Provided by: dafny_1.9.7-1_all bug


       dafny - compiler for the Dafny programming language


       dafny [options] file.dfy ...


       dafny  is  a  compiler  for Microsoft Research's Dafny programming language, an imperative
       language with built-in specification  constructs.   The  integrated  static  analyzer  can
       verify functional correctness as part of the compilation process.


       dafny accepts a number of different types of options.

   File macros
       A number of dafny options accept a file argument, which may contain the following macros:

       @FILE@ Expands to the last filename specified on the command line.

              Expands to the concatenation of strings given by /logPrefix options.

       @TIME@ Expands to the current time.

   General options
       /env:n Control printing of command-line arguments.  Accepted values for n are:

              0      Suppress printing of command-line arguments.

              1      (default) Print command-line arguments during BPL print and prover log.

              2      Print  command-line  arguments  during BPL print and prover log, and also to
                     standard output.

              Suppress printing of the version number and copyright message.

       /wait  Wait for a carriage return from the keyboard before exiting.

              Also produce output in XML format to file.

   Dafny options
       Multiple .dfy files supplied on the command line are concatenated into one Dafny program.

              Allow the implicit class  _default  to  contain  fields,  instance  functions,  and
              instance  methods.   These  class  members are declared at module scope, outside of
              explicit classes.  This command-line option is provided to simplify a a  transition
              from  the  behavior in the language prior to version 1.9.3, from which point onward
              all functions and methods declared at the module scope are  implicitly  static  and
              field declarations are not allowed at the module scope.

              Print requirements automatically generated by autoReq to the specified file.

              Enable or disable compilation.  Accepted values for n are:

              0      Do not compile.

              1      (default)  Compile  Dafny  to CLI assembly.  The output file name shares the
                     base name of the last .dfy file on the command line.  If the program  has  a
                     Main  method, the output will have the extension .exe; otherwise, it will be
                     a .dll.

              Disable features not supported by DafnyCC.

              Control how far compilation proceeds.  Accepted values for n are:

              0      Stop after typechecking.

              1      Typecheck, verify, and compile.

              Choose Dafny prelude file.

              Print Dafny program to the specified file  after  parsing.   Specify  /dprint:-  to
              print to standard output.

              Control when Dafny performs induction.  Accepted values for n are:

              0      Never do induction, not even when attributes request it.

              1      Apply induction only when attributes request it.

              2      Apply induction as requested by attributes and also for heuristically chosen

              3      (default) Apply induction as  requested  by  attributes,  for  heuristically
                     chosen quantifiers, and for ghost methods.

              Control  how  discriminating  the induction heuristic is.  /inductionHeuristic:0 is
              the least discriminating (that is, it leans toward applying induction most  often);
              increasing n up to 6, the default, increases dafny's reluctance to apply induction.

              Ignore autoReq attributes.

              Control how strict dafny is about unproven constructs.  Accepted values for n are:

              0      (default) Allow assume statements and free invariants.

              1      Treat all assumptions as assertions, and drop free.

              Ignore include directives.

              Reduce  Z3's knowledge of nonlinear arithmetic (multiplication and division).  This
              results in more manual work but also tends to produce more predictable behavior.

              Control printing.  Accepted values for mode are:

                     (default) Print everything.

                     Disable printing of "{:verify false} methods incorporated  via  the  include
                     mechanism, as well as datatypes and fields included from other files.

                     Like  NoIncludes,  but also disable printing of functions ghost methods, and
                     proof statements in implementation methods.

              Print Dafny program to the specified file after resolving it.  Specify /rprint:- to
              print to standard output.

              Control  whether  or  not  dafny emits intermediate C# code.  Accepted values for n

              0      (default) Don't save intermediate C# code.

              1      Save intermediate C# code as a .cs file.

   Boogie options
       Multiple .bpl files supplied on the command line are concatenated into one Boogie program.

              Control printing of enhanced error messages.  Accepted values for n are:

              0      (default) Do not print enhanced error messages.

              1      Print Z3 error model enhanced error messages.

              Unroll loops, following up to n back edges (and then some).

              Save the model in BVD format to the specified file.

              Parse only.

              Parse and resolve only.

              Skip any implementation with resolution or type checking errors.

              Control pretty-printing of Boogie code.  Accepted values for n are:

              0      Print each Boogie statement on one line.

              1      (default) Pretty-print with some line breaks.  This is slower but easier  to

              Print  Boogie  program to the specified file after parsing it.  Specify /print:- to
              print to standard output.

              Print the control flow graph of each implementation in dot(1) format to files named

              With /print, desugar calls.

              Control printing of Z3's error model.  Accepted values for n are:

              0      (default) Do not print Z3's error model.

              1      Print Z3's error model.

              2      Print Z3's error model and reverse mappings.

              3      Print Z3's error model in a more human-readable way.

              With /print, desugar all structured statements.

              Print augmented information that uniquely identifies variables.

              Limit which procedures to check.

              Enable sound loop unrolling.

              When parsing, use the base name of the file for tokens instead of the path supplied
              on the command line.

   Inference options
              Instrument inferred invariants as asserts to be checked by the theorem prover.

              Perform procedure contract inference.

              Use abstract interpretation to  infer  invariants.   domains  may  be  any  of  the

              c      constant propagation

              d      dynamic type

              i      intervals

              j      stronger intervals (cannot be combined with other domains)

              n      nullness

              p      polyhedra for linear inequalities

              t      trivial bottom/top lattice (cannot be combined with other domains)

              You may also specify the following options as pseudo-domains:

              s      debug statistics

              0...9  number of iterations before applying a widen (default: 0)

              The default is /infer:i.  With /infer (and no domains), all domains will be used.

              Control when inferred invariants are instrumented.  Accepted values for flag are:

              h      (default)  Instrument  inferred  invariants  only  at  the beginning of loop

              e      Instrument inferred invariants at the beginning  and  end  of  every  block.
                     This mode is intended for use in debugging abstract domains.

              Turn off the default inference, and override any previous /infer flags.

              Print Boogie program after it has been instrumented with invariants.

   Debugging and tracing options
       /break Launch and break into the debugger.

              Print debug output during translation.

       /trace Blurt out various debug trace information.  Implies /tracePOs.

              Output information about the number of proof obligations.

              Output timing information at certain points in the pipeline.

   Verification condition generation options
              Include  free loop invariants as assumptions in checking contexts.  Usually, a free
              loop invariant (or assume statement  in  that  position)  is  ignored  in  checking
              contexts (like other free things).

              Translate Boogie's A ==> B into prover's A ==> A && B.

              Control when to coalesce blocks.  Accepted values for n are:

              0      Do not coalesce blocks.

              1      (default) Coalesce blocks.

              Use the specified fixed point engine for inference.

              Infer  the least number of constants (whose names are prefixed by prefix) that need
              to be set to true for the program to be correct.  Implies /stratifiedInline:1.

              Use the specified inlining strategy for  procedures  with  the  :inline  attribute.
              Accepted strategies are none, assume (the default), assert, and spec.

              Use the lazy inlining algorithm.

              Control when and how to perform live variable analysis.  Accepted values for n are:

              0      Do not perform live variable analysis.

              1      (default) Perform live variable analysis.

              2      Perform interprocedural live variable analysis.

              Do  not  abstract map types in the encoding.  This is an experimental feature which
              will not do the right thing if the program uses polymorphism.

              Skip verification condition generation and invocation of the theorem prover.

              Print the implementation after  inlining  calls  to  procedures  with  the  :inline

              Set the recursion bound for stratified inlining to n.  By default, n is 500.

              In  the  verification condition, generate an auxiliary symbol, elsewhere defined to
              be +, instead of +.

              Control whether to remove empty blocks during  verification  condition  generation.
              Accepted values for n are:

              0      Do not remove empty blocks.

              1      (default) Remove empty blocks.

       /smoke Run  the soundness smoke test: try to stick assert false; in some places in the BPL
              and see if we can still prove it.

              Set the timeout, in seconds, for a single  theorem  prover  invocation  during  the
              smoke test.  By default, n is 10.

              Use the stratified inlining algorithm.

              Control  when subsumption is applied to asserted conditions.  Accepted values for n

              0      Never apply subsumption.

              1      Do not apply subsumption for quantifiers.

              2      (default) Always apply subsumption.

              Print debug output during verification condition generation.

              Control how to encode types when sending the  verification  condition  to  the  the
              theorem prover.  Allowed methods are:

              a      arguments

              m      monomorphic

              n      none (unsound)

              p      (default) predicates

              Specify the verification condition variety.  Accepted varieties are:

              b      flat block

              d      (default) DAG

              doomed doomed

              l      local

              m      nested block reach

              n      nested block

              r      flat block reach

              s      structured

              Verify each input program separately.

              Control verification result caching.  Accepted values for n are:

              0      (default) Do not use any verification result caching.

              1      Verify  several program snapshots (named filename.v0.bpl to filename.vN.bpl)
                     using basic verification result caching.

              2      Use more advanced verification result caching.

   Verification condition splitting
              Try to verify n verification conditions at once.  Defaults to 1.

              For the nth split, dump and split.n.bpl.  Note that this affects  error

              Set  the timeout, in seconds, for the single last assertion in keep-going mode.  By
              default, n is 30.

              Set the timeout, in seconds, for a single theorem prover invocation  in  keep-going
              mode, except for the final single-assertion case.  By default, n is 1.

              Like  /vcsCores:n,  where  n  is  the machine's processor count multiplied by f and
              rounded to the nearest integer.  f must be in the  range  [0.0,  3.0].   This  will
              never set n less than 1.

              Verification  conditions  will  not  be  split  unless  the  cost of a verification
              condition exceeds f.  f defaults to 2000.0.  This does not apply in the  keep-going
              mode after the first round of splitting.

              If  n  is set to more than 1, this activates keep-going mode, where after the first
              round of splitting, verification conditions that time out are split into  n  pieces
              and  retried until either proving them is successful or there is only one assertion
              on a single path and it times out.  (In such a case, dafny  reports  an  error  for
              that assertion).  By default, n is 1 (that is, keep-going mode is disabled).

              Set  the  maximal number of verification conditions generated per method.  In keep-
              going mode, this only applies to the first round.  By default, n is 1.

       /vcsPathCostMult:f1, /vcsAssumeMult:f2
              Controls the cost of a block.  Block cost is computed according to the formula

                  (assert-cost + f2 × assume-cost) × (1 + f1 × entering-paths)

              where f1 defaults to 1.0 and f2 defaults to 0.01.  The cost of a  single  assertion
              or assumption is always 1.0.

              Sets  a scale factor which dafny will multiply by the number of paths in a block if
              more than one path join at a block.  This is intended to reflect the fact that  the
              prover will learn something on one path before proceeding to the next.  By default,
              f is 0.8.

              If the best path split of a verification condition of cost A is  into  verification
              conditions  of  cost  B and C,  then  the  split  is  applied  if  Af × (B + C).
              Otherwise, assertion splitting will be applied.  By default, f  is  0.5  (that  is,
              always  do  path  splitting if possible).  Increase f to do less path splitting and
              more assertion splitting.

   Prover options
              Limit the number of errors produced for each procedure.  By default, n  is  5,  but
              some provers may only support 1.

              Control  whether  or  not trace labels appear in the error output.  Accepted values
              for n are:

              0      Print no trace labels in the error output.

              1      (default) Print useful trace labels in error output.

              2      Print all trace labels in error output.

              Define the expansion of the macro @PREFIX@.

       /p:key[:value], /proverOpt:key[:value]
              Provide a prover-specific option.

              Set the platform type and location.  ptype may be v11, v2, or  cli1,  and  location
              should be the platform libraries directory.

              Use  theorem  prover  p.  p may be a full path to a prover DLL, or it may be one of
              the following standard provers:


                     This implies /vc:n and /vcBrackets:1.

              SMTLib (default) Use the SMTLib2 format, and call Z3.

              Z3     Z3 with the Simplify format.

              Z3api  Z3 with the managed (CLI) API.

              Log input for the theorem prover.

              In addition to the standard file name macros, file can use the @PROC@ macro,  which
              causes  dafny to generate one prover log file per verification condition, expanding
              @PROC@ to the name of the procedure that the verification condition is for.

              Append (do not overwrite) the specified prover log file.

              Limit the prover to n megabytes of virtual memory before forcing it to restart.   n
              defaults to 100.

              Set  the time, in seconds, between closing the stream to the prover and killing the
              prover process.  n defaults to 0.

              Control warning output from the prover.  Accepted values for n are:

              0      (default) Don't print warning output from the prover.

              1      Print warnings to standard output.

              2      Print warnings to standard error.

              Restart the prover after each query.

              Limit the number of seconds spent trying to verify each procedure.

              Control whether or not odd-charactered identifier names will be bracketed with pipe
              characters ('|').  Accepted values for n are:

              0      (default) Do not bracket odd-charactered identifier names.

              1      Bracket odd-charactered identifier names.

   Prover options (CVC4)
              Set the path to the CVC4 executable.

   Prover options (Simplify)
              Set Simplify's matching depth limit.

   Prover options (Z3)
              Use Z3's native array theory, as opposed to axioms.  Implies /monomorphize.

              Output a model in SMTLib2 format.

              Set  the  path  to  the  Z3  executable.   On  Debian  systems,  this  defaults  to

              Configure use of LETs in Z3.  Accepted values for n are:

              0      Do not use LETs.

              1      Use only LET TERM.

              2      Use only LET FORMULA.

              3      (default) Use any LET.

              Report multiple counterexamples for each error.

              Set an additional Z3 option.

              Generate a multi-sorted verification condition that makes use of Z3 types.




       Dafny is copyright © 2003-2015 Microsoft Corporation  and  licensed  under  the  Microsoft
       Public License <>.

       This  manual  page  is  copyright  ©  2013, 2015 Benjamin Barenblat and licensed under the
       Apache License, Version 2.0.