From a998879897ed9240d1df3fb44362e02b1fcc8d41 Mon Sep 17 00:00:00 2001
From: Arthur Baars <aibaars@github.com>
Date: Thu, 4 Feb 2021 13:49:55 +0100
Subject: [PATCH] Add local flow step for parenthesized expressions

---
 ql/src/codeql_ruby/controlflow/CfgNodes.qll              | 5 +++++
 ql/src/codeql_ruby/dataflow/internal/DataFlowPrivate.qll | 3 +++
 2 files changed, 8 insertions(+)

diff --git a/ql/src/codeql_ruby/controlflow/CfgNodes.qll b/ql/src/codeql_ruby/controlflow/CfgNodes.qll
index fed5005f2de..c08df48c8a6 100644
--- a/ql/src/codeql_ruby/controlflow/CfgNodes.qll
+++ b/ql/src/codeql_ruby/controlflow/CfgNodes.qll
@@ -249,6 +249,11 @@ module ExprNodes {
     final ExprCfgNode getExpr(int n) { e.hasCfgChild(e.getExpr(n), this, result) }
   }
 
+  /** A control-flow node that wraps an `ExprSequence` AST expression. */
+  class ParenthesizedExprCfgNode extends ExprSequenceCfgNode {
+    ParenthesizedExprCfgNode() { this.getExpr() instanceof ParenthesizedExpr }
+  }
+
   /** A control-flow node that wraps a `VariableReadAccess` AST expression. */
   class VariableReadAccessCfgNode extends ExprCfgNode {
     override VariableReadAccess e;
diff --git a/ql/src/codeql_ruby/dataflow/internal/DataFlowPrivate.qll b/ql/src/codeql_ruby/dataflow/internal/DataFlowPrivate.qll
index 7802e098324..bbfb4019c33 100644
--- a/ql/src/codeql_ruby/dataflow/internal/DataFlowPrivate.qll
+++ b/ql/src/codeql_ruby/dataflow/internal/DataFlowPrivate.qll
@@ -124,6 +124,9 @@ private module Cached {
     exists(Ssa::Definition def | LocalFlow::localSsaFlowStep(def, nodeFrom, nodeTo))
     or
     nodeFrom.asExpr() = nodeTo.asExpr().(CfgNodes::ExprNodes::AssignExprCfgNode).getRhs()
+    or
+    nodeFrom.asExpr() =
+      nodeTo.asExpr().(CfgNodes::ExprNodes::ParenthesizedExprCfgNode).getLastExpr()
   }
 
   cached