Auto merge of #104013 - notriddle:notriddle/rustdoc-sizeof, r=GuillaumeGomez

rustdoc: use `ThinVec` and `Box<str>` to shrink `clean::ItemKind`

src/librustdoc/clean/utils.rs

@@ -21,7 +21,7 @@ use rustc_middle::ty::{self, DefIdTree, TyCtxt};
 use rustc_span::symbol::{kw, sym, Symbol};
 use std::fmt::Write as _;
 use std::mem;
-use thin_vec::ThinVec;
+use thin_vec::{thin_vec, ThinVec};
 
 #[cfg(test)]
 mod tests;
@@ -136,7 +136,7 @@ pub(super) fn external_path<'tcx>(
     let name = cx.tcx.item_name(did);
     Path {
         res: Res::Def(def_kind, did),
-        segments: vec![PathSegment {
+        segments: thin_vec![PathSegment {
             name,
             args: external_generic_args(cx, did, has_self, bindings, substs),
         }],
@@ -242,19 +242,13 @@ pub(crate) fn print_const(cx: &DocContext<'_>, n: ty::Const<'_>) -> String {
 
             s
         }
-        _ => {
-            let mut s = n.to_string();
-            // array lengths are obviously usize
-            if s.ends_with("_usize") {
-                let n = s.len() - "_usize".len();
-                s.truncate(n);
-                if s.ends_with(": ") {
-                    let n = s.len() - ": ".len();
-                    s.truncate(n);
-                }
-            }
-            s
+        // array lengths are obviously usize
+        ty::ConstKind::Value(ty::ValTree::Leaf(scalar))
+            if *n.ty().kind() == ty::Uint(ty::UintTy::Usize) =>
+        {
+            scalar.to_string()
         }
+        _ => n.to_string(),
     }
 }