Calling method with contract shouldn't result in nullability suspicion (IDEA-113763, IDEA-113699, almost IDEA-113143)

java/java-tests/testData/inspection/dataFlow/fixture/ContractPreservesUnknownNullability.java

@@ -0,0 +1,19 @@
+import org.jetbrains.annotations.Contract;
+import org.jetbrains.annotations.NotNull;
+
+public class Foo {
+
+  @Contract("null->null")
+  String foo(String s){
+    return s;
+  }
+
+  void bar(String s, String s2) {
+    foo(s);
+    s.hashCode();
+    goo(foo(s2));
+  }
+  
+  void goo(@NotNull String s) {}
+
+}