Re-add type_name.rs changes

Author: TankhouseAle

src/librustc_mir/interpret/intrinsics/type_name.rs

@@ -213,16 +213,23 @@ impl Write for AbsolutePathPrinter<'_, '_> {
 /// Produces an absolute path representation of the given type. See also the documentation on
 /// `std::any::type_name`
 pub fn type_name<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, ty: Ty<'tcx>) -> &'tcx ty::Const<'tcx> {
-    let path = AbsolutePathPrinter { tcx, path: String::new() }.print_type(ty).unwrap().path;
-    let len = path.len();
-    let alloc = Allocation::from_byte_aligned_bytes(path.into_bytes());
-    let alloc = tcx.intern_const_alloc(alloc);
+    let alloc = alloc_type_name(tcx, ty);
     tcx.mk_const(ty::Const {
         val: ConstValue::Slice {
             data: alloc,
             start: 0,
-            end: len,
+            end: alloc.bytes.len(),
         },
         ty: tcx.mk_static_str(),
     })
 }
+
+/// Directly returns an `Allocation` containing an absolute path representation of the given type.
+pub(super) fn alloc_type_name<'a, 'tcx>(
+    tcx: TyCtxt<'a, 'tcx, 'tcx>,
+    ty: Ty<'tcx>
+) -> &'tcx Allocation {
+    let path = AbsolutePathPrinter { tcx, path: String::new() }.print_type(ty).unwrap().path;
+    let alloc = Allocation::from_byte_aligned_bytes(path.into_bytes());
+    tcx.intern_const_alloc(alloc)
+}