From 79478c8153c0d9568dd0c019e726125c1edac7ca Mon Sep 17 00:00:00 2001
From: "Matthew \"strager\" Glazar" <strager.nds@gmail.com>
Date: Thu, 28 Dec 2023 13:59:09 -0500
Subject: [PATCH] fix(typescript): replace assertion failures with unexpected
 token diagnostics

---
 src/quick-lint-js/fe/parse-statement.cpp |  6 ++++--
 test/test-parse-typescript.cpp           | 15 +++++++++++++++
 2 files changed, 19 insertions(+), 2 deletions(-)

diff --git a/src/quick-lint-js/fe/parse-statement.cpp b/src/quick-lint-js/fe/parse-statement.cpp
index 739eb164d6..1d30bf565b 100644
--- a/src/quick-lint-js/fe/parse-statement.cpp
+++ b/src/quick-lint-js/fe/parse-statement.cpp
@@ -6301,11 +6301,13 @@ void Parser::parse_and_visit_declare_statement(
     this->parse_and_visit_declare_global(v, declare_context);
     break;
 
-  // declare:  // Label.
+  // declare:               // Label.
   // declare();
+  // export declare export  // Invalid?
   case Token_Type::colon:
+  case Token_Type::left_paren:
   default:
-    QLJS_ASSERT(false);
+    QLJS_PARSER_UNIMPLEMENTED();
     break;
   }
 }
diff --git a/test/test-parse-typescript.cpp b/test/test-parse-typescript.cpp
index 2be4c21df9..5bc9b0989e 100644
--- a/test/test-parse-typescript.cpp
+++ b/test/test-parse-typescript.cpp
@@ -77,6 +77,21 @@ TEST_F(Test_Parse_TypeScript, unicode_next_line_is_whitespace) {
                                                  typescript_options);
   EXPECT_THAT(v.variable_uses, ElementsAreArray({u8"x"_sv, u8"y"_sv}));
 }
+
+// These examples used to crash with assertion failures.
+TEST_F(Test_Parse_TypeScript, no_crash) {
+  for (String8_View code : {
+           u8"export declare:"_sv,
+           u8"export declare export"_sv,
+           u8"export declare()"_sv,
+       }) {
+    Spy_Visitor v;
+    Padded_String code_string(code);
+    Parser p(&code_string, &v, typescript_options);
+    // Should not crash:
+    p.parse_and_visit_module_catching_fatal_parse_errors(v);
+  }
+}
 }
 }