Remove unchecked_cast_to

Author: bjorn3

src/base.rs

@@ -485,7 +485,7 @@ fn trans_stmt<'tcx>(
                 | Rvalue::Cast(CastKind::Pointer(PointerCast::ArrayToPointer), operand, to_ty) => {
                     let to_layout = fx.layout_of(fx.monomorphize(to_ty));
                     let operand = trans_operand(fx, operand);
-                    lval.write_cvalue(fx, operand.unchecked_cast_to(to_layout));
+                    lval.write_cvalue(fx, operand.cast_pointer_to(to_layout));
                 }
                 Rvalue::Cast(CastKind::Misc, operand, to_ty) => {
                     let operand = trans_operand(fx, operand);
@@ -509,7 +509,7 @@ fn trans_stmt<'tcx>(
                     if is_fat_ptr(fx, from_ty) {
                         if is_fat_ptr(fx, to_ty) {
                             // fat-ptr -> fat-ptr
-                            lval.write_cvalue(fx, operand.unchecked_cast_to(dest_layout));
+                            lval.write_cvalue(fx, operand.cast_pointer_to(dest_layout));
                         } else {
                             // fat-ptr -> thin-ptr
                             let (ptr, _extra) = operand.load_scalar_pair(fx);

src/value_and_place.rs

@@ -243,7 +243,10 @@ impl<'tcx> CValue<'tcx> {
         CValue::by_val(val, layout)
     }
 
-    pub(crate) fn unchecked_cast_to(self, layout: TyAndLayout<'tcx>) -> Self {
+    pub(crate) fn cast_pointer_to(self, layout: TyAndLayout<'tcx>) -> Self {
+        assert!(matches!(self.layout().ty.kind, ty::Ref(..) | ty::RawPtr(..) | ty::FnPtr(..)));
+        assert!(matches!(layout.ty.kind, ty::Ref(..) | ty::RawPtr(..) | ty::FnPtr(..)));
+        assert_eq!(self.layout().abi, layout.abi);
         CValue(self.0, layout)
     }
 }
@@ -560,20 +563,16 @@ impl<'tcx> CPlace<'tcx> {
         }
     }
 
-    pub(crate) fn unchecked_cast_to(self, layout: TyAndLayout<'tcx>) -> Self {
-        assert!(!self.layout().is_unsized());
-        CPlace {
-            inner: self.inner,
-            layout,
-        }
-    }
-
     pub(crate) fn downcast_variant(
         self,
         fx: &FunctionCx<'_, 'tcx, impl Backend>,
         variant: VariantIdx,
     ) -> Self {
+        assert!(!self.layout().is_unsized());
         let layout = self.layout().for_variant(fx, variant);
-        self.unchecked_cast_to(layout)
+        CPlace {
+            inner: self.inner,
+            layout,
+        }
     }
 }