checker/tests/index/RefineNeqLength.java

// Test case for Issue panacekcz#12:
// https://github.com/panacekcz/checker-framework/issues/12

import org.checkerframework.checker.index.qual.IndexFor;
import org.checkerframework.checker.index.qual.IndexOrHigh;
import org.checkerframework.checker.index.qual.LTLengthOf;
import org.checkerframework.checker.index.qual.LTOMLengthOf;
import org.checkerframework.checker.index.qual.NonNegative;
import org.checkerframework.common.value.qual.IntVal;

public class RefineNeqLength {
  void refineNeqLength(int[] array, @IndexOrHigh("#1") int i) {
    // Refines i <= array.length to i < array.length
    if (i != array.length) {
      refineNeqLengthMOne(array, i);
    }
    // No refinement
    if (i != array.length - 1) {
      // :: error: (argument)
      refineNeqLengthMOne(array, i);
    }
  }

  void refineNeqLengthMOne(int[] array, @IndexFor("#1") int i) {
    // Refines i < array.length to i < array.length - 1
    if (i != array.length - 1) {
      refineNeqLengthMTwo(array, i);
      // :: error: (argument)
      refineNeqLengthMThree(array, i);
    }
  }

  void refineNeqLengthMTwo(int[] array, @NonNegative @LTOMLengthOf("#1") int i) {
    // Refines i < array.length - 1 to i < array.length - 2
    if (i != array.length - 2) {
      refineNeqLengthMThree(array, i);
    }
    // No refinement
    if (i != array.length - 1) {
      // :: error: (argument)
      refineNeqLengthMThree(array, i);
    }
  }

  void refineNeqLengthMTwoNonLiteral(
      int[] array,
      @NonNegative @LTOMLengthOf("#1") int i,
      @IntVal(3) int c3,
      @IntVal({2, 3}) int c23) {
    // Refines i < array.length - 1 to i < array.length - 2
    if (i != array.length - (5 - c3)) {
      refineNeqLengthMThree(array, i);
    }
    // No refinement
    if (i != array.length - c23) {
      // :: error: (argument)
      refineNeqLengthMThree(array, i);
    }
  }

  @LTLengthOf(value = "#1", offset = "3") int refineNeqLengthMThree(
      int[] array, @NonNegative @LTLengthOf(value = "#1", offset = "2") int i) {
    // Refines i < array.length - 2 to i < array.length - 3
    if (i != array.length - 3) {
      return i;
    }
    // :: error: (return)
    return i;
  }

  // The same test for a string.
  @LTLengthOf(value = "#1", offset = "3") int refineNeqLengthMThree(
      String str, @NonNegative @LTLengthOf(value = "#1", offset = "2") int i) {
    // Refines i < str.length() - 2 to i < str.length() - 3
    if (i != str.length() - 3) {
      return i;
    }
    // :: error: (return)
    return i;
  }
}