diff -r 11d015697e44 -r 28ecd3e2d8c9 Collection.st
--- a/Collection.st	Thu Feb 23 12:50:27 2012 +0100
+++ b/Collection.st	Mon Feb 27 20:44:04 2012 +0100
@@ -2945,6 +2945,32 @@
     "Modified: / 30.10.1997 / 15:52:18 / cg"
 !
 
+noModificationError
+    "a store is attempted into an immutable collection (typically: a literal).
+     For our convenience, find the method that contains me, for a nicer error message"
+
+    |creator msg context|
+
+    creator := Method allSubInstances detect:[:aMethod | (aMethod referencesGlobal:self)] ifNone:nil.
+    creator notNil ifTrue:[
+        msg := ' (' , creator whoString , ')'
+    ].
+    context := thisContext sender.
+     "
+     this error is reported on an attempt to store into an immutable collection (typically: a literal). 
+     The literal was created in creator.
+     If you press continue in the debugger, the store will be performed.
+     If you don't want this, press abort and check your code.
+     Storing into literals is VERY VERY bad coding style.
+    "
+    NoModificationError
+        raiseRequestWith:self
+        errorString:msg
+        in:context.
+
+    "Created: / 03-08-1998 / 14:47:45 / cg"
+!
+
 notEnoughElementsError
     "report an error that the operation is not allowed,  
      since not enough elements are in the collection"
@@ -4182,11 +4208,11 @@
 !Collection class methodsFor:'documentation'!
 
 version
-    ^ '$Header: /cvs/stx/stx/libbasic/Collection.st,v 1.270 2011-12-21 14:59:45 cg Exp $'
+    ^ '$Header: /cvs/stx/stx/libbasic/Collection.st,v 1.271 2012-02-27 19:44:04 cg Exp $'
 !
 
 version_CVS
-    ^ '$Header: /cvs/stx/stx/libbasic/Collection.st,v 1.270 2011-12-21 14:59:45 cg Exp $'
+    ^ '$Header: /cvs/stx/stx/libbasic/Collection.st,v 1.271 2012-02-27 19:44:04 cg Exp $'
 ! !
 
 Collection initialize!