overload resolution: boxing should ignore null types (IDEA-148692)

java/java-psi-impl/src/com/intellij/psi/impl/source/resolve/graphInference/PsiPolyExpressionUtil.java

@@ -154,7 +154,8 @@ public class PsiPolyExpressionUtil {
 
   public static boolean isExpressionOfPrimitiveType(@Nullable PsiExpression arg) {
     if (arg != null && !isPolyExpression(arg)) {
-      return arg.getType() instanceof PsiPrimitiveType;
+      final PsiType type = arg.getType();
+      return type instanceof PsiPrimitiveType && type != PsiType.NULL;
     }
     else if (arg instanceof PsiNewExpression || arg instanceof PsiFunctionalExpression) {
       return false;

java/java-tests/testData/codeInsight/daemonCodeAnalyzer/lambda/overloadResolution/NoBoxingWithNullType.java

@@ -0,0 +1,13 @@
+class Test {
+  private void <warning descr="Private method 'foo(java.lang.String, java.lang.Object)' is never used">foo</warning>(String s, Object o) {
+    System.out.println(s + "; o:" + o);
+  }
+
+  private void foo(String s, boolean b) {
+    System.out.println(s + "; b:" + b);
+  }
+  
+  {
+    foo(null, false);
+  }
+}

java/java-tests/testSrc/com/intellij/codeInsight/daemon/lambda/OverloadResolutionTest.java

@@ -175,6 +175,10 @@ public class OverloadResolutionTest extends LightDaemonAnalyzerTestCase {
     doTest();
   }
 
+  public void testNoBoxingWithNullType() throws Exception {
+    doTest();
+  }
+
   private void doTest() {
     doTest(true);
   }