diff --git a/CMakeLists.txt b/CMakeLists.txt
index 818eb71c..0594e2ba 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -210,7 +210,6 @@ target_sources(ccls PRIVATE
                src/config.cc
                src/diagnostics_engine.cc
                src/file_consumer.cc
-               src/file_contents.cc
                src/filesystem.cc
                src/fuzzy_match.cc
                src/iindexer.cc
diff --git a/src/clang_cursor.cc b/src/clang_cursor.cc
index efb297c4..369da744 100644
--- a/src/clang_cursor.cc
+++ b/src/clang_cursor.cc
@@ -17,8 +17,8 @@ Range ResolveCXSourceRange(const CXSourceRange& range, CXFile* cx_file) {
   unsigned int end_line, end_column;
   clang_getSpellingLocation(end, nullptr, &end_line, &end_column, nullptr);
 
-  return Range(Position((int16_t)start_line - 1, (int16_t)start_column - 1),
-               Position((int16_t)end_line - 1, (int16_t)end_column - 1));
+  return Range{{int16_t(start_line - 1), (int16_t)(start_column - 1)},
+               {int16_t(end_line - 1), int16_t(end_column - 1)}};
 }
 
 ClangCursor ClangType::get_declaration() const {
diff --git a/src/clang_indexer.cc b/src/clang_indexer.cc
index b03ef730..e335a750 100644
--- a/src/clang_indexer.cc
+++ b/src/clang_indexer.cc
@@ -9,6 +9,7 @@
 
 #include <loguru.hpp>
 
+#include <inttypes.h>
 #include <limits.h>
 #include <algorithm>
 #include <cassert>
@@ -280,7 +281,7 @@ struct ConstructorCache {
 struct IndexParam {
   std::unordered_set<CXFile> seen_cx_files;
   std::vector<std::string> seen_files;
-  FileContentsMap file_contents;
+  std::unordered_map<std::string, FileContents> file_contents;
   std::unordered_map<std::string, int64_t> file_modification_times;
 
   // Only use this when strictly needed (ie, primary translation unit is
@@ -729,7 +730,10 @@ IndexTypeId IndexFile::ToTypeId(Usr usr) {
     return it->second;
 
   IndexTypeId id(types.size());
-  types.push_back(IndexType(id, usr));
+  IndexType type;
+  type.usr = usr;
+  type.id = id;
+  types.push_back(type);
   id_cache.usr_to_type_id[usr] = id;
   id_cache.type_id_to_usr[id] = usr;
   return id;
@@ -740,7 +744,10 @@ IndexFuncId IndexFile::ToFuncId(Usr usr) {
     return it->second;
 
   IndexFuncId id(funcs.size());
-  funcs.push_back(IndexFunc(id, usr));
+  IndexFunc func;
+  func.usr = usr;
+  func.id = id;
+  funcs.push_back(std::move(func));
   id_cache.usr_to_func_id[usr] = id;
   id_cache.func_id_to_usr[id] = usr;
   return id;
@@ -751,7 +758,10 @@ IndexVarId IndexFile::ToVarId(Usr usr) {
     return it->second;
 
   IndexVarId id(vars.size());
-  vars.push_back(IndexVar(id, usr));
+  IndexVar var;
+  var.usr = usr;
+  var.id = id;
+  vars.push_back(std::move(var));
   id_cache.usr_to_var_id[usr] = id;
   id_cache.var_id_to_usr[id] = usr;
   return id;
@@ -783,8 +793,6 @@ std::string IndexFile::ToString() {
   return Serialize(SerializeFormat::Json, *this);
 }
 
-IndexType::IndexType(IndexTypeId id, Usr usr) : usr(usr), id(id) {}
-
 template <typename T>
 void Uniquify(std::vector<Id<T>>& ids) {
   std::unordered_set<Id<T>> seen;
@@ -796,11 +804,19 @@ void Uniquify(std::vector<Id<T>>& ids) {
 }
 
 void Uniquify(std::vector<Use>& uses) {
-  std::unordered_set<Range> seen;
+  union U {
+    Range range = {};
+    uint64_t u64;
+  };
+  static_assert(sizeof(Range) == 8);
+  std::unordered_set<uint64_t> seen;
   size_t n = 0;
-  for (size_t i = 0; i < uses.size(); i++)
-    if (seen.insert(uses[i].range).second)
+  for (size_t i = 0; i < uses.size(); i++) {
+    U u;
+    u.range = uses[i].range;
+    if (seen.insert(u.u64).second)
       uses[n++] = uses[i];
+  }
   uses.resize(n);
 }
 
@@ -2343,10 +2359,6 @@ void IndexInit() {
     clang_toggleCrashRecovery(1);
 }
 
-std::string GetClangVersion() {
-  return ToString(clang_getClangVersion());
-}
-
 // |SymbolRef| is serialized this way.
 // |Use| also uses this though it has an extra field |file|,
 // which is not used by Index* so it does not need to be serialized.
@@ -2354,7 +2366,7 @@ void Reflect(Reader& visitor, Reference& value) {
   if (visitor.Format() == SerializeFormat::Json) {
     std::string t = visitor.GetString();
     char* s = const_cast<char*>(t.c_str());
-    value.range = Range(s);
+    value.range = Range::FromString(s);
     s = strchr(s, '|');
     value.id.id = RawId(strtol(s + 1, &s, 10));
     value.kind = static_cast<SymbolKind>(strtol(s + 1, &s, 10));
@@ -2368,12 +2380,13 @@ void Reflect(Reader& visitor, Reference& value) {
 }
 void Reflect(Writer& visitor, Reference& value) {
   if (visitor.Format() == SerializeFormat::Json) {
-    std::string s = value.range.ToString();
     // RawId(-1) -> "-1"
-    s += '|' + std::to_string(
-                   static_cast<std::make_signed<RawId>::type>(value.id.id));
-    s += '|' + std::to_string(int(value.kind));
-    s += '|' + std::to_string(int(value.role));
+    char buf[99];
+    snprintf(buf, sizeof buf, "%s|%" PRId32 "|%d|%d",
+             value.range.ToString().c_str(),
+             static_cast<std::make_signed<RawId>::type>(value.id.id),
+             int(value.kind), int(value.role));
+    std::string s(buf);
     Reflect(visitor, s);
   } else {
     Reflect(visitor, value.range);
diff --git a/src/file_consumer.cc b/src/file_consumer.cc
index c237c5b7..9d1d276a 100644
--- a/src/file_consumer.cc
+++ b/src/file_consumer.cc
@@ -9,8 +9,9 @@
 
 namespace {
 
-std::optional<std::string> GetFileContents(const std::string& path,
-                                      FileContentsMap* file_contents) {
+std::optional<std::string> GetFileContents(
+    const std::string& path,
+    std::unordered_map<std::string, FileContents>* file_contents) {
   auto it = file_contents->find(path);
   if (it == file_contents->end()) {
     std::optional<std::string> content = ReadContent(path);
@@ -28,6 +29,34 @@ bool operator==(const CXFileUniqueID& a, const CXFileUniqueID& b) {
          a.data[2] == b.data[2];
 }
 
+FileContents::FileContents() : line_offsets_{0} {}
+
+FileContents::FileContents(const std::string& path, const std::string& content)
+    : path(path), content(content) {
+  line_offsets_.push_back(0);
+  for (size_t i = 0; i < content.size(); i++) {
+    if (content[i] == '\n')
+      line_offsets_.push_back(i + 1);
+  }
+}
+
+std::optional<int> FileContents::ToOffset(Position p) const {
+  if (0 <= p.line && size_t(p.line) < line_offsets_.size()) {
+    int ret = line_offsets_[p.line] + p.column;
+    if (size_t(ret) < content.size())
+      return ret;
+  }
+  return std::nullopt;
+}
+
+std::optional<std::string> FileContents::ContentsInRange(Range range) const {
+  std::optional<int> start_offset = ToOffset(range.start),
+                end_offset = ToOffset(range.end);
+  if (start_offset && end_offset && *start_offset < *end_offset)
+    return content.substr(*start_offset, *end_offset - *start_offset);
+  return std::nullopt;
+}
+
 bool FileConsumerSharedState::Mark(const std::string& file) {
   std::lock_guard<std::mutex> lock(mutex);
   return used_files.insert(file).second;
@@ -44,9 +73,10 @@ FileConsumer::FileConsumer(FileConsumerSharedState* shared_state,
                            const std::string& parse_file)
     : shared_(shared_state), parse_file_(parse_file) {}
 
-IndexFile* FileConsumer::TryConsumeFile(CXFile file,
-                                        bool* is_first_ownership,
-                                        FileContentsMap* file_contents_map) {
+IndexFile* FileConsumer::TryConsumeFile(
+    CXFile file,
+    bool* is_first_ownership,
+    std::unordered_map<std::string, FileContents>* file_contents_map) {
   assert(is_first_ownership);
 
   CXFileUniqueID file_id;
diff --git a/src/file_consumer.h b/src/file_consumer.h
index 6ac94edd..de7162c3 100644
--- a/src/file_consumer.h
+++ b/src/file_consumer.h
@@ -1,6 +1,6 @@
 #pragma once
 
-#include "file_contents.h"
+#include "position.h"
 #include "utils.h"
 
 #include <clang-c/Index.h>
@@ -9,6 +9,7 @@
 #include <mutex>
 #include <unordered_map>
 #include <unordered_set>
+#include <vector>
 
 struct IndexFile;
 
@@ -16,6 +17,19 @@ struct IndexFile;
 MAKE_HASHABLE(CXFileUniqueID, t.data[0], t.data[1], t.data[2]);
 bool operator==(const CXFileUniqueID& a, const CXFileUniqueID& b);
 
+struct FileContents {
+  FileContents();
+  FileContents(const std::string& path, const std::string& content);
+
+  std::optional<int> ToOffset(Position p) const;
+  std::optional<std::string> ContentsInRange(Range range) const;
+
+  std::string path;
+  std::string content;
+  // {0, 1 + position of first newline, 1 + position of second newline, ...}
+  std::vector<int> line_offsets_;
+};
+
 struct FileConsumerSharedState {
   mutable std::unordered_set<std::string> used_files;
   mutable std::mutex mutex;
@@ -48,7 +62,7 @@ struct FileConsumer {
   // variable since it is large and we do not want to copy it.
   IndexFile* TryConsumeFile(CXFile file,
                             bool* is_first_ownership,
-                            FileContentsMap* file_contents);
+                            std::unordered_map<std::string, FileContents>* file_contents);
 
   // Returns and passes ownership of all local state.
   std::vector<std::unique_ptr<IndexFile>> TakeLocalState();
@@ -59,4 +73,4 @@ struct FileConsumer {
   std::unordered_map<CXFileUniqueID, std::unique_ptr<IndexFile>> local_;
   FileConsumerSharedState* shared_;
   std::string parse_file_;
-};
\ No newline at end of file
+};
diff --git a/src/file_contents.cc b/src/file_contents.cc
deleted file mode 100644
index 5a7bc0f4..00000000
--- a/src/file_contents.cc
+++ /dev/null
@@ -1,29 +0,0 @@
-#include "file_contents.h"
-
-FileContents::FileContents() : line_offsets_{0} {}
-
-FileContents::FileContents(const std::string& path, const std::string& content)
-    : path(path), content(content) {
-  line_offsets_.push_back(0);
-  for (size_t i = 0; i < content.size(); i++) {
-    if (content[i] == '\n')
-      line_offsets_.push_back(i + 1);
-  }
-}
-
-std::optional<int> FileContents::ToOffset(Position p) const {
-  if (0 <= p.line && size_t(p.line) < line_offsets_.size()) {
-    int ret = line_offsets_[p.line] + p.column;
-    if (size_t(ret) < content.size())
-      return ret;
-  }
-  return std::nullopt;
-}
-
-std::optional<std::string> FileContents::ContentsInRange(Range range) const {
-  std::optional<int> start_offset = ToOffset(range.start),
-                end_offset = ToOffset(range.end);
-  if (start_offset && end_offset && *start_offset < *end_offset)
-    return content.substr(*start_offset, *end_offset - *start_offset);
-  return std::nullopt;
-}
diff --git a/src/file_contents.h b/src/file_contents.h
deleted file mode 100644
index 21c484d4..00000000
--- a/src/file_contents.h
+++ /dev/null
@@ -1,23 +0,0 @@
-#pragma once
-
-#include "position.h"
-
-#include <string>
-#include <optional>
-#include <unordered_map>
-#include <vector>
-
-struct FileContents {
-  FileContents();
-  FileContents(const std::string& path, const std::string& content);
-
-  std::optional<int> ToOffset(Position p) const;
-  std::optional<std::string> ContentsInRange(Range range) const;
-
-  std::string path;
-  std::string content;
-  // {0, 1 + position of first newline, 1 + position of second newline, ...}
-  std::vector<int> line_offsets_;
-};
-
-using FileContentsMap = std::unordered_map<std::string, FileContents>;
diff --git a/src/indexer.h b/src/indexer.h
index a57febe1..05c8e610 100644
--- a/src/indexer.h
+++ b/src/indexer.h
@@ -4,7 +4,6 @@
 #include "clang_translation_unit.h"
 #include "clang_utils.h"
 #include "file_consumer.h"
-#include "file_contents.h"
 #include "language.h"
 #include "lsp.h"
 #include "maybe.h"
@@ -54,7 +53,7 @@ struct Id {
   // Needed for google::dense_hash_map.
   explicit operator RawId() const { return id; }
 
-  bool HasValueForMaybe_() const { return id != RawId(-1); }
+  bool Valid() const { return id != RawId(-1); }
 
   bool operator==(const Id& o) const { return id == o.id; }
   bool operator!=(const Id& o) const { return id != o.id; }
@@ -101,7 +100,7 @@ struct Reference {
   SymbolKind kind;
   Role role;
 
-  bool HasValueForMaybe_() const { return range.HasValueForMaybe_(); }
+  bool Valid() const { return range.Valid(); }
   operator SymbolIdx() const { return {id, kind}; }
   std::tuple<Range, Id<void>, SymbolKind, Role> ToTuple() const {
     return std::make_tuple(range, id, kind, role);
@@ -126,8 +125,6 @@ struct Use : Reference {
   Use(Range range, Id<void> id, SymbolKind kind, Role role, Id<QueryFile> file)
       : Reference{range, id, kind, role}, file(file) {}
 };
-// Used by |HANDLE_MERGEABLE| so only |range| is needed.
-MAKE_HASHABLE(Use, t.range);
 
 void Reflect(Reader& visitor, Reference& value);
 void Reflect(Writer& visitor, Reference& value);
@@ -241,9 +238,6 @@ struct IndexType {
   // NOTE: Do not insert directly! Use AddUsage instead.
   std::vector<Use> uses;
 
-  IndexType() {}  // For serialization.
-  IndexType(IndexTypeId id, Usr usr);
-
   bool operator<(const IndexType& other) const { return id < other.id; }
 };
 MAKE_HASHABLE(IndexType, t.id);
@@ -336,9 +330,6 @@ struct IndexFunc : NameMixin<IndexFunc> {
   // def.spell.
   std::vector<Use> uses;
 
-  IndexFunc() {}  // For serialization.
-  IndexFunc(IndexFuncId id, Usr usr) : usr(usr), id(id) {}
-
   bool operator<(const IndexFunc& other) const { return id < other.id; }
 };
 MAKE_HASHABLE(IndexFunc, t.id);
@@ -408,9 +399,6 @@ struct IndexVar {
   std::vector<Use> declarations;
   std::vector<Use> uses;
 
-  IndexVar() {}  // For serialization.
-  IndexVar(IndexVarId id, Usr usr) : usr(usr), id(id) {}
-
   bool operator<(const IndexVar& other) const { return id < other.id; }
 };
 MAKE_HASHABLE(IndexVar, t.id);
@@ -519,7 +507,3 @@ std::vector<std::unique_ptr<IndexFile>> ParseWithTu(
 bool ConcatTypeAndName(std::string& type, const std::string& name);
 
 void IndexInit();
-
-void ClangSanityCheck();
-
-std::string GetClangVersion();
diff --git a/src/maybe.h b/src/maybe.h
index c26c9708..328fc71e 100644
--- a/src/maybe.h
+++ b/src/maybe.h
@@ -5,7 +5,7 @@
 #include <utility>
 
 // Like std::optional, but the stored data is responsible for containing the empty
-// state. T should define a function `bool T::HasValueForMaybe_()`.
+// state. T should define a function `bool T::Valid()`.
 template <typename T>
 class Maybe {
   T storage;
@@ -28,10 +28,10 @@ class Maybe {
   const T& operator*() const { return storage; }
   T& operator*() { return storage; }
 
-  bool HasValue() const { return storage.HasValueForMaybe_(); }
-  explicit operator bool() const { return HasValue(); }
+  bool Valid() const { return storage.Valid(); }
+  explicit operator bool() const { return Valid(); }
   operator std::optional<T>() const {
-    if (HasValue())
+    if (Valid())
       return storage;
     return std::nullopt;
   }
diff --git a/src/messages/text_document_definition.cc b/src/messages/text_document_definition.cc
index 35fec5bd..f431e146 100644
--- a/src/messages/text_document_definition.cc
+++ b/src/messages/text_document_definition.cc
@@ -105,7 +105,8 @@ struct Handler_TextDocumentDefinition
         if (uses.empty() && on_def)
           uses.push_back(*on_def);
       }
-      AddRange(&out.result, GetLsLocationExs(db, working_files, uses));
+      auto locs = GetLsLocationExs(db, working_files, uses);
+      out.result.insert(out.result.end(), locs.begin(), locs.end());
       if (!out.result.empty())
         break;
     }
diff --git a/src/method.cc b/src/method.cc
index f1e38590..99af41a3 100644
--- a/src/method.cc
+++ b/src/method.cc
@@ -5,13 +5,3 @@ MethodType kMethodType_Exit = "exit";
 MethodType kMethodType_TextDocumentPublishDiagnostics = "textDocument/publishDiagnostics";
 MethodType kMethodType_CclsPublishInactiveRegions = "$ccls/publishInactiveRegions";
 MethodType kMethodType_CclsPublishSemanticHighlighting = "$ccls/publishSemanticHighlighting";
-
-InMessage::~InMessage() = default;
-
-lsRequestId RequestInMessage::GetRequestId() const {
-  return id;
-}
-
-lsRequestId NotificationInMessage::GetRequestId() const {
-  return std::monostate();
-}
\ No newline at end of file
diff --git a/src/method.h b/src/method.h
index 7931673e..a336ed5b 100644
--- a/src/method.h
+++ b/src/method.h
@@ -15,7 +15,7 @@ extern MethodType kMethodType_CclsPublishSemanticHighlighting;
 using lsRequestId = std::variant<std::monostate, int64_t, std::string>;
 
 struct InMessage {
-  virtual ~InMessage();
+  virtual ~InMessage() = default;
 
   virtual MethodType GetMethodType() const = 0;
   virtual lsRequestId GetRequestId() const = 0;
@@ -24,10 +24,14 @@ struct InMessage {
 struct RequestInMessage : public InMessage {
   // number or string, actually no null
   lsRequestId id;
-  lsRequestId GetRequestId() const override;
+  lsRequestId GetRequestId() const override {
+    return id;
+  }
 };
 
 // NotificationInMessage does not have |id|.
 struct NotificationInMessage : public InMessage {
-  lsRequestId GetRequestId() const override;
+  lsRequestId GetRequestId() const override {
+    return std::monostate();
+  }
 };
diff --git a/src/position.cc b/src/position.cc
index 37c94c6e..abcab312 100644
--- a/src/position.cc
+++ b/src/position.cc
@@ -1,74 +1,29 @@
 #include "position.h"
 
+#include "serializer.h"
+
+#include <limits.h>
+#include <stdio.h>
 #include <stdlib.h>
 
-Position::Position() : line(-1), column(-1) {}
-
-Position::Position(int16_t line, int16_t column) : line(line), column(column) {}
-
-Position::Position(const char* encoded) {
-  char* p = const_cast<char*>(encoded);
-  line = int16_t(strtol(p, &p, 10)) - 1;
+Position Position::FromString(const std::string& encoded) {
+  char* p = const_cast<char*>(encoded.c_str());
+  int16_t line = int16_t(strtol(p, &p, 10)) - 1;
   assert(*p == ':');
   p++;
-  column = int16_t(strtol(p, &p, 10)) - 1;
+  int16_t column = int16_t(strtol(p, &p, 10)) - 1;
+  return {line, column};
 }
 
 std::string Position::ToString() {
-  // Output looks like this:
-  //
-  //  1:2
-  //
-  // 1 => line
-  // 2 => column
-
-  std::string result;
-  result += std::to_string(line + 1);
-  result += ':';
-  result += std::to_string(column + 1);
-  return result;
+  char buf[99];
+  snprintf(buf, sizeof buf, "%d:%d", line + 1, column + 1);
+  return buf;
 }
 
-std::string Position::ToPrettyString(const std::string& filename) {
-  // Output looks like this:
-  //
-  //  1:2:3
-  //
-  // 1 => filename
-  // 2 => line
-  // 3 => column
-
-  std::string result;
-  result += filename;
-  result += ':';
-  result += std::to_string(line + 1);
-  result += ':';
-  result += std::to_string(column + 1);
-  return result;
-}
-
-bool Position::operator==(const Position& that) const {
-  return line == that.line && column == that.column;
-}
-
-bool Position::operator!=(const Position& that) const {
-  return !(*this == that);
-}
-
-bool Position::operator<(const Position& that) const {
-  if (line != that.line)
-    return line < that.line;
-  return column < that.column;
-}
-
-Range::Range() {}
-
-Range::Range(Position position) : Range(position, position) {}
-
-Range::Range(Position start, Position end) : start(start), end(end) {}
-
-Range::Range(const char* encoded) {
-  char* p = const_cast<char*>(encoded);
+Range Range::FromString(const std::string& encoded) {
+  Position start, end;
+  char* p = const_cast<char*>(encoded.c_str());
   start.line = int16_t(strtol(p, &p, 10)) - 1;
   assert(*p == ':');
   p++;
@@ -80,18 +35,14 @@ Range::Range(const char* encoded) {
   assert(*p == ':');
   p++;
   end.column = int16_t(strtol(p, nullptr, 10)) - 1;
+  return {start, end};
 }
 
 bool Range::Contains(int line, int column) const {
-  if (line == start.line && line == end.line)
-    return column >= start.column && column < end.column;
-  if (line == start.line)
-    return column >= start.column;
-  if (line == end.line)
-    return column < end.column;
-  if (line > start.line && line < end.line)
-    return true;
-  return false;
+  if (line > INT16_MAX)
+    return false;
+  Position p{int16_t(line), int16_t(std::min(column, INT16_MAX))};
+  return !(p < start) && p < end;
 }
 
 Range Range::RemovePrefix(Position position) const {
@@ -99,47 +50,16 @@ Range Range::RemovePrefix(Position position) const {
 }
 
 std::string Range::ToString() {
-  // Output looks like this:
-  //
-  //  1:2-3:4
-  //
-  // 1 => start line
-  // 2 => start column
-  // 3 => end line
-  // 4 => end column
-
-  std::string output;
-
-  output += std::to_string(start.line + 1);
-  output += ':';
-  output += std::to_string(start.column + 1);
-  output += '-';
-  output += std::to_string(end.line + 1);
-  output += ':';
-  output += std::to_string(end.column + 1);
-
-  return output;
-}
-
-bool Range::operator==(const Range& that) const {
-  return start == that.start && end == that.end;
-}
-
-bool Range::operator!=(const Range& that) const {
-  return !(*this == that);
-}
-
-bool Range::operator<(const Range& that) const {
-  if (start != that.start)
-    return start < that.start;
-  return end < that.end;
+  char buf[99];
+  snprintf(buf, sizeof buf, "%d:%d-%d:%d", start.line + 1, start.column + 1,
+           end.line + 1, end.column + 1);
+  return buf;
 }
 
 // Position
 void Reflect(Reader& visitor, Position& value) {
   if (visitor.Format() == SerializeFormat::Json) {
-    std::string s = visitor.GetString();
-    value = Position(s.c_str());
+    value = Position::FromString(visitor.GetString());
   } else {
     Reflect(visitor, value.line);
     Reflect(visitor, value.column);
@@ -158,8 +78,7 @@ void Reflect(Writer& visitor, Position& value) {
 // Range
 void Reflect(Reader& visitor, Range& value) {
   if (visitor.Format() == SerializeFormat::Json) {
-    std::string s = visitor.GetString();
-    value = Range(s.c_str());
+    value = Range::FromString(visitor.GetString());
   } else {
     Reflect(visitor, value.start.line);
     Reflect(visitor, value.start.column);
diff --git a/src/position.h b/src/position.h
index 8d238b55..748bb741 100644
--- a/src/position.h
+++ b/src/position.h
@@ -1,57 +1,56 @@
 #pragma once
 
 #include "maybe.h"
-#include "serializer.h"
 #include "utils.h"
 
 #include <stdint.h>
 #include <string>
 
 struct Position {
-  int16_t line;
-  int16_t column;
+  int16_t line = -1;
+  int16_t column = -1;
 
-  Position();
-  Position(int16_t line, int16_t column);
-  explicit Position(const char* encoded);
+  static Position FromString(const std::string& encoded);
 
-  bool HasValueForMaybe_() const { return line >= 0; }
+  bool Valid() const { return line >= 0; }
   std::string ToString();
-  std::string ToPrettyString(const std::string& filename);
 
   // Compare two Positions and check if they are equal. Ignores the value of
   // |interesting|.
-  bool operator==(const Position& that) const;
-  bool operator!=(const Position& that) const;
-  bool operator<(const Position& that) const;
+  bool operator==(const Position& o) const {
+    return line == o.line && column == o.column;
+  }
+  bool operator<(const Position& o) const {
+    if (line != o.line)
+      return line < o.line;
+    return column < o.column;
+  }
 };
-static_assert(
-    sizeof(Position) == 4,
-    "Investigate, Position should be 32-bits for indexer size reasons");
 MAKE_HASHABLE(Position, t.line, t.column);
 
 struct Range {
   Position start;
   Position end;
 
-  Range();
-  explicit Range(Position position);
-  Range(Position start, Position end);
-  explicit Range(const char* encoded);
+  static Range FromString(const std::string& encoded);
 
-  bool HasValueForMaybe_() const { return start.HasValueForMaybe_(); }
+  bool Valid() const { return start.Valid(); }
   bool Contains(int line, int column) const;
   Range RemovePrefix(Position position) const;
 
   std::string ToString();
 
-  bool operator==(const Range& that) const;
-  bool operator!=(const Range& that) const;
-  bool operator<(const Range& that) const;
+  bool operator==(const Range& o) const {
+    return start == o.start && end == o.end;
+  }
+  bool operator<(const Range& o) const {
+    return !(start == o.start) ? start < o.start : end < o.end;
+  }
 };
-MAKE_HASHABLE(Range, t.start, t.end);
 
 // Reflection
+class Reader;
+class Writer;
 void Reflect(Reader& visitor, Position& value);
 void Reflect(Writer& visitor, Position& value);
 void Reflect(Reader& visitor, Range& value);
diff --git a/src/query.cc b/src/query.cc
index e504619b..8d28f2a0 100644
--- a/src/query.cc
+++ b/src/query.cc
@@ -11,14 +11,30 @@
 #include <cassert>
 #include <cstdint>
 #include <functional>
+#include <iterator>
 #include <string>
 #include <unordered_map>
 #include <unordered_set>
 
 // TODO: Make all copy constructors explicit.
 
+// Used by |HANDLE_MERGEABLE| so only |range| is needed.
+MAKE_HASHABLE(Range, t.start, t.end);
+MAKE_HASHABLE(Use, t.range);
+
 namespace {
 
+template <typename T>
+void AddRange(std::vector<T>* dest, const std::vector<T>& to_add) {
+  dest->insert(dest->end(), to_add.begin(), to_add.end());
+}
+
+template <typename T>
+void AddRange(std::vector<T>* dest, std::vector<T>&& to_add) {
+  dest->insert(dest->end(), std::make_move_iterator(to_add.begin()),
+               std::make_move_iterator(to_add.end()));
+}
+
 template <typename T>
 void RemoveRange(std::vector<T>* dest, const std::vector<T>& to_remove) {
   std::unordered_set<T> to_remove_set(to_remove.begin(), to_remove.end());
@@ -897,7 +913,7 @@ void QueryDatabase::ImportOrUpdate(std::vector<QueryVar::DefUpdate>&& updates) {
 void QueryDatabase::UpdateSymbols(Maybe<Id<void>>* symbol_idx,
                                   SymbolKind kind,
                                   Id<void> idx) {
-  if (!symbol_idx->HasValue()) {
+  if (!symbol_idx->Valid()) {
     *symbol_idx = Id<void>(symbols.size());
     symbols.push_back(SymbolIdx{idx, kind});
   }
@@ -928,255 +944,3 @@ std::string_view QueryDatabase::GetSymbolName(RawId symbol_idx,
   }
   return "";
 }
-
-TEST_SUITE("query") {
-  IndexUpdate GetDelta(IndexFile previous, IndexFile current) {
-    QueryDatabase db;
-    IdMap previous_map(&db, previous.id_cache);
-    IdMap current_map(&db, current.id_cache);
-    return IndexUpdate::CreateDelta(&previous_map, &current_map, &previous,
-                                    &current);
-  }
-
-  TEST_CASE("remove defs") {
-    IndexFile previous("foo.cc", "<empty>");
-    IndexFile current("foo.cc", "<empty>");
-
-    previous.Resolve(previous.ToTypeId(HashUsr("usr1")))->def.spell =
-        Use(Range(Position(1, 0)), {}, {}, {}, {});
-    previous.Resolve(previous.ToFuncId(HashUsr("usr2")))->def.spell =
-        Use(Range(Position(2, 0)), {}, {}, {}, {});
-    previous.Resolve(previous.ToVarId(HashUsr("usr3")))->def.spell =
-        Use(Range(Position(3, 0)), {}, {}, {}, {});
-
-    IndexUpdate update = GetDelta(previous, current);
-
-    REQUIRE(update.types_removed == std::vector<Usr>{HashUsr("usr1")});
-    REQUIRE(update.funcs_removed.size() == 1);
-    REQUIRE(update.funcs_removed[0].usr == HashUsr("usr2"));
-    REQUIRE(update.vars_removed.size() == 1);
-    REQUIRE(update.vars_removed[0].usr == HashUsr("usr3"));
-  }
-
-  TEST_CASE("do not remove ref-only defs") {
-    IndexFile previous("foo.cc", "<empty>");
-    IndexFile current("foo.cc", "<empty>");
-
-    previous.Resolve(previous.ToTypeId(HashUsr("usr1")))
-        ->uses.push_back(Use{Range(Position(1, 0)), {}, {}, {}, {}});
-    previous.Resolve(previous.ToFuncId(HashUsr("usr2")))
-        ->uses.push_back(Use(Range(Position(2, 0)), {}, {}, {}, {}));
-    previous.Resolve(previous.ToVarId(HashUsr("usr3")))
-        ->uses.push_back(Use(Range(Position(3, 0)), {}, {}, {}, {}));
-
-    IndexUpdate update = GetDelta(previous, current);
-
-    REQUIRE(update.types_removed == std::vector<Usr>{});
-    REQUIRE(update.funcs_removed.empty());
-    REQUIRE(update.vars_removed.empty());
-  }
-
-  TEST_CASE("func callers") {
-    IndexFile previous("foo.cc", "<empty>");
-    IndexFile current("foo.cc", "<empty>");
-
-    IndexFunc* pf = previous.Resolve(previous.ToFuncId(HashUsr("usr")));
-    IndexFunc* cf = current.Resolve(current.ToFuncId(HashUsr("usr")));
-
-    pf->uses.push_back(Use(Range(Position(1, 0)), {}, {}, {}, {}));
-    cf->uses.push_back(Use(Range(Position(2, 0)), {}, {}, {}, {}));
-
-    IndexUpdate update = GetDelta(previous, current);
-
-    REQUIRE(update.funcs_removed.empty());
-    REQUIRE(update.funcs_uses.size() == 1);
-    REQUIRE(update.funcs_uses[0].id == QueryFuncId(0));
-    REQUIRE(update.funcs_uses[0].to_remove.size() == 1);
-    REQUIRE(update.funcs_uses[0].to_remove[0].range == Range(Position(1, 0)));
-    REQUIRE(update.funcs_uses[0].to_add.size() == 1);
-    REQUIRE(update.funcs_uses[0].to_add[0].range == Range(Position(2, 0)));
-  }
-
-  TEST_CASE("type usages") {
-    IndexFile previous("foo.cc", "<empty>");
-    IndexFile current("foo.cc", "<empty>");
-
-    IndexType* pt = previous.Resolve(previous.ToTypeId(HashUsr("usr")));
-    IndexType* ct = current.Resolve(current.ToTypeId(HashUsr("usr")));
-
-    pt->uses.push_back(Use(Range(Position(1, 0)), {}, {}, {}, {}));
-    ct->uses.push_back(Use(Range(Position(2, 0)), {}, {}, {}, {}));
-
-    IndexUpdate update = GetDelta(previous, current);
-
-    REQUIRE(update.types_removed == std::vector<Usr>{});
-    REQUIRE(update.types_def_update.empty());
-    REQUIRE(update.types_uses.size() == 1);
-    REQUIRE(update.types_uses[0].to_remove.size() == 1);
-    REQUIRE(update.types_uses[0].to_remove[0].range == Range(Position(1, 0)));
-    REQUIRE(update.types_uses[0].to_add.size() == 1);
-    REQUIRE(update.types_uses[0].to_add[0].range == Range(Position(2, 0)));
-  }
-
-  TEST_CASE("apply delta") {
-    IndexFile previous("foo.cc", "<empty>");
-    IndexFile current("foo.cc", "<empty>");
-
-    IndexFunc* pf = previous.Resolve(previous.ToFuncId(HashUsr("usr")));
-    IndexFunc* cf = current.Resolve(current.ToFuncId(HashUsr("usr")));
-    pf->uses.push_back(Use(Range(Position(1, 0)), {}, {}, {}, {}));
-    pf->uses.push_back(Use(Range(Position(2, 0)), {}, {}, {}, {}));
-    cf->uses.push_back(Use(Range(Position(4, 0)), {}, {}, {}, {}));
-    cf->uses.push_back(Use(Range(Position(5, 0)), {}, {}, {}, {}));
-
-    QueryDatabase db;
-    IdMap previous_map(&db, previous.id_cache);
-    IdMap current_map(&db, current.id_cache);
-    REQUIRE(db.funcs.size() == 1);
-
-    IndexUpdate import_update =
-        IndexUpdate::CreateDelta(nullptr, &previous_map, nullptr, &previous);
-    IndexUpdate delta_update = IndexUpdate::CreateDelta(
-        &previous_map, &current_map, &previous, &current);
-
-    db.ApplyIndexUpdate(&import_update);
-    REQUIRE(db.funcs[0].uses.size() == 2);
-    REQUIRE(db.funcs[0].uses[0].range == Range(Position(1, 0)));
-    REQUIRE(db.funcs[0].uses[1].range == Range(Position(2, 0)));
-
-    db.ApplyIndexUpdate(&delta_update);
-    REQUIRE(db.funcs[0].uses.size() == 2);
-    REQUIRE(db.funcs[0].uses[0].range == Range(Position(4, 0)));
-    REQUIRE(db.funcs[0].uses[1].range == Range(Position(5, 0)));
-  }
-
-  TEST_CASE("Remove variable with usage") {
-    auto load_index_from_json = [](const char* json) {
-      return Deserialize(SerializeFormat::Json, "foo.cc", json, "<empty>",
-                         std::nullopt);
-    };
-
-    auto previous = load_index_from_json(R"RAW(
-{
-  "types": [
-    {
-      "id": 0,
-      "usr": 17,
-      "detailed_name": "",
-      "short_name_offset": 0,
-      "short_name_size": 0,
-      "kind": 0,
-      "hover": "",
-      "comments": "",
-      "parents": [],
-      "derived": [],
-      "types": [],
-      "funcs": [],
-      "vars": [],
-      "instances": [
-        0
-      ],
-      "uses": []
-    }
-  ],
-  "funcs": [
-    {
-      "id": 0,
-      "usr": 4259594751088586730,
-      "detailed_name": "void foo()",
-      "short_name_offset": 5,
-      "short_name_size": 3,
-      "kind": 12,
-      "storage": 1,
-      "hover": "",
-      "comments": "",
-      "declarations": [],
-      "spell": "1:6-1:9|-1|1|2",
-      "extent": "1:1-4:2|-1|1|0",
-      "base": [],
-      "derived": [],
-      "locals": [],
-      "uses": [],
-      "callees": []
-    }
-  ],
-  "vars": [
-    {
-      "id": 0,
-      "usr": 16837348799350457167,
-      "detailed_name": "int a",
-      "short_name_offset": 4,
-      "short_name_size": 1,
-      "hover": "",
-      "comments": "",
-      "declarations": [],
-      "spell": "2:7-2:8|0|3|2",
-      "extent": "2:3-2:8|0|3|2",
-      "type": 0,
-      "uses": [
-        "3:3-3:4|0|3|4"
-      ],
-      "kind": 13,
-      "storage": 1
-    }
-  ]
-}
-    )RAW");
-
-    auto current = load_index_from_json(R"RAW(
-{
-  "types": [],
-  "funcs": [
-    {
-      "id": 0,
-      "usr": 4259594751088586730,
-      "detailed_name": "void foo()",
-      "short_name_offset": 5,
-      "short_name_size": 3,
-      "kind": 12,
-      "storage": 1,
-      "hover": "",
-      "comments": "",
-      "declarations": [],
-      "spell": "1:6-1:9|-1|1|2",
-      "extent": "1:1-5:2|-1|1|0",
-      "base": [],
-      "derived": [],
-      "locals": [],
-      "uses": [],
-      "callees": []
-    }
-  ],
-  "vars": []
-}
-    )RAW");
-
-    // Validate previous/current were parsed.
-    REQUIRE(previous->vars.size() == 1);
-    REQUIRE(current->vars.size() == 0);
-
-    QueryDatabase db;
-
-    // Apply initial file.
-    {
-      IdMap previous_map(&db, previous->id_cache);
-      IndexUpdate import_update = IndexUpdate::CreateDelta(
-          nullptr, &previous_map, nullptr, previous.get());
-      db.ApplyIndexUpdate(&import_update);
-    }
-
-    REQUIRE(db.vars.size() == 1);
-    REQUIRE(db.vars[0].uses.size() == 1);
-
-    // Apply change.
-    {
-      IdMap previous_map(&db, previous->id_cache);
-      IdMap current_map(&db, current->id_cache);
-      IndexUpdate delta_update = IndexUpdate::CreateDelta(
-          &previous_map, &current_map, previous.get(), current.get());
-      db.ApplyIndexUpdate(&delta_update);
-    }
-    REQUIRE(db.vars.size() == 1);
-    REQUIRE(db.vars[0].uses.size() == 0);
-  }
-}
diff --git a/src/query_utils.cc b/src/query_utils.cc
index bf61ba64..95d33b5a 100644
--- a/src/query_utils.cc
+++ b/src/query_utils.cc
@@ -47,8 +47,8 @@ Maybe<Use> GetDefinitionSpell(QueryDatabase* db, SymbolIdx sym) {
 Maybe<Use> GetDefinitionExtent(QueryDatabase* db, SymbolIdx sym) {
   // Used to jump to file.
   if (sym.kind == SymbolKind::File)
-    return Use(Range(Position(0, 0), Position(0, 0)), sym.id, sym.kind,
-               Role::None, QueryFileId(sym.id));
+    return Use(Range{{0, 0}, {0, 0}}, sym.id, sym.kind, Role::None,
+               QueryFileId(sym.id));
   Maybe<Use> ret;
   EachEntityDef(db, sym, [&](const auto& def) { return !(ret = def.extent); });
   return ret;
@@ -126,7 +126,7 @@ std::vector<Use> GetUsesForAllBases(QueryDatabase* db, QueryFunc& root) {
         if (!seen.count(func1.usr)) {
           seen.insert(func1.usr);
           stack.push_back(&func1);
-          AddRange(&ret, func1.uses);
+          ret.insert(ret.end(), func1.uses.begin(), func1.uses.end());
         }
       });
     }
@@ -147,7 +147,7 @@ std::vector<Use> GetUsesForAllDerived(QueryDatabase* db, QueryFunc& root) {
       if (!seen.count(func1.usr)) {
         seen.insert(func1.usr);
         stack.push_back(&func1);
-        AddRange(&ret, func1.uses);
+        ret.insert(ret.end(), func1.uses.begin(), func1.uses.end());
       }
     });
   }
diff --git a/src/serializer.h b/src/serializer.h
index 5807a595..4ea92cc7 100644
--- a/src/serializer.h
+++ b/src/serializer.h
@@ -231,7 +231,7 @@ void ReflectMember(Writer& visitor, const char* name, std::optional<T>& value) {
 // The same as std::optional
 template <typename T>
 void ReflectMember(Writer& visitor, const char* name, Maybe<T>& value) {
-  if (value.HasValue() || visitor.Format() != SerializeFormat::Json) {
+  if (value.Valid() || visitor.Format() != SerializeFormat::Json) {
     visitor.Key(name);
     Reflect(visitor, value);
   }
diff --git a/src/test.cc b/src/test.cc
index a8075815..7155b0bd 100644
--- a/src/test.cc
+++ b/src/test.cc
@@ -229,16 +229,17 @@ IndexFile* FindDbForPathEnding(
 
 bool RunIndexTests(const std::string& filter_path, bool enable_update) {
   gTestOutputMode = true;
+  std::string version = ToString(clang_getClangVersion());
 
   // Index tests change based on the version of clang used.
   static const char kRequiredClangVersion[] =
       "clang version 6.0.0 (tags/RELEASE_600/final)";
-  if (GetClangVersion() != kRequiredClangVersion &&
-      GetClangVersion().find("trunk") == std::string::npos) {
+  if (version != kRequiredClangVersion &&
+      version.find("trunk") == std::string::npos) {
     fprintf(stderr,
             "Index tests must be run using clang version %s, ccls is running "
             "with %s\n",
-            kRequiredClangVersion, GetClangVersion().c_str());
+            kRequiredClangVersion, version.c_str());
     return false;
   }
 
diff --git a/src/utils.h b/src/utils.h
index 82755e71..6b117d05 100644
--- a/src/utils.h
+++ b/src/utils.h
@@ -65,17 +65,6 @@ std::optional<std::string> ReadContent(const std::string& filename);
 
 void WriteToFile(const std::string& filename, const std::string& content);
 
-template <typename T>
-void AddRange(std::vector<T>* dest, const std::vector<T>& to_add) {
-  dest->insert(dest->end(), to_add.begin(), to_add.end());
-}
-
-template <typename T>
-void AddRange(std::vector<T>* dest, std::vector<T>&& to_add) {
-  dest->insert(dest->end(), std::make_move_iterator(to_add.begin()),
-               std::make_move_iterator(to_add.end()));
-}
-
 // http://stackoverflow.com/a/38140932
 //
 //  struct SomeHashKey {