fix(64627): reject deferred imports without namespace bindings

Author: a-tarasyuk

tsc/internal/checker/grammarchecks.go

@@ -2110,7 +2110,10 @@ func (c *Checker) checkGrammarImportClause(node *ast.ImportClause) bool {
 		if node.Name() != nil {
 			return c.grammarErrorOnNode(&node.Node, diagnostics.Default_imports_are_not_allowed_in_a_deferred_import)
 		}
-		if node.NamedBindings != nil && node.NamedBindings.Kind == ast.KindNamedImports {
+		if node.NamedBindings == nil {
+			return c.grammarErrorOnNode(&node.Node, diagnostics.A_deferred_import_must_specify_a_namespace_binding)
+		}
+		if node.NamedBindings.Kind == ast.KindNamedImports {
 			return c.grammarErrorOnNode(&node.Node, diagnostics.Named_imports_are_not_allowed_in_a_deferred_import)
 		}
 		if c.moduleKind.SupportsDeferredImports() {

tsc/internal/compiler/program.go

@@ -2427,6 +2427,7 @@ var plainJSErrors = collections.NewSetFromItems(
 	diagnostics.A_continue_statement_can_only_jump_to_a_label_of_an_enclosing_iteration_statement.Code(),
 	diagnostics.A_default_clause_cannot_appear_more_than_once_in_a_switch_statement.Code(),
 	diagnostics.A_default_export_must_be_at_the_top_level_of_a_file_or_module_declaration.Code(),
+	diagnostics.A_deferred_import_must_specify_a_namespace_binding.Code(),
 	diagnostics.A_definite_assignment_assertion_is_not_permitted_in_this_context.Code(),
 	diagnostics.A_destructuring_declaration_must_have_an_initializer.Code(),
 	diagnostics.A_get_accessor_cannot_have_parameters.Code(),

tsc/internal/diagnostics/diagnosticMessages.generated.json

@@ -1949,6 +1949,7 @@
     "Source_phase_imports_are_only_supported_when_the_module_option_is_set_to_esnext_nodenext_or_preserve_18113": "Source phase imports are only supported when the '--module' option is set to 'esnext', 'nodenext', or 'preserve'.",
     "Optional_chaining_cannot_be_used_with_import_source_18114": "Optional chaining cannot be used with 'import.source'.",
     "Source_phase_imports_are_not_allowed_on_statements_that_compile_to_CommonJS_require_calls_18115": "Source phase imports are not allowed on statements that compile to CommonJS 'require' calls.",
+    "A_deferred_import_must_specify_a_namespace_binding_18116": "A deferred import must specify a namespace binding.",
     "nodenext_if_module_is_nodenext_node16_if_module_is_node16_or_node18_otherwise_bundler_69010": "`nodenext` if `module` is `nodenext`; `node16` if `module` is `node16` or `node18`; otherwise, `bundler`.",
     "File_is_a_CommonJS_module_it_may_be_converted_to_an_ES_module_80001": "File is a CommonJS module; it may be converted to an ES module.",
     "This_constructor_function_may_be_converted_to_a_class_declaration_80002": "This constructor function may be converted to a class declaration.",

tsc/internal/diagnostics/diagnosticMessages.json

@@ -8915,5 +8915,9 @@
     "Source phase imports are not allowed on statements that compile to CommonJS 'require' calls.": {
         "category": "Error",
         "code": 18115
+    },
+    "A deferred import must specify a namespace binding.": {
+        "category": "Error",
+        "code": 18116
     }
 }

tsc/internal/diagnostics/diagnostics_generated.go

@@ -2409,7 +2409,7 @@ func (p *Parser) tryParseImportClause(identifier *ast.Node, pos int, phaseModifi
 		p.parseExpected(ast.KindFromKeyword)
 		return importClause
 	}
-	if phaseModifier == ast.KindSourceKeyword {
+	if phaseModifier == ast.KindDeferKeyword || phaseModifier == ast.KindSourceKeyword {
 		return p.finishNode(p.factory.NewImportClause(phaseModifier, nil /*name*/, nil /*namedBindings*/), pos)
 	}
 	return nil

tsc/internal/parser/parser.go

@@ -385,6 +385,5 @@ func getImportNeedsImportStarHelper(node *ast.ImportDeclaration) bool {
 func getImportNeedsImportDefaultHelper(node *ast.ImportDeclaration) bool {
 	// Import default is needed if there's a default import or a default ref and no other refs (meaning an import star helper wasn't requested)
 	return !getImportNeedsImportStarHelper(node) && (ast.IsDefaultImport(node.AsNode()) || (node.ImportClause != nil &&
-		ast.IsNamedImports(node.ImportClause.AsImportClause().NamedBindings) &&
 		containsDefaultReference(node.ImportClause.AsImportClause().NamedBindings)))
 }

tsc/internal/transformers/moduletransforms/externalmoduleinfo.go

@@ -0,0 +1,47 @@
+b.ts(1,8): error TS18058: Default imports are not allowed in a deferred import.
+b.ts(5,8): error TS18116: A deferred import must specify a namespace binding.
+b.ts(6,8): error TS18116: A deferred import must specify a namespace binding.
+b.ts(6,23): error TS2823: Import attributes are only supported when the '--module' option is set to 'esnext', 'node18', 'node20', 'nodenext', or 'preserve'.
+c.js(2,8): error TS18116: A deferred import must specify a namespace binding.
+c.js(3,8): error TS18116: A deferred import must specify a namespace binding.
+c.js(3,23): error TS2823: Import attributes are only supported when the '--module' option is set to 'esnext', 'node18', 'node20', 'nodenext', or 'preserve'.
+d.js(1,8): error TS18116: A deferred import must specify a namespace binding.
+
+
+==== a.ts (0 errors) ====
+    export default function foo() {
+        console.log("foo from a");
+    }
+    
+==== b.ts (4 errors) ====
+    import defer foo from "./a";
+           ~~~~~~~~~
+!!! error TS18058: Default imports are not allowed in a deferred import.
+    
+    foo();
+    
+    import defer "./a.js";
+           ~~~~~
+!!! error TS18116: A deferred import must specify a namespace binding.
+    import defer "./a.js" with { type: "json" };
+           ~~~~~
+!!! error TS18116: A deferred import must specify a namespace binding.
+                          ~~~~~~~~~~~~~~~~~~~~~
+!!! error TS2823: Import attributes are only supported when the '--module' option is set to 'esnext', 'node18', 'node20', 'nodenext', or 'preserve'.
+    
+==== c.js (3 errors) ====
+    // @ts-check
+    import defer "./a.js";
+           ~~~~~
+!!! error TS18116: A deferred import must specify a namespace binding.
+    import defer "./a.js" with { type: "json" };
+           ~~~~~
+!!! error TS18116: A deferred import must specify a namespace binding.
+                          ~~~~~~~~~~~~~~~~~~~~~
+!!! error TS2823: Import attributes are only supported when the '--module' option is set to 'esnext', 'node18', 'node20', 'nodenext', or 'preserve'.
+    
+==== d.js (1 errors) ====
+    import defer "./a.js";
+           ~~~~~
+!!! error TS18116: A deferred import must specify a namespace binding.
+    

tsc/testdata/baselines/reference/conformance/importDeferInvalidDefault(module=commonjs).errors.txt

@@ -0,0 +1,49 @@
+//// [tests/cases/conformance/importDefer/importDeferInvalidDefault.ts] ////
+
+//// [a.ts]
+export default function foo() {
+    console.log("foo from a");
+}
+
+//// [b.ts]
+import defer foo from "./a";
+
+foo();
+
+import defer "./a.js";
+import defer "./a.js" with { type: "json" };
+
+//// [c.js]
+// @ts-check
+import defer "./a.js";
+import defer "./a.js" with { type: "json" };
+
+//// [d.js]
+import defer "./a.js";
+
+
+//// [a.js]
+"use strict";
+Object.defineProperty(exports, "__esModule", { value: true });
+exports.default = foo;
+function foo() {
+    console.log("foo from a");
+}
+//// [b.js]
+"use strict";
+var __importDefault = (this && this.__importDefault) || function (mod) {
+    return (mod && mod.__esModule) ? mod : { "default": mod };
+};
+Object.defineProperty(exports, "__esModule", { value: true });
+const a_1 = __importDefault(require("./a"));
+(0, a_1.default)();
+//// [c.js]
+"use strict";
+Object.defineProperty(exports, "__esModule", { value: true });
+// @ts-check
+const a_js_1 = require("./a.js");
+const a_js_2 = require("./a.js");
+//// [d.js]
+"use strict";
+Object.defineProperty(exports, "__esModule", { value: true });
+const a_js_1 = require("./a.js");

tsc/testdata/baselines/reference/conformance/importDeferInvalidDefault(module=commonjs).js

@@ -17,3 +17,16 @@ import defer foo from "./a";
 foo();
 >foo : Symbol(foo, Decl(b.ts, 0, 6))
 
+import defer "./a.js";
+import defer "./a.js" with { type: "json" };
+
+=== c.js ===
+
+// @ts-check
+import defer "./a.js";
+import defer "./a.js" with { type: "json" };
+
+=== d.js ===
+
+import defer "./a.js";
+