diff --git a/crates/matcher/src/lib.rs b/crates/matcher/src/lib.rs
index 92365efb..5b43b0d8 100644
--- a/crates/matcher/src/lib.rs
+++ b/crates/matcher/src/lib.rs
@@ -116,7 +116,7 @@ impl Match {
     /// This method panics if `start > self.end`.
     #[inline]
     pub fn with_start(&self, start: usize) -> Match {
-        assert!(start <= self.end);
+        assert!(start <= self.end, "{} is not <= {}", start, self.end);
         Match { start, ..*self }
     }
 
@@ -128,7 +128,7 @@ impl Match {
     /// This method panics if `self.start > end`.
     #[inline]
     pub fn with_end(&self, end: usize) -> Match {
-        assert!(self.start <= end);
+        assert!(self.start <= end, "{} is not <= {}", self.start, end);
         Match { end, ..*self }
     }
 
diff --git a/crates/regex/src/word.rs b/crates/regex/src/word.rs
index d73dd6ca..aa08164b 100644
--- a/crates/regex/src/word.rs
+++ b/crates/regex/src/word.rs
@@ -111,8 +111,15 @@ impl WordMatcher {
         }
         let (_, slen) = bstr::decode_utf8(&haystack[cand]);
         let (_, elen) = bstr::decode_last_utf8(&haystack[cand]);
-        cand =
-            cand.with_start(cand.start() + slen).with_end(cand.end() - elen);
+        let new_start = cand.start() + slen;
+        let new_end = cand.end() - elen;
+        // This occurs the original regex can match the empty string. In this
+        // case, just bail instead of trying to get it right here since it's
+        // likely a pathological case.
+        if new_start > new_end {
+            return Err(());
+        }
+        cand = cand.with_start(new_start).with_end(new_end);
         if self.original.is_match(&haystack[cand]) {
             Ok(Some(cand))
         } else {
diff --git a/tests/regression.rs b/tests/regression.rs
index c905e736..e35e953f 100644
--- a/tests/regression.rs
+++ b/tests/regression.rs
@@ -1029,3 +1029,11 @@ rgtest!(r1878, |dir: Dir, _: TestCommand| {
     let args = &["-U", "--mmap", r"\Abaz", "test"];
     dir.command().args(args).assert_err();
 });
+
+// See: https://github.com/BurntSushi/ripgrep/issues/1891
+rgtest!(r1891, |dir: Dir, mut cmd: TestCommand| {
+    dir.create("test", "\n##\n");
+    // N.B. We use -o here to force the issue to occur, which seems to only
+    // happen when each match needs to be detected.
+    eqnice!("1:\n2:\n2:\n", cmd.args(&["-won", "", "test"]).stdout());
+});