Replace Scalar::zst with a Scalar::ZST constant

Author: oli-obk

compiler/rustc_middle/src/mir/interpret/value.rs

@@ -178,10 +178,7 @@ impl<'tcx, Tag> Scalar<Tag> {
         Scalar::Int(ScalarInt::null(cx.data_layout().pointer_size))
     }
 
-    #[inline]
-    pub fn zst() -> Self {
-        Scalar::Int(ScalarInt::ZST)
-    }
+    pub const ZST: Self = Scalar::Int(ScalarInt::ZST);
 
     #[inline(always)]
     fn ptr_op(

compiler/rustc_middle/src/ty/consts.rs

@@ -132,7 +132,7 @@ impl<'tcx> Const<'tcx> {
     #[inline]
     /// Creates an interned zst constant.
     pub fn zero_sized(tcx: TyCtxt<'tcx>, ty: Ty<'tcx>) -> &'tcx Self {
-        Self::from_scalar(tcx, Scalar::zst(), ty)
+        Self::from_scalar(tcx, Scalar::ZST, ty)
     }
 
     #[inline]

compiler/rustc_middle/src/ty/context.rs

@@ -844,7 +844,7 @@ impl<'tcx> CommonConsts<'tcx> {
 
         CommonConsts {
             unit: mk_const(ty::Const {
-                val: ty::ConstKind::Value(ConstValue::Scalar(Scalar::zst())),
+                val: ty::ConstKind::Value(ConstValue::Scalar(Scalar::ZST)),
                 ty: types.unit,
             }),
         }

compiler/rustc_mir/src/const_eval/eval_queries.rs

@@ -146,7 +146,7 @@ pub(super) fn op_to_const<'tcx>(
                 "this MPlaceTy must come from a validated constant, thus we can assume the \
                 alignment is correct",
             );
-            ConstValue::Scalar(Scalar::zst())
+            ConstValue::Scalar(Scalar::ZST)
         }
     };
     match immediate {

compiler/rustc_mir/src/interpret/operand.rs

@@ -259,7 +259,7 @@ impl<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
                 }
                 return Ok(Some(ImmTy {
                     // zero-sized type
-                    imm: Scalar::zst().into(),
+                    imm: Scalar::ZST.into(),
                     layout: mplace.layout,
                 }));
             }
@@ -358,7 +358,7 @@ impl<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
 
         let field_layout = op.layout.field(self, field)?;
         if field_layout.is_zst() {
-            let immediate = Scalar::zst().into();
+            let immediate = Scalar::ZST.into();
             return Ok(OpTy { op: Operand::Immediate(immediate), layout: field_layout });
         }
         let offset = op.layout.fields.offset(field);
@@ -443,7 +443,7 @@ impl<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
         let layout = self.layout_of_local(frame, local, layout)?;
         let op = if layout.is_zst() {
             // Do not read from ZST, they might not be initialized
-            Operand::Immediate(Scalar::zst().into())
+            Operand::Immediate(Scalar::ZST.into())
         } else {
             M::access_local(&self, frame, local)?
         };