//===-- XRefsTests.cpp  ---------------------------*- C++ -*--------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
#include "Annotations.h"
#include "ClangdUnit.h"
#include "Compiler.h"
#include "Matchers.h"
#include "SyncAPI.h"
#include "TestFS.h"
#include "TestTU.h"
#include "XRefs.h"
#include "index/FileIndex.h"
#include "index/SymbolCollector.h"
#include "clang/Index/IndexingAction.h"
#include "llvm/Support/Path.h"
#include "llvm/Support/ScopedPrinter.h"
#include "gmock/gmock.h"
#include "gtest/gtest.h"

namespace clang {
namespace clangd {
namespace {

using testing::ElementsAre;
using testing::IsEmpty;
using testing::Matcher;
using testing::UnorderedElementsAreArray;

class IgnoreDiagnostics : public DiagnosticsConsumer {
  void onDiagnosticsReady(PathRef File,
                          std::vector<Diag> Diagnostics) override {}
};

MATCHER_P2(FileRange, File, Range, "") {
  return Location{URIForFile::canonicalize(File, testRoot()), Range} == arg;
}

// Extracts ranges from an annotated example, and constructs a matcher for a
// highlight set. Ranges should be named $read/$write as appropriate.
Matcher<const std::vector<DocumentHighlight> &>
HighlightsFrom(const Annotations &Test) {
  std::vector<DocumentHighlight> Expected;
  auto Add = [&](const Range &R, DocumentHighlightKind K) {
    Expected.emplace_back();
    Expected.back().range = R;
    Expected.back().kind = K;
  };
  for (const auto &Range : Test.ranges())
    Add(Range, DocumentHighlightKind::Text);
  for (const auto &Range : Test.ranges("read"))
    Add(Range, DocumentHighlightKind::Read);
  for (const auto &Range : Test.ranges("write"))
    Add(Range, DocumentHighlightKind::Write);
  return UnorderedElementsAreArray(Expected);
}

TEST(HighlightsTest, All) {
  const char *Tests[] = {
      R"cpp(// Local variable
        int main() {
          int [[bonjour]];
          $write[[^bonjour]] = 2;
          int test1 = $read[[bonjour]];
        }
      )cpp",

      R"cpp(// Struct
        namespace ns1 {
        struct [[MyClass]] {
          static void foo([[MyClass]]*) {}
        };
        } // namespace ns1
        int main() {
          ns1::[[My^Class]]* Params;
        }
      )cpp",

      R"cpp(// Function
        int [[^foo]](int) {}
        int main() {
          [[foo]]([[foo]](42));
          auto *X = &[[foo]];
        }
      )cpp",

      R"cpp(// Function parameter in decl
        void foo(int [[^bar]]);
      )cpp",
  };
  for (const char *Test : Tests) {
    Annotations T(Test);
    auto AST = TestTU::withCode(T.code()).build();
    EXPECT_THAT(findDocumentHighlights(AST, T.point()), HighlightsFrom(T))
        << Test;
  }
}

MATCHER_P3(Sym, Name, Decl, DefOrNone, "") {
  llvm::Optional<Range> Def = DefOrNone;
  if (Name != arg.Name) {
    *result_listener << "Name is " << arg.Name;
    return false;
  }
  if (Decl != arg.PreferredDeclaration.range) {
    *result_listener << "Declaration is "
                     << llvm::to_string(arg.PreferredDeclaration);
    return false;
  }
  if (Def && !arg.Definition) {
    *result_listener << "Has no definition";
    return false;
  }
  if (Def && arg.Definition->range != *Def) {
    *result_listener << "Definition is " << llvm::to_string(arg.Definition);
    return false;
  }
  return true;
}
testing::Matcher<LocatedSymbol> Sym(std::string Name, Range Decl) {
  return Sym(Name, Decl, llvm::None);
}
MATCHER_P(Sym, Name, "") { return arg.Name == Name; }

MATCHER_P(RangeIs, R, "") { return arg.range == R; }

TEST(LocateSymbol, WithIndex) {
  Annotations SymbolHeader(R"cpp(
        class $forward[[Forward]];
        class $foo[[Foo]] {};

        void $f1[[f1]]();

        inline void $f2[[f2]]() {}
      )cpp");
  Annotations SymbolCpp(R"cpp(
      class $forward[[forward]] {};
      void  $f1[[f1]]() {}
    )cpp");

  TestTU TU;
  TU.Code = SymbolCpp.code();
  TU.HeaderCode = SymbolHeader.code();
  auto Index = TU.index();
  auto LocateWithIndex = [&Index](const Annotations &Main) {
    auto AST = TestTU::withCode(Main.code()).build();
    return clangd::locateSymbolAt(AST, Main.point(), Index.get());
  };

  Annotations Test(R"cpp(// only declaration in AST.
        void [[f1]]();
        int main() {
          ^f1();
        }
      )cpp");
  EXPECT_THAT(LocateWithIndex(Test),
              ElementsAre(Sym("f1", Test.range(), SymbolCpp.range("f1"))));

  Test = Annotations(R"cpp(// definition in AST.
        void [[f1]]() {}
        int main() {
          ^f1();
        }
      )cpp");
  EXPECT_THAT(LocateWithIndex(Test),
              ElementsAre(Sym("f1", SymbolHeader.range("f1"), Test.range())));

  Test = Annotations(R"cpp(// forward declaration in AST.
        class [[Foo]];
        F^oo* create();
      )cpp");
  EXPECT_THAT(LocateWithIndex(Test),
              ElementsAre(Sym("Foo", Test.range(), SymbolHeader.range("foo"))));

  Test = Annotations(R"cpp(// defintion in AST.
        class [[Forward]] {};
        F^orward create();
      )cpp");
  EXPECT_THAT(
      LocateWithIndex(Test),
      ElementsAre(Sym("Forward", SymbolHeader.range("forward"), Test.range())));
}

TEST(LocateSymbol, WithIndexPreferredLocation) {
  Annotations SymbolHeader(R"cpp(
        class $[[Proto]] {};
      )cpp");
  TestTU TU;
  TU.HeaderCode = SymbolHeader.code();
  TU.HeaderFilename = "x.proto"; // Prefer locations in codegen files.
  auto Index = TU.index();

  Annotations Test(R"cpp(// only declaration in AST.
        // Shift to make range different.
        class [[Proto]];
        P^roto* create();
      )cpp");

  auto AST = TestTU::withCode(Test.code()).build();
  auto Locs = clangd::locateSymbolAt(AST, Test.point(), Index.get());
  EXPECT_THAT(Locs, ElementsAre(Sym("Proto", SymbolHeader.range())));
}

TEST(LocateSymbol, All) {
  // Ranges in tests:
  //   $decl is the declaration location (if absent, no symbol is located)
  //   $def is the definition location (if absent, symbol has no definition)
  //   unnamed range becomes both $decl and $def.
  const char *Tests[] = {
      R"cpp(// Local variable
        int main() {
          int [[bonjour]];
          ^bonjour = 2;
          int test1 = bonjour;
        }
      )cpp",

      R"cpp(// Struct
        namespace ns1 {
        struct [[MyClass]] {};
        } // namespace ns1
        int main() {
          ns1::My^Class* Params;
        }
      )cpp",

      R"cpp(// Function definition via pointer
        int [[foo]](int) {}
        int main() {
          auto *X = &^foo;
        }
      )cpp",

      R"cpp(// Function declaration via call
        int $decl[[foo]](int);
        int main() {
          return ^foo(42);
        }
      )cpp",

      R"cpp(// Field
        struct Foo { int [[x]]; };
        int main() {
          Foo bar;
          bar.^x;
        }
      )cpp",

      R"cpp(// Field, member initializer
        struct Foo {
          int [[x]];
          Foo() : ^x(0) {}
        };
      )cpp",

      R"cpp(// Field, GNU old-style field designator
        struct Foo { int [[x]]; };
        int main() {
          Foo bar = { ^x : 1 };
        }
      )cpp",

      R"cpp(// Field, field designator
        struct Foo { int [[x]]; };
        int main() {
          Foo bar = { .^x = 2 };
        }
      )cpp",

      R"cpp(// Method call
        struct Foo { int $decl[[x]](); };
        int main() {
          Foo bar;
          bar.^x();
        }
      )cpp",

      R"cpp(// Typedef
        typedef int $decl[[Foo]];
        int main() {
          ^Foo bar;
        }
      )cpp",

      R"cpp(// Template type parameter
        template <typename [[T]]>
        void foo() { ^T t; }
      )cpp",

      R"cpp(// Template template type parameter
        template <template<typename> class [[T]]>
        void foo() { ^T<int> t; }
      )cpp",

      R"cpp(// Namespace
        namespace $decl[[ns]] {
        struct Foo { static void bar(); }
        } // namespace ns
        int main() { ^ns::Foo::bar(); }
      )cpp",

      R"cpp(// Macro
        #define MACRO 0
        #define [[MACRO]] 1
        int main() { return ^MACRO; }
        #define MACRO 2
        #undef macro
      )cpp",

      R"cpp(// Macro
       class TTT { public: int a; };
       #define [[FF]](S) if (int b = S.a) {}
       void f() {
         TTT t;
         F^F(t);
       }
      )cpp",

      R"cpp(// Macro argument
       int [[i]];
       #define ADDRESSOF(X) &X;
       int *j = ADDRESSOF(^i);
      )cpp",

      R"cpp(// Symbol concatenated inside macro (not supported)
       int *pi;
       #define POINTER(X) p # X;
       int i = *POINTER(^i);
      )cpp",

      R"cpp(// Forward class declaration
        class Foo;
        class [[Foo]] {};
        F^oo* foo();
      )cpp",

      R"cpp(// Function declaration
        void foo();
        void g() { f^oo(); }
        void [[foo]]() {}
      )cpp",

      R"cpp(
        #define FF(name) class name##_Test {};
        [[FF]](my);
        void f() { my^_Test a; }
      )cpp",

      R"cpp(
         #define FF() class [[Test]] {};
         FF();
         void f() { T^est a; }
      )cpp",

      R"cpp(// explicit template specialization
        template <typename T>
        struct Foo { void bar() {} };

        template <>
        struct [[Foo]]<int> { void bar() {} };

        void foo() {
          Foo<char> abc;
          Fo^o<int> b;
        }
      )cpp",

      R"cpp(// implicit template specialization
        template <typename T>
        struct [[Foo]] { void bar() {} };
        template <>
        struct Foo<int> { void bar() {} };
        void foo() {
          Fo^o<char> abc;
          Foo<int> b;
        }
      )cpp",

      R"cpp(// partial template specialization
        template <typename T>
        struct Foo { void bar() {} };
        template <typename T>
        struct [[Foo]]<T*> { void bar() {} };
        ^Foo<int*> x;
      )cpp",

      R"cpp(// function template specializations
        template <class T>
        void foo(T) {}
        template <>
        void [[foo]](int) {}
        void bar() {
          fo^o(10);
        }
      )cpp",

      R"cpp(// variable template decls
        template <class T>
        T var = T();

        template <>
        double [[var]]<int> = 10;

        double y = va^r<int>;
      )cpp",

      R"cpp(// No implicit constructors
        class X {
          X(X&& x) = default;
        };
        X [[makeX]]() {}
        void foo() {
          auto x = m^akeX();
        }
      )cpp",
  };
  for (const char *Test : Tests) {
    Annotations T(Test);
    llvm::Optional<Range> WantDecl;
    llvm::Optional<Range> WantDef;
    if (!T.ranges().empty())
      WantDecl = WantDef = T.range();
    if (!T.ranges("decl").empty())
      WantDecl = T.range("decl");
    if (!T.ranges("def").empty())
      WantDef = T.range("def");

    auto AST = TestTU::withCode(T.code()).build();
    auto Results = locateSymbolAt(AST, T.point());

    if (!WantDecl) {
      EXPECT_THAT(Results, IsEmpty()) << Test;
    } else {
      ASSERT_THAT(Results, ::testing::SizeIs(1)) << Test;
      EXPECT_EQ(Results[0].PreferredDeclaration.range, *WantDecl) << Test;
      llvm::Optional<Range> GotDef;
      if (Results[0].Definition)
        GotDef = Results[0].Definition->range;
      EXPECT_EQ(WantDef, GotDef) << Test;
    }
  }
}

TEST(LocateSymbol, Ambiguous) {
  auto T = Annotations(R"cpp(
    struct Foo {
      Foo();
      Foo(Foo&&);
      Foo(const char*);
    };

    Foo f();

    void g(Foo foo);

    void call() {
      const char* str = "123";
      Foo a = $1^str;
      Foo b = Foo($2^str);
      Foo c = $3^f();
      $4^g($5^f());
      g($6^str);
      Foo ab$7^c;
      Foo ab$8^cd("asdf");
      Foo foox = Fo$9^o("asdf");
    }
  )cpp");
  auto AST = TestTU::withCode(T.code()).build();
  // Ordered assertions are deliberate: we expect a predictable order.
  EXPECT_THAT(locateSymbolAt(AST, T.point("1")), ElementsAre(Sym("str")));
  EXPECT_THAT(locateSymbolAt(AST, T.point("2")), ElementsAre(Sym("str")));
  EXPECT_THAT(locateSymbolAt(AST, T.point("3")), ElementsAre(Sym("f")));
  EXPECT_THAT(locateSymbolAt(AST, T.point("4")), ElementsAre(Sym("g")));
  EXPECT_THAT(locateSymbolAt(AST, T.point("5")), ElementsAre(Sym("f")));
  EXPECT_THAT(locateSymbolAt(AST, T.point("6")), ElementsAre(Sym("str")));
  EXPECT_THAT(locateSymbolAt(AST, T.point("7")), ElementsAre(Sym("abc")));
  EXPECT_THAT(locateSymbolAt(AST, T.point("8")),
              ElementsAre(Sym("Foo"), Sym("abcd")));
  EXPECT_THAT(locateSymbolAt(AST, T.point("9")),
              // First one is class definition, second is the constructor.
              ElementsAre(Sym("Foo"), Sym("Foo")));
}

TEST(LocateSymbol, RelPathsInCompileCommand) {
  // The source is in "/clangd-test/src".
  // We build in "/clangd-test/build".

  Annotations SourceAnnotations(R"cpp(
#include "header_in_preamble.h"
int [[foo]];
#include "header_not_in_preamble.h"
int baz = f$p1^oo + bar_pre$p2^amble + bar_not_pre$p3^amble;
)cpp");

  Annotations HeaderInPreambleAnnotations(R"cpp(
int [[bar_preamble]];
)cpp");

  Annotations HeaderNotInPreambleAnnotations(R"cpp(
int [[bar_not_preamble]];
)cpp");

  // Make the compilation paths appear as ../src/foo.cpp in the compile
  // commands.
  SmallString<32> RelPathPrefix("..");
  llvm::sys::path::append(RelPathPrefix, "src");
  std::string BuildDir = testPath("build");
  MockCompilationDatabase CDB(BuildDir, RelPathPrefix);

  IgnoreDiagnostics DiagConsumer;
  MockFSProvider FS;
  ClangdServer Server(CDB, FS, DiagConsumer, ClangdServer::optsForTest());

  // Fill the filesystem.
  auto FooCpp = testPath("src/foo.cpp");
  FS.Files[FooCpp] = "";
  auto HeaderInPreambleH = testPath("src/header_in_preamble.h");
  FS.Files[HeaderInPreambleH] = HeaderInPreambleAnnotations.code();
  auto HeaderNotInPreambleH = testPath("src/header_not_in_preamble.h");
  FS.Files[HeaderNotInPreambleH] = HeaderNotInPreambleAnnotations.code();

  runAddDocument(Server, FooCpp, SourceAnnotations.code());

  // Go to a definition in main source file.
  auto Locations =
      runLocateSymbolAt(Server, FooCpp, SourceAnnotations.point("p1"));
  EXPECT_TRUE(bool(Locations)) << "findDefinitions returned an error";
  EXPECT_THAT(*Locations, ElementsAre(Sym("foo", SourceAnnotations.range())));

  // Go to a definition in header_in_preamble.h.
  Locations = runLocateSymbolAt(Server, FooCpp, SourceAnnotations.point("p2"));
  EXPECT_TRUE(bool(Locations)) << "findDefinitions returned an error";
  EXPECT_THAT(
      *Locations,
      ElementsAre(Sym("bar_preamble", HeaderInPreambleAnnotations.range())));

  // Go to a definition in header_not_in_preamble.h.
  Locations = runLocateSymbolAt(Server, FooCpp, SourceAnnotations.point("p3"));
  EXPECT_TRUE(bool(Locations)) << "findDefinitions returned an error";
  EXPECT_THAT(*Locations,
              ElementsAre(Sym("bar_not_preamble",
                              HeaderNotInPreambleAnnotations.range())));
}

TEST(Hover, All) {
  struct OneTest {
    StringRef Input;
    StringRef ExpectedHover;
  };

  OneTest Tests[] = {
      {
          R"cpp(// No hover
            ^int main() {
            }
          )cpp",
          "",
      },
      {
          R"cpp(// Local variable
            int main() {
              int bonjour;
              ^bonjour = 2;
              int test1 = bonjour;
            }
          )cpp",
          "Declared in function main\n\nint bonjour",
      },
      {
          R"cpp(// Local variable in method
            struct s {
              void method() {
                int bonjour;
                ^bonjour = 2;
              }
            };
          )cpp",
          "Declared in function s::method\n\nint bonjour",
      },
      {
          R"cpp(// Struct
            namespace ns1 {
              struct MyClass {};
            } // namespace ns1
            int main() {
              ns1::My^Class* Params;
            }
          )cpp",
          "Declared in namespace ns1\n\nstruct MyClass {}",
      },
      {
          R"cpp(// Class
            namespace ns1 {
              class MyClass {};
            } // namespace ns1
            int main() {
              ns1::My^Class* Params;
            }
          )cpp",
          "Declared in namespace ns1\n\nclass MyClass {}",
      },
      {
          R"cpp(// Union
            namespace ns1 {
              union MyUnion { int x; int y; };
            } // namespace ns1
            int main() {
              ns1::My^Union Params;
            }
          )cpp",
          "Declared in namespace ns1\n\nunion MyUnion {}",
      },
      {
          R"cpp(// Function definition via pointer
            int foo(int) {}
            int main() {
              auto *X = &^foo;
            }
          )cpp",
          "Declared in global namespace\n\nint foo(int)",
      },
      {
          R"cpp(// Function declaration via call
            int foo(int);
            int main() {
              return ^foo(42);
            }
          )cpp",
          "Declared in global namespace\n\nint foo(int)",
      },
      {
          R"cpp(// Field
            struct Foo { int x; };
            int main() {
              Foo bar;
              bar.^x;
            }
          )cpp",
          "Declared in struct Foo\n\nint x",
      },
      {
          R"cpp(// Field with initialization
            struct Foo { int x = 5; };
            int main() {
              Foo bar;
              bar.^x;
            }
          )cpp",
          "Declared in struct Foo\n\nint x = 5",
      },
      {
          R"cpp(// Static field
            struct Foo { static int x; };
            int main() {
              Foo::^x;
            }
          )cpp",
          "Declared in struct Foo\n\nstatic int x",
      },
      {
          R"cpp(// Field, member initializer
            struct Foo {
              int x;
              Foo() : ^x(0) {}
            };
          )cpp",
          "Declared in struct Foo\n\nint x",
      },
      {
          R"cpp(// Field, GNU old-style field designator
            struct Foo { int x; };
            int main() {
              Foo bar = { ^x : 1 };
            }
          )cpp",
          "Declared in struct Foo\n\nint x",
      },
      {
          R"cpp(// Field, field designator
            struct Foo { int x; };
            int main() {
              Foo bar = { .^x = 2 };
            }
          )cpp",
          "Declared in struct Foo\n\nint x",
      },
      {
          R"cpp(// Method call
            struct Foo { int x(); };
            int main() {
              Foo bar;
              bar.^x();
            }
          )cpp",
          "Declared in struct Foo\n\nint x()",
      },
      {
          R"cpp(// Static method call
            struct Foo { static int x(); };
            int main() {
              Foo::^x();
            }
          )cpp",
          "Declared in struct Foo\n\nstatic int x()",
      },
      {
          R"cpp(// Typedef
            typedef int Foo;
            int main() {
              ^Foo bar;
            }
          )cpp",
          "Declared in global namespace\n\ntypedef int Foo",
      },
      {
          R"cpp(// Namespace
            namespace ns {
            struct Foo { static void bar(); }
            } // namespace ns
            int main() { ^ns::Foo::bar(); }
          )cpp",
          "Declared in global namespace\n\nnamespace ns {\n}",
      },
      {
          R"cpp(// Anonymous namespace
            namespace ns {
              namespace {
                int foo;
              } // anonymous namespace
            } // namespace ns
            int main() { ns::f^oo++; }
          )cpp",
          "Declared in namespace ns::(anonymous)\n\nint foo",
      },
      {
          R"cpp(// Macro
            #define MACRO 0
            #define MACRO 1
            int main() { return ^MACRO; }
            #define MACRO 2
            #undef macro
          )cpp",
          "#define MACRO 1",
      },
      {
          R"cpp(// Macro
            #define MACRO 0
            #define MACRO2 ^MACRO
          )cpp",
          "#define MACRO 0",
      },
      {
          R"cpp(// Macro
            #define MACRO {\
              return 0;\
            }
            int main() ^MACRO
          )cpp",
          R"cpp(#define MACRO {\
              return 0;\
            })cpp",
      },
      {
          R"cpp(// Forward class declaration
            class Foo;
            class Foo {};
            F^oo* foo();
          )cpp",
          "Declared in global namespace\n\nclass Foo {}",
      },
      {
          R"cpp(// Function declaration
            void foo();
            void g() { f^oo(); }
            void foo() {}
          )cpp",
          "Declared in global namespace\n\nvoid foo()",
      },
      {
          R"cpp(// Enum declaration
            enum Hello {
              ONE, TWO, THREE,
            };
            void foo() {
              Hel^lo hello = ONE;
            }
          )cpp",
          "Declared in global namespace\n\nenum Hello {\n}",
      },
      {
          R"cpp(// Enumerator
            enum Hello {
              ONE, TWO, THREE,
            };
            void foo() {
              Hello hello = O^NE;
            }
          )cpp",
          "Declared in enum Hello\n\nONE",
      },
      {
          R"cpp(// Enumerator in anonymous enum
            enum {
              ONE, TWO, THREE,
            };
            void foo() {
              int hello = O^NE;
            }
          )cpp",
          "Declared in enum (anonymous)\n\nONE",
      },
      {
          R"cpp(// Global variable
            static int hey = 10;
            void foo() {
              he^y++;
            }
          )cpp",
          "Declared in global namespace\n\nstatic int hey = 10",
      },
      {
          R"cpp(// Global variable in namespace
            namespace ns1 {
              static int hey = 10;
            }
            void foo() {
              ns1::he^y++;
            }
          )cpp",
          "Declared in namespace ns1\n\nstatic int hey = 10",
      },
      {
          R"cpp(// Field in anonymous struct
            static struct {
              int hello;
            } s;
            void foo() {
              s.he^llo++;
            }
          )cpp",
          "Declared in struct (anonymous)\n\nint hello",
      },
      {
          R"cpp(// Templated function
            template <typename T>
            T foo() {
              return 17;
            }
            void g() { auto x = f^oo<int>(); }
          )cpp",
          "Declared in global namespace\n\ntemplate <typename T> T foo()",
      },
      {
          R"cpp(// Anonymous union
            struct outer {
              union {
                int abc, def;
              } v;
            };
            void g() { struct outer o; o.v.d^ef++; }
          )cpp",
          "Declared in union outer::(anonymous)\n\nint def",
      },
      {
          R"cpp(// Nothing
            void foo() {
              ^
            }
          )cpp",
          "",
      },
      {
          R"cpp(// Simple initialization with auto
            void foo() {
              ^auto i = 1;
            }
          )cpp",
          "int",
      },
      {
          R"cpp(// Simple initialization with const auto
            void foo() {
              const ^auto i = 1;
            }
          )cpp",
          "int",
      },
      {
          R"cpp(// Simple initialization with const auto&
            void foo() {
              const ^auto& i = 1;
            }
          )cpp",
          "int",
      },
      {
          R"cpp(// Simple initialization with auto&
            void foo() {
              ^auto& i = 1;
            }
          )cpp",
          "int",
      },
      {
          R"cpp(// Simple initialization with auto*
            void foo() {
              int a = 1;
              ^auto* i = &a;
            }
          )cpp",
          "int",
      },
      {
          R"cpp(// Auto with initializer list.
            namespace std
            {
              template<class _E>
              class initializer_list {};
            }
            void foo() {
              ^auto i = {1,2};
            }
          )cpp",
          "class std::initializer_list<int>",
      },
      {
          R"cpp(// User defined conversion to auto
            struct Bar {
              operator ^auto() const { return 10; }
            };
          )cpp",
          "int",
      },
      {
          R"cpp(// Simple initialization with decltype(auto)
            void foo() {
              ^decltype(auto) i = 1;
            }
          )cpp",
          "int",
      },
      {
          R"cpp(// Simple initialization with const decltype(auto)
            void foo() {
              const int j = 0;
              ^decltype(auto) i = j;
            }
          )cpp",
          "const int",
      },
      {
          R"cpp(// Simple initialization with const& decltype(auto)
            void foo() {
              int k = 0;
              const int& j = k;
              ^decltype(auto) i = j;
            }
          )cpp",
          "const int &",
      },
      {
          R"cpp(// Simple initialization with & decltype(auto)
            void foo() {
              int k = 0;
              int& j = k;
              ^decltype(auto) i = j;
            }
          )cpp",
          "int &",
      },
      {
          R"cpp(// decltype with initializer list: nothing
            namespace std
            {
              template<class _E>
              class initializer_list {};
            }
            void foo() {
              ^decltype(auto) i = {1,2};
            }
          )cpp",
          "",
      },
      {
          R"cpp(// simple trailing return type
            ^auto main() -> int {
              return 0;
            }
          )cpp",
          "int",
      },
      {
          R"cpp(// auto function return with trailing type
            struct Bar {};
            ^auto test() -> decltype(Bar()) {
              return Bar();
            }
          )cpp",
          "struct Bar",
      },
      {
          R"cpp(// trailing return type
            struct Bar {};
            auto test() -> ^decltype(Bar()) {
              return Bar();
            }
          )cpp",
          "struct Bar",
      },
      {
          R"cpp(// auto in function return
            struct Bar {};
            ^auto test() {
              return Bar();
            }
          )cpp",
          "struct Bar",
      },
      {
          R"cpp(// auto& in function return
            struct Bar {};
            ^auto& test() {
              return Bar();
            }
          )cpp",
          "struct Bar",
      },
      {
          R"cpp(// auto* in function return
            struct Bar {};
            ^auto* test() {
              Bar* bar;
              return bar;
            }
          )cpp",
          "struct Bar",
      },
      {
          R"cpp(// const auto& in function return
            struct Bar {};
            const ^auto& test() {
              return Bar();
            }
          )cpp",
          "struct Bar",
      },
      {
          R"cpp(// decltype(auto) in function return
            struct Bar {};
            ^decltype(auto) test() {
              return Bar();
            }
          )cpp",
          "struct Bar",
      },
      {
          R"cpp(// decltype(auto) reference in function return
            struct Bar {};
            ^decltype(auto) test() {
              int a;
              return (a);
            }
          )cpp",
          "int &",
      },
      {
          R"cpp(// decltype lvalue reference
            void foo() {
              int I = 0;
              ^decltype(I) J = I;
            }
          )cpp",
          "int",
      },
      {
          R"cpp(// decltype lvalue reference
            void foo() {
              int I= 0;
              int &K = I;
              ^decltype(K) J = I;
            }
          )cpp",
          "int &",
      },
      {
          R"cpp(// decltype lvalue reference parenthesis
            void foo() {
              int I = 0;
              ^decltype((I)) J = I;
            }
          )cpp",
          "int &",
      },
      {
          R"cpp(// decltype rvalue reference
            void foo() {
              int I = 0;
              ^decltype(static_cast<int&&>(I)) J = static_cast<int&&>(I);
            }
          )cpp",
          "int &&",
      },
      {
          R"cpp(// decltype rvalue reference function call
            int && bar();
            void foo() {
              int I = 0;
              ^decltype(bar()) J = bar();
            }
          )cpp",
          "int &&",
      },
      {
          R"cpp(// decltype of function with trailing return type.
            struct Bar {};
            auto test() -> decltype(Bar()) {
              return Bar();
            }
            void foo() {
              ^decltype(test()) i = test();
            }
          )cpp",
          "struct Bar",
      },
      {
          R"cpp(// decltype of var with decltype.
            void foo() {
              int I = 0;
              decltype(I) J = I;
              ^decltype(J) K = J;
            }
          )cpp",
          "int",
      },
      {
          R"cpp(// structured binding. Not supported yet
            struct Bar {};
            void foo() {
              Bar a[2];
              ^auto [x,y] = a;
            }
          )cpp",
          "",
      },
      {
          R"cpp(// Template auto parameter. Nothing (Not useful).
            template<^auto T>
            void func() {
            }
            void foo() {
               func<1>();
            }
          )cpp",
          "",
      },
      {
          R"cpp(// More compilcated structured types.
            int bar();
            ^auto (*foo)() = bar;
          )cpp",
          "int",
      },
  };

  for (const OneTest &Test : Tests) {
    Annotations T(Test.Input);
    TestTU TU = TestTU::withCode(T.code());
    TU.ExtraArgs.push_back("-std=c++17");
    auto AST = TU.build();
    if (auto H = getHover(AST, T.point())) {
      EXPECT_NE("", Test.ExpectedHover) << Test.Input;
      EXPECT_EQ(H->contents.value, Test.ExpectedHover.str()) << Test.Input;
    } else
      EXPECT_EQ("", Test.ExpectedHover.str()) << Test.Input;
  }
}

TEST(GoToInclude, All) {
  MockFSProvider FS;
  IgnoreDiagnostics DiagConsumer;
  MockCompilationDatabase CDB;
  ClangdServer Server(CDB, FS, DiagConsumer, ClangdServer::optsForTest());

  auto FooCpp = testPath("foo.cpp");
  const char *SourceContents = R"cpp(
  #include ^"$2^foo.h$3^"
  #include "$4^invalid.h"
  int b = a;
  // test
  int foo;
  #in$5^clude "$6^foo.h"$7^
  )cpp";
  Annotations SourceAnnotations(SourceContents);
  FS.Files[FooCpp] = SourceAnnotations.code();
  auto FooH = testPath("foo.h");

  const char *HeaderContents = R"cpp([[]]#pragma once
                                     int a;
                                     )cpp";
  Annotations HeaderAnnotations(HeaderContents);
  FS.Files[FooH] = HeaderAnnotations.code();

  Server.addDocument(FooH, HeaderAnnotations.code());
  Server.addDocument(FooCpp, SourceAnnotations.code());

  // Test include in preamble.
  auto Locations = runLocateSymbolAt(Server, FooCpp, SourceAnnotations.point());
  ASSERT_TRUE(bool(Locations)) << "locateSymbolAt returned an error";
  EXPECT_THAT(*Locations, ElementsAre(Sym("foo.h", HeaderAnnotations.range())));

  // Test include in preamble, last char.
  Locations = runLocateSymbolAt(Server, FooCpp, SourceAnnotations.point("2"));
  ASSERT_TRUE(bool(Locations)) << "locateSymbolAt returned an error";
  EXPECT_THAT(*Locations, ElementsAre(Sym("foo.h", HeaderAnnotations.range())));

  Locations = runLocateSymbolAt(Server, FooCpp, SourceAnnotations.point("3"));
  ASSERT_TRUE(bool(Locations)) << "locateSymbolAt returned an error";
  EXPECT_THAT(*Locations, ElementsAre(Sym("foo.h", HeaderAnnotations.range())));

  // Test include outside of preamble.
  Locations = runLocateSymbolAt(Server, FooCpp, SourceAnnotations.point("6"));
  ASSERT_TRUE(bool(Locations)) << "locateSymbolAt returned an error";
  EXPECT_THAT(*Locations, ElementsAre(Sym("foo.h", HeaderAnnotations.range())));

  // Test a few positions that do not result in Locations.
  Locations = runLocateSymbolAt(Server, FooCpp, SourceAnnotations.point("4"));
  ASSERT_TRUE(bool(Locations)) << "locateSymbolAt returned an error";
  EXPECT_THAT(*Locations, IsEmpty());

  Locations = runLocateSymbolAt(Server, FooCpp, SourceAnnotations.point("5"));
  ASSERT_TRUE(bool(Locations)) << "locateSymbolAt returned an error";
  EXPECT_THAT(*Locations, ElementsAre(Sym("foo.h", HeaderAnnotations.range())));

  Locations = runLocateSymbolAt(Server, FooCpp, SourceAnnotations.point("7"));
  ASSERT_TRUE(bool(Locations)) << "locateSymbolAt returned an error";
  EXPECT_THAT(*Locations, ElementsAre(Sym("foo.h", HeaderAnnotations.range())));
}

TEST(LocateSymbol, WithPreamble) {
  // Test stragety: AST should always use the latest preamble instead of last
  // good preamble.
  MockFSProvider FS;
  IgnoreDiagnostics DiagConsumer;
  MockCompilationDatabase CDB;
  ClangdServer Server(CDB, FS, DiagConsumer, ClangdServer::optsForTest());

  auto FooCpp = testPath("foo.cpp");
  // The trigger locations must be the same.
  Annotations FooWithHeader(R"cpp(#include "fo^o.h")cpp");
  Annotations FooWithoutHeader(R"cpp(double    [[fo^o]]();)cpp");

  FS.Files[FooCpp] = FooWithHeader.code();

  auto FooH = testPath("foo.h");
  Annotations FooHeader(R"cpp([[]])cpp");
  FS.Files[FooH] = FooHeader.code();

  runAddDocument(Server, FooCpp, FooWithHeader.code());
  // LocateSymbol goes to a #include file: the result comes from the preamble.
  EXPECT_THAT(
      cantFail(runLocateSymbolAt(Server, FooCpp, FooWithHeader.point())),
      ElementsAre(Sym("foo.h", FooHeader.range())));

  // Only preamble is built, and no AST is built in this request.
  Server.addDocument(FooCpp, FooWithoutHeader.code(), WantDiagnostics::No);
  // We build AST here, and it should use the latest preamble rather than the
  // stale one.
  EXPECT_THAT(
      cantFail(runLocateSymbolAt(Server, FooCpp, FooWithoutHeader.point())),
      ElementsAre(Sym("foo", FooWithoutHeader.range())));

  // Reset test environment.
  runAddDocument(Server, FooCpp, FooWithHeader.code());
  // Both preamble and AST are built in this request.
  Server.addDocument(FooCpp, FooWithoutHeader.code(), WantDiagnostics::Yes);
  // Use the AST being built in above request.
  EXPECT_THAT(
      cantFail(runLocateSymbolAt(Server, FooCpp, FooWithoutHeader.point())),
      ElementsAre(Sym("foo", FooWithoutHeader.range())));
}

TEST(FindReferences, WithinAST) {
  const char *Tests[] = {
      R"cpp(// Local variable
        int main() {
          int [[foo]];
          [[^foo]] = 2;
          int test1 = [[foo]];
        }
      )cpp",

      R"cpp(// Struct
        namespace ns1 {
        struct [[Foo]] {};
        } // namespace ns1
        int main() {
          ns1::[[Fo^o]]* Params;
        }
      )cpp",

      R"cpp(// Forward declaration
        class [[Foo]];
        class [[Foo]] {}
        int main() {
          [[Fo^o]] foo;
        }
      )cpp",

      R"cpp(// Function
        int [[foo]](int) {}
        int main() {
          auto *X = &[[^foo]];
          [[foo]](42)
        }
      )cpp",

      R"cpp(// Field
        struct Foo {
          int [[foo]];
          Foo() : [[foo]](0) {}
        };
        int main() {
          Foo f;
          f.[[f^oo]] = 1;
        }
      )cpp",

      R"cpp(// Method call
        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; };
      void f() {
        if (Foo* T = foo.[^self]()) {} // Foo member call expr.
      }
      )cpp",

      R"cpp(
      struct Foo { Foo(int); };
      Foo f() {
        int [b];
        return [^b]; // Foo constructor expr.
      }
      )cpp",

      R"cpp(
      struct Foo {};
      void g(Foo);
      Foo [f]();
      void call() {
        g([^f]());  // Foo constructor expr.
      }
      )cpp",

      R"cpp(
      void [foo](int);
      void [foo](double);

      namespace ns {
      using ::[fo^o];
      }
      )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, NeedsIndex) {
  const char *Header = "int foo();";
  Annotations Main("int main() { [[f^oo]](); }");
  TestTU TU;
  TU.Code = Main.code();
  TU.HeaderCode = Header;
  auto AST = TU.build();

  // References in main file are returned without index.
  EXPECT_THAT(findReferences(AST, Main.point(), 0, /*Index=*/nullptr),
              ElementsAre(RangeIs(Main.range())));
  Annotations IndexedMain(R"cpp(
    int main() { [[f^oo]](); }
  )cpp");

  // References from indexed files are included.
  TestTU IndexedTU;
  IndexedTU.Code = IndexedMain.code();
  IndexedTU.Filename = "Indexed.cpp";
  IndexedTU.HeaderCode = Header;
  EXPECT_THAT(findReferences(AST, Main.point(), 0, IndexedTU.index().get()),
              ElementsAre(RangeIs(Main.range()), RangeIs(IndexedMain.range())));

  EXPECT_EQ(1u, findReferences(AST, Main.point(), /*Limit*/ 1,
                               IndexedTU.index().get())
                    .size());

  // If the main file is in the index, we don't return duplicates.
  // (even if the references are in a different location)
  TU.Code = ("\n\n" + Main.code()).str();
  EXPECT_THAT(findReferences(AST, Main.point(), 0, TU.index().get()),
              ElementsAre(RangeIs(Main.range())));
}

TEST(FindReferences, NoQueryForLocalSymbols) {
  struct RecordingIndex : public MemIndex {
    mutable Optional<llvm::DenseSet<SymbolID>> RefIDs;
    void refs(const RefsRequest &Req,
              llvm::function_ref<void(const Ref &)>) const override {
      RefIDs = Req.IDs;
    }
  };

  struct Test {
    StringRef AnnotatedCode;
    bool WantQuery;
  } Tests[] = {
      {"int ^x;", true},
      // For now we don't assume header structure which would allow skipping.
      {"namespace { int ^x; }", true},
      {"static int ^x;", true},
      // Anything in a function certainly can't be referenced though.
      {"void foo() { int ^x; }", false},
      {"void foo() { struct ^x{}; }", false},
      {"auto lambda = []{ int ^x; };", false},
  };
  for (Test T : Tests) {
    Annotations File(T.AnnotatedCode);
    RecordingIndex Rec;
    auto AST = TestTU::withCode(File.code()).build();
    findReferences(AST, File.point(), 0, &Rec);
    if (T.WantQuery)
      EXPECT_NE(Rec.RefIDs, None) << T.AnnotatedCode;
    else
      EXPECT_EQ(Rec.RefIDs, None) << T.AnnotatedCode;
  }
}

} // namespace
} // namespace clangd
} // namespace clang