Object (Test t) { if (t == null) <error descr="Missing return value">return;</error> if (<warning descr="Condition 't instanceof Test' is always 'true'">t instanceof Test</warning>) { // always true error here. t can't be null foo(null); } if (bar(null) instanceof Test) return null; // no error here. if (<warning descr="Condition 'foo(null) instanceof Test' is redundant and can be replaced with a null check">foo(null) instanceof Test</warning>) return null; // redundant instanceof error here. foo(null) can be null return null; }