C#: Consider datetime expressions as simple sanitizers.

Author: michaelnebel

csharp/ql/lib/semmle/code/csharp/security/Sanitizers.qll

@@ -54,7 +54,12 @@ class UrlSanitizedExpr extends Expr {
  * An expression node with a simple type.
  */
 class SimpleTypeSanitizedExpr extends DataFlow::ExprNode {
-  SimpleTypeSanitizedExpr() { this.getType() instanceof SimpleType }
+  SimpleTypeSanitizedExpr() {
+    exists(Type t | t = this.getType() |
+      t instanceof SimpleType or
+      t instanceof SystemDateTimeStruct
+    )
+  }
 }
 
 /**