[clang] [clang] Reject 'auto' storage class with type specifier in C++ (PR #166004)

[Aaron Ballman via cfe-commits]

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@@ -0,0 +1,22 @@
+// RUN: %clang_cc1 -fsyntax-only -verify -std=c++11 %s
+// RUN: %clang_cc1 -fsyntax-only -verify -std=c++14 %s
+// RUN: %clang_cc1 -fsyntax-only -verify -std=c++17 %s
+// RUN: %clang_cc1 -fsyntax-only -verify -std=c++20 %s
+// RUN: %clang_cc1 -fsyntax-only -verify -std=c++23 %s
+
+// Test that 'auto' cannot be combined with a type specifier in C++.
+void f() {
+  auto int x = 1;        // expected-error {{'auto' cannot be combined with a type specifier}}
----------------
AaronBallman wrote:

One more test to add:
```
template <typename Ty>
void g() {
  auto Ty x;
}

void test() {
  g<float>();
}
```

https://github.com/llvm/llvm-project/pull/166004