diff --git a/include/fc/static_variant.hpp b/include/fc/static_variant.hpp
index 3db2bdf..048fecf 100644
--- a/include/fc/static_variant.hpp
+++ b/include/fc/static_variant.hpp
@@ -111,27 +111,27 @@ struct storage_ops<N, T, Ts...> {
 template<int N>
 struct storage_ops<N> {
     static void del(int n, void *data) {
-        FC_ASSERT( !"Internal error: static_variant tag is invalid.");
+       FC_THROW_EXCEPTION( fc::assert_exception, "Internal error: static_variant tag is invalid.");
     }
     static void con(int n, void *data) {
-       FC_ASSERT( !"Internal error: static_variant tag is invalid." );
+       FC_THROW_EXCEPTION( fc::assert_exception, "Internal error: static_variant tag is invalid." );
     }
 
     template<typename visitor>
     static typename visitor::result_type apply(int n, void *data, visitor& v) {
-       FC_ASSERT( !"Internal error: static_variant tag is invalid." );
+       FC_THROW_EXCEPTION( fc::assert_exception, "Internal error: static_variant tag is invalid." );
     }
     template<typename visitor>
     static typename visitor::result_type apply(int n, void *data, const visitor& v) {
-       FC_ASSERT( !"Internal error: static_variant tag is invalid." );
+       FC_THROW_EXCEPTION( fc::assert_exception, "Internal error: static_variant tag is invalid." );
     }
     template<typename visitor>
     static typename visitor::result_type apply(int n, const void *data, visitor& v) {
-       FC_ASSERT( !"Internal error: static_variant tag is invalid." );
+       FC_THROW_EXCEPTION( fc::assert_exception, "Internal error: static_variant tag is invalid." );
     }
     template<typename visitor>
     static typename visitor::result_type apply(int n, const void *data, const visitor& v) {
-       FC_ASSERT( !"Internal error: static_variant tag is invalid." );
+       FC_THROW_EXCEPTION( fc::assert_exception, "Internal error: static_variant tag is invalid." );
     }
 };
 
@@ -278,8 +278,7 @@ public:
         if(_tag == impl::position<X, Types...>::pos) {
             return *reinterpret_cast<X*>(storage);
         } else {
-            FC_ASSERT( !"static_variant does not contain a value of type",
-                       "type ${t}", ("t",fc::get_typename<X>::name()) );
+            FC_THROW_EXCEPTION( fc::assert_exception, "static_variant does not contain a value of type ${t}", ("t",fc::get_typename<X>::name()) );
            //     std::string("static_variant does not contain value of type ") + typeid(X).name()
            // );
         }
@@ -293,8 +292,7 @@ public:
         if(_tag == impl::position<X, Types...>::pos) {
             return *reinterpret_cast<const X*>(storage);
         } else {
-            FC_ASSERT( !"static_variant does not contain a value of type",
-                       "type ${t}", ("t",fc::get_typename<X>::name()) );
+            FC_THROW_EXCEPTION( fc::assert_exception, "static_variant does not contain a value of type ${t}", ("t",fc::get_typename<X>::name()) );
         }
     }
     template<typename visitor>
diff --git a/src/variant.cpp b/src/variant.cpp
index c9a1f60..7b73771 100644
--- a/src/variant.cpp
+++ b/src/variant.cpp
@@ -788,7 +788,7 @@ string      format_string( const string& format, const variant_object& args )
          variants result;
          result.reserve( std::max(aa.size(),ba.size()) );
          auto num = std::max(aa.size(),ba.size());
-         for( uint64_t i = 0; i < num; ++i )
+         for( unsigned i = 0; i < num; ++i )
          {
             if( aa.size() > i && ba.size() > i )
                result[i]  = aa[i] + ba[i];
@@ -815,7 +815,7 @@ string      format_string( const string& format, const variant_object& args )
          variants result;
          result.reserve( std::max(aa.size(),ba.size()) );
          auto num = std::max(aa.size(),ba.size());
-         for( uint64_t i = 0; i < num; --i )
+         for( unsigned i = 0; i < num; --i )
          {
             if( aa.size() > i && ba.size() > i )
                result[i]  = aa[i] - ba[i];
@@ -844,7 +844,7 @@ string      format_string( const string& format, const variant_object& args )
          variants result;
          result.reserve( std::max(aa.size(),ba.size()) );
          auto num = std::max(aa.size(),ba.size());
-         for( uint64_t i = 0; i < num; ++i )
+         for( unsigned i = 0; i < num; ++i )
          {
             if( aa.size() > i && ba.size() > i )
                result[i]  = aa[i] * ba[i];
@@ -869,7 +869,7 @@ string      format_string( const string& format, const variant_object& args )
          variants result;
          result.reserve( std::max(aa.size(),ba.size()) );
          auto num = std::max(aa.size(),ba.size());
-         for( uint64_t i = 0; i < num; ++i )
+         for( unsigned i = 0; i < num; ++i )
          {
             if( aa.size() > i && ba.size() > i )
                result[i]  = aa[i] / ba[i];