Add some size assertions for const eval types

Author: oli-obk

src/librustc/mir/interpret/pointer.rs

@@ -76,6 +76,8 @@ pub struct Pointer<Tag=(),Id=AllocId> {
     pub tag: Tag,
 }
 
+static_assert!(POINTER_SIZE: ::std::mem::size_of::<Pointer>() == 16);
+
 /// Produces a `Pointer` which points to the beginning of the Allocation
 impl From<AllocId> for Pointer {
     #[inline(always)]

src/librustc/mir/interpret/value.rs

@@ -32,6 +32,9 @@ pub enum ConstValue<'tcx> {
     ByRef(AllocId, &'tcx Allocation, Size),
 }
 
+#[cfg(target_arch = "x86_64")]
+static_assert!(CONST_SIZE: ::std::mem::size_of::<ConstValue<'static>>() == 56);
+
 impl<'tcx> ConstValue<'tcx> {
     #[inline]
     pub fn try_to_scalar(&self) -> Option<Scalar> {
@@ -90,6 +93,8 @@ pub enum Scalar<Tag=(), Id=AllocId> {
     Ptr(Pointer<Tag, Id>),
 }
 
+static_assert!(SCALAR_SIZE: ::std::mem::size_of::<Scalar>() == 24);
+
 impl<Tag> fmt::Display for Scalar<Tag> {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         match self {

src/librustc/ty/sty.rs

@@ -2063,6 +2063,9 @@ pub enum LazyConst<'tcx> {
     Evaluated(Const<'tcx>),
 }
 
+#[cfg(target_arch = "x86_64")]
+static_assert!(LAZY_CONST_SIZE: ::std::mem::size_of::<LazyConst<'static>>() == 72);
+
 impl<'tcx> LazyConst<'tcx> {
     pub fn map_evaluated<R>(self, f: impl FnOnce(Const<'tcx>) -> Option<R>) -> Option<R> {
         match self {
@@ -2089,6 +2092,9 @@ pub struct Const<'tcx> {
     pub val: ConstValue<'tcx>,
 }
 
+#[cfg(target_arch = "x86_64")]
+static_assert!(CONST_SIZE: ::std::mem::size_of::<Const<'static>>() == 64);
+
 impl<'tcx> Const<'tcx> {
     #[inline]
     pub fn from_scalar(