[clang-tools-extra] [clang-tidy] Rename "clang-diagnostic-error" to "clang-compiler-error" (PR #153870)

[Baranov Victor via cfe-commits]

https://github.com/vbvictor updated https://github.com/llvm/llvm-project/pull/153870

>From e4d7203f8444ce40adbe93e9855fc0e7e0ae73eb Mon Sep 17 00:00:00 2001
From: Victor Baranov <bar.victor.2002 at gmail.com>
Date: Sun, 17 Aug 2025 13:44:11 +0300
Subject: [PATCH] [clang-tidy][docs] Add description of
 "clang-diagnostic-error"

---
 clang-tools-extra/docs/clang-tidy/index.rst | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/clang-tools-extra/docs/clang-tidy/index.rst b/clang-tools-extra/docs/clang-tidy/index.rst
index e8ce903fcb076..e0cf5ef720b01 100644
--- a/clang-tools-extra/docs/clang-tidy/index.rst
+++ b/clang-tools-extra/docs/clang-tidy/index.rst
@@ -111,6 +111,13 @@ Diagnostics which have a corresponding warning option, are named
 ``-Wliteral-conversion`` will be reported with check name
 ``clang-diagnostic-literal-conversion``.
 
+Clang compiler errors (such as syntax errors, semantic errors, or other failures
+that prevent Clang from compiling the code) are reported with the check name
+``clang-diagnostic-error``. These represent fundamental compilation failures that
+must be fixed before :program:`clang-tidy` can perform its analysis. Unlike other
+diagnostics, ``clang-diagnostic-error`` cannot be disabled, as :program:`clang-tidy`
+requires valid code to function.
+
 The ``-fix`` flag instructs :program:`clang-tidy` to fix found errors if
 supported by corresponding checks.