Port #[rustc_layout_scalar_valid_range_start/end] to the new attribute parsing infrastructure

Signed-off-by: Jonathan Brouwer <jonathantbrouwer@gmail.com>

compiler/rustc_attr_data_structures/src/attributes.rs

@@ -273,6 +273,12 @@ pub enum AttributeKind {
     /// Represents [`#[repr]`](https://doc.rust-lang.org/stable/reference/type-layout.html#representations).
     Repr(ThinVec<(ReprAttr, Span)>),
 
+    /// Represents `#[rustc_layout_scalar_valid_range_end]`.
+    RustcLayoutScalarValidRangeEnd(Box<u128>, Span),
+
+    /// Represents `#[rustc_layout_scalar_valid_range_start]`.
+    RustcLayoutScalarValidRangeStart(Box<u128>, Span),
+
     /// Represents `#[rustc_skip_during_method_dispatch]`.
     SkipDuringMethodDispatch { array: bool, boxed_slice: bool, span: Span },
 

compiler/rustc_attr_data_structures/src/encode_cross_crate.rs

@@ -36,6 +36,8 @@ impl AttributeKind {
             NoMangle(..) => No,
             Optimize(..) => No,
             PubTransparent(..) => Yes,
+            RustcLayoutScalarValidRangeEnd(..) => Yes,
+            RustcLayoutScalarValidRangeStart(..) => Yes,
             SkipDuringMethodDispatch { .. } => No,
             TrackCaller(..) => Yes,
         }

compiler/rustc_attr_data_structures/src/lib.rs

@@ -49,6 +49,16 @@ pub trait PrintAttribute {
     fn print_attribute(&self, p: &mut Printer);
 }
 
+impl PrintAttribute for u128 {
+    fn should_render(&self) -> bool {
+        true
+    }
+
+    fn print_attribute(&self, p: &mut Printer) {
+        p.word(self.to_string())
+    }
+}
+
 impl<T: PrintAttribute> PrintAttribute for &T {
     fn should_render(&self) -> bool {
         T::should_render(self)