Merge pull request #10064 from MathiasVP/fix-ssa-for-getters

Swift: Fix SSA for calls to getter functions

Author: MathiasVP

swift/ql/lib/codeql/swift/dataflow/Ssa.qll

@@ -61,7 +61,7 @@ module Ssa {
      * to the underlying variable.
      */
     cached
-    predicate assigns(ExprCfgNode value) {
+    predicate assigns(CfgNode value) {
       exists(
         AssignExpr a, BasicBlock bb, int i // TODO: use CFG node for assignment expr
       |
@@ -70,15 +70,21 @@ module Ssa {
         value.getNode().asAstNode() = a.getSource()
       )
       or
-      exists(VarDecl var, BasicBlock bb, int blockIndex, PatternBindingDecl pbd |
+      exists(VarDecl var, BasicBlock bb, int blockIndex, PatternBindingDecl pbd, Expr init |
         this.definesAt(var, bb, blockIndex) and
         pbd.getAPattern() = bb.getNode(blockIndex).getNode().asAstNode() and
-        value.getNode().asAstNode() = var.getParentInitializer()
+        init = var.getParentInitializer()
+      |
+        value.getNode().asAstNode() = init
+        or
+        // TODO: We should probably enumerate more cfg nodes here.
+        value.(PropertyGetterCfgNode).getRef() = init
       )
     }
 
     cached
     predicate isInoutDef(ExprCfgNode argument) {
+      // TODO: This should probably not be only `ExprCfgNode`s.
       exists(
         ApplyExpr c, BasicBlock bb, int blockIndex, int argIndex, VarDecl v, InOutExpr argExpr // TODO: use CFG node for assignment expr
       |