[clang-tools-extra] dff8dac - [clang-tidy][docs] Add description of "clang-diagnostic-error" (#153870)

[via cfe-commits]

Author: Baranov Victor
Date: 2025-08-18T00:18:32+03:00
New Revision: dff8dac9dca2b1bca3814e6240c41d9cbda42b71

URL: https://github.com/llvm/llvm-project/commit/dff8dac9dca2b1bca3814e6240c41d9cbda42b71
DIFF: https://github.com/llvm/llvm-project/commit/dff8dac9dca2b1bca3814e6240c41d9cbda42b71.diff

LOG: [clang-tidy][docs] Add description of "clang-diagnostic-error" (#153870)

This helps better distinguish warnings that could be disabled via
`.clang-tidy` config (like `clang-diagnostic-literal-conversion`) from
errors that could not be suppressed at all (like
`clang-diagnostic-error`) because it's a hard compiler error.

Added: 
    

Modified: 
    clang-tools-extra/docs/clang-tidy/index.rst

Removed: 
    


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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.