fix: Use standard API for dependent name lookup (#300)

This takes inheritance into account correctly

Author: varungandhi-src

indexer/Indexer.cc

@@ -11,6 +11,7 @@
 #include "spdlog/fmt/fmt.h"
 
 #include "clang/AST/ASTContext.h"
+#include "clang/AST/CXXInheritance.h"
 #include "clang/AST/Decl.h"
 #include "clang/AST/DeclCXX.h"
 #include "clang/AST/DeclTemplate.h"
@@ -856,10 +857,9 @@ void TuIndexer::trySaveMemberReferenceViaLookup(
   if (!recordDecl) {
     return;
   }
-  // FIXME(issue: https://github.com/sourcegraph/scip-clang/issues/296):
-  // We should try to use more standard code which takes
-  // inheritance into account.
-  auto lookupResult = recordDecl->lookup(memberNameInfo.getName());
+  auto lookupResult = recordDecl->lookupDependentName(
+      memberNameInfo.getName(),
+      [](const clang::NamedDecl *) -> bool { return true; });
   for (auto *namedDecl : lookupResult) {
     auto optSymbol = this->symbolFormatter.getNamedDeclSymbol(*namedDecl);
     if (optSymbol) {

test/index/functions/template_body.snapshot.cc

@@ -75,14 +75,17 @@
     void ff0() {
 //       ^^^ definition [..] ZZ#ff0(49f6e7a06ebc5aa8).
       this->f0();
+//          ^^ reference [..] Z#f0(49f6e7a06ebc5aa8).
     }
 
     template <typename U>
 //                     ^ definition local 6
     void gg0() {
 //       ^^^ definition [..] ZZ#gg0(49f6e7a06ebc5aa8).
       this->f0();
+//          ^^ reference [..] Z#f0(49f6e7a06ebc5aa8).
       this->template g0<U>();
+//                   ^^ reference [..] Z#g0(49f6e7a06ebc5aa8).
 //                      ^ reference local 6
     }
   };

test/index/functions/templates.snapshot.cc

@@ -25,6 +25,7 @@
 //          ^ reference local 2
 //            ^ definition local 3
       this->f0(t);
+//          ^^ reference [..] T0#f0(9b289cee16747614).
 //             ^ reference local 3
     }
 
@@ -35,6 +36,7 @@
 //          ^ reference local 4
 //            ^ definition local 5
       this->template g0<U>(u);
+//                   ^^ reference [..] T0#g0(b07662a27bd562f9).
 //                      ^ reference local 4
 //                         ^ reference local 5
     }