From 9570f1e5a612348e92c2f149f5073ef06f9e5da5 Mon Sep 17 00:00:00 2001
From: Kadir Cetinkaya <kadircet@google.com>
Date: Tue, 21 Jan 2020 15:15:06 +0100
Subject: [PATCH] [clangd] Do not duplicate TemplatedDecls in
 findExplicitReferences

Reviewers: hokein

Subscribers: ilya-biryukov, MaskRay, jkorous, arphaman, usaxena95, cfe-commits

Tags: #clang

Differential Revision: https://reviews.llvm.org/D73101
---
 clang-tools-extra/clangd/FindTarget.cpp            |  7 +++
 .../clangd/unittests/FindTargetTests.cpp           | 58 ++++++++++++++++++----
 2 files changed, 54 insertions(+), 11 deletions(-)

diff --git a/clang-tools-extra/clangd/FindTarget.cpp b/clang-tools-extra/clangd/FindTarget.cpp
index bed32c39408..31cdcee0cfe 100644
--- a/clang-tools-extra/clangd/FindTarget.cpp
+++ b/clang-tools-extra/clangd/FindTarget.cpp
@@ -586,6 +586,13 @@ llvm::SmallVector<ReferenceLoc, 2> refInDecl(const Decl *D) {
     }
 
     void VisitNamedDecl(const NamedDecl *ND) {
+      // We choose to ignore {Class, Function, Var, TypeAlias}TemplateDecls. As
+      // as their underlying decls, covering the same range, will be visited.
+      if (llvm::isa<ClassTemplateDecl>(ND) ||
+          llvm::isa<FunctionTemplateDecl>(ND) ||
+          llvm::isa<VarTemplateDecl>(ND) ||
+          llvm::isa<TypeAliasTemplateDecl>(ND))
+        return;
       // FIXME: decide on how to surface destructors when we need them.
       if (llvm::isa<CXXDestructorDecl>(ND))
         return;
diff --git a/clang-tools-extra/clangd/unittests/FindTargetTests.cpp b/clang-tools-extra/clangd/unittests/FindTargetTests.cpp
index c6ad75144f9..ed3da28aa0d 100644
--- a/clang-tools-extra/clangd/unittests/FindTargetTests.cpp
+++ b/clang-tools-extra/clangd/unittests/FindTargetTests.cpp
@@ -741,21 +741,17 @@ TEST_F(FindExplicitReferencesTest, All) {
        {R"cpp(
             namespace foo {
               template <typename $0^T>
-              class $1^$2^Bar {
-                ~$3^Bar();
-                void $4^f($5^Bar);
+              class $1^Bar {
+                ~$2^Bar();
+                void $3^f($4^Bar);
               };
             }
           )cpp",
         "0: targets = {foo::Bar::T}, decl\n"
-        // FIXME: avoid the 2 duplicated foo::Bar references below, the first
-        // one comes from ClassTemplateDecl; the second comes from the
-        // underlying CXXRecordDecl.
         "1: targets = {foo::Bar}, decl\n"
-        "2: targets = {foo::Bar}, decl\n"
-        "3: targets = {foo::Bar}\n"
-        "4: targets = {foo::Bar::f}, decl\n"
-        "5: targets = {foo::Bar}\n"},
+        "2: targets = {foo::Bar}\n"
+        "3: targets = {foo::Bar::f}, decl\n"
+        "4: targets = {foo::Bar}\n"},
        // MemberExpr should know their using declaration.
        {R"cpp(
             struct X { void func(int); };
@@ -1055,7 +1051,47 @@ TEST_F(FindExplicitReferencesTest, All) {
               }
             )cpp",
            "0: targets = {Test}\n"
-           "1: targets = {a}, decl\n"}};
+           "1: targets = {a}, decl\n"},
+       // Templates
+       {R"cpp(
+            namespace foo {
+              template <typename $0^T>
+              class $1^Bar {};
+            }
+          )cpp",
+        "0: targets = {foo::Bar::T}, decl\n"
+        "1: targets = {foo::Bar}, decl\n"},
+       // Templates
+       {R"cpp(
+            namespace foo {
+              template <typename $0^T>
+              void $1^func();
+            }
+          )cpp",
+        "0: targets = {T}, decl\n"
+        "1: targets = {foo::func}, decl\n"},
+       // Templates
+       {R"cpp(
+            namespace foo {
+              template <typename $0^T>
+              $1^T $2^x;
+            }
+          )cpp",
+        "0: targets = {foo::T}, decl\n"
+        "1: targets = {foo::T}\n"
+        "2: targets = {foo::x}, decl\n"},
+       // Templates
+       {R"cpp(
+            template<typename T> class vector {};
+            namespace foo {
+              template <typename $0^T>
+              using $1^V = $2^vector<$3^T>;
+            }
+          )cpp",
+        "0: targets = {foo::T}, decl\n"
+        "1: targets = {foo::V}, decl\n"
+        "2: targets = {vector}\n"
+        "3: targets = {foo::T}\n"}};
 
   for (const auto &C : Cases) {
     llvm::StringRef ExpectedCode = C.first;
-- 
2.11.0