fix: raise SyntaxError for final class constants before PHP 8.1 (#1234)

Author: jorgsowa

src/parser/class.js

@@ -344,6 +344,10 @@ module.exports = {
     if (flags[1] === 1 || flags[2] === 1 || flags[3] === 1) {
       this.error();
     }
+    // final class constants require PHP 8.1+
+    if (flags[2] === 2 && this.version < 801) {
+      this.raiseError("Final class constants are not allowed before PHP 8.1");
+    }
 
     const [nullable, type] =
       this.version >= 803 ? this.read_optional_type() : [false, null];

test/snapshot/classconstant.test.js

@@ -59,6 +59,13 @@ describe("classconstant", () => {
       ),
     ).toMatchSnapshot();
   });
+  it("final should throw before PHP 8.1", () => {
+    expect(() =>
+      parser.parseEval("class Foo { final const CONSTANT = 1; }", {
+        parser: { version: 800 },
+      }),
+    ).toThrow(SyntaxError);
+  });
   it("type hinted (supported)", () => {
     expect(
       parser.parseEval(