From 427d203dfcd5a62267ac5e37d52760b166507247 Mon Sep 17 00:00:00 2001
From: Ethan Smith <ethansmith@google.com>
Date: Fri, 27 Mar 2026 14:32:50 -0700
Subject: [PATCH] Don't emit empty namespaces.

PiperOrigin-RevId: 890639061
---
 bazel/llvm.bzl                                       |  2 +-
 cc_bindings_from_rs/generate_bindings/lib.rs         |  3 +++
 cc_bindings_from_rs/test/enums/cpp_enums_cc_api.h    |  6 ------
 .../test/golden/type_aliases_cc_api.h                |  2 --
 cc_bindings_from_rs/test/modules/modules_cc_api.h    | 12 ------------
 cc_bindings_from_rs/test/structs/structs_cc_api.h    |  2 --
 6 files changed, 4 insertions(+), 23 deletions(-)

diff --git a/bazel/llvm.bzl b/bazel/llvm.bzl
index 03ddda0ae..e3ac59ed1 100644
--- a/bazel/llvm.bzl
+++ b/bazel/llvm.bzl
@@ -53,7 +53,7 @@ def _llvm_loader_repository(repository_ctx):
             executable = False,
         )
 
-LLVM_COMMIT_SHA = "5a403150b468a5de7ddf9f1e295643c9c518aee8"
+LLVM_COMMIT_SHA = "9a0b003dde83d46f2ed6d95d85d1d9de3c1fe908"
 
 def llvm_loader_repository_dependencies():
     # This *declares* the dependency, but it won't actually be *downloaded* unless it's used.
diff --git a/cc_bindings_from_rs/generate_bindings/lib.rs b/cc_bindings_from_rs/generate_bindings/lib.rs
index 0b80a4cca..4b88d5372 100644
--- a/cc_bindings_from_rs/generate_bindings/lib.rs
+++ b/cc_bindings_from_rs/generate_bindings/lib.rs
@@ -367,6 +367,9 @@ fn format_with_cc_body(
     mut tokens: TokenStream,
     attributes: Vec<TokenStream>,
 ) -> Result<TokenStream> {
+    if tokens.is_empty() {
+        return Ok(quote! {});
+    }
     let mut namespaces = ns.parts().map(|s| format_cc_ident(db, s)).collect::<Result<Vec<_>>>()?;
 
     // Nested namespace syntax does not accept attributes (see b/445613694), so we have to split out
diff --git a/cc_bindings_from_rs/test/enums/cpp_enums_cc_api.h b/cc_bindings_from_rs/test/enums/cpp_enums_cc_api.h
index c33048abe..8da94a7ae 100644
--- a/cc_bindings_from_rs/test/enums/cpp_enums_cc_api.h
+++ b/cc_bindings_from_rs/test/enums/cpp_enums_cc_api.h
@@ -83,12 +83,6 @@ enum class CRUBIT_INTERNAL_RUST_TYPE(
 
 }  // namespace cpp_enums::forward_declared_enum
 
-namespace cpp_enums::classless_enum {}
-
-namespace cpp_enums::cpp_enum {}
-
-namespace cpp_enums::deprecated_enum {}
-
 namespace cpp_enums::forward_declared_enum {
 
 namespace __crubit_internal {
diff --git a/cc_bindings_from_rs/test/golden/type_aliases_cc_api.h b/cc_bindings_from_rs/test/golden/type_aliases_cc_api.h
index 2c8c8392a..8b8028a72 100644
--- a/cc_bindings_from_rs/test/golden/type_aliases_cc_api.h
+++ b/cc_bindings_from_rs/test/golden/type_aliases_cc_api.h
@@ -48,8 +48,6 @@ std::int32_t func_using_alias();
 
 }  // namespace type_aliases_rust::test_type_aliases
 
-namespace type_aliases_rust::test_deprecated_type_alias {}
-
 namespace type_aliases_rust::test_type_aliases {
 
 namespace __crubit_internal {
diff --git a/cc_bindings_from_rs/test/modules/modules_cc_api.h b/cc_bindings_from_rs/test/modules/modules_cc_api.h
index 5e2e0571b..61f9b380d 100644
--- a/cc_bindings_from_rs/test/modules/modules_cc_api.h
+++ b/cc_bindings_from_rs/test/modules/modules_cc_api.h
@@ -183,17 +183,5 @@ inline void Foo::__crubit_field_offset_assertions() {
 }
 }  // namespace modules::impl_in_separate_private_module
 
-namespace modules::outer {
-
-namespace [[deprecated]] inner_deprecated {}
-
-}  // namespace modules::outer
-
-namespace modules::outer::middle {
-
-namespace [[deprecated]] innermost_deprecated {}
-
-}  // namespace modules::outer::middle
-
 #pragma clang diagnostic pop
 #endif  // THIRD_PARTY_CRUBIT_CC_BINDINGS_FROM_RS_TEST_MODULES_MODULES_GOLDEN
diff --git a/cc_bindings_from_rs/test/structs/structs_cc_api.h b/cc_bindings_from_rs/test/structs/structs_cc_api.h
index a34c24a43..ee8e16f71 100644
--- a/cc_bindings_from_rs/test/structs/structs_cc_api.h
+++ b/cc_bindings_from_rs/test/structs/structs_cc_api.h
@@ -959,8 +959,6 @@ inline std::int32_t get_x(::structs::default_repr::Point p) {
 
 }  // namespace structs::default_repr
 
-namespace structs::dynamically_sized_type {}
-
 namespace structs::interior_mutability {
 
 static_assert(