diff --git a/src/test/compile-fail/no-constraint-prop.rs b/src/test/compile-fail/no-constraint-prop.rs
new file mode 100644
index 00000000000..510b7ab0491
--- /dev/null
+++ b/src/test/compile-fail/no-constraint-prop.rs
@@ -0,0 +1,21 @@
+// error-pattern:Unsatisfied precondition constraint (for example, le(b, d
+// xfail-stage0
+use std;
+import std::str::*;
+import std::uint::*;
+
+fn main() {
+  let uint a = 1u;
+  let uint b = 4u;
+  let uint c = 5u;
+  // make sure that the constraint le(b, a) exists...
+  check le(b, a);
+  // ...invalidate it...
+  b += 1u;
+  check le(c, a);
+  // ...and check that it doesn't get set in the poststate of
+  // the next statement, since it's not true in the
+  // prestate.
+  auto d <- a;
+  log (safe_slice("kitties", b, d)); 
+}
\ No newline at end of file
diff --git a/src/test/run-pass/constraint-prop-expr-move.rs b/src/test/run-pass/constraint-prop-expr-move.rs
new file mode 100644
index 00000000000..e7ef7f63bd5
--- /dev/null
+++ b/src/test/run-pass/constraint-prop-expr-move.rs
@@ -0,0 +1,13 @@
+// xfail-stage0
+use std;
+import std::str::*;
+import std::uint::*;
+
+fn main() {
+  let uint a = 1u;
+  let uint b = 4u;
+  let uint c = 17u;
+  check le(a, b);
+  c <- a;
+  log (safe_slice("kitties", c, b)); 
+}
\ No newline at end of file
diff --git a/src/test/run-pass/constraint-prop-move.rs b/src/test/run-pass/constraint-prop-move.rs
new file mode 100644
index 00000000000..1c426c21fc3
--- /dev/null
+++ b/src/test/run-pass/constraint-prop-move.rs
@@ -0,0 +1,12 @@
+// xfail-stage0
+use std;
+import std::str::*;
+import std::uint::*;
+
+fn main() {
+  let uint a = 1u;
+  let uint b = 4u;
+  check le(a, b);
+  auto c <- a;
+  log (safe_slice("kitties", c, b)); 
+}
\ No newline at end of file
diff --git a/src/test/run-pass/constraint-prop-swap.rs b/src/test/run-pass/constraint-prop-swap.rs
new file mode 100644
index 00000000000..c4ac4801135
--- /dev/null
+++ b/src/test/run-pass/constraint-prop-swap.rs
@@ -0,0 +1,12 @@
+// xfail-stage0
+use std;
+import std::str::*;
+import std::uint::*;
+
+fn main() {
+  let uint a = 4u;
+  let uint b = 1u;
+  check le(b, a);
+  b <-> a;
+  log (safe_slice("kitties", a, b)); 
+}
\ No newline at end of file
diff --git a/src/test/run-pass/constraint-prop.rs b/src/test/run-pass/constraint-prop.rs
new file mode 100644
index 00000000000..9508daecadb
--- /dev/null
+++ b/src/test/run-pass/constraint-prop.rs
@@ -0,0 +1,12 @@
+// xfail-stage0
+use std;
+import std::str::*;
+import std::uint::*;
+
+fn main() {
+  let uint a = 1u;
+  let uint b = 4u;
+  check le(a, b);
+  auto c = b;
+  log (safe_slice("kitties", a, c)); 
+}
\ No newline at end of file