Add error explanation for E0010 #24892
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Thanks for the pull request, and welcome! The Rust team is excited to review your changes, and you should hear from @pcwalton (or someone else) soon. If any changes to this PR are deemed necessary, please add them as extra commits. This ensures that the reviewer can see what has changed since they last reviewed the code. The way Github handles out-of-date commits, this should also make it reasonably obvious what issues have or haven't been addressed. Large or tricky changes may require several passes of review and changes. Please see CONTRIBUTING.md for more information. |
| @@ -168,6 +168,11 @@ match x { | |||
| ``` | |||
| "##, | |||
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| E0010: r##" | |||
| The value of static and const variables must be known at compile time, and they | |||
| live for the entire lifetime of a program. They can not use allocation. | |||
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The word "allocation" already occurs in the message currently emitted for E0010. Rather than "They can not use allocation" (which will not enlighten someone who did not already know what the first message meant), I would say "They are not allowed to create Box values", maybe?)
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How about "They are not allowed to allocate values using box"?
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I think a longer comment about allocation on the heap being a run-time operation would be ideal. Mentioning Box values could also be good but the core concept is allocation.
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What if that second sentence were this?
Creating a boxed value allocates memory on the heap at run-time, and therefore cannot be done at compile-time.
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that looks good to me, especially I think this error code is currently only emitted for uses of box (and not other methods of dynamic memory allocation, all of which would currently also be illegal to even attempt to encode).
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r? @pnkfelix |
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☔ The latest upstream changes (presumably #24893) made this pull request unmergeable. Please resolve the merge conflicts. |
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@robinst: If you add that second sentence and do a rebase we can merge this 😄 |
| @@ -168,6 +168,11 @@ match x { | |||
| ``` | |||
| "##, | |||
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| E0010: r##" | |||
| The value of static and const variables must be known at compile time, and they | |||
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‘const variable’ is an oxymoron. This should probably just read something like ‘The value of constants (declared with either const or static) must be known…’
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I think using 'constants' is worse, since statics are not constants (either in theory or in practice).
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Perhaps ‘The value of constants and statics must be known…’?
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Or maybe?
Both constants and statics are given values at compile-time. In the case of constants, the value is fixed for the duration of the program's execution, while statics are given an initial value in the program binary.
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Done using @P1start's suggestion.
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@bors r+ rollup |
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📌 Commit 95ad630 has been approved by |
Part of #24407.