# Erase-generics screws up IMap casting in C#

**URL:** https://community.haxe.org/t/erase-generics-screws-up-imap-casting-in-c/2538
**Category:** Haxe
**Tags:** haxe-cs
**Created:** [June 29, 2020, 4:39pm UTC](https://community.haxe.org/t/erase-generics-screws-up-imap-casting-in-c/2538 "2020-06-29T16:39:00Z")
**Posts on this page:** 3
**Page:** 1

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### Author: ![pshtif](https://community.haxe.org/user_avatar/community.haxe.org/pshtif/32/783_2.png) [@pshtif](https://community.haxe.org/u/pshtif)
#### Post date: [June 29, 2020, 4:39pm UTC](https://community.haxe.org/t/erase-generics-screws-up-imap-casting-in-c/2538/1 "2020-06-29T16:39:00Z")

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Hi guys, today I encountered a strange problem. When working with colorMap of type Map\<Int,UInt\> like this:

> var color:UInt = colorMap.get(index);

it transpiles to C# as

> color = (((global::haxe.ds.IntMap) (global::haxe.ds.IntMap.\_\_hx\_cast(((global::haxe.ds.IntMap) (((global::haxe.IMap\<int, uint\>) (this.colorMap) )) ))) ).@get(index)).@value;

which is correct however if I define -D erase-generics it transpiles like this

> color = ((uint) (global::haxe.lang.Runtime.toInt(((global::haxe.ds.IntMap) (((global::haxe.IMap) (this.colorMap) )) ).@get(((int) (index) )))) );

which is incorrect as it tries to cast UInt into Int and will fail for large UInts.

Any suggestions?  
Thanks.

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### Author: ![nadako](https://community.haxe.org/user_avatar/community.haxe.org/nadako/32/5_2.png) [@nadako](https://community.haxe.org/u/nadako)
#### Post date: [June 30, 2020, 10:52am UTC](https://community.haxe.org/t/erase-generics-screws-up-imap-casting-in-c/2538/2 "2020-06-30T10:52:29Z")

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Well that seems to be a bug, tho are you sure it doesn’t work? I.e. is there an actual failing case? Because `int` and `uint` should have the same in-memory representation. If that’s not the case - please report an issue. C# target is a bit undermaintained at the moment, but we still want to be aware of all the casting cases for the potential CIL target ^^

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### Author: ![pshtif](https://community.haxe.org/user_avatar/community.haxe.org/pshtif/32/783_2.png) [@pshtif](https://community.haxe.org/u/pshtif)
#### Post date: [June 30, 2020, 11:14am UTC](https://community.haxe.org/t/erase-generics-screws-up-imap-casting-in-c/2538/3 "2020-06-30T11:14:34Z")

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It actually fails in C# when I send a -1 there for some reason, which was surprising due to the as you said same memory representation. It fails with overflow

> onUncaughtError : [{ id : 0, message : OverflowException: Value was either too large or too small for an Int32., stackTrace : System.Convert.ToInt32 (System.UInt32 value) (at \<437ba245d8404784b9fbab9b439ac908\>:0)  
> System.UInt32.System.IConvertible.ToInt32 (System.IFormatProvider provider) (at \<437ba245d8404784b9fbab9b439ac908\>:0)  
> haxe.lang.Runtime.toInt (System.Object obj) (at C:/HaxeToolkit/haxe/std/cs/internal/Runtime.hx:146)