Skip to content

Rust: Fix rust/unused-variable FPs #17913

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Merged
merged 10 commits into from
Nov 8, 2024
Merged

Rust: Fix rust/unused-variable FPs #17913

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
10 commits
Select commit Hold shift + click to select a range
3091083
Rust: Call all the test cases.
geoffw0 Nov 5, 2024
35ffd0c
Rust: Add more test cases for unused variables (inspired by real worl…
geoffw0 Nov 5, 2024
278760c
Rust: Add another exception to rust/unused-variable.
geoffw0 Nov 5, 2024
93836a5
Rust: Clean up code / clarify responsibilities and fix the issue in r…
geoffw0 Nov 5, 2024
1a5d2e1
Rust: Correct a comment and autoformat.
geoffw0 Nov 5, 2024
8a35e15
Rust: Move the function pointer parameter exclusion into VariableImpl…
geoffw0 Nov 6, 2024
18ce8be
Update rust/ql/lib/codeql/rust/elements/internal/VariableImpl.qll
geoffw0 Nov 6, 2024
df7bcfd
Rust: Accept dataflow consistency check changes.
geoffw0 Nov 7, 2024
fc444f1
Merge branch 'main' into unusedvar8
geoffw0 Nov 8, 2024
7c2c5ee
Rust: Fix expected consistency results.
geoffw0 Nov 8, 2024
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
4 changes: 3 additions & 1 deletion rust/ql/lib/codeql/rust/elements/internal/VariableImpl.qll
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -87,7 +87,9 @@ module Impl {
not name.charAt(0).isUppercase() and
// exclude parameters from functions without a body as these are trait method declarations
// without implementations
not exists(Function f | not f.hasBody() and f.getParamList().getAParam().getPat() = p)
not exists(Function f | not f.hasBody() and f.getParamList().getAParam().getPat() = p) and
// exclude parameters from function pointer types (e.g. `x` in `fn(x: i32) -> i32`)
not exists(FnPtrType fp | fp.getParamList().getParam(_).getPat() = p)
}

/** A variable. */
Expand Down
5 changes: 4 additions & 1 deletion rust/ql/src/queries/unusedentities/UnusedVariable.ql
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -12,5 +12,8 @@ import rust
import UnusedVariable

from Variable v
where isUnused(v)
where
isUnused(v) and
not isAllowableUnused(v) and
not v instanceof DiscardVariable
select v, "Variable '" + v + "' is not used."
22 changes: 17 additions & 5 deletions rust/ql/src/queries/unusedentities/UnusedVariable.qll
View file
Open in desktop
Original file line number Diff line number Diff line change
@@ -1,14 +1,26 @@
import rust

/** A deliberately unused variable. */
/**
* A deliberately unused variable, for example `_` or `_x`.
*/
class DiscardVariable extends Variable {
DiscardVariable() { this.getName().charAt(0) = "_" }
}

/** Holds if variable `v` is unused. */
/**
* Holds if variable `v` is unused.
*/
predicate isUnused(Variable v) {
// variable is not accessed or initialized
not exists(v.getAnAccess()) and
not exists(v.getInitializer()) and
not v instanceof DiscardVariable and
not v.getPat().isInMacroExpansion()
not exists(v.getInitializer())
Copy link
Contributor

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

@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;

Copy link
Contributor Author

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

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.

Copy link
Contributor

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

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.

}

/**
* Holds if variable `v` is in a context where we may not find a use for it,
* but that's expected and should not be considered a problem.
*/
predicate isAllowableUnused(Variable v) {
// in a macro expansion
v.getPat().isInMacroExpansion()
}
167 changes: 91 additions & 76 deletions rust/ql/test/query-tests/unusedentities/CONSISTENCY/DataFlowConsistency.expected
View file
Open in desktop
Original file line number Diff line number Diff line change
@@ -1,85 +1,100 @@
uniqueEnclosingCallable
| main.rs:382:19:382:21 | Param | Node should have one enclosing callable but has 0. |
| main.rs:430:29:430:38 | Param | Node should have one enclosing callable but has 0. |
| main.rs:430:41:430:56 | Param | Node should have one enclosing callable but has 0. |
| main.rs:392:19:392:21 | Param | Node should have one enclosing callable but has 0. |
| main.rs:440:29:440:38 | Param | Node should have one enclosing callable but has 0. |
| main.rs:440:41:440:56 | Param | Node should have one enclosing callable but has 0. |
| main.rs:493:16:493:18 | Param | Node should have one enclosing callable but has 0. |
| main.rs:494:16:494:21 | Param | Node should have one enclosing callable but has 0. |
| main.rs:495:16:496:25 | Param | Node should have one enclosing callable but has 0. |
| main.rs:496:12:496:17 | Param | Node should have one enclosing callable but has 0. |
| main.rs:499:18:499:23 | Param | Node should have one enclosing callable but has 0. |
| main.rs:502:24:502:29 | Param | Node should have one enclosing callable but has 0. |
| more.rs:4:23:4:28 | Param | Node should have one enclosing callable but has 0. |
| more.rs:8:19:8:24 | Param | Node should have one enclosing callable but has 0. |
uniqueCallEnclosingCallable
| main.rs:11:13:11:29 | CallExpr | Call should have one enclosing callable but has 0. |
| main.rs:12:13:12:29 | CallExpr | Call should have one enclosing callable but has 0. |
| main.rs:16:14:16:24 | CallExpr | Call should have one enclosing callable but has 0. |
| main.rs:18:8:18:13 | CallExpr | Call should have one enclosing callable but has 0. |
| main.rs:19:18:19:28 | CallExpr | Call should have one enclosing callable but has 0. |
| main.rs:22:14:22:24 | CallExpr | Call should have one enclosing callable but has 0. |
| main.rs:23:5:23:19 | CallExpr | Call should have one enclosing callable but has 0. |
| main.rs:23:5:23:19 | CallExpr | Call should have one enclosing callable but has 0. |
| main.rs:41:14:41:24 | CallExpr | Call should have one enclosing callable but has 0. |
| main.rs:45:8:45:13 | CallExpr | Call should have one enclosing callable but has 0. |
| main.rs:50:14:50:24 | CallExpr | Call should have one enclosing callable but has 0. |
| main.rs:53:8:53:13 | CallExpr | Call should have one enclosing callable but has 0. |
| main.rs:58:14:58:24 | CallExpr | Call should have one enclosing callable but has 0. |
| main.rs:62:14:62:24 | CallExpr | Call should have one enclosing callable but has 0. |
| main.rs:67:12:67:17 | CallExpr | Call should have one enclosing callable but has 0. |
| main.rs:68:12:68:17 | CallExpr | Call should have one enclosing callable but has 0. |
| main.rs:13:13:13:29 | CallExpr | Call should have one enclosing callable but has 0. |
| main.rs:14:13:14:29 | CallExpr | Call should have one enclosing callable but has 0. |
| main.rs:18:14:18:24 | CallExpr | Call should have one enclosing callable but has 0. |
| main.rs:20:8:20:13 | CallExpr | Call should have one enclosing callable but has 0. |
| main.rs:21:18:21:28 | CallExpr | Call should have one enclosing callable but has 0. |
| main.rs:24:14:24:24 | CallExpr | Call should have one enclosing callable but has 0. |
| main.rs:25:5:25:19 | CallExpr | Call should have one enclosing callable but has 0. |
| main.rs:25:5:25:19 | CallExpr | Call should have one enclosing callable but has 0. |
| main.rs:43:14:43:24 | CallExpr | Call should have one enclosing callable but has 0. |
| main.rs:47:8:47:13 | CallExpr | Call should have one enclosing callable but has 0. |
| main.rs:52:14:52:24 | CallExpr | Call should have one enclosing callable but has 0. |
| main.rs:55:8:55:13 | CallExpr | Call should have one enclosing callable but has 0. |
| main.rs:60:14:60:24 | CallExpr | Call should have one enclosing callable but has 0. |
| main.rs:64:14:64:24 | CallExpr | Call should have one enclosing callable but has 0. |
| main.rs:69:12:69:17 | CallExpr | Call should have one enclosing callable but has 0. |
| main.rs:70:14:70:24 | CallExpr | Call should have one enclosing callable but has 0. |
| main.rs:96:14:96:45 | CallExpr | Call should have one enclosing callable but has 0. |
| main.rs:99:14:99:38 | CallExpr | Call should have one enclosing callable but has 0. |
| main.rs:70:12:70:17 | CallExpr | Call should have one enclosing callable but has 0. |
| main.rs:71:12:71:17 | CallExpr | Call should have one enclosing callable but has 0. |
| main.rs:72:14:72:24 | CallExpr | Call should have one enclosing callable but has 0. |
| main.rs:98:14:98:45 | CallExpr | Call should have one enclosing callable but has 0. |
| main.rs:101:14:101:38 | CallExpr | Call should have one enclosing callable but has 0. |
| main.rs:114:14:114:32 | CallExpr | Call should have one enclosing callable but has 0. |
| main.rs:117:18:117:33 | CallExpr | Call should have one enclosing callable but has 0. |
| main.rs:174:18:174:29 | CallExpr | Call should have one enclosing callable but has 0. |
| main.rs:178:18:178:31 | CallExpr | Call should have one enclosing callable but has 0. |
| main.rs:182:18:182:37 | CallExpr | Call should have one enclosing callable but has 0. |
| main.rs:187:22:187:33 | CallExpr | Call should have one enclosing callable but has 0. |
| main.rs:192:18:192:27 | CallExpr | Call should have one enclosing callable but has 0. |
| main.rs:196:21:196:30 | CallExpr | Call should have one enclosing callable but has 0. |
| main.rs:196:21:196:30 | CallExpr | Call should have one enclosing callable but has 0. |
| main.rs:200:18:200:38 | CallExpr | Call should have one enclosing callable but has 0. |
| main.rs:204:9:204:24 | CallExpr | Call should have one enclosing callable but has 0. |
| main.rs:204:9:204:24 | CallExpr | Call should have one enclosing callable but has 0. |
| main.rs:208:9:208:24 | CallExpr | Call should have one enclosing callable but has 0. |
| main.rs:213:9:213:32 | CallExpr | Call should have one enclosing callable but has 0. |
| main.rs:213:20:213:24 | CallExpr | Call should have one enclosing callable but has 0. |
| main.rs:213:27:213:31 | CallExpr | Call should have one enclosing callable but has 0. |
| main.rs:240:22:240:29 | CallExpr | Call should have one enclosing callable but has 0. |
| main.rs:243:22:243:29 | CallExpr | Call should have one enclosing callable but has 0. |
| main.rs:247:20:247:27 | CallExpr | Call should have one enclosing callable but has 0. |
| main.rs:254:21:254:28 | CallExpr | Call should have one enclosing callable but has 0. |
| main.rs:260:13:260:20 | CallExpr | Call should have one enclosing callable but has 0. |
| main.rs:267:13:267:20 | CallExpr | Call should have one enclosing callable but has 0. |
| main.rs:275:13:275:28 | CallExpr | Call should have one enclosing callable but has 0. |
| main.rs:282:13:282:30 | CallExpr | Call should have one enclosing callable but has 0. |
| main.rs:289:31:289:37 | CallExpr | Call should have one enclosing callable but has 0. |
| main.rs:337:21:337:51 | CallExpr | Call should have one enclosing callable but has 0. |
| main.rs:338:5:338:39 | CallExpr | Call should have one enclosing callable but has 0. |
| main.rs:340:58:340:92 | CallExpr | Call should have one enclosing callable but has 0. |
| main.rs:340:61:340:91 | CallExpr | Call should have one enclosing callable but has 0. |
| main.rs:343:22:343:59 | CallExpr | Call should have one enclosing callable but has 0. |
| main.rs:346:22:346:29 | CallExpr | Call should have one enclosing callable but has 0. |
| main.rs:396:13:396:24 | CallExpr | Call should have one enclosing callable but has 0. |
| main.rs:400:13:400:22 | CallExpr | Call should have one enclosing callable but has 0. |
| main.rs:460:9:464:10 | CallExpr | Call should have one enclosing callable but has 0. |
| main.rs:471:5:471:14 | CallExpr | Call should have one enclosing callable but has 0. |
| main.rs:472:5:472:14 | CallExpr | Call should have one enclosing callable but has 0. |
| main.rs:473:5:473:13 | CallExpr | Call should have one enclosing callable but has 0. |
| main.rs:474:5:474:12 | CallExpr | Call should have one enclosing callable but has 0. |
| main.rs:475:5:475:13 | CallExpr | Call should have one enclosing callable but has 0. |
| main.rs:476:14:476:54 | CallExpr | Call should have one enclosing callable but has 0. |
| main.rs:476:36:476:54 | CallExpr | Call should have one enclosing callable but has 0. |
| main.rs:477:5:477:11 | CallExpr | Call should have one enclosing callable but has 0. |
| main.rs:478:5:478:21 | CallExpr | Call should have one enclosing callable but has 0. |
| main.rs:479:5:479:15 | CallExpr | Call should have one enclosing callable but has 0. |
| main.rs:480:5:480:15 | CallExpr | Call should have one enclosing callable but has 0. |
| main.rs:481:5:481:24 | CallExpr | Call should have one enclosing callable but has 0. |
| main.rs:483:5:483:22 | CallExpr | Call should have one enclosing callable but has 0. |
| main.rs:485:5:485:23 | CallExpr | Call should have one enclosing callable but has 0. |
| main.rs:487:5:487:23 | CallExpr | Call should have one enclosing callable but has 0. |
| main.rs:488:5:488:23 | CallExpr | Call should have one enclosing callable but has 0. |
| main.rs:489:5:489:23 | CallExpr | Call should have one enclosing callable but has 0. |
| main.rs:490:5:490:22 | CallExpr | Call should have one enclosing callable but has 0. |
| main.rs:491:5:491:22 | CallExpr | Call should have one enclosing callable but has 0. |
| main.rs:493:5:493:12 | CallExpr | Call should have one enclosing callable but has 0. |
| main.rs:103:14:103:38 | CallExpr | Call should have one enclosing callable but has 0. |
| main.rs:116:14:116:32 | CallExpr | Call should have one enclosing callable but has 0. |
| main.rs:119:18:119:33 | CallExpr | Call should have one enclosing callable but has 0. |
| main.rs:176:18:176:29 | CallExpr | Call should have one enclosing callable but has 0. |
| main.rs:180:18:180:31 | CallExpr | Call should have one enclosing callable but has 0. |
| main.rs:184:18:184:37 | CallExpr | Call should have one enclosing callable but has 0. |
| main.rs:189:22:189:33 | CallExpr | Call should have one enclosing callable but has 0. |
| main.rs:194:18:194:27 | CallExpr | Call should have one enclosing callable but has 0. |
| main.rs:198:21:198:30 | CallExpr | Call should have one enclosing callable but has 0. |
| main.rs:198:21:198:30 | CallExpr | Call should have one enclosing callable but has 0. |
| main.rs:202:21:202:32 | CallExpr | Call should have one enclosing callable but has 0. |
| main.rs:202:21:202:32 | CallExpr | Call should have one enclosing callable but has 0. |
| main.rs:206:21:206:30 | CallExpr | Call should have one enclosing callable but has 0. |
| main.rs:206:21:206:30 | CallExpr | Call should have one enclosing callable but has 0. |
| main.rs:210:18:210:38 | CallExpr | Call should have one enclosing callable but has 0. |
| main.rs:214:9:214:24 | CallExpr | Call should have one enclosing callable but has 0. |
| main.rs:214:9:214:24 | CallExpr | Call should have one enclosing callable but has 0. |
| main.rs:218:9:218:24 | CallExpr | Call should have one enclosing callable but has 0. |
| main.rs:223:9:223:32 | CallExpr | Call should have one enclosing callable but has 0. |
| main.rs:223:20:223:24 | CallExpr | Call should have one enclosing callable but has 0. |
| main.rs:223:27:223:31 | CallExpr | Call should have one enclosing callable but has 0. |
| main.rs:250:22:250:29 | CallExpr | Call should have one enclosing callable but has 0. |
| main.rs:253:22:253:29 | CallExpr | Call should have one enclosing callable but has 0. |
| main.rs:257:20:257:27 | CallExpr | Call should have one enclosing callable but has 0. |
| main.rs:264:21:264:28 | CallExpr | Call should have one enclosing callable but has 0. |
| main.rs:270:13:270:20 | CallExpr | Call should have one enclosing callable but has 0. |
| main.rs:277:13:277:20 | CallExpr | Call should have one enclosing callable but has 0. |
| main.rs:285:13:285:28 | CallExpr | Call should have one enclosing callable but has 0. |
| main.rs:292:13:292:30 | CallExpr | Call should have one enclosing callable but has 0. |
| main.rs:299:31:299:37 | CallExpr | Call should have one enclosing callable but has 0. |
| main.rs:347:21:347:51 | CallExpr | Call should have one enclosing callable but has 0. |
| main.rs:348:5:348:39 | CallExpr | Call should have one enclosing callable but has 0. |
| main.rs:350:58:350:92 | CallExpr | Call should have one enclosing callable but has 0. |
| main.rs:350:61:350:91 | CallExpr | Call should have one enclosing callable but has 0. |
| main.rs:353:22:353:59 | CallExpr | Call should have one enclosing callable but has 0. |
| main.rs:356:22:356:29 | CallExpr | Call should have one enclosing callable but has 0. |
| main.rs:406:13:406:24 | CallExpr | Call should have one enclosing callable but has 0. |
| main.rs:410:13:410:22 | CallExpr | Call should have one enclosing callable but has 0. |
| main.rs:470:9:474:10 | CallExpr | Call should have one enclosing callable but has 0. |
| main.rs:487:5:487:21 | CallExpr | Call should have one enclosing callable but has 0. |
| main.rs:487:5:487:21 | CallExpr | Call should have one enclosing callable but has 0. |
| main.rs:508:5:508:14 | CallExpr | Call should have one enclosing callable but has 0. |
| main.rs:509:5:509:14 | CallExpr | Call should have one enclosing callable but has 0. |
| main.rs:510:5:510:13 | CallExpr | Call should have one enclosing callable but has 0. |
| main.rs:511:5:511:12 | CallExpr | Call should have one enclosing callable but has 0. |
| main.rs:512:5:512:13 | CallExpr | Call should have one enclosing callable but has 0. |
| main.rs:513:14:513:54 | CallExpr | Call should have one enclosing callable but has 0. |
| main.rs:513:36:513:54 | CallExpr | Call should have one enclosing callable but has 0. |
| main.rs:514:5:514:11 | CallExpr | Call should have one enclosing callable but has 0. |
| main.rs:515:5:515:21 | CallExpr | Call should have one enclosing callable but has 0. |
| main.rs:516:5:516:15 | CallExpr | Call should have one enclosing callable but has 0. |
| main.rs:517:5:517:15 | CallExpr | Call should have one enclosing callable but has 0. |
| main.rs:518:5:518:24 | CallExpr | Call should have one enclosing callable but has 0. |
| main.rs:519:5:519:12 | CallExpr | Call should have one enclosing callable but has 0. |
| main.rs:520:5:520:16 | CallExpr | Call should have one enclosing callable but has 0. |
| main.rs:522:5:522:14 | CallExpr | Call should have one enclosing callable but has 0. |
| main.rs:523:5:523:14 | CallExpr | Call should have one enclosing callable but has 0. |
| main.rs:525:5:525:22 | CallExpr | Call should have one enclosing callable but has 0. |
| main.rs:527:5:527:23 | CallExpr | Call should have one enclosing callable but has 0. |
| main.rs:529:5:529:23 | CallExpr | Call should have one enclosing callable but has 0. |
| main.rs:530:5:530:23 | CallExpr | Call should have one enclosing callable but has 0. |
| main.rs:531:5:531:23 | CallExpr | Call should have one enclosing callable but has 0. |
| main.rs:532:5:532:22 | CallExpr | Call should have one enclosing callable but has 0. |
| main.rs:533:5:533:22 | CallExpr | Call should have one enclosing callable but has 0. |
| more.rs:45:14:45:26 | CallExpr | Call should have one enclosing callable but has 0. |
| more.rs:46:14:46:25 | CallExpr | Call should have one enclosing callable but has 0. |
| more.rs:47:14:47:26 | CallExpr | Call should have one enclosing callable but has 0. |
Expand Down
Loading
Loading