iset - Fix missing boundary check

#1166

Author: shirok

ChangeLog

@@ -1,3 +1,8 @@
+2025-09-09  Shiro Kawai  <shiro@acm.org>
+
+	* lib/srfi/217.scm (iset-closed-interval): Fix missing boundary check
+	  https://github.com/shirok/Gauche/issues/1166
+
 2025-09-06  Shiro Kawai  <shiro@acm.org>
 
 	* libsrc/gauche/collection.scm (group-by-size, group-by-size-to):

lib/srfi/217.scm

@@ -651,6 +651,7 @@
                    [g (x->generator tmap)])
                (let loop ()
                  (match (g)
+                   [(? eof-object?) (%make-iset #f rmap)]
                    [(s . e)
                     (cond
                      [(< e lo) (loop)]               ;non overwrapping

tests/srfi.scm

@@ -3082,6 +3082,12 @@
        '(0 1 2 5 6 7)
        '(-1 0 1 2 3 4 5 6 7 8))
     )
+
+  ;; https://github.com/shirok/Gauche/issues/1166
+  (test* "iset-closed-interval corner case" '(1)
+         (iset->list (iset-closed-interval (iset 1) 1 2)))
+  (test* "iset-closed-interval corner case" '(2 3 5 6 7)
+         (iset->list (iset-closed-interval (iset 1 2 3 5 6 7) 2 10)))
   )
 
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