diff --git a/Cargo.toml b/Cargo.toml
index c07a0bf5e247..058dc012cfa5 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -23,7 +23,7 @@ regex_macros = { version = "0.1.33", optional = true }
 semver = "0.2.1"
 toml = "0.1"
 unicode-normalization = "0.1"
-quine-mc_cluskey = "0.2.1"
+quine-mc_cluskey = "0.2.2"
 
 [dev-dependencies]
 compiletest_rs = "0.1.0"
diff --git a/src/booleans.rs b/src/booleans.rs
index b43f22973115..b603d5188aad 100644
--- a/src/booleans.rs
+++ b/src/booleans.rs
@@ -275,7 +275,7 @@ impl<'a, 'tcx> NonminimalBoolVisitor<'a, 'tcx> {
                         return;
                     }
                     // if the number of occurrences of a terminal decreases or any of the stats decreases while none increases
-                    improvement = (stats.terminals[i] > simplified_stats.terminals[i]) ||
+                    improvement |= (stats.terminals[i] > simplified_stats.terminals[i]) ||
                         (stats.negations > simplified_stats.negations && stats.ops == simplified_stats.ops) ||
                         (stats.ops > simplified_stats.ops && stats.negations == simplified_stats.negations);
                 }
diff --git a/tests/compile-fail/booleans.rs b/tests/compile-fail/booleans.rs
index ecaa52019c6c..008e6dcdda90 100644
--- a/tests/compile-fail/booleans.rs
+++ b/tests/compile-fail/booleans.rs
@@ -77,5 +77,8 @@ fn equality_stuff() {
     //|~ SUGGESTION let _ = false;
     let _ = a > b && a == b;
 
-    let _ = a != b || !(a != b || c == d);
+    let _ = a != b || !(a != b || c == d); //~ ERROR this boolean expression can be simplified
+    //|~ HELP for further information visit
+    //|~ SUGGESTION let _ = !c == d || a != b;
+    //|~ SUGGESTION let _ = !(!a != b && c == d);
 }