diff --git a/codegen/build.rs b/codegen/build.rs
index 8b5c311b..cd097465 100644
--- a/codegen/build.rs
+++ b/codegen/build.rs
@@ -8,8 +8,8 @@ use yansi::Color::{Red, Yellow, Blue, White};
 use version_check::{supports_features, is_min_version, is_min_date};
 
 // Specifies the minimum nightly version needed to compile Rocket's codegen.
-const MIN_DATE: &'static str = "2017-07-09";
-const MIN_VERSION: &'static str = "1.20.0-nightly";
+const MIN_DATE: &'static str = "2017-08-10";
+const MIN_VERSION: &'static str = "1.21.0-nightly";
 
 fn main() {
     let ok_channel = supports_features();
diff --git a/codegen/src/lints/mod.rs b/codegen/src/lints/mod.rs
index 802625e2..559b8aca 100644
--- a/codegen/src/lints/mod.rs
+++ b/codegen/src/lints/mod.rs
@@ -7,7 +7,7 @@ use ::{ROUTE_ATTR, ROUTE_INFO_ATTR};
 use std::mem::transmute;
 use std::collections::HashMap;
 
-use rustc::lint::{Level, LateContext, LintContext, LintPass, LateLintPass, LintArray};
+use rustc::lint::{Level, LateContext, LintPass, LateLintPass, LintArray};
 use rustc::hir::{Item, Expr, Crate, Decl, FnDecl, Body, QPath, PatKind};
 use rustc::hir::def_id::DefId;
 use rustc::ty::Ty;
@@ -249,13 +249,13 @@ impl<'a, 'tcx> LateLintPass<'a, 'tcx> for RocketLint {
 
         // Add this to the list of declared routes to check for mounting later
         // unless unmounted routes were explicitly allowed for this function.
-        if cx.current_level(UNMOUNTED_ROUTE) != Level::Allow {
+        if cx.tcx.lint_level_at_node(UNMOUNTED_ROUTE, fn_id).0 != Level::Allow {
             self.declared.push((fn_name, fn_sp, def_id.clone()));
         }
 
         // If unmanaged state was explicitly allowed for this function, don't
         // record any additional information. Just return now.
-        if cx.current_level(UNMANAGED_STATE) == Level::Allow {
+        if cx.tcx.lint_level_at_node(UNMANAGED_STATE, fn_id).0 == Level::Allow {
             return;
         }
 
diff --git a/lib/src/rocket.rs b/lib/src/rocket.rs
index 1fdf58c1..197182b4 100644
--- a/lib/src/rocket.rs
+++ b/lib/src/rocket.rs
@@ -138,7 +138,7 @@ impl Rocket {
                 hyp_res.headers_mut().set(header::ContentLength(0));
                 hyp_res.start()?.end()
             }
-            Some(Body::Sized(mut body, size)) => {
+            Some(Body::Sized(body, size)) => {
                 hyp_res.headers_mut().set(header::ContentLength(size));
                 let mut stream = hyp_res.start()?;
                 io::copy(body, &mut stream)?;