diff options
| author |  Rustan Leino <leino@microsoft.com> | 2011-11-09 00:00:04 -0800 |
|---|---|---|
| committer | Rustan Leino <leino@microsoft.com> | 2011-11-09 00:00:04 -0800 |
| commit | b66ed178322cd26bbaae2591f2518e20652733bb (patch) | |
| tree | 067ab42de8d0be87f477e46e3d625cfe6f839948 /Test/dafny0 | |
| parent | c6644a9a2fa34be7bbbfbd4fa7b63c23accb4296 (diff) | |
Dafny: fixed part of a type-inference issue with datatypes and the < operator on datatypes
Dafny: allow the well-formedness check of a function's specification to know that the function, on the current arguments, returns a value of the declared result type
Diffstat (limited to 'Test/dafny0')
| -rw-r--r-- | Test/dafny0/Answer | 5 | ||||
| -rw-r--r-- | Test/dafny0/NatTypes.dfy | 27 |
2 files changed, 31 insertions, 1 deletions
diff --git a/Test/dafny0/Answer b/Test/dafny0/Answer index bdbb8822..bae3aa50 100644 --- a/Test/dafny0/Answer +++ b/Test/dafny0/Answer @@ -133,8 +133,11 @@ Execution trace: (0,0): anon6_Else
(0,0): anon7_Else
(0,0): anon8_Then
+NatTypes.dfy(127,21): Error: value assigned to a nat must be non-negative
+Execution trace:
+ (0,0): anon3_Then
-Dafny program verifier finished with 12 verified, 8 errors
+Dafny program verifier finished with 15 verified, 9 errors
-------------------- SmallTests.dfy --------------------
SmallTests.dfy(30,11): Error: index out of range
diff --git a/Test/dafny0/NatTypes.dfy b/Test/dafny0/NatTypes.dfy index 47bc22e1..0513591c 100644 --- a/Test/dafny0/NatTypes.dfy +++ b/Test/dafny0/NatTypes.dfy @@ -108,3 +108,30 @@ function Abs(x: int): nat {
if 0 <= x then x else -x
}
+
+// ----- Here are tests that the type of the result value of a function is known by the
+// ----- time the well-formedness of the function's specification is checked.
+
+function TakesANat(n: nat): bool
+{
+ n < 29
+}
+
+function Naturally(): nat
+ ensures TakesANat(Naturally()); // the wellformedness of this check requires
+{
+ 17
+}
+
+function Integrally_Bad(): int
+ ensures TakesANat(Integrally_Bad()); // error: well-formedness check fails
+{
+ 17
+}
+
+function Integrally_Good(): int
+ ensures 0 <= Integrally_Good();
+ ensures TakesANat(Integrally_Good()); // here, the needed information follows from the preceding ensures clause
+{
+ 17
+}
|