[clang-tools-extra] Improve attribute range handling for attributed function types in sel… (PR #163926)

[Quan Zhuo via cfe-commits]

https://github.com/quanzhuo created https://github.com/llvm/llvm-project/pull/163926

…ection

This fix https://github.com/clangd/clangd/issues/2488

>From 4239775554b399c9db5e86a83fd79476734a0e85 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=E5=85=A8=E5=8D=93?= <quanzhuo at kylinos.cn>
Date: Fri, 17 Oct 2025 16:24:39 +0800
Subject: [PATCH] Improve attribute range handling for attributed function
 types in selection

This fix https://github.com/clangd/clangd/issues/2488
---
 clang-tools-extra/clangd/Selection.cpp               | 12 ++++++++++++
 .../clangd/unittests/SelectionTests.cpp              |  9 +++++++++
 2 files changed, 21 insertions(+)

diff --git a/clang-tools-extra/clangd/Selection.cpp b/clang-tools-extra/clangd/Selection.cpp
index 06165dfbbcdd2..faa00d20497fa 100644
--- a/clang-tools-extra/clangd/Selection.cpp
+++ b/clang-tools-extra/clangd/Selection.cpp
@@ -958,6 +958,18 @@ class SelectionVisitor : public RecursiveASTVisitor<SelectionVisitor> {
         claimRange(SourceRange(FTL.getLParenLoc(), FTL.getEndLoc()), Result);
         return;
       }
+      if (auto ATL = TL->getAs<AttributedTypeLoc>()) {
+        // For attributed function types like `int foo() [[attr]]`, the
+        // AttributedTypeLoc's range includes the function name. We want to
+        // allow the function name to be associated with the FunctionDecl
+        // rather than the AttributedTypeLoc, so we only claim the attribute
+        // range itself.
+        if (ATL.getModifiedLoc().getAs<FunctionTypeLoc>()) {
+          // Only claim the attribute's source range, not the whole type.
+          claimRange(ATL.getLocalSourceRange(), Result);
+          return;
+        }
+      }
     }
     claimRange(getSourceRange(N), Result);
   }
diff --git a/clang-tools-extra/clangd/unittests/SelectionTests.cpp b/clang-tools-extra/clangd/unittests/SelectionTests.cpp
index 3df19d8fc174d..103c00ebd5696 100644
--- a/clang-tools-extra/clangd/unittests/SelectionTests.cpp
+++ b/clang-tools-extra/clangd/unittests/SelectionTests.cpp
@@ -311,6 +311,15 @@ TEST(SelectionTest, CommonAncestor) {
       {"[[void foo^()]];", "FunctionProtoTypeLoc"},
       {"[[^void foo^()]];", "FunctionDecl"},
       {"[[void ^foo()]];", "FunctionDecl"},
+      // Tricky case: with function attributes, the AttributedTypeLoc's range
+      // includes the function name, but we want the name to be associated with
+      // the FunctionDecl.
+      {"struct X { [[void ^foo() [[clang::lifetimebound]]]]; };",
+       "FunctionDecl"},
+      {"struct X { [[void ^foo() const [[clang::lifetimebound]]]]; };",
+       "FunctionDecl"},
+      {"struct X { [[const int* ^Get() const [[clang::lifetimebound]]]]; };",
+       "FunctionDecl"},
       // Tricky case: two VarDecls share a specifier.
       {"[[int ^a]], b;", "VarDecl"},
       {"[[int a, ^b]];", "VarDecl"},