Fix: disallow optional call chaining on import.defer expressions (#63679)

tsc/internal/checker/grammarchecks.go

@@ -2168,7 +2168,7 @@ func (c *Checker) checkGrammarImportCallExpression(node *ast.Node) bool {
 	}
 
 	nodeAsCall := node.AsCallExpression()
-	if nodeAsCall.TypeArguments != nil {
+	if nodeAsCall.TypeArguments != nil || nodeAsCall.QuestionDotToken != nil {
 		return c.grammarErrorOnNode(node, diagnostics.This_use_of_import_is_invalid_import_calls_can_be_written_but_they_must_have_parentheses_and_cannot_have_type_arguments)
 	}
 

tsc/internal/parser/parser.go

@@ -5245,7 +5245,7 @@ func (p *Parser) parseLeftHandSideExpressionOrHigher() *ast.Expression {
 			p.nextToken() // advance past the dot
 			expression = p.finishNode(p.factory.NewMetaProperty(ast.KindImportKeyword, p.parseIdentifierName()), pos)
 			if expression.Text() == "defer" {
-				if p.token == ast.KindOpenParenToken || p.token == ast.KindLessThanToken {
+				if p.token == ast.KindOpenParenToken || p.token == ast.KindLessThanToken || p.token == ast.KindQuestionDotToken {
 					p.sourceFlags |= ast.NodeFlagsPossiblyContainsDynamicImport
 				}
 			} else {

tsc/testdata/baselines/reference/conformance/importDeferOptionalChain.errors.txt

@@ -0,0 +1,11 @@
+importDeferOptionalChain.ts(1,1): error TS1326: This use of 'import' is invalid. 'import()' calls can be written, but they must have parentheses and cannot have type arguments.
+importDeferOptionalChain.ts(1,16): error TS2307: Cannot find module './a' or its corresponding type declarations.
+
+
+==== importDeferOptionalChain.ts (2 errors) ====
+    import.defer?.("./a");
+    ~~~~~~~~~~~~~~~~~~~~~
+!!! error TS1326: This use of 'import' is invalid. 'import()' calls can be written, but they must have parentheses and cannot have type arguments.
+                   ~~~~~
+!!! error TS2307: Cannot find module './a' or its corresponding type declarations.
+

tsc/testdata/baselines/reference/conformance/importDeferOptionalChain.js

@@ -0,0 +1,9 @@
+//// [tests/cases/conformance/importDefer/importDeferOptionalChain.ts] ////
+
+//// [importDeferOptionalChain.ts]
+import.defer?.("./a");
+
+
+//// [importDeferOptionalChain.js]
+"use strict";
+import.defer?.("./a");

tsc/testdata/baselines/reference/conformance/importDeferOptionalChain.symbols

@@ -0,0 +1,6 @@
+//// [tests/cases/conformance/importDefer/importDeferOptionalChain.ts] ////
+
+=== importDeferOptionalChain.ts ===
+
+import.defer?.("./a");
+

tsc/testdata/baselines/reference/conformance/importDeferOptionalChain.types

@@ -0,0 +1,8 @@
+//// [tests/cases/conformance/importDefer/importDeferOptionalChain.ts] ////
+
+=== importDeferOptionalChain.ts ===
+import.defer?.("./a");
+>import.defer?.("./a") : Promise<any>
+>defer : any
+>"./a" : "./a"
+

tsc/testdata/tests/cases/conformance/importDefer/importDeferOptionalChain.ts

@@ -0,0 +1,4 @@
+// @target: esnext
+// @module: esnext
+
+import.defer?.("./a");