Restore cast in possibly important context; fix ReplaceInefficientStreamCount tests

GitOrigin-RevId: 84ef59c2941462b3060c31cfea85f90ee6d39af8

java/java-psi-api/src/com/intellij/psi/util/RedundantCastUtil.java

@@ -766,7 +766,13 @@ public class RedundantCastUtil {
     PsiType castType = typeElement.getType();
     if (castType instanceof PsiPrimitiveType) {
       if (opType instanceof PsiPrimitiveType) {
-        return !TypeConversionUtil.isSafeConversion(castType, opType); // let's suppose that casts losing precision are important 
+        PsiElement parent = PsiUtil.skipParenthesizedExprUp(typeCast.getParent());
+        if (parent instanceof PsiReturnStatement || parent instanceof PsiMethodCallExpression || parent instanceof PsiVariable ||
+            parent instanceof PsiAssignmentExpression) {
+          return !TypeConversionUtil.isSafeConversion(castType, opType); // let's suppose that casts losing precision are important 
+        } else {
+          return !castType.equals(opType); // cast might be necessary (e.g. ((double)1)/5)
+        }
       }
       final PsiPrimitiveType unboxedOpType = PsiPrimitiveType.getUnboxedType(opType);
       if (unboxedOpType != null && !unboxedOpType.equals(castType) ) {

java/java-tests/testData/inspection/inefficientStreamCount/afterStreamCount.java

@@ -5,6 +5,6 @@ import java.util.Arrays;
 class Test {
   long cnt() {
       /*count*/
-      return (long) Arrays.asList('d', 'e', 'f')./*stream*/size()/*after*/;
+      return Arrays.asList('d', 'e', 'f')./*stream*/size()/*after*/;
   }
 }

java/java-tests/testData/inspection/inefficientStreamCount/afterStreamCountField.java

@@ -4,5 +4,5 @@ import java.util.Arrays;
 
 class Test {
     /*count*/
-    long cnt = (long) Arrays.asList('d', 'e', 'f')./*stream*/size()/*after*/;
+    long cnt = Arrays.asList('d', 'e', 'f')./*stream*/size()/*after*/;
 }

java/java-tests/testData/inspection/inefficientStreamCount/afterStreamCountParameter.java

@@ -7,6 +7,6 @@ public class Main {
     public static long test() {
         List<String> s = new ArrayList<>();
         /* unused parameter */
-        return (long) s.size();
+        return s.size();
     }
 }