allow to use keywords as jsx identifiers

src/compiler/parser.ts

@@ -12,6 +12,10 @@ namespace ts {
     export function createNode(kind: SyntaxKind): Node {
         return new (getNodeConstructor(kind))();
     }
+    
+    export function tokenIsIdentifierOrKeyword(token: SyntaxKind): boolean {
+        return token >= SyntaxKind.Identifier;
+    }
 
     function visitNode<T>(cbNode: (node: Node) => T, node: Node): T {
         if (node) {
@@ -4102,7 +4106,7 @@ namespace ts {
         }
 
         function isIdentifierOrKeyword() {
-            return token >= SyntaxKind.Identifier;
+            return tokenIsIdentifierOrKeyword(token);
         }
 
         function nextTokenIsIdentifierOrKeywordOnSameLine() {

src/compiler/scanner.ts

@@ -1590,7 +1590,7 @@ namespace ts {
         // Scans a JSX identifier; these differ from normal identifiers in that
         // they allow dashes
         function scanJsxIdentifier(): SyntaxKind {
-            if (token === SyntaxKind.Identifier) {
+            if (tokenIsIdentifierOrKeyword(token)) {
                 let firstCharPosition = pos;
                 while (pos < end) {
                     let ch = text.charCodeAt(pos);

tests/baselines/reference/keywordInJsxIdentifier.js

@@ -0,0 +1,7 @@
+//// [keywordInJsxIdentifier.tsx]
+
+declare var React: any;
+<foo class-id/>
+
+//// [keywordInJsxIdentifier.js]
+React.createElement("foo", {"class-id": true});

tests/baselines/reference/keywordInJsxIdentifier.symbols

@@ -0,0 +1,8 @@
+=== tests/cases/compiler/keywordInJsxIdentifier.tsx ===
+
+declare var React: any;
+>React : Symbol(React, Decl(keywordInJsxIdentifier.tsx, 1, 11))
+
+<foo class-id/>
+>class-id : Symbol(unknown)
+

tests/baselines/reference/keywordInJsxIdentifier.types

@@ -0,0 +1,10 @@
+=== tests/cases/compiler/keywordInJsxIdentifier.tsx ===
+
+declare var React: any;
+>React : any
+
+<foo class-id/>
+><foo class-id/> : any
+>foo : any
+>class-id : any
+

tests/cases/compiler/keywordInJsxIdentifier.tsx

@@ -0,0 +1,4 @@
+//@jsx: react
+
+declare var React: any;
+<foo class-id/>