Merge #60

60: Add PtrUnion::as_untagged_ptr r=CAD97 a=CAD97



Co-authored-by: CAD97 <[email protected]>

Author: bors[bot]

crates/ptr-union/README.md

@@ -3,6 +3,11 @@ by storing the tag in the alignment bits.
 
 ## Changelist
 
+### 2.1.0
+#### Added
+
+- `fn Union*::as_untagged_ptr(&self) -> ErasedPtr`
+
 ### 2.0.0
 #### Fixes
 

crates/ptr-union/src/lib.rs

@@ -44,6 +44,11 @@ fn unset_tag(ptr: ErasedPtr, mask: usize, tag: usize) -> ErasedPtr {
     unsafe { ErasedPtr::new_unchecked((ptr.as_ptr() as usize & !mask) as *mut _) }
 }
 
+#[inline(always)]
+fn unset_any_tag(ptr: ErasedPtr, mask: usize) -> ErasedPtr {
+    unsafe { ErasedPtr::new_unchecked((ptr.as_ptr() as usize & !mask) as *mut _) }
+}
+
 #[cfg(has_never)]
 pub type NeverPtr = !;
 #[cfg(not(has_never))]
@@ -248,6 +253,11 @@ macro_rules! impl_union {
                         .unwrap_or_else(|_| unsafe { unreachable_unchecked() })
                 }
             }
+
+            /// Get the raw type-erased untagged pointer to the payload.
+            pub fn as_untagged_ptr(&self) -> ErasedPtr {
+                unset_any_tag(self.raw, $mask)
+            }
         }
 
         impl<$($A: ErasablePtr),*> $Enum<$($A),*> {