[clang-tools-extra] [clang-tidy] Add regression tests for readability-redundant-typename. NFC. (PR #207318)

[Zeyi Xu via cfe-commits]

https://github.com/zeyi2 created https://github.com/llvm/llvm-project/pull/207318

None

>From 287198f216c5854d977ce36c60a24ed9a3147277 Mon Sep 17 00:00:00 2001
From: Zeyi Xu <mitchell.xu2 at gmail.com>
Date: Fri, 3 Jul 2026 11:47:53 +0800
Subject: [PATCH] [clang-tidy] Add regression tests for
 readability-redundant-typename. NFC.

---
 .../readability/redundant-typename.cpp        | 19 +++++++++++++++++++
 1 file changed, 19 insertions(+)

diff --git a/clang-tools-extra/test/clang-tidy/checkers/readability/redundant-typename.cpp b/clang-tools-extra/test/clang-tidy/checkers/readability/redundant-typename.cpp
index e2be40530865f..c4021662264f4 100644
--- a/clang-tools-extra/test/clang-tidy/checkers/readability/redundant-typename.cpp
+++ b/clang-tools-extra/test/clang-tidy/checkers/readability/redundant-typename.cpp
@@ -378,3 +378,22 @@ template <typename T>
 struct SubClass : BaseClass<typename T::R> {};
 
 template struct SubClass<Int>;
+
+template <typename T>
+struct Sink {};
+
+template <typename...>
+using VoidT = void;
+
+template <typename C, typename = void>
+inline constexpr bool HasValueType = false;
+
+template <typename C>
+inline constexpr bool HasValueType<C, VoidT<typename C::value_type>> =
+    sizeof(Sink<typename C::value_type>) != 0;
+
+struct IntVector {
+  using value_type = int;
+};
+
+static_assert(HasValueType<IntVector>);