fix: trait alias with no visibility and no alias now raises an error (#1230)

Author: jorgsowa

src/parser/class.js

@@ -725,7 +725,7 @@ module.exports = {
         const name = this.text();
         this.next();
         alias = alias(name);
-      } else if (flags === false) {
+      } else if (flags === null) {
         // no visibility flags and no name => too bad
         this.expect(this.tok.T_STRING);
       }

test/snapshot/__snapshots__/trait.test.js.snap

@@ -1,5 +1,57 @@
 // Jest Snapshot v1, https://jestjs.io/docs/snapshot-testing
 
+exports[`trait trait alias with no visibility and no alias raises an error 1`] = `
+Program {
+  "children": [
+    Class {
+      "attrGroups": [],
+      "body": [
+        TraitUse {
+          "adaptations": [
+            TraitAlias {
+              "as": null,
+              "kind": "traitalias",
+              "method": "foo",
+              "trait": null,
+              "visibility": "",
+            },
+          ],
+          "kind": "traituse",
+          "traits": [
+            Name {
+              "kind": "name",
+              "name": "Foo",
+              "resolution": "uqn",
+            },
+          ],
+        },
+      ],
+      "extends": null,
+      "implements": null,
+      "isAbstract": false,
+      "isAnonymous": false,
+      "isFinal": false,
+      "isReadonly": false,
+      "kind": "class",
+      "name": Identifier {
+        "kind": "identifier",
+        "name": "A",
+      },
+    },
+  ],
+  "errors": [
+    Error {
+      "expected": 105,
+      "kind": "error",
+      "line": 1,
+      "message": "Parse Error : syntax error, unexpected ';', expecting T_STRING on line 1",
+      "token": "';'",
+    },
+  ],
+  "kind": "program",
+}
+`;
+
 exports[`trait trait name as identifier 1`] = `
 Program {
   "children": [

test/snapshot/trait.test.js

@@ -4,4 +4,9 @@ describe("trait", function () {
   it("trait name as identifier", function () {
     expect(parser.parseEval("trait A {}")).toMatchSnapshot();
   });
+
+  it("trait alias with no visibility and no alias raises an error", function () {
+    const test = parser.create({ parser: { suppressErrors: true } });
+    expect(test.parseEval("class A { use Foo { foo as; } }")).toMatchSnapshot();
+  });
 });