diff --git a/.travis.yml b/.travis.yml
index 4f5511c..40df879 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -32,7 +32,7 @@ matrix:
       rust: stable
       env: TARGET=x86_64-unknown-linux-gnu
     - name: "x86_64-unknown-linux-gnu (Rust 1.29.0)"
-      rust: stable
+      rust: 1.29.0
       env: TARGET=x86_64-unknown-linux-gnu
     - name: "i686-unknown-linux-gnu"
       env: TARGET=i686-unknown-linux-gnu CROSS=1
diff --git a/ci/run.sh b/ci/run.sh
index 28f7330..99ed427 100644
--- a/ci/run.sh
+++ b/ci/run.sh
@@ -7,7 +7,7 @@ set -ex
 FEATURES="rayon,serde"
 if [ "${TRAVIS_RUST_VERSION}" = "nightly" ]; then
     FEATURES="${FEATURES},nightly"
-    export RUSTFLAGS="$RUSTFLAGS --cfg hashbrown_deny_warnings"
+    export RUSTFLAGS="$RUSTFLAGS -D warnings"
 fi
 
 CARGO=cargo
@@ -25,7 +25,7 @@ export RUSTFLAGS="$RUSTFLAGS --cfg hashbrown_deny_warnings"
 "${CARGO}" -vv test --target="${TARGET}" --features "${FEATURES}"
 
 "${CARGO}" -vv test --target="${TARGET}" --release
-"${CARGO}" -vv test --target="${TARGET}" --features "${FEATURES}"
+"${CARGO}" -vv test --target="${TARGET}" --release --features "${FEATURES}"
 
 if [ "${TRAVIS_RUST_VERSION}" = "nightly" ]; then
     # Run benchmark on native targets, build them on non-native ones:
diff --git a/clippy.toml b/clippy.toml
index 5b5d8cb..d98bf2c 100644
--- a/clippy.toml
+++ b/clippy.toml
@@ -1 +1 @@
-doc-valid-idents = [ "CppCon", "SwissTable", "SipHash", "HashDoS" ]
\ No newline at end of file
+doc-valid-idents = [ "CppCon", "SwissTable", "SipHash", "HashDoS" ]
diff --git a/src/lib.rs b/src/lib.rs
index 276eedc..1c0723b 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -23,7 +23,6 @@
     )
 )]
 #![warn(missing_docs)]
-#![cfg_attr(hashbrown_deny_warnings, deny(warnings))]
 #![allow(clippy::module_name_repetitions)]
 
 #[cfg(test)]
diff --git a/src/map.rs b/src/map.rs
index 2780528..665c1e2 100644
--- a/src/map.rs
+++ b/src/map.rs
@@ -3398,7 +3398,13 @@ mod test_map {
 
         if let Err(AllocErr) = empty_bytes.try_reserve(MAX_USIZE / 8) {
         } else {
-            panic!("usize::MAX / 8 should trigger an OOM!")
+            // This may succeed if there is enough free memory. Attempt to
+            // allocate a second hashmap to ensure the allocation will fail.
+            let mut empty_bytes2: HashMap<u8, u8> = HashMap::new();
+            if let Err(AllocErr) = empty_bytes2.try_reserve(MAX_USIZE / 8) {
+            } else {
+                panic!("usize::MAX / 8 should trigger an OOM!");
+            }
         }
     }