new inference: nested varargs

(cherry picked from commit 0d293e439ffcbe97db98c1a1b8072e798d94323e)

java/java-tests/testData/codeInsight/daemonCodeAnalyzer/lambda/diamond/Varargs.java

@@ -7,7 +7,7 @@ class A<T> {
     foo(new A<>("", ""));
     bar(new A<>("", ""));
     bar(new A<>(get()));
-    //bar(new A<>(get( ), ""));
+    bar(new A<>(get( ), ""));
   }
 
   void foo(A<String> s) {}

java/java-tests/testData/codeInsight/daemonCodeAnalyzer/lambda/highlighting/ConflictResolution.java

@@ -1,7 +1,7 @@
 class Demo {
 
     public void f1() {
-        f2<error descr="'f2()' in 'Demo' cannot be applied to '(int, <lambda expression>)'">(2, input -> input)</error>;
+        f2(2, <error descr="Target type of a lambda conversion must be an interface">input -> input</error>);
     }
 
     public void f2() {

java/java-tests/testData/codeInsight/daemonCodeAnalyzer/lambda/mostSpecific/NestedVarargs.java

@@ -0,0 +1,46 @@
+import java.util.List;
+
+abstract class StreamMain {
+  public abstract  <T> Iterable<T> concat(final Iterable<? extends T>... iterables);
+  public abstract  <T> Iterable<T> concat(final List<? extends T>... iterables);
+
+  public final List<String> errorFixesToShow = null;
+  public final List<String> inspectionFixesToShow = null;
+
+  void foo() {
+    exists(concat(errorFixesToShow, inspectionFixesToShow), "");
+  }
+
+  public abstract <T> boolean exists(T[] iterable, T t);
+  public abstract <T> boolean exists(Iterable<T> iterable, T t);
+
+}
+
+
+abstract class StreamMainComplexSecendArgument {
+  public abstract  <T> Iterable<T> concat(final Iterable<? extends T>... iterables);
+  public abstract  <T> Iterable<T> concat(final List<? extends T>... iterables);
+
+
+  public final List<String> errorFixesToShow = null;
+  public final List<String> inspectionFixesToShow = null;
+
+  void foo() {
+    Condition<String> condition = new Condition<String>() {
+      @Override
+      public boolean value(String s) {
+        return false;
+      }
+    };
+    exists(concat(errorFixesToShow, inspectionFixesToShow), condition);
+  }
+
+  public abstract <T> boolean exists(T[] iterable, Condition<T> condition);
+
+  public abstract <T> boolean exists(Iterable<T> iterable, Condition<T> condition);
+
+
+  interface Condition<T> {
+    boolean value(T t);
+  }
+}