RFC: Allow static properties in enums

Zend/tests/enum/no-inherited-properties.phpt

@@ -0,0 +1,16 @@
+--TEST--
+Enum disallows inherited instance properties
+--FILE--
+<?php
+
+trait T {
+    public $bar;
+}
+
+enum Foo {
+    use T;
+}
+
+?>
+--EXPECTF--
+Fatal error: Enum "Foo" may not include instance properties in %s on line 7

Zend/tests/enum/no-name-property.phpt

@@ -9,4 +9,4 @@ enum Foo {
 
 ?>
 --EXPECTF--
-Fatal error: Enums may not include properties in %s on line %d
+Fatal error: Enums may not include instance properties in %s on line %d

Zend/tests/enum/no-properties.phpt

@@ -1,5 +1,5 @@
 --TEST--
-Enum disallows properties
+Enum disallows instance properties
 --FILE--
 <?php
 
@@ -9,4 +9,4 @@ enum Foo {
 
 ?>
 --EXPECTF--
-Fatal error: Enums may not include properties in %s on line %d
+Fatal error: Enums may not include instance properties in %s on line %d

Zend/tests/enum/no-value-property.phpt

@@ -9,4 +9,4 @@ enum Foo: int {
 
 ?>
 --EXPECTF--
-Fatal error: Enums may not include properties in %s on line %d
+Fatal error: Enums may not include instance properties in %s on line %d

Zend/tests/enum/static-properties.phpt

@@ -0,0 +1,32 @@
+--TEST--
+Enum allows static properties
+--FILE--
+<?php
+
+trait Logger {
+    protected static bool $loggingEnabled;
+}
+
+enum Environment {
+    case DEV;
+    case STAGE;
+    case PROD;
+
+    use Logger;
+
+    protected static Environment $current;
+
+    public static function set(Environment $new): void {
+        self::$current = $new;
+        echo self::$current->name, "\n";
+        self::$loggingEnabled = self::$current !== self::PROD;
+        var_dump(self::$loggingEnabled);
+    }
+}
+
+Environment::set(Environment::DEV);
+
+?>
+--EXPECT--
+DEV
+bool(true)

Zend/tests/enum/traits-no-properties.phpt

@@ -22,4 +22,4 @@ enum Suit {
 
 ?>
 --EXPECTF--
-Fatal error: Enum "Suit" may not include properties in %s on line %d
+Fatal error: Enum "Suit" may not include instance properties in %s on line %d

Zend/zend_compile.c

@@ -7159,8 +7159,8 @@ void zend_compile_prop_decl(zend_ast *ast, zend_ast *type_ast, uint32_t flags, z
 		zend_error_noreturn(E_COMPILE_ERROR, "Interfaces may not include properties");
 	}
 
-	if (ce->ce_flags & ZEND_ACC_ENUM) {
-		zend_error_noreturn(E_COMPILE_ERROR, "Enums may not include properties");
+	if ((ce->ce_flags & ZEND_ACC_ENUM) && !(flags & ZEND_ACC_STATIC)) {
+		zend_error_noreturn(E_COMPILE_ERROR, "Enums may not include instance properties");
 	}
 
 	if (flags & ZEND_ACC_ABSTRACT) {

Zend/zend_enum.c

@@ -66,8 +66,11 @@ static void zend_verify_enum_properties(zend_class_entry *ce)
 		) {
 			continue;
 		}
+		if (property_info->flags & ZEND_ACC_STATIC) {
+			continue;
+		}
 		// FIXME: File/line number for traits?
-		zend_error_noreturn(E_COMPILE_ERROR, "Enum \"%s\" may not include properties",
+		zend_error_noreturn(E_COMPILE_ERROR, "Enum \"%s\" may not include instance properties",
 			ZSTR_VAL(ce->name));
 	} ZEND_HASH_FOREACH_END();
 }
@@ -212,7 +215,7 @@ void zend_enum_add_interfaces(zend_class_entry *ce)
 
 	if (ce->enum_backing_type != IS_UNDEF) {
 		ce->interface_names[num_interfaces_before + 1].name = zend_string_copy(zend_ce_backed_enum->name);
-		ce->interface_names[num_interfaces_before + 1].lc_name = zend_string_init("backedenum", sizeof("backedenum") - 1, 0);	
+		ce->interface_names[num_interfaces_before + 1].lc_name = zend_string_init("backedenum", sizeof("backedenum") - 1, 0);
 	}
 }