Fix ?-> with succeeding PHP keyword (#1124)

* Use same path in `?->` for eating properties as `->`

* Add test for `?->` with reserved keyword

Author: sxxov

src/lexer/tokens.js

@@ -238,7 +238,8 @@ module.exports = {
         this._input[this.offset] === "-" &&
         this._input[this.offset + 1] === ">"
       ) {
-        this.consume(2);
+        this.consume(1);
+        this.begin("ST_LOOKING_FOR_PROPERTY").input();
         return this.tok.T_NULLSAFE_OBJECT_OPERATOR;
       }
       return "?";

test/snapshot/__snapshots__/lexer.test.js.snap

@@ -125,6 +125,30 @@ exports[`Test lexer test #148 - sensitive lexer 1`] = `
 ]
 `;
 
+exports[`Test lexer test #1003 - null-safe operator with reserved keyword 1`] = `
+Program {
+  "children": [
+    ExpressionStatement {
+      "expression": NullSafePropertyLookup {
+        "kind": "nullsafepropertylookup",
+        "offset": Identifier {
+          "kind": "identifier",
+          "name": "class",
+        },
+        "what": Variable {
+          "curly": false,
+          "kind": "variable",
+          "name": "a",
+        },
+      },
+      "kind": "expressionstatement",
+    },
+  ],
+  "errors": [],
+  "kind": "program",
+}
+`;
+
 exports[`Test lexer test comments 1`] = `
 Program {
   "children": [

test/snapshot/lexer.test.js

@@ -81,4 +81,8 @@ describe("Test lexer", function () {
   it("test #148 - sensitive lexer", function () {
     expect(parser.tokenGetAll("<?php $this-> list;")).toMatchSnapshot();
   });
+
+  it("test #1003 - null-safe operator with reserved keyword", function () {
+    expect(parser.parseCode("<?php $a?->class;")).toMatchSnapshot();
+  });
 });