diff --git a/src/quick-lint-js/diag/diag-list.cpp b/src/quick-lint-js/diag/diag-list.cpp
index a8613c0ab..132cc8207 100644
--- a/src/quick-lint-js/diag/diag-list.cpp
+++ b/src/quick-lint-js/diag/diag-list.cpp
@@ -23,6 +23,11 @@ static_assert(alignof(Diag_List::Node) == alignof(Diag_List::Node_Base),
 
 Diag_List::Diag_List(Memory_Resource *memory) : memory_(memory) {}
 
+Diag_List::Diag_List(Diag_List &&other)
+    : memory_(other.memory_), first_(other.first_), last_(other.last_) {
+  other.clear();
+}
+
 Diag_List::~Diag_List() { this->clear(); }
 
 void Diag_List::add_many(const Diag_List &other) {
diff --git a/src/quick-lint-js/diag/diag-list.h b/src/quick-lint-js/diag/diag-list.h
index afd2eca5e..f00e385cc 100644
--- a/src/quick-lint-js/diag/diag-list.h
+++ b/src/quick-lint-js/diag/diag-list.h
@@ -36,8 +36,11 @@ class Diag_List {
 
   explicit Diag_List(Memory_Resource *);
 
-  Diag_List(Diag_List &&) = delete;
-  Diag_List &operator=(Diag_List &&) = delete;
+  Diag_List(const Diag_List &) = delete;
+  Diag_List &operator=(const Diag_List &) = delete;
+
+  Diag_List(Diag_List &&);
+  Diag_List &operator=(Diag_List &&) = delete;  // TODO(strager)
 
   ~Diag_List();
 
diff --git a/test/test-diag-list.cpp b/test/test-diag-list.cpp
index 96db2d4c6..c57ae366c 100644
--- a/test/test-diag-list.cpp
+++ b/test/test-diag-list.cpp
@@ -7,6 +7,7 @@
 #include <quick-lint-js/diag-matcher.h>
 #include <quick-lint-js/diag/diag-list.h>
 #include <quick-lint-js/diag/diagnostic-types.h>
+#include <quick-lint-js/diagnostic-assertion.h>
 #include <quick-lint-js/fe/lex.h>
 #include <quick-lint-js/identifier-support.h>
 #include <type_traits>
@@ -189,6 +190,41 @@ TEST(Test_Diag_List, pretty_print_one_diag) {
     EXPECT_EQ(ss.str(), "1 diagnostic: {\n  Diag_Let_With_No_Bindings,\n}");
   }
 }
+
+TEST(Test_Diag_List, moving_diag_list_clears_original) {
+  Linked_Bump_Allocator memory("test");
+  Diag_List diags_1(&memory);
+  Padded_String code(u8"hello"_sv);
+  diags_1.add(Diag_Let_With_No_Bindings{.where = span_of(code)});
+  Diag_List diags_2 = std::move(diags_1);
+  EXPECT_EQ(diags_1.size(), 0);
+}
+
+TEST(Test_Diag_List, moving_diag_list_keeps_single_diag) {
+  Linked_Bump_Allocator memory("test");
+  Diag_List diags_1(&memory);
+  Padded_String code(u8"hello"_sv);
+  diags_1.add(Diag_Let_With_No_Bindings{.where = span_of(code)});
+
+  Diag_List diags_2 = std::move(diags_1);
+  EXPECT_EQ(diags_2.size(), 1);
+}
+
+TEST(Test_Diag_List, moving_diag_list_keeps_multiple_diags) {
+  Linked_Bump_Allocator memory("test");
+  Diag_List diags_1(&memory);
+  Padded_String code(u8"hello"_sv);
+  diags_1.add(Diag_Let_With_No_Bindings{.where = span_of(code)});
+  diags_1.add(Diag_Expected_Parenthesis_Around_If_Condition{
+      .where = span_of(code),
+      .token = u8')',
+  });
+
+  Diag_List diags_2 = std::move(diags_1);
+  assert_diagnostics(&code, diags_2,
+                     {u8"Diag_Let_With_No_Bindings"_diag,
+                      u8"Diag_Expected_Parenthesis_Around_If_Condition"_diag});
+}
 }
 }