git-issue-2026.dfy(19,18): Error: this invariant could not be proved to be maintained by the loop
 Related message: loop invariant violation
 Related counterexample:
 WARNING: the following counterexample may be inconsistent or invalid. See dafny.org/dafny/DafnyRef/DafnyRef#sec-counterexamples
 Temporary variables to describe counterexamples: 
 ghost var counterexampleLoopGuard0 : bool := false;
 git-issue-2026.dfy(12,0): initial state:
 assume 2 == n;
 git-issue-2026.dfy(13,24):
 assume ret != null && ret.Length > 0 && 2 == n && 2 == ret.Length && ['o', 'd', 'd'] == ret[0];
 git-issue-2026.dfy(15,14):
 assume ret != null && ret.Length > 0 && 2 == n && 2 == ret.Length && ['o', 'd', 'd'] == ret[0] && 0 == i;
 git-issue-2026.dfy(16,4): after some loop iterations:
 counterexampleLoopGuard0 := ret != null && 2 == n && 2 == ret.Length && 0 == i;
 git-issue-2026.dfy(22,27):
 assume counterexampleLoopGuard0 ==> ret != null && ret.Length > 0 && 2 == n && 2 == ret.Length && ['o', 'd', 'd'] == ret[0] && 0 == i;
 git-issue-2026.dfy(26,18):
 assume counterexampleLoopGuard0 ==> ret != null && ret.Length > 0 && 2 == n && 2 == ret.Length && ['o', 'd', 'd'] == ret[0] && 1 == i;
 

Dafny program verifier finished with 0 verified, 1 error
