Microsoft.CSharp.RuntimeBinder.RuntimeBinder.BindImplicitConversion C# (CSharp) Method

        private EXPR BindImplicitConversion(
            ArgumentObject[] arguments,
            Type returnType,
            Dictionary<int, LocalVariableSymbol> dictionary,
            bool bIsArrayCreationConversion)
        {
            if (arguments.Length != 1)
            {
                throw Error.BindImplicitConversionRequireOneArgument();
            }

            // Load the conversions on the target.
            _symbolTable.AddConversionsForType(returnType);

            EXPR argument = CreateArgumentEXPR(arguments[0], dictionary[0]);
            CType destinationType = _symbolTable.GetCTypeFromType(returnType);

            if (bIsArrayCreationConversion)
            {
                // If we are converting for an array index, we want to convert to int, uint,
                // long, or ulong, depending on what the argument will allow. However, since
                // the compiler had to pick a particular type for the return value when it
                // made the callsite, we need to make sure that we ultimately return a type
                // of that value. So we "mustConvert" to the best type that chooseArrayIndexType
                // can find, and then we cast the result of that to the returnType, which is
                // incidentally Int32 in the existing compiler. For that cast, we do not consider
                // user defined conversions (since the convert is guaranteed to return one of
                // the primitive types), and we check for overflow since we don't want truncation.

                CType pDestType = _binder.chooseArrayIndexType(argument);
                if (null == pDestType)
                {
                    pDestType = SymbolLoader.GetReqPredefType(PredefinedType.PT_INT, true);
                }

                return _binder.mustCast(
                    _binder.mustConvert(argument, pDestType),
                    destinationType,
                    CONVERTTYPE.CHECKOVERFLOW | CONVERTTYPE.NOUDC);
            }

            return _binder.mustConvert(argument, destinationType);
        }