From c56f49dc34f43568122f057d72f3472b3fcd4d8e Mon Sep 17 00:00:00 2001 From: Vadim Petrochenkov Date: Mon, 28 Jul 2025 17:24:28 +0300 Subject: expand: Micro-optimize prelude injection Use `splice` to avoid shifting the other items twice. Put `extern crate std;` first so it's already resolved when we resolve `::std::prelude::rust_20XX`. --- compiler/rustc_builtin_macros/src/standard_library_imports.rs | 4 +--- 1 file changed, 1 insertion(+), 3 deletions(-) (limited to 'compiler') diff --git a/compiler/rustc_builtin_macros/src/standard_library_imports.rs b/compiler/rustc_builtin_macros/src/standard_library_imports.rs index 682e7c9b17a..2068b5ca54d 100644 --- a/compiler/rustc_builtin_macros/src/standard_library_imports.rs +++ b/compiler/rustc_builtin_macros/src/standard_library_imports.rs @@ -47,8 +47,6 @@ pub fn inject( ast::ItemKind::ExternCrate(None, Ident::new(name, ident_span)), ); - krate.items.insert(0, item); - let root = (edition == Edition2015).then_some(kw::PathRoot); let import_path = root @@ -75,6 +73,6 @@ pub fn inject( }), ); - krate.items.insert(0, use_item); + krate.items.splice(0..0, [item, use_item]); krate.items.len() - orig_num_items } -- cgit 1.4.1-3-g733a5