[clang] [clang-tools-extra] [clang-tidy][NFC] Expose HeuristicResolver::lookupDependentName() and use it in StandaloneEmptyCheck (PR #128391)

[Nathan Ridge via cfe-commits]

https://github.com/HighCommander4 created https://github.com/llvm/llvm-project/pull/128391

The use replaces CXXRecordDecl::lookupDependentName() which HeuristicResolver aims to supersede.

>From b44bc0bb4772ff503c8d93430331606d2f2356e3 Mon Sep 17 00:00:00 2001
From: Nathan Ridge <zeratul976 at hotmail.com>
Date: Sat, 22 Feb 2025 22:40:01 -0500
Subject: [PATCH] [clang-tidy][NFC] Expose
 HeuristicResolver::lookupDependentName() and use it in StandaloneEmptyCheck

The use replaces CXXRecordDecl::lookupDependentName() which
HeuristicResolver aims to supersede.
---
 .../clang-tidy/bugprone/CMakeLists.txt         |  1 +
 .../bugprone/StandaloneEmptyCheck.cpp          |  9 +++++----
 clang/include/clang/Sema/HeuristicResolver.h   |  7 +++++++
 clang/lib/Sema/HeuristicResolver.cpp           | 18 ++++++++----------
 4 files changed, 21 insertions(+), 14 deletions(-)

diff --git a/clang-tools-extra/clang-tidy/bugprone/CMakeLists.txt b/clang-tools-extra/clang-tidy/bugprone/CMakeLists.txt
index e8309c68b7fca..cad6b456fc268 100644
--- a/clang-tools-extra/clang-tidy/bugprone/CMakeLists.txt
+++ b/clang-tools-extra/clang-tidy/bugprone/CMakeLists.txt
@@ -117,6 +117,7 @@ clang_target_link_libraries(clangTidyBugproneModule
   clangASTMatchers
   clangBasic
   clangLex
+  clangSema
   clangTooling
   clangTransformer
   )
diff --git a/clang-tools-extra/clang-tidy/bugprone/StandaloneEmptyCheck.cpp b/clang-tools-extra/clang-tidy/bugprone/StandaloneEmptyCheck.cpp
index 2bce72cca98c6..a1d7b9931e419 100644
--- a/clang-tools-extra/clang-tidy/bugprone/StandaloneEmptyCheck.cpp
+++ b/clang-tools-extra/clang-tidy/bugprone/StandaloneEmptyCheck.cpp
@@ -20,6 +20,7 @@
 #include "clang/Basic/Diagnostic.h"
 #include "clang/Basic/SourceLocation.h"
 #include "clang/Lex/Lexer.h"
+#include "clang/Sema/HeuristicResolver.h"
 #include "llvm/ADT/STLExtras.h"
 #include "llvm/ADT/SmallVector.h"
 #include "llvm/Support/Casting.h"
@@ -125,8 +126,8 @@ void StandaloneEmptyCheck::check(const MatchFinder::MatchResult &Result) {
     DeclarationName Name =
         Context.DeclarationNames.getIdentifier(&Context.Idents.get("clear"));
 
-    auto Candidates = MemberCall->getRecordDecl()->lookupDependentName(
-        Name, [](const NamedDecl *ND) {
+    auto Candidates = HeuristicResolver(Context).lookupDependentName(
+        MemberCall->getRecordDecl(), Name, [](const NamedDecl *ND) {
           return isa<CXXMethodDecl>(ND) &&
                  llvm::cast<CXXMethodDecl>(ND)->getMinRequiredArguments() ==
                      0 &&
@@ -174,8 +175,8 @@ void StandaloneEmptyCheck::check(const MatchFinder::MatchResult &Result) {
     DeclarationName Name =
         Context.DeclarationNames.getIdentifier(&Context.Idents.get("clear"));
 
-    auto Candidates =
-        ArgRecordDecl->lookupDependentName(Name, [](const NamedDecl *ND) {
+    auto Candidates = HeuristicResolver(Context).lookupDependentName(
+        ArgRecordDecl, Name, [](const NamedDecl *ND) {
           return isa<CXXMethodDecl>(ND) &&
                  llvm::cast<CXXMethodDecl>(ND)->getMinRequiredArguments() ==
                      0 &&
diff --git a/clang/include/clang/Sema/HeuristicResolver.h b/clang/include/clang/Sema/HeuristicResolver.h
index 3760003aab89f..f511815b40199 100644
--- a/clang/include/clang/Sema/HeuristicResolver.h
+++ b/clang/include/clang/Sema/HeuristicResolver.h
@@ -69,6 +69,13 @@ class HeuristicResolver {
   QualType
   resolveNestedNameSpecifierToType(const NestedNameSpecifier *NNS) const;
 
+  // Perform an imprecise lookup of a dependent name in `RD`.
+  // This function does not follow strict semantic rules and should be used
+  // only when lookup rules can be relaxed, e.g. indexing.
+  std::vector<const NamedDecl *>
+  lookupDependentName(CXXRecordDecl *RD, DeclarationName Name,
+                      llvm::function_ref<bool(const NamedDecl *ND)> Filter);
+
   // Given the type T of a dependent expression that appears of the LHS of a
   // "->", heuristically find a corresponding pointee type in whose scope we
   // could look up the name appearing on the RHS.
diff --git a/clang/lib/Sema/HeuristicResolver.cpp b/clang/lib/Sema/HeuristicResolver.cpp
index 3af4d001d6c1a..7aecd2a73b539 100644
--- a/clang/lib/Sema/HeuristicResolver.cpp
+++ b/clang/lib/Sema/HeuristicResolver.cpp
@@ -44,6 +44,9 @@ class HeuristicResolverImpl {
       const DependentTemplateSpecializationType *DTST);
   QualType resolveNestedNameSpecifierToType(const NestedNameSpecifier *NNS);
   QualType getPointeeType(QualType T);
+  std::vector<const NamedDecl *>
+  lookupDependentName(CXXRecordDecl *RD, DeclarationName Name,
+                      llvm::function_ref<bool(const NamedDecl *ND)> Filter);
 
 private:
   ASTContext &Ctx;
@@ -83,16 +86,6 @@ class HeuristicResolverImpl {
   // during simplification, and the operation fails if no pointer type is found.
   QualType simplifyType(QualType Type, const Expr *E, bool UnwrapPointer);
 
-  // This is a reimplementation of CXXRecordDecl::lookupDependentName()
-  // so that the implementation can call into other HeuristicResolver helpers.
-  // FIXME: Once HeuristicResolver is upstreamed to the clang libraries
-  // (https://github.com/clangd/clangd/discussions/1662),
-  // CXXRecordDecl::lookupDepenedentName() can be removed, and its call sites
-  // can be modified to benefit from the more comprehensive heuristics offered
-  // by HeuristicResolver instead.
-  std::vector<const NamedDecl *>
-  lookupDependentName(CXXRecordDecl *RD, DeclarationName Name,
-                      llvm::function_ref<bool(const NamedDecl *ND)> Filter);
   bool findOrdinaryMemberInDependentClasses(const CXXBaseSpecifier *Specifier,
                                             CXXBasePath &Path,
                                             DeclarationName Name);
@@ -539,6 +532,11 @@ QualType HeuristicResolver::resolveNestedNameSpecifierToType(
     const NestedNameSpecifier *NNS) const {
   return HeuristicResolverImpl(Ctx).resolveNestedNameSpecifierToType(NNS);
 }
+std::vector<const NamedDecl *> HeuristicResolver::lookupDependentName(
+    CXXRecordDecl *RD, DeclarationName Name,
+    llvm::function_ref<bool(const NamedDecl *ND)> Filter) {
+  return HeuristicResolverImpl(Ctx).lookupDependentName(RD, Name, Filter);
+}
 const QualType HeuristicResolver::getPointeeType(QualType T) const {
   return HeuristicResolverImpl(Ctx).getPointeeType(T);
 }