Unified: Support capture declarations in the CFG.

Author: aschackmull

unified/ql/lib/codeql/unified/internal/ControlFlowGraph.qll

@@ -40,6 +40,8 @@ private module Ast implements AstSig<Location> {
     not n instanceof Callable and
     not skipControlFlow(n) and
     not skipControlFlow(result)
+    or
+    n.(FunctionExpr).getCaptureDeclaration(index) = result
   }
 
   Callable getEnclosingCallable(AstNode node) { result = node.getEnclosingCallable() }

unified/ql/test/library-tests/controlflow/basicblock-slices.expected

@@ -311,7 +311,7 @@
 | 380 | cfg.swift:380:1:384:1 | FunctionDeclaration | 'FunctionDeclaration' |
 | 380 | cfg.swift:380:18:380:18 | x | 'x -> y -^ Block' |
 | 381 | cfg.swift:381:10:383:3 | Block | 'Block' |
-| 381 | cfg.swift:381:10:383:3 | FunctionExpr | 'FunctionExpr -^ ReturnExpr' |
+| 381 | cfg.swift:381:13:381:22 | VariableDeclaration | 'VariableDeclaration -V z -> x -> y -^ BinaryExpr -> VariableDeclaration -V t -> "literal" -^ FunctionExpr -^ ReturnExpr' |
 | 382 | cfg.swift:382:12:382:12 | z | 'z -^ ReturnExpr' |
 | 386 | cfg.swift:386:1:388:1 | FunctionDeclaration | 'FunctionDeclaration' |
 | 386 | cfg.swift:386:23:386:23 | t | 't -^ Block' |

unified/ql/test/library-tests/controlflow/cfg.expected

@@ -149,7 +149,6 @@ noCfg
 | cfg.swift:358:6:358:28 | loop_with_identity_expr |
 | cfg.swift:371:8:371:18 | getOptional |
 | cfg.swift:380:45:380:47 | Int |
-| cfg.swift:381:13:381:13 | z |
 | cfg.swift:421:6:421:22 | localDeclarations |
 | cfg.swift:468:6:468:17 | testIfConfig |
 | cfg.swift:497:6:497:18 | testAvailable |

unified/ql/test/library-tests/controlflow/cfg.swift

@@ -378,7 +378,7 @@ func testOptional(c : OptionalC?) -> Int? {
 }
 
 func testCapture(x : Int, y : Int) -> () -> Int { // $ noCfg
-  return { [z = x + y, t = "literal"] in // $ noCfg
+  return { [z = x + y, t = "literal"] in
     return z
   }
 }