From 2c189f0b08ecd1e636568a559c95699e130e79f8 Mon Sep 17 00:00:00 2001
From: David Blaikie <dblaikie@gmail.com>
Date: Mon, 23 Mar 2026 12:11:42 +0000
Subject: [PATCH] Comment scope_map_

---
 toolchain/check/cpp/generate_ast.cpp | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/toolchain/check/cpp/generate_ast.cpp b/toolchain/check/cpp/generate_ast.cpp
index e0140d353fa0..8d9545d7de40 100644
--- a/toolchain/check/cpp/generate_ast.cpp
+++ b/toolchain/check/cpp/generate_ast.cpp
@@ -355,6 +355,11 @@ class CarbonExternalASTSource : public clang::ExternalASTSource {
 
   Check::Context* context_;
   clang::ASTContext* ast_context_;
+  // The association between clang DeclContexts and the corresponding
+  // SemIR::Namespaces in Carbon.
+  // TODO: reuse the SemIR::File::ClangDeclStore to avoid duplicates, and to
+  // enable roundtripping through forward and reverse interop (once we have
+  // syntax/support for that).
   Map<clang::DeclContext*, SemIR::InstId> scope_map_;
 };