diff --git a/src/CMakeLists.txt b/src/CMakeLists.txt
index bc56e03a6..846d26e45 100644
--- a/src/CMakeLists.txt
+++ b/src/CMakeLists.txt
@@ -313,8 +313,6 @@ quick_lint_js_add_library(
   quick-lint-js/debug/mongoose.h
   quick-lint-js/diag/diag-code-list.cpp
   quick-lint-js/diag/diag-code-list.h
-  quick-lint-js/diag/diag-list-diag-reporter.cpp
-  quick-lint-js/diag/diag-list-diag-reporter.h
   quick-lint-js/diag/diag-list.cpp
   quick-lint-js/diag/diag-list.h
   quick-lint-js/diag/diag-reporter.cpp
diff --git a/src/quick-lint-js/diag/diag-list-diag-reporter.cpp b/src/quick-lint-js/diag/diag-list-diag-reporter.cpp
deleted file mode 100644
index 7c826a246..000000000
--- a/src/quick-lint-js/diag/diag-list-diag-reporter.cpp
+++ /dev/null
@@ -1,45 +0,0 @@
-// Copyright (C) 2020  Matthew "strager" Glazar
-// See end of file for extended copyright information.
-
-#include <quick-lint-js/diag/diag-list-diag-reporter.h>
-#include <quick-lint-js/diag/diag-list.h>
-#include <quick-lint-js/diag/diagnostic-types.h>
-
-namespace quick_lint_js {
-Diag_List_Diag_Reporter::Diag_List_Diag_Reporter(Memory_Resource* memory)
-    : diags_(memory) {}
-
-Diag_List_Diag_Reporter::~Diag_List_Diag_Reporter() = default;
-
-Diag_List& Diag_List_Diag_Reporter::diags() { return this->diags_; }
-
-const Diag_List& Diag_List_Diag_Reporter::diags() const { return this->diags_; }
-
-void Diag_List_Diag_Reporter::report_impl(Diag_Type type, void* diag) {
-  static constexpr unsigned char diag_sizes[] = {
-#define QLJS_DIAG_TYPE_NAME(name) sizeof(::quick_lint_js::name),
-      QLJS_X_DIAG_TYPE_NAMES
-#undef QLJS_DIAG_TYPE_NAME
-  };
-  this->diags_.add_impl(type, diag,
-                        diag_sizes[static_cast<std::ptrdiff_t>(type)]);
-}
-}
-
-// quick-lint-js finds bugs in JavaScript programs.
-// Copyright (C) 2020  Matthew "strager" Glazar
-//
-// This file is part of quick-lint-js.
-//
-// quick-lint-js is free software: you can redistribute it and/or modify
-// it under the terms of the GNU General Public License as published by
-// the Free Software Foundation, either version 3 of the License, or
-// (at your option) any later version.
-//
-// quick-lint-js is distributed in the hope that it will be useful,
-// but WITHOUT ANY WARRANTY; without even the implied warranty of
-// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-// GNU General Public License for more details.
-//
-// You should have received a copy of the GNU General Public License
-// along with quick-lint-js.  If not, see <https://www.gnu.org/licenses/>.
diff --git a/src/quick-lint-js/diag/diag-list-diag-reporter.h b/src/quick-lint-js/diag/diag-list-diag-reporter.h
deleted file mode 100644
index daae32169..000000000
--- a/src/quick-lint-js/diag/diag-list-diag-reporter.h
+++ /dev/null
@@ -1,45 +0,0 @@
-// Copyright (C) 2020  Matthew "strager" Glazar
-// See end of file for extended copyright information.
-
-#pragma once
-
-#include <quick-lint-js/diag/diag-list.h>
-#include <quick-lint-js/diag/diag-reporter.h>
-#include <quick-lint-js/diag/diagnostic-types.h>
-
-namespace quick_lint_js {
-// TODO(#1154): Delete this class.
-class Diag_List_Diag_Reporter final : public Diag_Reporter {
- public:
-  explicit Diag_List_Diag_Reporter(Memory_Resource* memory);
-
-  ~Diag_List_Diag_Reporter() override;
-
-  Diag_List& diags();
-  const Diag_List& diags() const;
-
-  void report(const Diag_List&) override;
-  void report_impl(Diag_Type type, void* diag) override;
-
- private:
-  Diag_List diags_;
-};
-}
-
-// quick-lint-js finds bugs in JavaScript programs.
-// Copyright (C) 2020  Matthew "strager" Glazar
-//
-// This file is part of quick-lint-js.
-//
-// quick-lint-js is free software: you can redistribute it and/or modify
-// it under the terms of the GNU General Public License as published by
-// the Free Software Foundation, either version 3 of the License, or
-// (at your option) any later version.
-//
-// quick-lint-js is distributed in the hope that it will be useful,
-// but WITHOUT ANY WARRANTY; without even the implied warranty of
-// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-// GNU General Public License for more details.
-//
-// You should have received a copy of the GNU General Public License
-// along with quick-lint-js.  If not, see <https://www.gnu.org/licenses/>.
diff --git a/src/quick-lint-js/diag/diag-list.h b/src/quick-lint-js/diag/diag-list.h
index 2e1d52535..afd2eca5e 100644
--- a/src/quick-lint-js/diag/diag-list.h
+++ b/src/quick-lint-js/diag/diag-list.h
@@ -8,8 +8,6 @@
 #include <quick-lint-js/port/memory-resource.h>
 
 namespace quick_lint_js {
-class Diag_List_Diag_Reporter;
-
 // Internally, Diag_List is implemented as a singly linked list.
 class Diag_List {
  public:
@@ -86,8 +84,6 @@ class Diag_List {
   Memory_Resource *memory_;
   Node_Base *first_ = nullptr;
   Node_Base *last_ = nullptr;
-
-  friend class Diag_List_Diag_Reporter;
 };
 
 std::ostream &operator<<(std::ostream &, const Diag_List &);
diff --git a/src/quick-lint-js/fe/lex.h b/src/quick-lint-js/fe/lex.h
index 2428a1755..c9ed20374 100644
--- a/src/quick-lint-js/fe/lex.h
+++ b/src/quick-lint-js/fe/lex.h
@@ -10,7 +10,7 @@
 #include <quick-lint-js/container/monotonic-allocator.h>
 #include <quick-lint-js/container/optional.h>
 #include <quick-lint-js/container/padded-string.h>
-#include <quick-lint-js/diag/diag-list-diag-reporter.h>
+#include <quick-lint-js/diag/diag-list.h>
 #include <quick-lint-js/fe/identifier.h>
 #include <quick-lint-js/fe/source-code-span.h>
 #include <quick-lint-js/fe/token.h>