graph inference: conditional expressions then/else branches inference based on context (IDEA-100453)

java/java-tests/testData/codeInsight/daemonCodeAnalyzer/lambda/graphInference/ConditionalExpressionsInference.java

@@ -0,0 +1,16 @@
+class Test<U> {
+    public Optional<U> bar(boolean empty, U state) {
+        Optional<U> o = empty ? Optional.empty() : Optional.of(state);
+        return empty ? Optional.empty() : Optional.empty();
+    }
+
+    static class Optional<T> {
+        public static <U> Optional<U> empty() {
+            return null;
+        }
+
+        public static <U> Optional<U> of(U state) {
+            return null;
+        }
+    }
+}