[clang] [clang][NFC] Bump the maximum number of Frontend diagnostics (PR #210345)

[Tony Varghese via cfe-commits]

https://github.com/tonykuttai created https://github.com/llvm/llvm-project/pull/210345

The number of Frontend diagnostics in DiagnosticFrontendKinds.td is close to the DIAG_SIZE_FRONTEND limit of 200 (195 in use), and in-flight PRs adding frontend diagnostics (e.g. #187986) run into the static assert in DiagnosticIDs.cpp. Increase the limit to 300, following the precedent of #200948 which did the same for Sema diagnostics.

>From a55340d7775897b542a23b5a32ecf3a9d68da8a9 Mon Sep 17 00:00:00 2001
From: Tony Varghese <tony.varghese at ibm.com>
Date: Fri, 17 Jul 2026 19:45:10 +0530
Subject: [PATCH] [clang][NFC] Bump the maximum number of Frontend diagnostics

The number of Frontend diagnostics in DiagnosticFrontendKinds.td is close
to the DIAG_SIZE_FRONTEND limit of 200 (195 in use). Increase the limit
to 300.
---
 clang/include/clang/Basic/DiagnosticIDs.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/clang/include/clang/Basic/DiagnosticIDs.h b/clang/include/clang/Basic/DiagnosticIDs.h
index f71e47b5cba70..8e714efac46ae 100644
--- a/clang/include/clang/Basic/DiagnosticIDs.h
+++ b/clang/include/clang/Basic/DiagnosticIDs.h
@@ -36,7 +36,7 @@ enum class Group;
 enum {
   DIAG_SIZE_COMMON = 300,
   DIAG_SIZE_DRIVER = 400,
-  DIAG_SIZE_FRONTEND = 200,
+  DIAG_SIZE_FRONTEND = 300,
   DIAG_SIZE_SERIALIZATION = 120,
   DIAG_SIZE_LEX = 500,
   DIAG_SIZE_PARSE = 800,