Rust: Fix rust/unused-variable FPs #17913
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…ust/unused-value as well.
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DCA shows the total number of results for |
| // variable is in a context where is may not have a use | ||
| not v.getPat().isInMacroExpansion() and | ||
| not exists(FnPtrType fp | fp.getParamList().getParam(_).getPat() = v.getPat()) | ||
| not exists(v.getInitializer()) |
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@hvitved Should there be a "write access" for a variable with an initializer? The following two examples should probably be considered equivalent.
let x : i32 = 10;
and
let x : i32;
x = 10;
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Yep, I have plans to flip this behaviour so that both would be considered an unused variable (and not an unused value). There's an issue tracking this, it will probably be simple, but I haven't got around to it yet.
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The x in let x : i 32 = 10; is a pattern and not an expression, so making it a write access is not that natural.
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The second DCA run LGTM.
One project in particular uses them a huge amount. |
Co-authored-by: Simon Friis Vindum <[email protected]>
Add more test cases for
rust/unused-variable, inspired by syntax in real world false positive results for the query. I could only get one pattern to reproduce in the test and I've fixed it here.In one of our largest DCA databases this reduces the total number of results from 212,420 -> 100. A DCA run will confirm the overall picture.