From a453f210b35b6200bb7603b1a378db264892c478 Mon Sep 17 00:00:00 2001
From: Nilstrieb <48135649+Nilstrieb@users.noreply.github.com>
Date: Sun, 3 Apr 2022 13:25:41 +0200
Subject: [PATCH] get drop working

---
 src/lib.rs        | 11 ++++++++++-
 src/strategies.rs | 39 ++++++++++++++++++++++++++++-----------
 2 files changed, 38 insertions(+), 12 deletions(-)

diff --git a/src/lib.rs b/src/lib.rs
index aa45424..377db9d 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -130,7 +130,7 @@ fn map_ptr<T>(ptr: *mut T, map: impl FnOnce(usize) -> usize) -> *mut T {
 
 #[cfg(test)]
 mod tests {
-    use crate::strategies::test_strategies::HasDebug;
+    use crate::strategies::test_strategies::{HasDebug, PanicsInDrop};
     use crate::StuffedPtr;
 
     #[test]
@@ -160,4 +160,13 @@ mod tests {
             "StuffedPtr::Extra { extra: hello! }"
         );
     }
+
+    #[test]
+    #[should_panic]
+    fn needs_drop() {
+        let extra = PanicsInDrop;
+        let stuffed_ptr: StuffedPtr<(), PanicsInDrop> = StuffedPtr::new_extra(extra);
+        // the panicking drop needs to be called here!
+        drop(stuffed_ptr);
+    }
 }
diff --git a/src/strategies.rs b/src/strategies.rs
index 6d5142c..1201dca 100644
--- a/src/strategies.rs
+++ b/src/strategies.rs
@@ -21,6 +21,27 @@ pub mod test_strategies {
     use crate::StuffingStrategy;
     use std::fmt::{Debug, Formatter};
 
+    macro_rules! impl_usize_max_zst {
+        ($ty:ident) => {
+            // this one lives in usize::MAX
+            unsafe impl StuffingStrategy for $ty {
+                type Extra = Self;
+
+                fn is_extra(data: usize) -> bool {
+                    data == usize::MAX
+                }
+
+                fn stuff_extra(_inner: Self::Extra) -> usize {
+                    usize::MAX
+                }
+
+                fn extract_extra(_data: usize) -> Self::Extra {
+                    $ty
+                }
+            }
+        };
+    }
+
     pub struct HasDebug;
 
     impl Debug for HasDebug {
@@ -29,19 +50,15 @@ pub mod test_strategies {
         }
     }
 
-    unsafe impl StuffingStrategy for HasDebug {
-        type Extra = Self;
+    impl_usize_max_zst!(HasDebug);
 
-        fn is_extra(data: usize) -> bool {
-            data == usize::MAX
-        }
+    pub struct PanicsInDrop;
 
-        fn stuff_extra(_inner: Self::Extra) -> usize {
-            usize::MAX
-        }
-
-        fn extract_extra(_data: usize) -> Self::Extra {
-            Self
+    impl Drop for PanicsInDrop {
+        fn drop(&mut self) {
+            panic!("oh no!!!");
         }
     }
+
+    impl_usize_max_zst!(PanicsInDrop);
 }