IDEA-86945 'Redundant type cast' and 'Constant conditions & exceptions' inspections

java/java-impl/src/com/intellij/codeInspection/dataFlow/StandardInstructionVisitor.java

@@ -147,6 +147,10 @@ public class StandardInstructionVisitor extends InstructionVisitor {
       }
     }
 
+    if (instruction.getCastTo() instanceof PsiPrimitiveType) {
+      memState.push(runner.getFactory().getBoxedFactory().createUnboxed(memState.pop()));
+    }
+
     return nextInstruction(instruction, runner, memState);
   }
 

java/java-tests/testData/inspection/dataFlow/fixture/Boxing128.java

@@ -0,0 +1,11 @@
+class Foo {
+  public void foo() {
+    Integer a = 128;
+    Integer b = (int) a;// cast is necessary because new object is created
+    Integer c = 128;
+
+    System.out.println(a == b);
+    System.out.println(<warning descr="Condition 'a == c' is always 'false'">a == c</warning>);
+  }
+
+}

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

@@ -64,4 +64,6 @@ public class DataFlowInspectionFixtureTest extends JavaCodeInsightFixtureTestCas
   public void testComparingToNotNullShouldNotAffectNullity() throws Throwable { doTest(); }
   public void testStringTernaryAlwaysTrue() throws Throwable { doTest(); }
 
+  public void testBoxing128() throws Throwable { doTest(); }
+
 }