diff --git a/ChangeLog b/ChangeLog
index b9b465922..9ff86c908 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+2012-03-02  Richard Frith-Macdonald <rfm@gnu.org>
+
+	* Source/GSString.m: Compatribility fix ... copy strings implicitly
+	when taking a substring of a string whose buffer is not owned.
+
 2012-03-02  Richard Frith-Macdonald <rfm@gnu.org>
 
 	* Source/NSURLConnection.m: Compatibility fix for bug #35686
diff --git a/Source/GSString.m b/Source/GSString.m
index cc3e1fda8..255e027b5 100644
--- a/Source/GSString.m
+++ b/Source/GSString.m
@@ -3768,14 +3768,22 @@ agree, create a new GSCInlineString otherwise.
 
 - (NSString*) substringFromRange: (NSRange)aRange
 {
-  GS_RANGE_CHECK(aRange, _count);
-  return substring_c((GSStr)self, aRange);
+  if (_flags.owned)
+    {
+      GS_RANGE_CHECK(aRange, _count);
+      return substring_c((GSStr)self, aRange);
+    }
+  return [super substringWithRange: aRange];
 }
 
 - (NSString*) substringWithRange: (NSRange)aRange
 {
-  GS_RANGE_CHECK(aRange, _count);
-  return substring_c((GSStr)self, aRange);
+  if (_flags.owned)
+    {
+      GS_RANGE_CHECK(aRange, _count);
+      return substring_c((GSStr)self, aRange);
+    }
+  return [super substringWithRange: aRange];
 }
 
 - (id) uppercaseString
@@ -4106,14 +4114,22 @@ agree, create a new GSCInlineString otherwise.
 
 - (NSString*) substringFromRange: (NSRange)aRange
 {
-  GS_RANGE_CHECK(aRange, _count);
-  return substring_u((GSStr)self, aRange);
+  if (_flags.owned)
+    {
+      GS_RANGE_CHECK(aRange, _count);
+      return substring_u((GSStr)self, aRange);
+    }
+  return [super substringWithRange: aRange];
 }
 
 - (NSString*) substringWithRange: (NSRange)aRange
 {
-  GS_RANGE_CHECK(aRange, _count);
-  return substring_u((GSStr)self, aRange);
+  if (_flags.owned)
+    {
+      GS_RANGE_CHECK(aRange, _count);
+      return substring_u((GSStr)self, aRange);
+    }
+  return [super substringWithRange: aRange];
 }
 
 - (id) uppercaseString