# Compilation error following the sample counter contract using forc build? **URL:** \ **Category:** Sway\ **Created:** [February 2, 2024, 10:40am UTC](https://forum.fuel.network/t/compilation-error-following-the-sample-counter-contract-using-forc-build/4114 "2024-02-02T10:40:12Z")\ **Posts on this page:** 3\ **Page:** 1
**Author:** ![Sheys](https://sea2.discourse-cdn.com/flex022/user_avatar/forum.fuel.network/sheys/32/2075_2.png) [@Sheys](https://forum.fuel.network/u/Sheys)\ **Post date:** [February 2, 2024, 10:40am UTC](https://forum.fuel.network/t/compilation-error-following-the-sample-counter-contract-using-forc-build/4114/1 "2024-02-02T10:40:12Z")
Lines of codes: ```auto contract; storage { //declare a storage variable counter: u64 = 0, } abi Counter { //reads and write to storage #[storage(read, write)] fn increment(); //reads from storage #[storage(read)] fn counter() -> u64; } impl Counter for Contract { #[storage(read)] fn counter() -> u64 { //using implicit return return storage.counter; } #[storage(read, write)] fn increment() { storage.counter = storage.counter + 1; } } ``` My toolchain using “$fuelup show”: Default host: x86\_64-unknown-linux-gnu fuelup home: /home/sheys/.fuelup ## installed toolchains beta-3-x86\_64-unknown-linux-gnu beta-4-x86\_64-unknown-linux-gnu (default) latest-x86\_64-unknown-linux-gnu ## active toolchain beta-4-x86\_64-unknown-linux-gnu (default) forc : 0.46.1 - forc-client - forc-deploy : 0.46.1 - forc-run : 0.46.1 - forc-crypto : not found - forc-doc : 0.46.1 - forc-explore : 0.28.1 - forc-fmt : 0.46.1 - forc-lsp : 0.46.1 - forc-tx : 0.46.1 - forc-wallet : 0.3.0 fuel-core : 0.20.5 fuel-core-keygen : Error getting version string ## fuels versions forc : 0.45 forc-wallet : 0.45 Now, I could use beta-3 but I also have trouble deploying to beta-3 ---
**Author:** ![calldelegation](https://sea2.discourse-cdn.com/flex022/user_avatar/forum.fuel.network/calldelegation/32/1484_2.png) [@calldelegation](https://forum.fuel.network/u/calldelegation)\ **Post date:** [February 2, 2024, 8:18pm UTC](https://forum.fuel.network/t/compilation-error-following-the-sample-counter-contract-using-forc-build/4114/2 "2024-02-02T20:18:07Z")
Hello @Sheys, I hope you’re doing well. I wanted to address a couple of points: 1. I’ve attempted to reproduce the issue you mentioned but haven’t been successful so far. To gain a better understanding, could you confirm if the error occurs when you run `forc build` in the root directory of your Sway project? Additionally, it would be really helpful if you could share the specific error message you’re encountering. This will enable me to diagnose the problem more accurately. 2. Regarding the beta-3 network, it has been officially deprecated. For more details, you can refer to this link: [Sunsetting Beta-3 Testnet](https://forum.fuel.network/t/sunsetting-beta-3-testnet/3145). To deploy on the beta-4 network, you can use the following command: `forc deploy --testnet`. Let me know if you need more help! 🙂 ---
**Author:** ![Sheys](https://sea2.discourse-cdn.com/flex022/user_avatar/forum.fuel.network/sheys/32/2075_2.png) [@Sheys](https://forum.fuel.network/u/Sheys)\ **Post date:** [February 8, 2024, 3:08pm UTC](https://forum.fuel.network/t/compilation-error-following-the-sample-counter-contract-using-forc-build/4114/3 "2024-02-08T15:08:36Z")
Hello @calldelegation, thank you. 1. Here’s the compilation error it shows using `forc build` in the root directory of my Sway project: ```auto sheys@DESKTOP-MRD72SV:~/fuelvm-projects/counter$ forc build Compiling library core (/home/sheys/.forc/git/checkouts/std-9be0d6062747ea7/512a3386f8961185188302f391ccc96553d23a7a/sway-lib-core) Compiling library std (git+https://github.com/fuellabs/sway?tag=v0.46.1#512a3386f8961185188302f391ccc96553d23a7a) Compiling contract counter (/home/sheys/fuelvm-projects/counter) warning --> /home/sheys/fuelvm-projects/counter/src/main.sw:5:5 | 3 | 4 | //declare a storage variable 5 | counter: u64 = 0, | ------- This storage declaration is never accessed and can be removed. 6 | } | ____ error --> /home/sheys/fuelvm-projects/counter/src/main.sw:22:16 | 20 | 21 | //using implicit return 22 | return storage.counter; | ^^^^^^^^^^^^^^^ Mismatched types. expected: u64 found: StorageKey. help: Return statement must return the declared function return type. 23 | 24 | } | ____ error --> /home/sheys/fuelvm-projects/counter/src/main.sw:28:9 | 26 | 27 | fn increment() { 28 | storage.counter = storage.counter + 1; | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ This expression is not valid on the left hand side of a reassignment. 29 | } 30 | } | ____ error --> /home/sheys/fuelvm-projects/counter/src/main.sw:20:5 | 18 | 19 | #[storage(read)] 20 | fn counter() -> u64 { | _____ ^ 21 | | //using implicit return 22 | | return storage.counter; 23 | | 24 | | } | | _____ ^ This path must return a value of type "u64" from function "counter", but it does not. 25 | 26 | #[storage(read, write)] | ____ Aborting due to 3 errors. Error: Failed to compile counter ``` I recently read that there’s a storage issue with beta-4 testnet [here](https://forum.fuel.network/t/error-compiling-counter-smart-contract/2482/2), I don’t think that has been resolved yet… But how can I move forward? 1. Regarding point 2, thanks for the information 👍