Merge pull request #19413 from ShoyuVanilla/issue-19399

fix: Properly calculate the layouts of tuple ptrs whose last fields are DST

Author: Veykril

crates/hir-ty/src/layout.rs

@@ -388,6 +388,15 @@ fn struct_tail_erasing_lifetimes(db: &dyn HirDatabase, pointee: Ty) -> Ty {
                 None => pointee,
             }
         }
+        TyKind::Tuple(_, subst) => {
+            if let Some(last_field_ty) =
+                subst.iter(Interner).last().and_then(|arg| arg.ty(Interner))
+            {
+                struct_tail_erasing_lifetimes(db, last_field_ty.clone())
+            } else {
+                pointee
+            }
+        }
         _ => pointee,
     }
 }

crates/hir-ty/src/layout/tests.rs

@@ -468,6 +468,16 @@ fn tuple() {
     }
 }
 
+#[test]
+fn tuple_ptr_with_dst_tail() {
+    size_and_align!(
+        struct Goal(*const ([u8],));
+    );
+    size_and_align!(
+        struct Goal(*const (u128, [u8]));
+    );
+}
+
 #[test]
 fn non_zero_and_non_null() {
     size_and_align! {