From 0a09ab1e3c024c3e797c6cc3efc86d807a35f0d4 Mon Sep 17 00:00:00 2001
From: Chandler Carruth <chandlerc@gmail.com>
Date: Tue, 14 Jul 2026 17:59:58 -0700
Subject: [PATCH] Reduce Clang header exposure in check_unit.h (#7509)

Remove clang/Frontend/CompilerInvocation.h from check_unit.h and forward
declare clang::CompilerInvocation instead to reduce header exposure.

Add an explicit include of CompilerInvocation.h to check_unit.cpp.

Assisted-by: Antigravity with Gemini
---
 toolchain/check/check_unit.cpp | 1 +
 toolchain/check/check_unit.h   | 5 ++++-
 2 files changed, 5 insertions(+), 1 deletion(-)

diff --git a/toolchain/check/check_unit.cpp b/toolchain/check/check_unit.cpp
index 49a067274960..9a1d9e431cff 100644
--- a/toolchain/check/check_unit.cpp
+++ b/toolchain/check/check_unit.cpp
@@ -9,6 +9,7 @@
 #include <tuple>
 #include <utility>
 
+#include "clang/Frontend/CompilerInvocation.h"
 #include "clang/Sema/Sema.h"
 #include "common/growing_range.h"
 #include "common/pretty_stack_trace_function.h"
diff --git a/toolchain/check/check_unit.h b/toolchain/check/check_unit.h
index d961c81dd8cd..786e5577e073 100644
--- a/toolchain/check/check_unit.h
+++ b/toolchain/check/check_unit.h
@@ -5,7 +5,6 @@
 #ifndef CARBON_TOOLCHAIN_CHECK_CHECK_UNIT_H_
 #define CARBON_TOOLCHAIN_CHECK_CHECK_UNIT_H_
 
-#include "clang/Frontend/CompilerInvocation.h"
 #include "common/map.h"
 #include "llvm/ADT/SmallVector.h"
 #include "toolchain/check/check.h"
@@ -14,6 +13,10 @@
 #include "toolchain/parse/node_ids.h"
 #include "toolchain/sem_ir/ids.h"
 
+namespace clang {
+class CompilerInvocation;
+}
+
 namespace Carbon::Check {
 
 struct UnitAndImports;