Not detected invalid FETCH variable references

[torobito]

It's not detected that the second FETCH is not referencing @i_field3:

ALTER PROCEDURE [proc_with_cursor]
AS
  BEGIN
      CREATE TABLE #mytemp (i_field1 INT, i_field2 INT, i_field4 INT, i_field3 INT )
      DECLARE mycursor CURSOR local fast_forward read_only FOR SELECT i_field1,i_field2,i_field3,i_field4 FROM #mytemp
      OPEN mycursor
      FETCH next FROM mycursor INTO @idGiro, @i_field2, @i_field3, @i_field4
      WHILE @@fetch_status = 0
        BEGIN
            IF ( @i_field4 = 1 )
              BEGIN
                  EXEC [Proc_when_1]
              END
            ELSE
              BEGIN
                  EXEC [Proc_when_0]
              END
            FETCH next FROM mycursor INTO @idGiro, @i_field2, @i_field4
        END
      CLOSE mycursor
      DEALLOCATE mycursor
  END