From 640f2c7371bf652d8ea31ca0179ac692f4ded586 Mon Sep 17 00:00:00 2001
From: Kanchalai Tanglertsampan <yuisu@microsoft.com>
Date: Fri, 24 Mar 2017 15:30:57 -0700
Subject: [PATCH] Error when dynamic import has type arguments

---
 src/compiler/checker.ts              | 15 ++++++++-------
 src/compiler/diagnosticMessages.json |  4 ++++
 src/compiler/parser.ts               |  7 ++++++-
 3 files changed, 18 insertions(+), 8 deletions(-)

diff --git a/src/compiler/checker.ts b/src/compiler/checker.ts
index fe471ba7002..59fcabb9ffa 100644
--- a/src/compiler/checker.ts
+++ b/src/compiler/checker.ts
@@ -14834,11 +14834,6 @@ namespace ts {
             // Grammar checking; stop grammar-checking if checkGrammarTypeArguments return true
             checkGrammarTypeArguments(node, node.typeArguments) || checkGrammarArguments(node, node.arguments);
 
-            // Dynamic import is not need  to go through regular resolve signature.
-            if (node.expression.kind === SyntaxKind.ImportKeyword) {
-                return checkImportCallExpression(<ImportCall>node);
-            }
-
             const signature = getResolvedSignature(node);
 
             if (node.expression.kind === SyntaxKind.SuperKeyword) {
@@ -14885,7 +14880,7 @@ namespace ts {
 
         function checkImportCallExpression(node: ImportCall): Type {
             // Check grammar of dynamic import
-            if (checkGrammarImportCallExpression(node)) {
+            if (checkGrammarArguments(node, node.arguments) || checkGrammarImportCallExpression(node)) {
                 return createPromiseReturnType(node, anyType);
             }
 
@@ -14893,7 +14888,6 @@ namespace ts {
                 grammarErrorOnNode(node, Diagnostics.Dynamic_import_cannot_be_used_when_targeting_ECMAScript_2015_modules);
             }
 
-            // We already error in parse if arguments list is not length of 1
             const specifier = node.arguments[0];
             const specifierType = checkExpression(specifier);
             if (!isTypeAssignableTo(specifierType, stringType)) {
@@ -16449,6 +16443,9 @@ namespace ts {
                     return checkIndexedAccess(<ElementAccessExpression>node);
                 case SyntaxKind.CallExpression:
                 case SyntaxKind.NewExpression:
+                    if ((<CallExpression>node).expression.kind === SyntaxKind.ImportKeyword) {
+                        return checkImportCallExpression(<ImportCall>node);
+                    }
                     return checkCallExpression(<CallExpression>node);
                 case SyntaxKind.TaggedTemplateExpression:
                     return checkTaggedTemplateExpression(<TaggedTemplateExpression>node);
@@ -23388,6 +23385,10 @@ namespace ts {
                 return grammarErrorOnNode(node, Diagnostics.Dynamic_import_must_have_one_specifier_as_an_argument);
             }
 
+            if (node.typeArguments) {
+                return grammarErrorOnNode(node, Diagnostics.Dynamic_import_cannot_have_type_arguments);
+            }
+
             // see: parseArgumentOrArrayLiteralElement...we use this function which parse arguments of callExpression to parse specifier for dynamic import.
             // parseArgumentOrArrayLiteralElement allows spread element to be in an argument list which is not allowed as specifier in dynamic import.
             if (isSpreadExpression(arguments[0])) {
diff --git a/src/compiler/diagnosticMessages.json b/src/compiler/diagnosticMessages.json
index 880dc7750f1..deb1ae90524 100644
--- a/src/compiler/diagnosticMessages.json
+++ b/src/compiler/diagnosticMessages.json
@@ -879,6 +879,10 @@
         "category": "Error",
         "code": 1322
     },
+    "Dynamic import cannot have type arguments": {
+        "category": "Error",
+        "code": 1323
+    },
 
     "Duplicate identifier '{0}'.": {
         "category": "Error",
diff --git a/src/compiler/parser.ts b/src/compiler/parser.ts
index 1575ec0c0f0..fd9a66151cc 100644
--- a/src/compiler/parser.ts
+++ b/src/compiler/parser.ts
@@ -3688,7 +3688,7 @@ namespace ts {
             // 3)we have a MemberExpression which either completes the LeftHandSideExpression,
             // or starts the beginning of the first four CallExpression productions.
             let expression: MemberExpression;
-            if (token() === SyntaxKind.ImportKeyword && lookAhead(nextTokenIsOpenParen)) {
+            if (token() === SyntaxKind.ImportKeyword && lookAhead(nextTokenIsOpenParenOrLessThan)) {
                 // We don't want to eagerly consume all import keyword as import call expression so we look a head to find "("
                 // For example:
                 //      var foo3 = require("subfolder
@@ -5602,6 +5602,11 @@ namespace ts {
             return nextToken() === SyntaxKind.OpenParenToken;
         }
 
+        function nextTokenIsOpenParenOrLessThan() {
+            const next = nextToken();
+            return next === SyntaxKind.OpenParenToken || next === SyntaxKind.LessThanToken;
+        }
+
         function nextTokenIsSlash() {
             return nextToken() === SyntaxKind.SlashToken;
         }