Fixed error message about explicit type conversion.

libsolidity/AST.cpp

@@ -746,7 +746,7 @@ void FunctionCall::checkTypeRequirements(TypePointers const*)
 		//@todo for structs, we have to check the number of arguments to be equal to the
 		// number of non-mapping members
 		if (m_arguments.size() != 1)
-			BOOST_THROW_EXCEPTION(createTypeError("More than one argument for explicit type conversion."));
+			BOOST_THROW_EXCEPTION(createTypeError("Exactly one argument expected for explicit type conversion."));
 		if (!isPositionalCall)
 			BOOST_THROW_EXCEPTION(createTypeError("Type conversion cannot allow named arguments."));
 		if (!m_arguments.front()->getType()->isExplicitlyConvertibleTo(*type.getActualType()))