redundant casts: skip casts in conditional branches of calls when resulted call would resolve to another method (IDEA-15720)

java/java-tests/testData/inspection/redundantCast/InConditionalPreserveResolve/expected.xml

@@ -0,0 +1,9 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<problems>
+  <problem>
+    <file>A.java</file>
+    <line>4</line>
+    <problem_class severity="WARNING" attribute_key="NOT_USED_ELEMENT_ATTRIBUTES">Redundant type cast</problem_class>
+    <description>Casting &lt;code&gt;param&lt;/code&gt; to &lt;code&gt;Object&lt;/code&gt; is redundant</description>
+  </problem>
+</problems>

java/java-tests/testData/inspection/redundantCast/InConditionalPreserveResolve/src/A.java

@@ -0,0 +1,10 @@
+class A {
+  void add(Object o, String param) {
+    add(o, o != null ? null : (Object) param);
+    add(o, o == null ? new Object() : (Object) param);
+  }
+
+  void add(Object o, Object param) {
+
+  }
+}

java/java-tests/testSrc/com/intellij/codeInspection/RedundantCastTest.java

@@ -91,4 +91,6 @@ public class RedundantCastTest extends InspectionTestCase {
   
   public void testNestedCast() throws Exception { doTest(); }
   public void testPrimitiveInsideSynchronized() throws Exception { doTest(); }
+
+  public void testInConditionalPreserveResolve() throws Exception { doTest();}
 }