[clangd] Make sure constructors do not reference class

[gribozavr]

unittests/clangd/XRefsTests.cpp

1370

Add the new test right after the "Method call" test, to keep it grouped? Constructor calls are kinda like method calls.

[kadircet]

Re-arrange test location

[kadircet]

• Make use of NameReference symbol role

[gribozavr]

clangd/XRefs.cpp

160

Maybe add a blank line so that it is clear that the comment is only attached to the if stmt?

[kadircet]

• Address comments

clangd/XRefs.cpp

 #include "Logger.h"
 #include "SourceCode.h"
 #include "URI.h"
 #include "index/Merge.h"
 #include "index/SymbolLocation.h"
 #include "clang/AST/DeclTemplate.h"
 #include "clang/AST/RecursiveASTVisitor.h"
 #include "clang/Index/IndexDataConsumer.h"
+#include "clang/Index/IndexSymbol.h"
 #include "clang/Index/IndexingAction.h"
 #include "clang/Index/USRGeneration.h"
 #include "llvm/Support/Path.h"
 
 namespace clang {
 namespace clangd {
 namespace {
 
std::vector<MacroDecl> takeMacroInfos() {
     return std::move(MacroInfos);
   }
 
   bool
   handleDeclOccurence(const Decl *D, index::SymbolRoleSet Roles,
                       llvm::ArrayRef<index::SymbolRelation> Relations,
                       SourceLocation Loc,
                       index::IndexDataConsumer::ASTNodeInfo ASTNode) override {
+    // Skip non-semantic references.
+    if (Roles & static_cast<unsigned>(index::SymbolRole::NameReference))
+      return true;
+
     if (Loc == SearchedLocation) {
       auto IsImplicitExpr = [](const Expr *E) {
         if (!E)
           return false;
         // We assume that a constructor expression is implict (was inserted by
         // clang) if it has an invalid paren/brace location, since such
         // experssion is impossible to write down.
         if (const auto *CtorExpr = dyn_cast<CXXConstructExpr>(E))

clangd/index/SymbolCollector.cpp

 
 // Checks whether \p ND is a definition of a TagDecl (class/struct/enum/union)
 // in a header file, in which case clangd would prefer to use ND as a canonical
 // declaration.
 // FIXME: handle symbol types that are not TagDecl (e.g. functions), if using
 // the first seen declaration as canonical declaration is not a good enough
 // heuristic.
 bool isPreferredDeclaration(const NamedDecl &ND, index::SymbolRoleSet Roles) {
-  const auto& SM = ND.getASTContext().getSourceManager();
+  const auto &SM = ND.getASTContext().getSourceManager();
   return (Roles & static_cast<unsigned>(index::SymbolRole::Definition)) &&
          isa<TagDecl>(&ND) &&
          !SM.isWrittenInMainFile(SM.getExpansionLoc(ND.getLocation()));
 }
 
 RefKind toRefKind(index::SymbolRoleSet Roles) {
   return static_cast<RefKind>(static_cast<unsigned>(RefKind::All) & Roles);
 }
bool SymbolCollector::handleDeclOccurence(
   assert(ASTNode.OrigD);
   // If OrigD is an declaration associated with a friend declaration and it's
   // not a definition, skip it. Note that OrigD is the occurrence that the
   // collector is currently visiting.
   if ((ASTNode.OrigD->getFriendObjectKind() !=
        Decl::FriendObjectKind::FOK_None) &&
       !(Roles & static_cast<unsigned>(index::SymbolRole::Definition)))
     return true;
+  // Skip non-semantic references, we should start processing these when we
+  // decide to implement renaming with index support.
+  if ((Roles & static_cast<unsigned>(index::SymbolRole::NameReference)))
+    return true;
   // A declaration created for a friend declaration should not be used as the
   // canonical declaration in the index. Use OrigD instead, unless we've already
   // picked a replacement for D
   if (D->getFriendObjectKind() != Decl::FriendObjectKind::FOK_None)
     D = CanonicalDecls.try_emplace(D, ASTNode.OrigD).first->second;
   const NamedDecl *ND = dyn_cast<NamedDecl>(D);
   if (!ND)
     return true;

unittests/clangd/XRefsTests.cpp

const char *Tests[] = {
         struct Foo { int [[foo]](); };
         int Foo::[[foo]]() {}
         int main() {
           Foo f;
           f.[[^foo]]();
         }
       )cpp",
 
+      R"cpp(// Constructor
+        struct Foo {
+          [[F^oo]](int);
+        };
+        void foo() {
+          Foo f = [[Foo]](42);
+        }
+      )cpp",
+
       R"cpp(// Typedef
         typedef int [[Foo]];
         int main() {
           [[^Foo]] bar;
         }
       )cpp",
 
       R"cpp(// Namespace
         namespace [[ns]] {
         struct Foo {};
         } // namespace ns
         int main() { [[^ns]]::Foo foo; }
       )cpp",
   };
   for (const char *Test : Tests) {
     Annotations T(Test);
     auto AST = TestTU::withCode(T.code()).build();
     std::vector<Matcher<Location>> ExpectedLocations;
     for (const auto &R : T.ranges())
       ExpectedLocations.push_back(RangeIs(R));
     EXPECT_THAT(findReferences(AST, T.point(), 0),
                 ElementsAreArray(ExpectedLocations))
         << Test;
   }
 }
 
 TEST(FindReferences, ExplicitSymbols) {
   const char *Tests[] = {
       R"cpp(
       struct Foo { Foo* [self]() const; };