Merge branch 'null-stream-safety' of https://github.com/adri326/scryer-prolog into adri326-null-stream-safety

src/macros.rs

@@ -175,6 +175,7 @@ macro_rules! raw_ptr_as_cell {
         // TODO use <*{const,mut} _>::addr instead of as when the strict_provenance feature is stable rust-lang/rust#95228
         // we might need <*{const,mut} _>::expose_provenance for strict provenance, dependening on how we recreate a pointer later
         let ptr : *const _ = $ptr;
+        debug_assert!(!$ptr.is_null());
         HeapCellValue::from_ptr_addr(ptr as usize)
     }};
 }
@@ -217,12 +218,6 @@ macro_rules! string_as_pstr_cell {
     }};
 }
 
-macro_rules! stream_as_cell {
-    ($ptr:expr) => {
-        raw_ptr_as_cell!($ptr.as_ptr())
-    };
-}
-
 macro_rules! cell_as_stream {
     ($cell:expr) => {{
         let ptr = cell_as_untyped_arena_ptr!($cell);