In the following code:

  nabl-disambiguation-def(|ctx__, ctx-terms__, ctx-string__) =
    ?m
    ; where("disamb0" := ctx-string__)
    ; where([at*, cp, ct, a*] := ctx-terms__)
    ; ((((acc := <new-task(|ctx__, [])> Id(
                                          <get-or-create-property-task(|ctx__, NablProp_access())> m
                                        )
          ; {prev__:
              ?prev__
              ; pt* := <new-task(|ctx__, [prev__])> Id(
                                                      <get-or-create-property-task(|ctx__, NablProp_parameter-types())> m
                                                    )
            })
         ; {prev__:
             ?prev__
             ; mt := <new-task(|ctx__, [prev__])> SubURI(NablNsType(), m)
           })
        ; {prev__:
            ?prev__
            ; mp := <new-task(|ctx__, [prev__])> SubURI(NablNsPackage(), m)
          })
       ; {prev__:
           ?prev__
           ; {l__, r__:
               where({l__, r__:
                       where({l__, r__:
                               where({l__, r__:
                                       where(<new-task(|ctx__, [prev__])> Eq(Public(), acc)
                                             ; ?l__)
                                       ; where((<new-task(|ctx__, [prev__])> Eq(Private(), acc)
                                                ; {prev__:
                                                    ?prev__
                                                    ; <new-task(|ctx__, [prev__])> Eq(ct, mt)
                                                  })
                                               ; ?r__)
                                       ; <new-task(|ctx__, [prev__])> Choice([l__, r__])
                                     }
                                     ; ?l__)
                               ; where((<new-task(|ctx__, [prev__])> Eq(Default(), acc)
                                        ; {prev__:
                                            ?prev__
                                            ; <new-task(|ctx__, [prev__])> Eq(cp, mp)
                                          })
                                       ; ?r__)
                               ; <new-task(|ctx__, [prev__])> Choice([l__, r__])
                             }
                             ; ?l__)
                       ; where((<new-task(|ctx__, [prev__])> Eq(Protected(), acc)
                                ; {prev__:
                                    ?prev__
                                    ; <new-task(|ctx__, [prev__])> Eq(cp, mp)
                                  })
                               ; ?r__)
                       ; <new-task(|ctx__, [prev__])> Choice([l__, r__])
                     }
                     ; ?l__)
               ; where((<new-task(|ctx__, [prev__])> Eq(Protected(), acc)
                        ; {prev__:
                            ?prev__
                            ; <new-task(|ctx__, [prev__])> RelationMatch("<extends:", ct, mt)
                          })
                       ; ?r__)
               ; <new-task(|ctx__, [prev__])> Choice([l__, r__])
             }
         })
    ; !( m
       , <new-task(|ctx__, [prev__])> RelationDistance("<widens:", at*, pt*)
       )

The editor does not produce an error for the last reference to prev__ (in <new-task(|ctx__, [prev__])> RelationDistance("<widens:", at*, pt*)), but the compiler (correctly) does:

    [java] ** Error in definition nabl-disambiguation-def:
    [java]    variable 'prev__' used, but not bound
    [java] [ Main | error ] Compilation failed (3.28 secs)

Submitted by Gabriël Konat on 21 March 2014 at 09:46