➜  Issue-7290 cat TestClass.java                                          
public class TestClass {
 {
 	Object o = "";
	if (o instanceof String s) { // jep 305
		System.out.println(s.toLowerCase());
	}
 }
}
➜  Issue-7290 java -jar checkstyle-8.31-SNAPSHOT-all.jar -t TestClass.java
CLASS_DEF -> CLASS_DEF [1:0]
|--MODIFIERS -> MODIFIERS [1:0]
|   `--LITERAL_PUBLIC -> public [1:0]
|--LITERAL_CLASS -> class [1:7]
|--IDENT -> TestClass [1:13]
`--OBJBLOCK -> OBJBLOCK [1:23]
    |--LCURLY -> { [1:23]
    |--INSTANCE_INIT -> INSTANCE_INIT [2:1]
    |   `--SLIST -> { [2:1]
    |       |--VARIABLE_DEF -> VARIABLE_DEF [3:2]
    |       |   |--MODIFIERS -> MODIFIERS [3:2]
    |       |   |--TYPE -> TYPE [3:2]
    |       |   |   `--IDENT -> Object [3:2]
    |       |   |--IDENT -> o [3:9]
    |       |   `--ASSIGN -> = [3:11]
    |       |       `--EXPR -> EXPR [3:13]
    |       |           `--STRING_LITERAL -> "" [3:13]
    |       |--SEMI -> ; [3:15]
    |       |--LITERAL_IF -> if [4:1]
    |       |   |--LPAREN -> ( [4:4]
    |       |   |--EXPR -> EXPR [4:7]
    |       |   |   `--LITERAL_INSTANCEOF -> instanceof [4:7]
    |       |   |       |--IDENT -> o [4:5]
    |       |   |       |--TYPE -> TYPE [4:18]
    |       |   |       |   `--IDENT -> String [4:18]
    |       |   |       `--IDENT -> s [4:25]
    |       |   |--RPAREN -> ) [4:26]
    |       |   `--SLIST -> { [4:28]
    |       |       |--EXPR -> EXPR [5:20]
    |       |       |   `--METHOD_CALL -> ( [5:20]
    |       |       |       |--DOT -> . [5:12]
    |       |       |       |   |--DOT -> . [5:8]
    |       |       |       |   |   |--IDENT -> System [5:2]
    |       |       |       |   |   `--IDENT -> out [5:9]
    |       |       |       |   `--IDENT -> println [5:13]
    |       |       |       |--ELIST -> ELIST [5:34]
    |       |       |       |   `--EXPR -> EXPR [5:34]
    |       |       |       |       `--METHOD_CALL -> ( [5:34]
    |       |       |       |           |--DOT -> . [5:22]
    |       |       |       |           |   |--IDENT -> s [5:21]
    |       |       |       |           |   `--IDENT -> toLowerCase [5:23]
    |       |       |       |           |--ELIST -> ELIST [5:35]
    |       |       |       |           `--RPAREN -> ) [5:35]
    |       |       |       `--RPAREN -> ) [5:36]
    |       |       |--SEMI -> ; [5:37]
    |       |       `--RCURLY -> } [6:1]
    |       `--RCURLY -> } [7:1]
    `--RCURLY -> } [8:0]

CLASS_DEF -> CLASS_DEF [1:0]
|--MODIFIERS -> MODIFIERS [1:0]
|   `--LITERAL_PUBLIC -> public [1:0]
|--LITERAL_CLASS -> class [1:7]
|--IDENT -> TestClass [1:13]
...
    |       |--LITERAL_IF -> if [4:1]
    |       |   |--LPAREN -> ( [4:4]
    |       |   |--EXPR -> EXPR [4:7]
    |       |   |   `--LITERAL_INSTANCEOF -> instanceof [4:7]
    |       |   |       |--IDENT -> o [4:5]
    |       |   |       `--VARIABLE_DEF -> VARIABLE_DEF [4:18]
    |       |   |           |--MODIFIERS -> MODIFIERS [4:18]
    |       |   |           |--TYPE -> TYPE [4:18]
    |       |   |           |   `--IDENT -> String [4:18]
    |       |   |           `--IDENT -> s [4:25]
    |       |   |--RPAREN -> ) [4:26]
    |       |   `--SLIST -> { [4:28]
...
    `--RCURLY -> } [8:0]

RelationalExpression:
     ...
     RelationalExpression instanceof ReferenceType
     RelationalExpression instanceof Pattern

Pattern:
     ReferenceType Identifier

|--EXPR -> EXPR [4:7]
|   `--LITERAL_INSTANCEOF -> instanceof [4:7]
|       |--IDENT -> o [4:5]
|       `--PARRERN_DEF -> PARRERN_DEF [4:18]
|           `--VARIABLE_DEF -> VARIABLE_DEF [4:18]
|               |--MODIFIERS -> MODIFIERS [4:18]
|               |--TYPE -> TYPE [4:18]
|               |   `--IDENT -> String [4:18]
|               `--IDENT -> s [4:25]

if (o instanceof Point(x,y) && x > 0)

class Foo {
  String name;
  void method(Object obj) {
     if (obj instanceof String name) {
         bar(name); // (String)obj
     } else {
         bar(name); // this.name
     }
  }
}