Loose: yield support.

acorn_loose.js

@@ -271,7 +271,7 @@
     return (token.type === tt.eof || token.type === tt.braceR || newline.test(input.slice(lastEnd, token.start)));
   }
   function semicolon() {
-    eat(tt.semi);
+    return eat(tt.semi);
   }
 
   function expect(type) {
@@ -734,6 +734,18 @@
     case tt._new:
       return parseNew();
 
+    case tt._yield:
+      var node = startNode();
+      next();
+      if (semicolon() || canInsertSemicolon()) {
+        node.delegate = false;
+        node.argument = null;
+      } else {
+        node.delegate = eat(tt.star);
+        node.argument = parseExpression(true);
+      }
+      return finishNode(node, "YieldExpression");
+
     default:
       return dummyIdent();
     }

test/run.js

@@ -13,8 +13,9 @@ var stats, modes = {
       parse: (typeof require === "undefined") ? window.acorn_loose : require("../acorn_loose").parse_dammit,
       loose: true,
       filter: function (test) {
-        var ecmaVersion = (test.options || {}).ecmaVersion || 5;
-        return ecmaVersion <= 6;
+        var opts = test.options || {};
+        if (opts.loose === false) return false;
+        return (opts.ecmaVersion || 5) <= 6;
       }
     }
   }

test/tests-harmony.js

@@ -13714,6 +13714,7 @@ test("yield* 10", {
   }
 }, {
   ecmaVersion: 6,
+  loose: false,
   ranges: true,
   locations: true
 });
@@ -13778,6 +13779,7 @@ test("e => yield* 10", {
   }
 }, {
   ecmaVersion: 6,
+  loose: false,
   ranges: true,
   locations: true
 });
@@ -13851,6 +13853,7 @@ test("(function () { yield* 10 })", {
   }
 }, {
   ecmaVersion: 6,
+  loose: false,
   ranges: true,
   locations: true
 });