diff --git a/.travis.yml b/.travis.yml
index bc3b116a5093..ee990111af96 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -51,13 +51,12 @@ matrix:
     # We don't want to run these always because they go towards
     # the build limit within the Travis rust-lang account.
     # The jobs are approximately sorted by execution time
-    # disabled cargo and rls integration test due to https://github.com/rust-lang/rust-clippy/issues/4121
-    #- env: INTEGRATION=rust-lang/cargo
-    #  if: repo =~ /^rust-lang\/rust-clippy$/ AND branch IN (auto, try)
+    - env: INTEGRATION=rust-lang/cargo
+      if: repo =~ /^rust-lang\/rust-clippy$/ AND branch IN (auto, try)
     - env: INTEGRATION=rust-lang-nursery/chalk
       if: repo =~ /^rust-lang\/rust-clippy$/ AND branch IN (auto, try)
-    #- env: INTEGRATION=rust-lang/rls
-    #  if: repo =~ /^rust-lang\/rust-clippy$/ AND branch IN (auto, try)
+    - env: INTEGRATION=rust-lang/rls
+      if: repo =~ /^rust-lang\/rust-clippy$/ AND branch IN (auto, try)
     - env: INTEGRATION=Geal/nom
       if: repo =~ /^rust-lang\/rust-clippy$/ AND branch IN (auto, try)
     - env: INTEGRATION=rust-lang/rustfmt
diff --git a/tests/ui/ice-4121.rs b/tests/ui/ice-4121.rs
new file mode 100644
index 000000000000..e1a142fdcb67
--- /dev/null
+++ b/tests/ui/ice-4121.rs
@@ -0,0 +1,13 @@
+use std::mem;
+
+pub struct Foo<A, B>(A, B);
+
+impl<A, B> Foo<A, B> {
+    const HOST_SIZE: usize = mem::size_of::<B>();
+
+    pub fn crash() -> bool {
+        Self::HOST_SIZE == 0
+    }
+}
+
+fn main() {}