IG: ignore casting class types to primitive (IDEA-170332)

plugins/InspectionGadgets/InspectionGadgetsAnalysis/src/com/siyeh/ig/numeric/UnnecessaryExplicitNumericCastInspection.java

@@ -121,6 +121,7 @@ public class UnnecessaryExplicitNumericCastInspection extends BaseInspection {
       }
       final PsiType operandType = operand.getType();
       if (castType.equals(operandType) || isPrimitiveNumericCastNecessary(expression)) {
+        // equal types is caught by "Redundant type cast" inspection
         return;
       }
       final PsiTypeElement typeElement = expression.getCastType();
@@ -140,7 +141,7 @@ public class UnnecessaryExplicitNumericCastInspection extends BaseInspection {
       return true;
     }
     final PsiType operandType = operand.getType();
-    if (operandType == null) {
+    if (!(operandType instanceof PsiPrimitiveType)) {
       return true;
     }
     PsiElement parent = expression.getParent();

plugins/InspectionGadgets/test/com/siyeh/igtest/numeric/unnecessary_explicit_numeric_cast/UnnecessaryExplicitNumericCast.java

@@ -88,3 +88,17 @@ enum Numeric {
 
   Numeric(byte b) {}
 }
+class S {
+
+  static void doSomething() {
+    //   V --- this cast is reported as unnecessary
+    if ( (int) whatever() < 0 ) {
+    }
+  }
+
+  @SuppressWarnings("unchecked")
+  private static <T> T whatever() {
+    return (T) (Object) 0;
+  }
+
+}