From 59c83b7b8fabec61954af4eda93bd105f68a9551 Mon Sep 17 00:00:00 2001
From: Nick Rolfe <nickrolfe@github.com>
Date: Thu, 29 Apr 2021 14:00:27 +0100
Subject: [PATCH] Add clarifying comment

---
 ql/src/codeql_ruby/ast/Call.qll | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/ql/src/codeql_ruby/ast/Call.qll b/ql/src/codeql_ruby/ast/Call.qll
index bc2231d94f3..e301a1b5b9d 100644
--- a/ql/src/codeql_ruby/ast/Call.qll
+++ b/ql/src/codeql_ruby/ast/Call.qll
@@ -162,6 +162,9 @@ private class RegularMethodCall extends MethodCall, TRegularMethodCall {
     not exists(g.getReceiver()) and
     toGenerated(result) = g.getMethod().(Generated::ScopeResolution).getScope()
     or
+    // If there's no explicit receiver (or scope resolution that acts like a
+    // receiver), then the receiver is implicitly `self`.  N.B.  `::Foo()` is
+    // not valid Ruby.
     not exists(g.getReceiver()) and
     not exists(g.getMethod().(Generated::ScopeResolution).getScope()) and
     result = TRegularMethodCallImplicitSelf(g)