             ),*
         )?
         {
-            fn drop($(mut $self1:ident)? $($self2:ident)?: Pin<&mut Self>) {
+            fn drop($($arg:ident)+: Pin<&mut Self>) {
                 $($tt:tt)*
             }
         }
@@ -1341,28 +1341,10 @@ macro_rules! __pin_project_internal {
                 //
                 // Users can implement [`Drop`] safely using `pin_project!` and can drop a
                 // type that implements `PinnedDrop` using the [`drop`] function safely.
-                trait __DropInner {
-                    fn __drop_inner(self: $crate::__private::Pin<&mut Self>);
-                }
-                impl $(<
-                    $( $lifetime $(: $lifetime_bound)? ,)*
-                    $( $generics
-                        $(: $generics_bound)?
-                        $(: ?$generics_unsized_bound)?
-                        $(: $generics_lifetime_bound)?
-                    ),*
-                >)? __DropInner for $self_ty
-                $(where
-                    $( $where_clause_ty
-                        $(: $where_clause_bound)?
-                        $(: ?$where_clause_unsized_bound)?
-                        $(: $where_clause_lifetime_bound)?
-                    ),*
-                )?
-                {
-                    fn __drop_inner($(mut $self1)? $($self2)?: $crate::__private::Pin<&mut Self>) {
-                        $($tt)*
-                    }
+                fn __drop_inner($($arg)+: $crate::__private::Pin<&mut $self_ty>) {
+                    // A dummy `__drop_inner` function to prevent users call outer `__drop_inner`.
+                    fn __drop_inner() {}
+                    $($tt)*
                 }
 
                 // Safety - we're in 'drop', so we know that 'self' will
@@ -1370,7 +1352,7 @@ macro_rules! __pin_project_internal {
                 let pinned_self = unsafe { $crate::__private::Pin::new_unchecked(self) };
                 // We call `__drop_inner` only once. Since `__DropInner::__drop_inner`
                 // is not accessible by the users, it is never called again.
-                __DropInner::__drop_inner(pinned_self);
+                __drop_inner(pinned_self);
             }
         }
     };
diff --git a/tests/expand/tests/expand/pinned_drop-enum.expanded.rs b/tests/expand/tests/expand/pinned_drop-enum.expanded.rs
index c2cb77a..b161edd 100644
--- a/tests/expand/tests/expand/pinned_drop-enum.expanded.rs
+++ b/tests/expand/tests/expand/pinned_drop-enum.expanded.rs
@@ -82,16 +82,12 @@ const _: () = {
     }
     impl<T, U> ::pin_project_lite::__private::Drop for Enum<T, U> {
         fn drop(&mut self) {
-            trait __DropInner {
-                fn __drop_inner(self: ::pin_project_lite::__private::Pin<&mut Self>);
-            }
-            impl<T, U> __DropInner for Enum<T, U> {
-                fn __drop_inner(self: ::pin_project_lite::__private::Pin<&mut Self>) {
-                    let _ = self;
-                }
+            fn __drop_inner(this: ::pin_project_lite::__private::Pin<&mut Enum<T, U>>) {
+                fn __drop_inner() {}
+                let _ = this;
             }
             let pinned_self = unsafe { ::pin_project_lite::__private::Pin::new_unchecked(self) };
-            __DropInner::__drop_inner(pinned_self);
+            __drop_inner(pinned_self);
         }
     }
 };
diff --git a/tests/expand/tests/expand/pinned_drop-enum.rs b/tests/expand/tests/expand/pinned_drop-enum.rs
index aca67fd..1855cb7 100644
--- a/tests/expand/tests/expand/pinned_drop-enum.rs
+++ b/tests/expand/tests/expand/pinned_drop-enum.rs
@@ -13,8 +13,8 @@ pin_project! {
         Unit,
     }
     impl<T, U> PinnedDrop for Enum<T, U> {
-        fn drop(self: Pin<&mut Self>) {
-            let _ = self;
+        fn drop(this: Pin<&mut Self>) {
+            let _ = this;
         }
     }
 }
diff --git a/tests/expand/tests/expand/pinned_drop-struct.expanded.rs b/tests/expand/tests/expand/pinned_drop-struct.expanded.rs
index 5a5d2b2..00587a1 100644
--- a/tests/expand/tests/expand/pinned_drop-struct.expanded.rs
+++ b/tests/expand/tests/expand/pinned_drop-struct.expanded.rs
@@ -74,16 +74,12 @@ const _: () = {
     }
     impl<T, U> ::pin_project_lite::__private::Drop for Struct<T, U> {
         fn drop(&mut self) {
-            trait __DropInner {
-                fn __drop_inner(self: ::pin_project_lite::__private::Pin<&mut Self>);
-            }
-            impl<T, U> __DropInner for Struct<T, U> {
-                fn __drop_inner(self: ::pin_project_lite::__private::Pin<&mut Self>) {
-                    let _ = self;
-                }
+            fn __drop_inner(this: ::pin_project_lite::__private::Pin<&mut Struct<T, U>>) {
+                fn __drop_inner() {}
+                let _ = this;
             }
             let pinned_self = unsafe { ::pin_project_lite::__private::Pin::new_unchecked(self) };
-            __DropInner::__drop_inner(pinned_self);
+            __drop_inner(pinned_self);
         }
     }
     #[forbid(safe_packed_borrows)]
diff --git a/tests/expand/tests/expand/pinned_drop-struct.rs b/tests/expand/tests/expand/pinned_drop-struct.rs
index 405d005..0cc7567 100644
--- a/tests/expand/tests/expand/pinned_drop-struct.rs
+++ b/tests/expand/tests/expand/pinned_drop-struct.rs
@@ -8,8 +8,8 @@ pin_project! {
         unpinned: U,
     }
     impl<T, U> PinnedDrop for Struct<T, U> {
-        fn drop(self: Pin<&mut Self>) {
-            let _ = self;
+        fn drop(this: Pin<&mut Self>) {
+            let _ = this;
         }
     }
 }
diff --git a/tests/test.rs b/tests/test.rs
index 1bb1850..35d2d8b 100644
--- a/tests/test.rs
+++ b/tests/test.rs
@@ -620,19 +620,32 @@ fn attrs() {
 #[test]
 fn pinned_drop() {
     pin_project! {
-        pub struct Struct<'a> {
+        pub struct Struct1<'a> {
             was_dropped: &'a mut bool,
             #[pin]
             field: u8,
         }
-        impl PinnedDrop for Struct<'_> {
-            fn drop(self: Pin<&mut Self>) {
-                **self.project().was_dropped = true;
+        impl PinnedDrop for Struct1<'_> {
+            fn drop(this: Pin<&mut Self>) {
+                **this.project().was_dropped = true;
             }
         }
     }
 
     let mut was_dropped = false;
-    drop(Struct { was_dropped: &mut was_dropped, field: 42 });
+    drop(Struct1 { was_dropped: &mut was_dropped, field: 42 });
     assert!(was_dropped);
+
+    pin_project! {
+        pub struct Struct2<'a> {
+            was_dropped: &'a mut bool,
+            #[pin]
+            field: u8,
+        }
+        impl PinnedDrop for Struct2<'_> {
+            fn drop(mut this: Pin<&mut Self>) {
+                **this.as_mut().project().was_dropped = true;
+            }
+        }
+    }
 }
diff --git a/tests/ui/pinned_drop-1.rs b/tests/ui/pinned_drop-1.rs
index 2e1d4e4..b701312 100644
--- a/tests/ui/pinned_drop-1.rs
+++ b/tests/ui/pinned_drop-1.rs
@@ -6,8 +6,8 @@ pin_project! {
         field: u8,
     }
     impl PinnedDrop for S {
-        fn drop(self: Pin<&mut Self>) {
-            self.__drop_inner();
+        fn drop(this: Pin<&mut Self>) {
+            this.__drop_inner();
         }
     }
 }
diff --git a/tests/ui/pinned_drop-1.stderr b/tests/ui/pinned_drop-1.stderr
new file mode 100644
index 0000000..8730543
--- /dev/null
+++ b/tests/ui/pinned_drop-1.stderr
@@ -0,0 +1,5 @@
+error[E0599]: no method named `__drop_inner` found for struct `Pin<&mut S>` in the current scope
+  --> $DIR/pinned_drop-1.rs:10:18
+   |
+10 |             this.__drop_inner();
+   |                  ^^^^^^^^^^^^ method not found in `Pin<&mut S>`