Swift: Assigning to tuple values.

Author: geoffw0

swift/ql/lib/codeql/swift/dataflow/internal/DataFlowPrivate.qll

@@ -513,6 +513,13 @@ predicate storeStep(Node node1, ContentSet c, Node node2) {
     c.isSingleton(any(Content::TupleContent ct | ct.getIndex() = pos))
   )
   or
+  exists(TupleElementExpr tuple, AssignExpr assign |
+    tuple = assign.getDest() and
+    node1.asExpr() = assign.getSource() and
+    node2/*.(PostUpdateNode).getPreUpdateNode()*/.asExpr() = tuple.getSubExpr() and
+    c.isSingleton(any(Content::TupleContent ct | ct.getIndex() = tuple.getIndex()))
+  )
+  or
   FlowSummaryImpl::Private::Steps::summaryStoreStep(node1, c, node2)
 }
 

swift/ql/test/library-tests/dataflow/dataflow/DataFlow.expected

@@ -113,6 +113,9 @@ edges
 | test.swift:277:18:277:25 | call to source() :  | test.swift:277:14:277:26 | (...) [Tuple element at index 1] :  |
 | test.swift:281:15:281:15 | t1 [Tuple element at index 1] :  | test.swift:281:15:281:18 | .1 |
 | test.swift:287:15:287:15 | t1 [Tuple element at index 1] :  | test.swift:287:15:287:18 | .1 |
+| test.swift:289:5:289:5 | t1 [Tuple element at index 0] :  | test.swift:292:15:292:15 | t1 [Tuple element at index 0] :  |
+| test.swift:289:12:289:19 | call to source() :  | test.swift:289:5:289:5 | t1 [Tuple element at index 0] :  |
+| test.swift:292:15:292:15 | t1 [Tuple element at index 0] :  | test.swift:292:15:292:18 | .0 |
 | test.swift:293:15:293:15 | t1 [Tuple element at index 1] :  | test.swift:293:15:293:18 | .1 |
 | test.swift:297:14:297:45 | (...) [Tuple element at index 0] :  | test.swift:302:15:302:15 | t1 [Tuple element at index 0] :  |
 | test.swift:297:14:297:45 | (...) [Tuple element at index 0] :  | test.swift:306:15:306:15 | t2 [Tuple element at index 0] :  |
@@ -250,6 +253,10 @@ nodes
 | test.swift:281:15:281:18 | .1 | semmle.label | .1 |
 | test.swift:287:15:287:15 | t1 [Tuple element at index 1] :  | semmle.label | t1 [Tuple element at index 1] :  |
 | test.swift:287:15:287:18 | .1 | semmle.label | .1 |
+| test.swift:289:5:289:5 | t1 [Tuple element at index 0] :  | semmle.label | t1 [Tuple element at index 0] :  |
+| test.swift:289:12:289:19 | call to source() :  | semmle.label | call to source() :  |
+| test.swift:292:15:292:15 | t1 [Tuple element at index 0] :  | semmle.label | t1 [Tuple element at index 0] :  |
+| test.swift:292:15:292:18 | .0 | semmle.label | .0 |
 | test.swift:293:15:293:15 | t1 [Tuple element at index 1] :  | semmle.label | t1 [Tuple element at index 1] :  |
 | test.swift:293:15:293:18 | .1 | semmle.label | .1 |
 | test.swift:297:14:297:45 | (...) [Tuple element at index 0] :  | semmle.label | (...) [Tuple element at index 0] :  |
@@ -326,6 +333,7 @@ subpaths
 | test.swift:266:15:266:25 | OptionalEvaluationExpr | test.swift:259:12:259:19 | call to source() :  | test.swift:266:15:266:25 | OptionalEvaluationExpr | result |
 | test.swift:281:15:281:18 | .1 | test.swift:277:18:277:25 | call to source() :  | test.swift:281:15:281:18 | .1 | result |
 | test.swift:287:15:287:18 | .1 | test.swift:277:18:277:25 | call to source() :  | test.swift:287:15:287:18 | .1 | result |
+| test.swift:292:15:292:18 | .0 | test.swift:289:12:289:19 | call to source() :  | test.swift:292:15:292:18 | .0 | result |
 | test.swift:293:15:293:18 | .1 | test.swift:277:18:277:25 | call to source() :  | test.swift:293:15:293:18 | .1 | result |
 | test.swift:302:15:302:18 | .0 | test.swift:297:18:297:25 | call to source() :  | test.swift:302:15:302:18 | .0 | result |
 | test.swift:303:15:303:18 | .1 | test.swift:297:31:297:38 | call to source() :  | test.swift:303:15:303:18 | .1 | result |

swift/ql/test/library-tests/dataflow/dataflow/test.swift

@@ -289,7 +289,7 @@ func testTuples() {
     t1.0 = source()
 
     sink(arg: t1)
-    sink(arg: t1.0) // $ MISSING: flow=289
+    sink(arg: t1.0) // $ flow=289
     sink(arg: t1.1) // $ SPURIOUS: flow=277
 }