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JS: Rephrase dead store of local at declaration site

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Asger F
2019-07-30 17:55:38 +01:00
parent 6d10731b8f
commit ea563f8b97
2 changed files with 17 additions and 9 deletions
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14
javascript/ql/src/Declarations/DeadStoreOfLocal.ql
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@@ -26,7 +26,7 @@ predicate deadStoreOfLocal(VarDef vd, PurelyLocalVariable v) {
not exists(SsaExplicitDefinition ssa | ssa.defines(vd, v))
}
from VarDef dead, PurelyLocalVariable v // captured variables may be read by closures, so don't flag them
from VarDef dead, PurelyLocalVariable v, string msg // captured variables may be read by closures, so don't flag them
where
deadStoreOfLocal(dead, v) and
// the variable should be accessed somewhere; otherwise it will be flagged by UnusedVariable
@@ -51,5 +51,13 @@ where
// don't flag exported variables
not any(ES2015Module m).exportsAs(v, _) and
// don't flag 'exports' assignments in closure modules
not any(Closure::ClosureModule mod).getExportsVariable() = v
select dead, "This definition of " + v.getName() + " is useless, since its value is never read."
not any(Closure::ClosureModule mod).getExportsVariable() = v and
(
// To avoid confusion about the meaning of "definition" and "declaration" we avoid
// the term "definition" when the alert location is a variable declaration.
if dead instanceof VariableDeclarator then
msg = "The initial value of " + v.getName() + " is unused, since it is always overwritten."
else
msg = "This definition of " + v.getName() + " is useless, since its value is never read."
)
select dead, msg

12
javascript/ql/test/query-tests/Declarations/DeadStoreOfLocal/DeadStoreOfLocal.expected
View File

@@ -1,12 +1,12 @@
| overload.ts:10:12:10:14 | baz | This definition of baz is useless, since its value is never read. |
| tst2.js:26:9:26:14 | x = 23 | This definition of x is useless, since its value is never read. |
| tst2.js:26:9:26:14 | x = 23 | The initial value of x is unused, since it is always overwritten. |
| tst2.js:28:9:28:14 | x = 42 | This definition of x is useless, since its value is never read. |
| tst3.js:2:1:2:36 | exports ... a: 23 } | This definition of exports is useless, since its value is never read. |
| tst3b.js:2:18:2:36 | exports = { a: 23 } | This definition of exports is useless, since its value is never read. |
| tst.js:6:2:6:7 | y = 23 | This definition of y is useless, since its value is never read. |
| tst.js:13:6:13:11 | a = 23 | This definition of a is useless, since its value is never read. |
| tst.js:13:6:13:11 | a = 23 | The initial value of a is unused, since it is always overwritten. |
| tst.js:13:14:13:19 | a = 42 | This definition of a is useless, since its value is never read. |
| tst.js:45:6:45:11 | x = 23 | This definition of x is useless, since its value is never read. |
| tst.js:51:6:51:11 | x = 23 | This definition of x is useless, since its value is never read. |
| tst.js:132:7:132:13 | {x} = o | This definition of x is useless, since its value is never read. |
| tst.js:162:6:162:14 | [x] = [0] | This definition of x is useless, since its value is never read. |
| tst.js:45:6:45:11 | x = 23 | The initial value of x is unused, since it is always overwritten. |
| tst.js:51:6:51:11 | x = 23 | The initial value of x is unused, since it is always overwritten. |
| tst.js:132:7:132:13 | {x} = o | The initial value of x is unused, since it is always overwritten. |
| tst.js:162:6:162:14 | [x] = [0] | The initial value of x is unused, since it is always overwritten. |