[jsx mode] Support trailing-comma generics syntax in JSX with TS

Issue #7073

Author: lukehaas

mode/jsx/jsx.js

@@ -103,7 +103,7 @@
     }
 
     function jsToken(stream, state, cx) {
-      if (stream.peek() == "<" && jsMode.expressionAllowed(stream, cx.state)) {
+      if (stream.peek() == "<" && !/,\s*>/.test(stream.string) && jsMode.expressionAllowed(stream, cx.state)) {
         state.context = new Context(CodeMirror.startState(xmlMode, jsMode.indent(cx.state, "", "")),
                                     xmlMode, 0, state.context)
         jsMode.skipExpression(cx.state)

mode/jsx/test.js

@@ -95,4 +95,6 @@
      "[bracket&tag <][tag MyComponent] [attribute foo]=[string \"bar\"] [bracket&tag />]; [comment //ok]",
      "[bracket&tag <][tag MyComponent] [attribute foo]={[number 0]} [bracket&tag />]; [comment //error]")
 
+   TS("tsx_react_generics",
+      "[variable x] [operator =] [operator <] [variable T],[operator >] ([def v]: [type T]) [operator =>] [variable-2 v];")
 })()