feat(typescript): allow 'export default I; interface I {}'

Allow 'export default' to find TypeScript types (such as interfaces), not just run-time variables.
quick-lint · Nov 21, 2023 · d85ec29 · d85ec29
1 parent 1c03c4f
commit d85ec29
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Showing 3 changed files with 49 additions and 10 deletions.
diff --git a/docs/CHANGELOG.md b/docs/CHANGELOG.md
@@ -21,6 +21,8 @@ Semantic Versioning.
     an arrow function parameter list.
   * If a type predicate appears outside a return type, quick-lint-js now reports
     [E0426][] ("type predicates are only allowed as function return types").
+  * `export default` now supports separately-declared TypeScript interfaces and
+    types.
 
 ### Fixed
 

diff --git a/src/quick-lint-js/fe/variable-analyzer.cpp b/src/quick-lint-js/fe/variable-analyzer.cpp
@@ -467,12 +467,22 @@ void Variable_Analyzer::visit_variable_use(Identifier name,
                                            Used_Variable_Kind use_kind) {
   QLJS_ASSERT(!this->scopes_.empty());
   Scope &current_scope = this->current_scope();
-  Declared_Variable *var =
-      use_kind == Used_Variable_Kind::type
-          ? current_scope.declared_variables.find_type(name)
-          : use_kind == Used_Variable_Kind::_export
-                ? current_scope.declared_variables.find(name)
-                : current_scope.declared_variables.find_runtime(name);
+  Declared_Variable *var;
+  switch (use_kind) {
+  case Used_Variable_Kind::type:
+    var = current_scope.declared_variables.find_type(name);
+    break;
+  case Used_Variable_Kind::_export:
+  case Used_Variable_Kind::_export_default:
+    var = current_scope.declared_variables.find(name);
+    break;
+  case Used_Variable_Kind::_delete:
+  case Used_Variable_Kind::_typeof:
+  case Used_Variable_Kind::assignment:
+  case Used_Variable_Kind::use:
+    var = current_scope.declared_variables.find_runtime(name);
+    break;
+  }
   if (var) {
     var->is_used = true;
   } else {
@@ -534,12 +544,15 @@ void Variable_Analyzer::visit_end_of_module() {
     switch (var.kind) {
     case Used_Variable_Kind::_delete:
     case Used_Variable_Kind::_export:
-    case Used_Variable_Kind::_export_default:
     case Used_Variable_Kind::_typeof:
     case Used_Variable_Kind::assignment:
     case Used_Variable_Kind::use:
       QLJS_ASSERT(!global_scope.declared_variables.find_runtime(var.name));
       break;
+    case Used_Variable_Kind::_export_default:
+      QLJS_ASSERT(!global_scope.declared_variables.find_runtime(var.name));
+      QLJS_ASSERT(!global_scope.declared_variables.find_type(var.name));
+      break;
     case Used_Variable_Kind::type:
       QLJS_ASSERT(!global_scope.declared_variables.find_type(var.name));
       break;
@@ -644,11 +657,11 @@ void Variable_Analyzer::propagate_variable_uses_to_parent_scope(
       Found_Variable_Type var = {};
       switch (used_var.kind) {
       case Used_Variable_Kind::_export:
+      case Used_Variable_Kind::_export_default:
         QLJS_ASSERT(!current_scope.declared_variables.find(used_var.name));
         var = parent_scope.declared_variables.find(used_var.name);
         break;
       case Used_Variable_Kind::_delete:
-      case Used_Variable_Kind::_export_default:
       case Used_Variable_Kind::_typeof:
       case Used_Variable_Kind::assignment:
       case Used_Variable_Kind::use:
@@ -688,10 +701,10 @@ void Variable_Analyzer::propagate_variable_uses_to_parent_scope(
       Found_Variable_Type var = {};
       switch (used_var.kind) {
       case Used_Variable_Kind::_export:
+      case Used_Variable_Kind::_export_default:
         var = parent_scope.declared_variables.find(used_var.name);
         break;
       case Used_Variable_Kind::_delete:
-      case Used_Variable_Kind::_export_default:
       case Used_Variable_Kind::_typeof:
       case Used_Variable_Kind::assignment:
       case Used_Variable_Kind::use:
@@ -1174,10 +1187,10 @@ bool Variable_Analyzer::Used_Variable::is_runtime() const {
 bool Variable_Analyzer::Used_Variable::is_type() const {
   switch (this->kind) {
   case Used_Variable_Kind::_export:
+  case Used_Variable_Kind::_export_default:
   case Used_Variable_Kind::type:
     return true;
   case Used_Variable_Kind::_delete:
-  case Used_Variable_Kind::_export_default:
   case Used_Variable_Kind::_typeof:
   case Used_Variable_Kind::assignment:
   case Used_Variable_Kind::use:

diff --git a/test/test-variable-analyzer-module.cpp b/test/test-variable-analyzer-module.cpp
@@ -155,6 +155,30 @@ TEST(
       u8"declare module 'm' { export default C; class C {} }"_sv, no_diags,
       typescript_analyze_options, default_globals);
 }
+
+TEST(Test_Variable_Analyzer_Module,
+     variable_export_can_export_typescript_types) {
+  test_parse_and_analyze(u8"interface I {}; export {I};"_sv, no_diags,
+                         typescript_analyze_options, default_globals);
+  test_parse_and_analyze(u8"export {T}; type T = null;"_sv, no_diags,
+                         typescript_analyze_options, default_globals);
+}
+
+TEST(Test_Variable_Analyzer_Module,
+     export_default_can_export_typescript_types_after_declaration) {
+  test_parse_and_analyze(u8"interface I {}; export default I;"_sv, no_diags,
+                         typescript_analyze_options, default_globals);
+  test_parse_and_analyze(u8"type T = null; export default T;"_sv, no_diags,
+                         typescript_analyze_options, default_globals);
+}
+
+TEST(Test_Variable_Analyzer_Module,
+     export_default_can_export_typescript_types_before_declaration) {
+  test_parse_and_analyze(u8"export default I; interface I {}"_sv, no_diags,
+                         typescript_analyze_options, default_globals);
+  test_parse_and_analyze(u8"export default T; type T = null;"_sv, no_diags,
+                         typescript_analyze_options, default_globals);
+}
 }
 }