From 562eab817cafc51cd857c9bf384fd0b74ea7aa11 Mon Sep 17 00:00:00 2001
From: Steve Vinoski <vinoski@ieee.org>
Date: Thu, 15 Nov 2018 11:01:51 -0500
Subject: [PATCH] Do not throw std::bad_cast from antlrcpp::Any::is

The antlrcpp::Any::is function should not throw a std::bad_cast
exception if the contained type can't be cast to the requested type,
but should instead just return a boolean result. Add a boolean
parameter to the private getDerived helper function to allow callers
to specify whether or not they want the cast results checked. In the
is() function, pass false for this parameter; in the as() functions,
pass true.
---
 runtime/Cpp/runtime/src/support/Any.h | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/runtime/Cpp/runtime/src/support/Any.h b/runtime/Cpp/runtime/src/support/Any.h
index 50fc1ed9f..5db59f6e6 100644
--- a/runtime/Cpp/runtime/src/support/Any.h
+++ b/runtime/Cpp/runtime/src/support/Any.h
@@ -46,21 +46,21 @@ struct ANTLR4CPP_PUBLIC Any
 
   template<class U>
   bool is() const {
-    auto derived = getDerived<U>();
+    auto derived = getDerived<U>(false);
 
     return derived != nullptr;
   }
 
   template<class U>
   StorageType<U>& as() {
-    auto derived = getDerived<U>();
+    auto derived = getDerived<U>(true);
 
     return derived->value;
   }
 
   template<class U>
   const StorageType<U>& as() const {
-    auto derived = getDerived<U>();
+    auto derived = getDerived<U>(true);
 
     return derived->value;
   }
@@ -143,12 +143,12 @@ private:
   }
 
   template<class U>
-  Derived<StorageType<U>>* getDerived() const {
+  Derived<StorageType<U>>* getDerived(bool checkCast) const {
     typedef StorageType<U> T;
 
     auto derived = dynamic_cast<Derived<T>*>(_ptr);
 
-    if (!derived)
+    if (checkCast && !derived)
       throw std::bad_cast();
 
     return derived;