IDEA-133946 Don't highlight private constructor as unused if it is called by dependency injection engine

java/java-analysis-impl/src/com/intellij/codeInsight/daemon/impl/UnusedSymbolUtil.java

@@ -315,7 +315,6 @@ public class UnusedSymbolUtil {
 
   private static boolean isIntentionalPrivateConstructor(@NotNull PsiMethod method, PsiClass containingClass) {
     return method.isConstructor() &&
-           method.getParameterList().getParametersCount() == 0 &&
            containingClass != null &&
            containingClass.getConstructors().length == 1;
   }

java/java-tests/testData/codeInsight/daemonCodeAnalyzer/advHighlighting/Unused.java

@@ -2,6 +2,13 @@ class a extends Exception {
   private <warning descr="Private constructor 'a(java.lang.String)' is never used">a</warning>(String s) {
     super(s);
   }
+  private <warning descr="Private constructor 'a()' is never used">a</warning>(){}
+}
+
+class TheOnlyCtr extends Exception {
+  private TheOnlyCtr(String s) {
+    super(s);
+  }
 }
 
 class s extends Exception {

java/java-tests/testData/codeInsight/daemonCodeAnalyzer/unusedDecls/PrivateConstructor.java

@@ -0,0 +1,14 @@
+import java.lang.Override;
+
+class PrivateConstructor {
+  private final int myA;
+
+  private PrivateConstructor(int a) {
+    myA = a;
+  }
+
+  @Override
+  public int hashCode() {
+    return myA;
+  }
+}

java/java-tests/testData/refactoring/changeSignatureGesture/AddParameter2UnusedConstructor.java

@@ -2,4 +2,6 @@ package refactoring.changeSignatureGesture;
 class TestMeabracadabra {
   private TestMeabracadabra(<caret>){
   }
+  private TestMeabracadabra(String f){
+  }
 }

java/java-tests/testSrc/com/intellij/codeInsight/daemon/UnusedSymbolLocalTest.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2000-2013 JetBrains s.r.o.
+ * Copyright 2000-2014 JetBrains s.r.o.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -36,6 +36,8 @@ public class UnusedSymbolLocalTest extends DaemonAnalyzerTestCase {
   public void testInnerClass() throws Exception { doTest(); }
   public void testInnerUsesSelf() throws Exception { doTest(); }
   public void testLocalClass() throws Exception { doTest(); }
+  public void testPrivateConstructor() throws Exception { doTest(); }
+
   //@Bombed(day = 5, month = Calendar.SEPTEMBER, user = "anet")
   //public void testInjectedAnno() throws Exception { doTest(); }