[isabelle-dev] NEWS: simultaneous sort constraints

Makarius makarius at sketis.net
Wed Nov 9 18:17:08 CET 2011

* Sort constraints are now propagated in simultaneous statements, just
like type constraints.  INCOMPATIBILITY in rare situations, where
distinct sorts used to be assigned accidentally.  For example:

   lemma "P (x::'a::foo)" and "Q (y::'a::bar)"  -- "now illegal"

   lemma "P (x::'a)" and "Q (y::'a::bar)"
     -- "now uniform 'a::bar instead of default sort for first occurence (!)"

This refers to Isabelle/fca432074fb2


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