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import org.checkerframework.checker.nullness.qual.*;
import org.checkerframework.checker.nullness.qual.EnsuresNonNullIf;
public class Asserts {
void propogateToExpr() {
String s = "m";
assert false : s.getClass();
}
void incorrectAssertExpr() {
String s = null;
assert s != null : "@AssumeAssertion(nullness)"; // error
s.getClass(); // OK
}
void correctAssertExpr() {
String s = null;
assert s == null : "@AssumeAssertion(nullness)";
// :: error: (dereference.of.nullable)
s.getClass(); // error
}
class ArrayCell {
@Nullable Object[] vals = new @Nullable Object[0];
}
void assertComplexExpr(ArrayCell ac, int i) {
assert ac.vals[i] != null : "@AssumeAssertion(nullness)";
@NonNull Object o = ac.vals[i];
i = 10;
// :: error: (assignment.type.incompatible)
@NonNull Object o2 = ac.vals[i];
}
boolean pairwiseEqual(boolean @Nullable [] seq1, boolean @Nullable [] seq2) {
if (!sameLength(seq1, seq2)) {
return false;
}
if (ne(seq1[0], seq2[0])) ;
return true;
}
@EnsuresNonNullIf(
result = true,
expression = {"#1", "#2"})
boolean sameLength(final boolean @Nullable [] seq1, final boolean @Nullable [] seq2) {
// don't bother with the implementation
// :: error: (contracts.conditional.postcondition.not.satisfied)
return true;
}
static boolean ne(boolean a, boolean b) {
return true;
}
void testAssertBad(boolean @Nullable [] seq1, boolean @Nullable [] seq2) {
assert sameLength(seq1, seq2);
// the @EnsuresNonNullIf is not taken from the assert, as it doesn't contain "nullness"
// :: error: (accessing.nullable)
if (seq1[0]) ;
}
void testAssertGood(boolean @Nullable [] seq1, boolean @Nullable [] seq2) {
assert sameLength(seq1, seq2) : "@AssumeAssertion(nullness)";
// The explanation contains "nullness" and we therefore take the additional assumption
if (seq1[0]) ;
}
void testAssertAnd(@Nullable Object o) {
assert o != null && o.hashCode() > 6;
}
void testAssertOr(@Nullable Object o) {
// :: error: (dereference.of.nullable)
assert o != null || o.hashCode() > 6;
}
}
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