[clang] [Clang] add fix-it hints for unknown attributes (PR #141305)

[Oleksandr T. via cfe-commits]

https://github.com/a-tarasyuk created https://github.com/llvm/llvm-project/pull/141305

This patch adds fix-it hints for unknown attribute names when Clang suggests a correction

>From 2b84b21462a4e66b8681e165fcd24e3107612448 Mon Sep 17 00:00:00 2001
From: Oleksandr Tarasiuk <oleksandr.tarasiuk at outlook.com>
Date: Sat, 24 May 2025 02:52:24 +0300
Subject: [PATCH] [Clang] add fix-it hints for unknown attributes

---
 clang/docs/ReleaseNotes.rst                   |  3 +++
 clang/lib/Sema/SemaDeclAttr.cpp               | 13 +++++-----
 clang/test/FixIt/fixit-unknown-attributes.cpp | 26 +++++++++++++++++++
 3 files changed, 36 insertions(+), 6 deletions(-)
 create mode 100644 clang/test/FixIt/fixit-unknown-attributes.cpp

diff --git a/clang/docs/ReleaseNotes.rst b/clang/docs/ReleaseNotes.rst
index b93fa33acc2a0..02cca0bb357f9 100644
--- a/clang/docs/ReleaseNotes.rst
+++ b/clang/docs/ReleaseNotes.rst
@@ -592,6 +592,9 @@ Improvements to Clang's diagnostics
   trigger a ``'Blue' is deprecated`` warning, which can be turned off with
   ``-Wno-deprecated-switch-case``.
 
+- Clang now emits fix-it hints for unknown attributes when a spelling
+  correction is suggested.
+
 Improvements to Clang's time-trace
 ----------------------------------
 
diff --git a/clang/lib/Sema/SemaDeclAttr.cpp b/clang/lib/Sema/SemaDeclAttr.cpp
index 8ce51cc2882bf..05b8e7d5a75f0 100644
--- a/clang/lib/Sema/SemaDeclAttr.cpp
+++ b/clang/lib/Sema/SemaDeclAttr.cpp
@@ -7867,15 +7867,16 @@ void Sema::checkUnusedDeclAttributes(Declarator &D) {
 
 void Sema::DiagnoseUnknownAttribute(const ParsedAttr &AL) {
   std::string NormalizedFullName = '\'' + AL.getNormalizedFullName() + '\'';
+  SourceRange NR = AL.getNormalizedRange();
+  SourceLocation Loc = NR.getBegin();
+
   if (auto CorrectedFullName =
           AL.getCorrectedFullName(Context.getTargetInfo(), getLangOpts())) {
-    Diag(AL.getNormalizedRange().getBegin(),
-         diag::warn_unknown_attribute_ignored_suggestion)
-        << NormalizedFullName << *CorrectedFullName << AL.getNormalizedRange();
+    Diag(Loc, diag::warn_unknown_attribute_ignored_suggestion)
+        << NormalizedFullName << *CorrectedFullName
+        << FixItHint::CreateReplacement(NR, *CorrectedFullName) << NR;
   } else {
-    Diag(AL.getNormalizedRange().getBegin(),
-         diag::warn_unknown_attribute_ignored)
-        << NormalizedFullName << AL.getNormalizedRange();
+    Diag(Loc, diag::warn_unknown_attribute_ignored) << NormalizedFullName << NR;
   }
 }
 
diff --git a/clang/test/FixIt/fixit-unknown-attributes.cpp b/clang/test/FixIt/fixit-unknown-attributes.cpp
new file mode 100644
index 0000000000000..6b74650942d0a
--- /dev/null
+++ b/clang/test/FixIt/fixit-unknown-attributes.cpp
@@ -0,0 +1,26 @@
+// RUN: %clang_cc1 -Wunknown-attributes -fsyntax-only -verify %s
+// RUN: %clang_cc1 -Wunknown-attributes -fsyntax-only -fdiagnostics-parseable-fixits %s 2>&1 | FileCheck %s
+
+[[gmu::deprected]] // expected-warning {{unknown attribute 'gmu::deprected' ignored; did you mean 'gnu::deprecated'?}}
+int f1(void) {
+  return 0;
+}
+// CHECK: fix-it:"{{.*}}":{[[@LINE-4]]:3-[[@LINE-4]]:17}:"gnu::deprecated"
+
+[[gmu::deprecated]] // expected-warning {{unknown attribute 'gmu::deprecated' ignored; did you mean 'gnu::deprecated'?}}
+int f2(void) {
+  return 0;
+}
+// CHECK: fix-it:"{{.*}}":{[[@LINE-4]]:3-[[@LINE-4]]:18}:"gnu::deprecated"
+
+[[gnu::deprected]] // expected-warning {{unknown attribute 'gnu::deprected' ignored; did you mean 'gnu::deprecated'?}}
+int f3(void) {
+  return 0;
+}
+// CHECK: fix-it:"{{.*}}":{[[@LINE-4]]:3-[[@LINE-4]]:17}:"gnu::deprecated"
+
+[[deprected]] // expected-warning {{unknown attribute 'deprected' ignored; did you mean 'deprecated'?}}
+int f4(void) {
+  return 0;
+}
+// CHECK: fix-it:"{{.*}}":{[[@LINE-4]]:3-[[@LINE-4]]:12}:"deprecated"