[clang] [clang][test] Combine and clean up decltype parser tests NFC (PR #228889)

[Shengxin Pei via cfe-commits]

https://github.com/TPPPP72 created https://github.com/llvm/llvm-project/pull/228889

Follow-up #211221 

>From 9f3f1c756db4a3dd3dd43402d7b11d81905a2413 Mon Sep 17 00:00:00 2001
From: Shengxin Pei <TPPPP72 at outlook.com>
Date: Sun, 4 Oct 2026 21:01:21 +0800
Subject: [PATCH] [clang][test] Combine and clean up decltype parser tests NFC

---
 clang/test/Parser/decltype-crash.cpp    | 39 +++++++++++++++----------
 clang/test/Parser/decltype-gh188014.cpp |  4 ---
 clang/test/Parser/gh114815.cpp          |  6 ----
 3 files changed, 23 insertions(+), 26 deletions(-)
 delete mode 100644 clang/test/Parser/decltype-gh188014.cpp
 delete mode 100644 clang/test/Parser/gh114815.cpp

diff --git a/clang/test/Parser/decltype-crash.cpp b/clang/test/Parser/decltype-crash.cpp
index 8471309665f1d..9f22baef698d5 100644
--- a/clang/test/Parser/decltype-crash.cpp
+++ b/clang/test/Parser/decltype-crash.cpp
@@ -1,20 +1,27 @@
 // RUN: %clang_cc1 -fsyntax-only -verify -std=c++11 %s
-// RUN: %clang_cc1 -fsyntax-only -verify -std=c++20 %s
 
-// A 'decltype' that is not followed by '(' fails to parse as a
-// decltype-specifier. ParseOptionalCXXScopeSpecifier used to still annotate it
-// and treat it as a nested-name-specifier, which tripped an assertion in
-// Preprocessor::AnnotatePreviousCachedTokens. It should just diagnose the
-// error instead.
-int decltype = 0;
-// expected-error at -1 {{expected '(' after 'decltype'}}
-// expected-error at -2 {{expected unqualified-id}}
+namespace GH114815{
+  #define ID(X) X
+  extern int ID(decltype);
+  // expected-error at -1 {{expected '(' after 'decltype'}}
+  // expected-error at -2 {{expected unqualified-id}}
+}
 
-int *decltype = 0;
-// expected-error at -1 {{expected '(' after 'decltype'}}
-// expected-error at -2 {{expected unqualified-id}}
+namespace GH165246 {
+  int decltype {};
+  // expected-error at -1 {{expected '(' after 'decltype'}}
+  // expected-error at -2 {{expected unqualified-id}}
+}
 
-// GH165246
-int decltype {};
-// expected-error at -1 {{expected '(' after 'decltype'}}
-// expected-error at -2 {{expected unqualified-id}}
+namespace GH211207 {
+  int decltype = 0;
+  // expected-error at -1 {{expected '(' after 'decltype'}}
+  // expected-error at -2 {{expected unqualified-id}}
+
+  int *decltype = 0;
+  // expected-error at -1 {{expected '(' after 'decltype'}}
+  // expected-error at -2 {{expected unqualified-id}}
+}
+
+// GH188014
+& decltype ( ( union { // expected-error {{expected ';' after union}} expected-error {{expected '}'}} expected-error {{expected ')'}} expected-error {{expected expression}} expected-error {{expected unqualified-id}} expected-note {{to match this '('}} expected-note {{to match this '{'}}
diff --git a/clang/test/Parser/decltype-gh188014.cpp b/clang/test/Parser/decltype-gh188014.cpp
deleted file mode 100644
index e8403bdcbe3bb..0000000000000
--- a/clang/test/Parser/decltype-gh188014.cpp
+++ /dev/null
@@ -1,4 +0,0 @@
-// RUN: %clang_cc1 -fsyntax-only -verify -std=c++11 %s
-
-// GH188014
-& decltype ( ( union { // expected-error {{expected ';' after union}} expected-error {{expected '}'}} expected-error {{expected ')'}} expected-error {{expected expression}} expected-error {{expected unqualified-id}} expected-note {{to match this '('}} expected-note {{to match this '{'}}
diff --git a/clang/test/Parser/gh114815.cpp b/clang/test/Parser/gh114815.cpp
deleted file mode 100644
index 6a89384e9e66d..0000000000000
--- a/clang/test/Parser/gh114815.cpp
+++ /dev/null
@@ -1,6 +0,0 @@
-// RUN: %clang_cc1 -verify %s -std=c++11 -fsyntax-only
-
-#define ID(X) X
-extern int ID(decltype);
-// expected-error at -1 {{expected '(' after 'decltype'}} \
-// expected-error at -1 {{expected unqualified-id}}