
Dafny program verifier finished with 0 verified, 0 errors
filter-symbol.dfy(14,27): Error: a postcondition could not be proved on this return path
filter-symbol.dfy(14,21): Related location: this is the postcondition that could not be proved
filter-symbol.dfy(12,29): Error: a postcondition could not be proved on this return path
filter-symbol.dfy(12,23): Related location: this is the postcondition that could not be proved
filter-symbol.dfy(19,29): Error: a postcondition could not be proved on this return path
filter-symbol.dfy(19,23): Related location: this is the postcondition that could not be proved

Dafny program verifier finished with 0 verified, 3 errors
filter-symbol.dfy(12,29): Error: a postcondition could not be proved on this return path
filter-symbol.dfy(12,23): Related location: this is the postcondition that could not be proved
filter-symbol.dfy(21,27): Error: a postcondition could not be proved on this return path
filter-symbol.dfy(21,21): Related location: this is the postcondition that could not be proved
filter-symbol.dfy(19,29): Error: a postcondition could not be proved on this return path
filter-symbol.dfy(19,23): Related location: this is the postcondition that could not be proved

Dafny program verifier finished with 0 verified, 3 errors
filter-symbol.dfy(12,29): Error: a postcondition could not be proved on this return path
filter-symbol.dfy(12,23): Related location: this is the postcondition that could not be proved

Dafny program verifier finished with 0 verified, 1 error
filter-symbol.dfy(19,29): Error: a postcondition could not be proved on this return path
filter-symbol.dfy(19,23): Related location: this is the postcondition that could not be proved

Dafny program verifier finished with 0 verified, 1 error
filter-symbol.dfy(26,27): Error: value does not satisfy the subset constraints of 'nat'
filter-symbol.dfy(26,46): Error: value does not satisfy the subset constraints of 'nat'

Dafny program verifier finished with 0 verified, 2 errors
filter-symbol.dfy(26,27): Error: value does not satisfy the subset constraints of 'nat'

Dafny program verifier finished with 0 verified, 1 error
