[java] AvoidArrayLoops regression: from false negative to false positive with final variables

[Androbin]

Affects PMD Version: 6.51.0

Rule: AvoidArrayLoops

Description:
While fixing #3847, a regression was introduced in #4159 @adangel, now instead of a false negative we have a false positive.
A final variable may only be ignored if it's computed before the loop (or otherwise constant over the loop).

Code Sample demonstrating the issue:

public class Test {
  public static void sample() {
    final int[] a = new int[10];
    final int[] b = new int[10];
    for (int i=0; i<10; i++) {
      final int c = i;
      b[i] = a[i+c];
    }
  }
}

Expected outcome:

PMD reports a violation at line 5, but that's wrong. That's a false positive.

Running PMD through: CLI

True positive code samples

public class Test {
  public static void sample() {
    final int[] a = new int[10];
    final int[] b = new int[10];
    final int c = 6;
    for (int i=0; i<10; i++) {
      b[i] = a[i+c];
    }
  }
}

public class Test {
  public static void sample() {
    final int[] a = new int[10];
    final int[] b = new int[10];
    for (int i=0; i<10; i++) {
      final int c = 6;
      b[i] = a[i+c];
    }
  }
}

True negative code samples

public class Test {
  public static void sample() {
    final int[] a = new int[10];
    final int[] b = new int[10];
    for (int i=0; i<10; i++) {
      int c = i;
      b[i] = a[i+c];
    }
  }
}