feat: add support for PHP 8.3 typed class constants (glayzzle#1136)

[Related RFC](https://wiki.php.net/rfc/typed_class_constants).

Closes glayzzle#1133

Author: Kenneth-Sills

src/ast/classconstant.js

@@ -19,14 +19,27 @@ const IS_PRIVATE = "private";
  * @memberOf module:php-parser
  * @extends {ConstantStatement}
  * @property {string} visibility
- * @property {bool} final
+ * @property {boolean} final
+ * @property {boolean} nullable
+ * @property {TypeReference|IntersectionType|UnionType|null} type
  * @property {AttrGroup[]} attrGroups
  */
 const ClassConstant = ConstantStatement.extends(
   KIND,
-  function ClassConstant(kind, constants, flags, attrGroups, docs, location) {
+  function ClassConstant(
+    kind,
+    constants,
+    flags,
+    nullable,
+    type,
+    attrGroups,
+    docs,
+    location
+  ) {
     ConstantStatement.apply(this, [kind || KIND, constants, docs, location]);
     this.parseFlags(flags);
+    this.nullable = nullable;
+    this.type = type;
     this.attrGroups = attrGroups;
   }
 );

src/parser/class.js

@@ -226,13 +226,17 @@ module.exports = {
   /*
    * Reads constant list
    * ```ebnf
-   *  constant_list ::= T_CONST (constant_declaration ',')* constant_declaration
+   *  constant_list ::= T_CONST [type] (constant_declaration ',')* constant_declaration
    * ```
    */
   read_constant_list: function (flags, attrs) {
     if (this.expect(this.tok.T_CONST)) {
       this.next();
     }
+
+    const [nullable, type] =
+      this.version >= 830 ? this.read_optional_type() : [false, null];
+
     const result = this.node("classconstant");
     const items = this.read_list(
       /*
@@ -266,7 +270,7 @@ module.exports = {
       ","
     );
 
-    return result(null, items, flags, attrs || []);
+    return result(null, items, flags, nullable, type, attrs || []);
   },
   /*
    * Read member flags

test/snapshot/__snapshots__/acid.test.js.snap

@@ -826,6 +826,8 @@ Program {
                   "offset": 544,
                 },
               },
+              "nullable": false,
+              "type": null,
               "visibility": "",
             },
             PropertyStatement {

test/snapshot/__snapshots__/attributes.test.js.snap

@@ -335,6 +335,8 @@ Program {
           ],
           "final": false,
           "kind": "classconstant",
+          "nullable": false,
+          "type": null,
           "visibility": "",
         },
       ],
@@ -524,6 +526,8 @@ Program {
           ],
           "final": false,
           "kind": "classconstant",
+          "nullable": false,
+          "type": null,
           "visibility": "",
         },
         Method {

test/snapshot/__snapshots__/class.test.js.snap

@@ -172,6 +172,8 @@ Program {
 ",
             },
           ],
+          "nullable": false,
+          "type": null,
           "visibility": "",
         },
         Method {
@@ -240,6 +242,8 @@ Program {
 ",
             },
           ],
+          "nullable": false,
+          "type": null,
           "visibility": "",
         },
         Method {
@@ -1338,6 +1342,8 @@ Program {
           ],
           "final": false,
           "kind": "classconstant",
+          "nullable": false,
+          "type": null,
           "visibility": "",
         },
         PropertyStatement {
@@ -1448,6 +1454,8 @@ Program {
           ],
           "final": false,
           "kind": "classconstant",
+          "nullable": false,
+          "type": null,
           "visibility": "",
         },
         Method {

test/snapshot/__snapshots__/classconstant.test.js.snap

@@ -26,6 +26,8 @@ Program {
           ],
           "final": true,
           "kind": "classconstant",
+          "nullable": false,
+          "type": null,
           "visibility": "public",
         },
       ],
@@ -87,6 +89,8 @@ Program {
           ],
           "final": false,
           "kind": "classconstant",
+          "nullable": false,
+          "type": null,
           "visibility": "",
         },
       ],
@@ -134,6 +138,8 @@ Program {
           ],
           "final": false,
           "kind": "classconstant",
+          "nullable": false,
+          "type": null,
           "visibility": "private",
         },
       ],
@@ -181,6 +187,8 @@ Program {
           ],
           "final": false,
           "kind": "classconstant",
+          "nullable": false,
+          "type": null,
           "visibility": "protected",
         },
       ],
@@ -228,6 +236,8 @@ Program {
           ],
           "final": false,
           "kind": "classconstant",
+          "nullable": false,
+          "type": null,
           "visibility": "public",
         },
       ],
@@ -275,6 +285,8 @@ Program {
           ],
           "final": false,
           "kind": "classconstant",
+          "nullable": false,
+          "type": null,
           "visibility": "",
         },
       ],
@@ -295,3 +307,58 @@ Program {
   "kind": "program",
 }
 `;
+
+exports[`classconstant type hinted (supported) 1`] = `
+Program {
+  "children": [
+    Class {
+      "attrGroups": [],
+      "body": [
+        ClassConstant {
+          "attrGroups": [],
+          "constants": [
+            Constant {
+              "kind": "constant",
+              "name": Identifier {
+                "kind": "identifier",
+                "name": "CONSTANT",
+              },
+              "value": String {
+                "isDoubleQuote": true,
+                "kind": "string",
+                "raw": ""Hello world!"",
+                "unicode": false,
+                "value": "Hello world!",
+              },
+            },
+          ],
+          "final": false,
+          "kind": "classconstant",
+          "nullable": false,
+          "type": TypeReference {
+            "kind": "typereference",
+            "name": "string",
+            "raw": "string",
+          },
+          "visibility": "public",
+        },
+      ],
+      "extends": null,
+      "implements": null,
+      "isAbstract": false,
+      "isAnonymous": false,
+      "isFinal": false,
+      "isReadonly": false,
+      "kind": "class",
+      "name": Identifier {
+        "kind": "identifier",
+        "name": "Foo",
+      },
+    },
+  ],
+  "errors": [],
+  "kind": "program",
+}
+`;
+
+exports[`classconstant type hinted (unsupported) 1`] = `"Parse Error : syntax error, unexpected 'CONSTANT' (T_STRING), expecting '=' on line 1"`;

test/snapshot/__snapshots__/enum.test.js.snap

@@ -38,6 +38,8 @@ Program {
           ],
           "final": false,
           "kind": "classconstant",
+          "nullable": false,
+          "type": null,
           "visibility": "public",
         },
       ],

test/snapshot/__snapshots__/heredoc.test.js.snap

@@ -1711,6 +1711,8 @@ FOOBAR",
           ],
           "final": false,
           "kind": "classconstant",
+          "nullable": false,
+          "type": null,
           "visibility": "",
         },
         PropertyStatement {

test/snapshot/__snapshots__/interface.test.js.snap

@@ -67,6 +67,8 @@ Program {
           ],
           "final": false,
           "kind": "classconstant",
+          "nullable": false,
+          "type": null,
           "visibility": "",
         },
       ],

test/snapshot/__snapshots__/nowdoc.test.js.snap

@@ -218,6 +218,8 @@ FOOBAR",
           ],
           "final": false,
           "kind": "classconstant",
+          "nullable": false,
+          "type": null,
           "visibility": "",
         },
         PropertyStatement {

test/snapshot/classconstant.test.js

@@ -37,4 +37,20 @@ describe("classconstant", () => {
       )
     ).toMatchSnapshot();
   });
+  it("type hinted (supported)", () => {
+    expect(
+      parser.parseEval(
+        'class Foo { public const string CONSTANT = "Hello world!"; }',
+        { parser: { version: 830 } }
+      )
+    ).toMatchSnapshot();
+  });
+  it("type hinted (unsupported)", () => {
+    expect(() =>
+      parser.parseEval(
+        'class Foo { public const string CONSTANT = "Hello world!"; }',
+        { parser: { version: 820 } }
+      )
+    ).toThrowErrorMatchingSnapshot();
+  });
 });