# Type error \[M0073\], expected mutable assignment target

**URL:** <https://forum.dfinity.org/t/type-error-m0073-expected-mutable-assignment-target/8364>\
**Category:** Developers\
**Created:** [November 5, 2021, 1:35am UTC](https://forum.dfinity.org/t/type-error-m0073-expected-mutable-assignment-target/8364 "2021-11-05T01:35:08Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![avi](https://sea1.discourse-cdn.com/flex023/user_avatar/forum.dfinity.org/avi/32/1904_2.png) [@avi](https://forum.dfinity.org/u/avi)\
**Post date:** [November 5, 2021, 1:35am UTC](https://forum.dfinity.org/t/type-error-m0073-expected-mutable-assignment-target/8364/1 "2021-11-05T01:35:08Z")

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```auto
    private stable var adIdCount : Nat = 0;
   public func setAdidCount(x:Nat):async (){
    adIdCount:=x;
 }

```

//type error [M0073], expected mutable assignment target

I’m a little confused

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<div class="post-metadata">

**Author:** ![avi](https://sea1.discourse-cdn.com/flex023/user_avatar/forum.dfinity.org/avi/32/1904_2.png) [@avi](https://forum.dfinity.org/u/avi)\
**Post date:** [November 5, 2021, 1:35am UTC](https://forum.dfinity.org/t/type-error-m0073-expected-mutable-assignment-target/8364/2 "2021-11-05T01:35:30Z")

</div>

dfx deploy  
//type error [M0073], expected mutable assignment target

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<div class="post-metadata">

**Author:** ![rossberg](https://sea1.discourse-cdn.com/flex023/user_avatar/forum.dfinity.org/rossberg/32/795_2.png) [@rossberg](https://forum.dfinity.org/u/rossberg)\
**Post date:** [November 5, 2021, 6:21am UTC](https://forum.dfinity.org/t/type-error-m0073-expected-mutable-assignment-target/8364/3 "2021-11-05T06:21:18Z")

</div>

Your example compiles fine for me: [Motoko Playground - DFINITY](https://m7sm4-2iaaa-aaaab-qabra-cai.raw.ic0.app/?tag=1038648180)

Are you sure the part you showed is what caused the error you see?