JS: whitelist js/unused-local-variable near direct eval calls

Esben Sparre Andreasen · Esben Sparre Andreasen · commit 74642b9b81a2 · 2018-10-30T13:08:24.000+01:00
diff --git a/javascript/ql/src/Declarations/UnusedVariable.ql b/javascript/ql/src/Declarations/UnusedVariable.ql
@@ -156,6 +156,12 @@ predicate whitelisted(UnusedLocal v) {
     isEnumMember(vd) or
     // ignore ambient declarations - too noisy
     vd.isAmbient()
+  ) or
+  exists (DirectEval eval |
+    // eval nearby
+    eval.getEnclosingFunction() = v.getADeclaration().getEnclosingFunction() and
+    // ... but not on the RHS
+    not v.getAnAssignedExpr() = eval
   )
 }
 
diff --git a/javascript/ql/test/query-tests/Declarations/UnusedVariable/UnusedVariable.expected b/javascript/ql/test/query-tests/Declarations/UnusedVariable/UnusedVariable.expected
@@ -1,7 +1,5 @@
 | decorated.ts:1:1:1:126 | import  ... where'; | Unused import actionHandler. |
 | decorated.ts:4:10:4:12 | fun | Unused function fun. |
-| eval.js:2:9:2:20 | used_by_eval | Unused variable used_by_eval. |
-| eval.js:7:9:7:20 | used_by_eval | Unused variable used_by_eval. |
 | eval.js:10:9:10:24 | not_used_by_eval | Unused variable not_used_by_eval. |
 | eval.js:19:9:19:24 | not_used_by_eval | Unused variable not_used_by_eval. |
 | externs.js:6:5:6:13 | iAmUnused | Unused variable iAmUnused. |

Original file line number	Diff line number	Diff line change
`@@ -156,6 +156,12 @@ predicate whitelisted(UnusedLocal v) {`
`156`	`156`	`isEnumMember(vd) or`
`157`	`157`	`// ignore ambient declarations - too noisy`
`158`	`158`	`vd.isAmbient()`
	`159`	`+ ) or`
	`160`	`+ exists (DirectEval eval \|`
	`161`	`+ // eval nearby`
	`162`	`+ eval.getEnclosingFunction() = v.getADeclaration().getEnclosingFunction() and`
	`163`	`+ // ... but not on the RHS`
	`164`	`+ not v.getAnAssignedExpr() = eval`
`159`	`165`	`)`
`160`	`166`	`}`
`161`	`167`