Add a wishlist folder to the test suite, with things that we do not support (yet!)

The curent examples include semi-bugs regarding calc statements and strings, and
stuff about sequences

8 files changed, 148 insertions, 0 deletions

diff --git a/Test/wishlist/calc.dfy b/Test/wishlist/calc.dfy
new file mode 100644
index 00000000..308fbb9a
--- /dev/null
+++ b/Test/wishlist/calc.dfy
@@ -0,0 +1,17 @@
+// RUN: %dafny /compile:0 /print:"%t.print" /dprint:"%t.dprint" "%s" > "%t"

+// RUN: %diff "%s.expect" "%t"

+

+// There is a bug in Dafny that causes the error from `L` to be reported at

+// position 0 in this file, instead of on a curly brace.

+

+lemma L()

+  ensures false {

+    calc { true; }

+}

+

+// Empty calc statements work fine, though:

+

+lemma L'()

+  ensures false {

+    calc { }

+}

diff --git a/Test/wishlist/calc.dfy.expect b/Test/wishlist/calc.dfy.expect
new file mode 100644
index 00000000..1d5a55a6
--- /dev/null
+++ b/Test/wishlist/calc.dfy.expect
@@ -0,0 +1,11 @@
+(0,-1): Error BP5003: A postcondition might not hold on this return path.

+calc.dfy(8,10): Related location: This is the postcondition that might not hold.

+Execution trace:

+    (0,0): anon0

+    calc.dfy(9,5): anon2_Else

+calc.dfy(15,16): Error BP5003: A postcondition might not hold on this return path.

+calc.dfy(15,10): Related location: This is the postcondition that might not hold.

+Execution trace:

+    (0,0): anon0

+

+Dafny program verifier finished with 2 verified, 2 errors

diff --git a/Test/wishlist/sequences-literals.dfy b/Test/wishlist/sequences-literals.dfy
new file mode 100644
index 00000000..382349a4
--- /dev/null
+++ b/Test/wishlist/sequences-literals.dfy
@@ -0,0 +1,58 @@
+// RUN: %dafny /compile:0 /autoTriggers:1 /print:"%t.print" /dprint:"%t.dprint" "%s" > "%t"

+// RUN: %diff "%s.expect" "%t"

+

+// Note: in the tests below, it could be useful to experiment with the

+// following triggers for some of the library axioms:

+//

+// axiom (forall<T> s0: Seq T, s1: Seq T, x: T ::

+//   { Seq#Contains(s0, x), Seq#Append(s0, s1) }

+//   { Seq#Contains(s1, x), Seq#Append(s0, s1) }

+//   Seq#Contains(Seq#Append(s0, s1), x)

+//      <==> Seq#Contains(s0, x) || Seq#Contains(s1, x));

+//

+// axiom (forall<T> s: Seq T, v: T, x: T ::

+//   { Seq#Contains(s, x), Seq#Build(s, v) }

+//   Seq#Contains(Seq#Build(s, v), x) <==> v == x || Seq#Contains(s, x));

+//

+// Another, not necessarily incompatible approach would be to explicitly add

+// `assume k in s` for each element k of constant lists.

+

+method SmallList() {

+  var s := [0, 1, 5, 6];

+  if * {

+    // This fails: Dafny needs a hint here, because the triggers on the library axioms are pretty strict:

+    assert exists n :: n in s; // WISH

+  } else if * {

+    // This works

+    assert 0 in s;

+    assert exists n :: n in s;

+  } else if * {

+    // This also works, thanks to the magic of triggering on `$Box`.

+    assert exists n {:autotriggers false} :: n in s;

+  }

+}

+

+method LargeList() {

+  var s := [0, 1, 2, 3, 4, 5, 6, 7, 8, /* 9, 10, 11, */ 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99, 100, 101, 102, 103, 104, 105, 106, 107, 108, 109, 110, 111, 112, 113, 114, 115, 116, 117, 118, /* 119, 120, 121, */ 122, 123, 124, 125, 126, 127, 128, 129, 130, 131, 132, 133, 134, 135, 136];

+  if * {

+    // The hint fails here. Maybe because z3 gets into a loop trying to unwrap

+    // this large list? This is also very slow.

+    assert 0 in s; // WISH

+    assert exists n :: n in s;

+  } else if * {

+    // Strangely, the hint works here. Why?

+    assert 122 in s;

+    assert exists n :: n in s;

+  } else if * {

+    // This also fails; since z3 only goes to a depth of 100, this probably

+    // wouldn't work with relaxed triggers eithers

+    assert exists n :: n in s && n >= 120;

+  } else if * {

+    // This works: this is certainly more `triggering-on-$Box` magic, but I'm

+    // not sure exactly how it works

+    assert exists n {:autotriggers false} :: n in s && n >= 120;

+  } else if * {

+    // `$Box` only offers limited solace, though

+    assert exists n {:autotriggers false} :: n in s && n < 3;

+  }

+}

diff --git a/Test/wishlist/sequences-literals.dfy.expect b/Test/wishlist/sequences-literals.dfy.expect
new file mode 100644
index 00000000..18e3f98a
--- /dev/null
+++ b/Test/wishlist/sequences-literals.dfy.expect
@@ -0,0 +1,20 @@
+sequences-literals.dfy(24,11): Error: assertion violation

+Execution trace:

+    (0,0): anon0

+    (0,0): anon7_Then

+sequences-literals.dfy(40,13): Error: assertion violation

+Execution trace:

+    (0,0): anon0

+    (0,0): anon17_Then

+sequences-literals.dfy(49,11): Error: assertion violation

+Execution trace:

+    (0,0): anon0

+    (0,0): anon20_Then

+    (0,0): anon7

+sequences-literals.dfy(56,11): Error: assertion violation

+Execution trace:

+    (0,0): anon0

+    (0,0): anon24_Then

+    (0,0): anon15

+

+Dafny program verifier finished with 2 verified, 4 errors

diff --git a/Test/wishlist/sequences-s0-in-s.dfy b/Test/wishlist/sequences-s0-in-s.dfy
new file mode 100644
index 00000000..20127917
--- /dev/null
+++ b/Test/wishlist/sequences-s0-in-s.dfy
@@ -0,0 +1,25 @@
+// RUN: %dafny /compile:0 /autoTriggers:1 /print:"%t.print" /dprint:"%t.dprint" "%s" > "%t"

+// RUN: %diff "%s.expect" "%t"

+

+// The following is also due to a weakness in the axiomatization: namely, it is

+// not easy to learn, using Dafny's axioms, that s[0] in s. One can of course

+// prove it, but it doesn't come for free.

+

+method InSeqTriggers(s: seq<int>, i: nat)

+  requires forall x :: x in s ==> x > 0;

+  requires |s| > 0 {

+    if * {

+      // Fails

+      assert s[0] > 0; // WISH

+    } else if * {

+      // Works

+      assert s[0] in s;

+      assert s[0] > 0;

+    }

+}

+

+method InSeqNoAutoTriggers(s: seq<int>, i: nat)

+  requires forall x {:autotriggers false} :: x in s ==> x > 0;

+  requires |s| > 0 {

+    assert s[0] > 0; // Works

+}

diff --git a/Test/wishlist/sequences-s0-in-s.dfy.expect b/Test/wishlist/sequences-s0-in-s.dfy.expect
new file mode 100644
index 00000000..4633e5f6
--- /dev/null
+++ b/Test/wishlist/sequences-s0-in-s.dfy.expect
@@ -0,0 +1,6 @@
+sequences-s0-in-s.dfy(13,18): Error: assertion violation

+Execution trace:

+    (0,0): anon0

+    (0,0): anon5_Then

+

+Dafny program verifier finished with 3 verified, 1 error

diff --git a/Test/wishlist/strings.dfy b/Test/wishlist/strings.dfy
new file mode 100644
index 00000000..372711b0
--- /dev/null
+++ b/Test/wishlist/strings.dfy
@@ -0,0 +1,6 @@
+// RUN: %dafny /compile:0 /print:"%t.print" /dprint:"%t.dprint" "%s" > "%t"

+// RUN: %diff "%s.expect" "%t"

+

+method EqualityOfStrings() {

+  assert "a" != "b"; // WISH

+}

diff --git a/Test/wishlist/strings.dfy.expect b/Test/wishlist/strings.dfy.expect
new file mode 100644
index 00000000..2817a66e
--- /dev/null
+++ b/Test/wishlist/strings.dfy.expect
@@ -0,0 +1,5 @@
+strings.dfy(5,13): Error: assertion violation

+Execution trace:

+    (0,0): anon0

+

+Dafny program verifier finished with 1 verified, 1 error