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Issue ID




[SerializedField] fields produce "Field is never assigned to..." warning



1. Open the attached project (
2. Observe the warning in the console

Expected: field with SerializeField attribute do not produce the warning

Reproduced in 2018.3.0a1, 2018.3.0b1, 2018.3.0b2, 2019.1.0a1
Did not reproduce in 2018.2.8f1
Regression introduced in 2018.3.0a1


The new C# compiler is correct in reporting the additional warnings. Unfortunately, there is no magic to fix this.

You can disable the warnings with pragmas:

#pragma warning disable 0649
// your code
#pragma warning restore 0649

Or disable it globally by adding a csc.rsp file to your project and adding command line switch to disable the warning.

Comments (43)

  1. 55d14f6d8457d63f7573846de069a09b?d=mm


    Sep 20, 2019 10:26

    Reopen this, please...

  2. 29b7224f3299d49bbc1741626aaeab16?d=mm


    Sep 18, 2019 11:47

    +1 for reopen....

  3. Bd8ae845fd68eef42682d25b6e516e0a?d=mm


    Sep 17, 2019 19:18

    This makes it really hard to see real warnings. Please fix this.

  4. 8dd865676b3397338a01a5b4b71383c8?d=mm


    Sep 11, 2019 07:32

    Poor design. Really Unity, just fix this...

  5. 12f8b1d899b95dbcab59e7eade28a119?d=mm


    Aug 29, 2019 15:35

    Please fix this. Yeah its "by desing" but that design in god damn horrible. Its making it harder to see actual warnings.

  6. 09b5416e1126419cc9ffd789e6ba2d5f?d=mm


    Aug 26, 2019 08:27

    i'd love to see better explained resolution please.

    `Or disable it globally by adding a csc.rsp file to your project and adding command line switch to disable the warning. `

    how could you do that ?

  7. B7f76d6e75f42c076a38c723d8886964?d=mm


    Aug 13, 2019 19:06

    Please reopen issue

  8. 152dddd9c528d451a1df8d446e76a250?d=mm


    Aug 12, 2019 14:24

    This is litterally the worst resolvement of an issue I've seen. This is an issue and is spamming the console window when it absolutely shouldn't. I would like you to re-open this issue. Pure annoyance.

  9. 41ee2402153fef1ac3f29b178fd7edc4?d=mm


    Aug 09, 2019 06:56

    I do not agree with this solution!

    SerializeField is am important tool to prevent public variables in scripts.
    Having to initialize every SerializeField variable to a default value as a workaround is redundant work, reduces readability and can cause confusion.

  10. 8382b669e96e7229ef2670c5f253f619?d=mm


    Jul 26, 2019 17:05

    So now when we're properly using one of Unity's features in the documented, recommended way, we have to either include a #suppress and #restore in EVERY CLASS (which is what I've done for my ~70 classes), or manually assign the default value to every field? That is unacceptable!

    Apart for the warning, when using the [SerializeField] private pattern on fields only changed from the inspector, I get a message stating I should make the field readonly - though making it readonly prevents it from being serialized!

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