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Flags `instanceof` checks where the expression can be determined to be a
supertype of the type it is compared to.
[JLS 15.28](https://docs.oracle.com/javase/specs/jls/se8/html/jls-15.html#jls-15.28)
specifically calls `instanceof` out as *not* being a compile-time constant
expression, so the usage of this pattern can lead to unreachable code that won't
be flagged by the compiler:
```java
class Foo {
void doSomething() {
if (this instanceof Foo) { // BAD: always true
return;
}
interestingProcessing();
}
}
```
In general, an `instanceof` comparison against a superclass is equivalent to a
null check:
```java
foo instanceof Foo
```
```java
foo != null
```
|
