diff --git a/dir.c b/dir.c
index f8a11aa1ec..fd689bbe66 100644
--- a/dir.c
+++ b/dir.c
@@ -88,6 +88,18 @@ int fspathncmp(const char *a, const char *b, size_t count)
 	return ignore_case ? strncasecmp(a, b, count) : strncmp(a, b, count);
 }
 
+int paths_collide(const char *a, const char *b)
+{
+	size_t len_a = strlen(a), len_b = strlen(b);
+
+	if (len_a == len_b)
+		return fspatheq(a, b);
+
+	if (len_a < len_b)
+		return is_dir_sep(b[len_a]) && !fspathncmp(a, b, len_a);
+	return is_dir_sep(a[len_b]) && !fspathncmp(a, b, len_b);
+}
+
 unsigned int fspathhash(const char *str)
 {
 	return ignore_case ? strihash(str) : strhash(str);
diff --git a/dir.h b/dir.h
index 674747d93a..62e89a053d 100644
--- a/dir.h
+++ b/dir.h
@@ -519,6 +519,13 @@ int fspatheq(const char *a, const char *b);
 int fspathncmp(const char *a, const char *b, size_t count);
 unsigned int fspathhash(const char *str);
 
+/*
+ * Reports whether paths collide. This may be because the paths differ only in
+ * case on a case-sensitive filesystem, or that one path refers to a symlink
+ * that collides with one of the parent directories of the other.
+ */
+int paths_collide(const char *a, const char *b);
+
 /*
  * The prefix part of pattern must not contains wildcards.
  */
diff --git a/entry.c b/entry.c
index 616e4f073c..a4c18c5645 100644
--- a/entry.c
+++ b/entry.c
@@ -454,7 +454,7 @@ static void mark_colliding_entries(const struct checkout *state,
 			continue;
 
 		if ((trust_ino && !match_stat_data(&dup->ce_stat_data, st)) ||
-		    (!trust_ino && !fspathcmp(ce->name, dup->name))) {
+		    paths_collide(ce->name, dup->name)) {
 			dup->ce_flags |= CE_MATCHED;
 			break;
 		}