Fix issue 139. Allow bound variables in nested case patterns to shadow variables

declared outside the enclosing match.

2 files changed, 27 insertions, 0 deletions

diff --git a/Test/dafny4/Bug139.dfy b/Test/dafny4/Bug139.dfy
new file mode 100644
index 00000000..bd4ded73
--- /dev/null
+++ b/Test/dafny4/Bug139.dfy
@@ -0,0 +1,25 @@
+// RUN: %dafny /compile:0  "%s" > "%t"

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

+

+datatype List = Nil | Cons(int, List)

+

+method R(xs: List)

+{

+  var a: int;

+  var b: int;

+  match xs

+  case Nil =>

+  case Cons(a, Nil()) =>  // this 'a' is allowed

+  case Cons(x, Cons(b, tail)) =>  // this 'b' (which is in a nested position) generates an error

+}

+

+function F(xs: List): int

+{

+  var a := 4;

+  var b := 7;

+  match xs

+  case Nil => 0

+  case Cons(a, Nil()) => 1

+  case Cons(x, Cons(b, tail)) => 2

+}

+

diff --git a/Test/dafny4/Bug139.dfy.expect b/Test/dafny4/Bug139.dfy.expect
new file mode 100644
index 00000000..52595bf9
--- /dev/null
+++ b/Test/dafny4/Bug139.dfy.expect
@@ -0,0 +1,2 @@
+

+Dafny program verifier finished with 3 verified, 0 errors