diff --git a/build.sh b/build.sh
index 522b3b3f592..d135c938bf5 100755
--- a/build.sh
+++ b/build.sh
@@ -32,7 +32,6 @@ done
 
 # Build cg_clif
 unset CARGO_TARGET_DIR
-export RUSTFLAGS="-Zrun_dsymutil=no"
 unamestr=$(uname)
 if [[ "$unamestr" == 'Linux' ]]; then
    export RUSTFLAGS='-Clink-arg=-Wl,-rpath=$ORIGIN/../lib '$RUSTFLAGS
diff --git a/build_sysroot/Cargo.lock b/build_sysroot/Cargo.lock
index b49518ee39a..0da9999c172 100644
--- a/build_sysroot/Cargo.lock
+++ b/build_sysroot/Cargo.lock
@@ -139,9 +139,9 @@ dependencies = [
 
 [[package]]
 name = "libc"
-version = "0.2.82"
+version = "0.2.84"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "89203f3fba0a3795506acaad8ebce3c80c0af93f994d5a1d7a0b1eeb23271929"
+checksum = "1cca32fa0182e8c0989459524dc356b8f2b5c10f1b9eb521b7d182c03cf8c5ff"
 dependencies = [
  "rustc-std-workspace-core",
 ]
diff --git a/rust-toolchain b/rust-toolchain
index 55ac079c0a9..a08f00d19c2 100644
--- a/rust-toolchain
+++ b/rust-toolchain
@@ -1 +1 @@
-nightly-2021-01-25
+nightly-2021-01-30
diff --git a/src/constant.rs b/src/constant.rs
index beff84fb2e2..5702832bcb6 100644
--- a/src/constant.rs
+++ b/src/constant.rs
@@ -134,11 +134,9 @@ pub(crate) fn codegen_constant<'tcx>(
             {
                 Ok(const_val) => const_val,
                 Err(_) => {
-                    if promoted.is_none() {
-                        fx.tcx
-                            .sess
-                            .span_err(constant.span, "erroneous constant encountered");
-                    }
+                    fx.tcx
+                        .sess
+                        .span_err(constant.span, "erroneous constant encountered");
                     return crate::trap::trap_unreachable_ret_value(
                         fx,
                         fx.layout_of(const_.ty),
diff --git a/src/lib.rs b/src/lib.rs
index ed7ee3b5365..170750461ca 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -82,7 +82,6 @@ mod vtable;
 mod prelude {
     pub(crate) use std::convert::{TryFrom, TryInto};
 
-    pub(crate) use rustc_ast::ast::{FloatTy, IntTy, UintTy};
     pub(crate) use rustc_span::Span;
 
     pub(crate) use rustc_hir::def_id::{DefId, LOCAL_CRATE};
@@ -90,7 +89,8 @@ mod prelude {
     pub(crate) use rustc_middle::mir::{self, *};
     pub(crate) use rustc_middle::ty::layout::{self, TyAndLayout};
     pub(crate) use rustc_middle::ty::{
-        self, Instance, InstanceDef, ParamEnv, Ty, TyCtxt, TypeAndMut, TypeFoldable,
+        self, FloatTy, Instance, InstanceDef, IntTy, ParamEnv, Ty, TyCtxt, TypeAndMut,
+        TypeFoldable, UintTy,
     };
     pub(crate) use rustc_target::abi::{Abi, LayoutOf, Scalar, Size, VariantIdx};