diff --git a/core/connection.js b/core/connection.js
index 3b8c82af8..dda3d4fe5 100644
--- a/core/connection.js
+++ b/core/connection.js
@@ -571,6 +571,18 @@ Blockly.Connection.prototype.checkType_ = function(otherConnection) {
   return false;
 };
 
+/**
+ * Function to be called when this connection's compatible types have changed.
+ * @private
+ */
+Blockly.Connection.prototype.onCheckChanged_ = function() {
+  // The new value type may not be compatible with the existing connection.
+  if (this.isConnected() && !this.checkType_(this.targetConnection)) {
+    var child = this.isSuperior() ? this.targetBlock() : this.sourceBlock_;
+    child.unplug();
+  }
+};
+
 /**
  * Change a connection's compatibility.
  * @param {*} check Compatible value type or list of value types.
@@ -585,13 +597,7 @@ Blockly.Connection.prototype.setCheck = function(check) {
       check = [check];
     }
     this.check_ = check;
-    // The new value type may not be compatible with the existing connection.
-    if (this.isConnected() && !this.checkType_(this.targetConnection)) {
-      var child = this.isSuperior() ? this.targetBlock() : this.sourceBlock_;
-      child.unplug();
-      // Bump away.
-      this.sourceBlock_.bumpNeighbours_();
-    }
+    this.onCheckChanged_();
   } else {
     this.check_ = null;
   }
diff --git a/core/rendered_connection.js b/core/rendered_connection.js
index 8a67d3d86..6425dcdfc 100644
--- a/core/rendered_connection.js
+++ b/core/rendered_connection.js
@@ -393,3 +393,17 @@ Blockly.RenderedConnection.prototype.connect_ = function(childConnection) {
     }
   }
 };
+
+/**
+ * Function to be called when this connection's compatible types have changed.
+ * @private
+ */
+Blockly.RenderedConnection.prototype.onCheckChanged_ = function() {
+  // The new value type may not be compatible with the existing connection.
+  if (this.isConnected() && !this.checkType_(this.targetConnection)) {
+    var child = this.isSuperior() ? this.targetBlock() : this.sourceBlock_;
+    child.unplug();
+    // Bump away.
+    this.sourceBlock_.bumpNeighbours_();
+  }
+};