add lineBreak test to tt.name.updateContext - fixes #2591

src/tokenizer/context.js

@@ -5,6 +5,7 @@
 // See https://github.com/mozilla/sweet.js/wiki/design
 
 import { types as tt } from "./types";
+import { lineBreak } from "../util/whitespace";
 
 export class TokContext {
   constructor(
@@ -54,6 +55,14 @@ tt.parenR.updateContext = tt.braceR.updateContext = function () {
   }
 };
 
+tt.name.updateContext = function (prevType) {
+  if (prevType === tt._let || prevType === tt._const || prevType === tt._var) {
+    if (lineBreak.test(this.input.slice(this.state.end))) {
+      this.state.exprAllowed = true;
+    }
+  }
+};
+
 tt.braceL.updateContext = function (prevType) {
   this.state.context.push(this.braceIsBlock(prevType) ? types.b_stat : types.b_expr);
   this.state.exprAllowed = true;