Camille/o were trying to fix a bug in the CriticsRules and found a strange limitation of the ParseTreeRewriter Given: Result: ------ ------- | a b | | a b | self halt. self bar. self bar. However this is not possible to specify directly: RBParseTreeRewriter new replace: '`@object halt' with: ''. As the parsed ' ' string will result in a SequenceNode, thus forcing the original message node ('self halt') to be a sequence node. So instead of looking for 'self halt' it will look for || self halt. and thus it tries to explicitly match the temporary. The result is, that we cannot remove 'self halt' with a rewrite rule if the method/block contains temporaries :/. Has anybody encountered this, or knows how to directly replace a message node with an "empty node"? best c&c