Fix leak caused by missing virtual destructor

nyalldawson · nyalldawson · commit 6d82cd63b69b · 2016-08-15T09:02:30.000+10:00
diff --git a/python/core/qgsexpressioncontextgenerator.sip b/python/core/qgsexpressioncontextgenerator.sip
@@ -38,4 +38,6 @@ class QgsExpressionContextGenerator
      * and return an expression context.
      */
     virtual QgsExpressionContext createExpressionContext() const = 0;
+
+    virtual ~QgsExpressionContextGenerator();
 };
diff --git a/src/core/qgsexpressioncontextgenerator.h b/src/core/qgsexpressioncontextgenerator.h
@@ -43,6 +43,8 @@ class QgsExpressionContextGenerator
      * @note Added in QGIS 3.0
      */
     virtual QgsExpressionContext createExpressionContext() const = 0;
+
+    virtual ~QgsExpressionContextGenerator() {}
 };
 
 #endif // QGSEXPRESSIONCONTEXTGENERATOR_H
