1 files changed, 1 insertions, 1 deletions
diff --git a/Source/DafnyExtension/ResolverTagger.cs b/Source/DafnyExtension/ResolverTagger.cs
index d1af6878..ca9ed169 100644
--- a/Source/DafnyExtension/ResolverTagger.cs
+++ b/Source/DafnyExtension/ResolverTagger.cs
@@ -311,7 +311,7 @@ namespace DafnyLanguage
       Snapshot = snapshot;
     }
     public SnapshotSpan Span() {
-      Contract.Requires(Snapshot != null);  // requires that Snapshot has been filled in
+      Contract.Assume(Snapshot != null);  // requires that Snapshot has been filled in
       var line = Snapshot.GetLineFromLineNumber(Line);
       Contract.Assume(Column <= line.Length);  // this is really a precondition of the constructor + FillInSnapshot
       var length = Math.Min(line.Length - Column, 5);