diff --git a/rust-toolchain b/rust-toolchain
index 3f315e09976..ee0822f6c31 100644
--- a/rust-toolchain
+++ b/rust-toolchain
@@ -1 +1 @@
-nightly-2021-10-30
+nightly-2021-12-30
diff --git a/src/base.rs b/src/base.rs
index c6df250d2fd..8b23e96066e 100644
--- a/src/base.rs
+++ b/src/base.rs
@@ -7,14 +7,12 @@
     GlobalKind,
 };
 use rustc_middle::dep_graph;
-use rustc_middle::middle::exported_symbols;
 use rustc_middle::ty::TyCtxt;
 use rustc_middle::mir::mono::Linkage;
 use rustc_codegen_ssa::{ModuleCodegen, ModuleKind};
 use rustc_codegen_ssa::base::maybe_create_entry_wrapper;
 use rustc_codegen_ssa::mono_item::MonoItemExt;
 use rustc_codegen_ssa::traits::DebugInfoMethods;
-use rustc_metadata::EncodedMetadata;
 use rustc_session::config::DebugInfo;
 use rustc_span::Symbol;