diff --git a/src/cast.rs b/src/cast.rs
index f01e8ac5261dde844015399ae1cac9f597c33bf0..ef147fcf8713e968491c4aa9702ebda6b379ff72 100644
--- a/src/cast.rs
+++ b/src/cast.rs
@@ -72,7 +72,7 @@ impl<'a, 'tcx> EvalContext<'a, 'tcx> {
             IntTy::I32 => v as i32 as u128,
             IntTy::I64 => v as i64 as u128,
             IntTy::I128 => v as u128,
-            IntTy::Is => {
+            IntTy::Isize => {
                 let ty = self.tcx.sess.target.isize_ty;
                 self.int_to_int(v, ty)
             }
@@ -85,7 +85,7 @@ impl<'a, 'tcx> EvalContext<'a, 'tcx> {
             UintTy::U32 => v as u32 as u128,
             UintTy::U64 => v as u64 as u128,
             UintTy::U128 => v,
-            UintTy::Us => {
+            UintTy::Usize => {
                 let ty = self.tcx.sess.target.usize_ty;
                 self.int_to_uint(v, ty)
             }
@@ -123,8 +123,8 @@ impl<'a, 'tcx> EvalContext<'a, 'tcx> {
         match ty.sty {
             // Casting to a reference or fn pointer is not permitted by rustc, no need to support it here.
             TyRawPtr(_) |
-            TyInt(IntTy::Is) |
-            TyUint(UintTy::Us) => Ok(PrimVal::Ptr(ptr)),
+            TyInt(IntTy::Isize) |
+            TyUint(UintTy::Usize) => Ok(PrimVal::Ptr(ptr)),
             TyInt(_) | TyUint(_) => return Err(EvalError::ReadPointerAsBytes),
             _ => return Err(EvalError::Unimplemented(format!("ptr to {:?} cast", ty))),
         }
diff --git a/src/eval_context.rs b/src/eval_context.rs
index 7448021af2845084f35aedf9bf95c1e1ecd8f088..d470d2880c7e404836ede567ab4a0593b142ac8b 100644
--- a/src/eval_context.rs
+++ b/src/eval_context.rs
@@ -1133,7 +1133,7 @@ impl<'a, 'tcx> EvalContext<'a, 'tcx> {
                     I32 => 4,
                     I64 => 8,
                     I128 => 16,
-                    Is => self.memory.pointer_size(),
+                    Isize => self.memory.pointer_size(),
                 };
                 PrimValKind::from_int_size(size)
             }
@@ -1146,7 +1146,7 @@ impl<'a, 'tcx> EvalContext<'a, 'tcx> {
                     U32 => 4,
                     U64 => 8,
                     U128 => 16,
-                    Us => self.memory.pointer_size(),
+                    Usize => self.memory.pointer_size(),
                 };
                 PrimValKind::from_uint_size(size)
             }
@@ -1262,7 +1262,7 @@ impl<'a, 'tcx> EvalContext<'a, 'tcx> {
                     I32 => 4,
                     I64 => 8,
                     I128 => 16,
-                    Is => self.memory.pointer_size(),
+                    Isize => self.memory.pointer_size(),
                 };
 
                 if !self.memory.points_to_concrete(ptr, size)? {
@@ -1285,7 +1285,7 @@ impl<'a, 'tcx> EvalContext<'a, 'tcx> {
                     U32 => 4,
                     U64 => 8,
                     U128 => 16,
-                    Us => self.memory.pointer_size(),
+                    Usize => self.memory.pointer_size(),
                 };
 
                 if !self.memory.points_to_concrete(ptr, size)? {