From f676547c9788b919762bfb379b1e26ebd94d3dc9 Mon Sep 17 00:00:00 2001
From: Niko Matsakis <niko@alum.mit.edu>
Date: Thu, 19 Jul 2012 10:10:22 -0700
Subject: [PATCH] Fix intersection of two region params in infer, cc #2962

---
 src/rustc/middle/typeck/infer.rs              |  4 ++--
 src/test/compile-fail/regions-infer-call-3.rs | 14 ++++++++++++++
 src/test/run-pass/regions-infer-call-2.rs     | 13 +++++++++++++
 src/test/run-pass/regions-infer-call.rs       |  9 +++++++++
 4 files changed, 38 insertions(+), 2 deletions(-)
 create mode 100644 src/test/compile-fail/regions-infer-call-3.rs
 create mode 100644 src/test/run-pass/regions-infer-call-2.rs
 create mode 100644 src/test/run-pass/regions-infer-call.rs

diff --git a/src/rustc/middle/typeck/infer.rs b/src/rustc/middle/typeck/infer.rs
index 2bc018395639..79df5975307d 100644
--- a/src/rustc/middle/typeck/infer.rs
+++ b/src/rustc/middle/typeck/infer.rs
@@ -2371,7 +2371,8 @@ fn regions(a: ty::region, b: ty::region) -> cres<ty::region> {
                 }
               }
 
-              (ty::re_scope(a_id), ty::re_scope(b_id)) {
+              (ty::re_scope(a_id), ty::re_scope(b_id)) |
+              (ty::re_free(a_id, _), ty::re_free(b_id, _)) {
                 // We want to generate a region that is contained by both of
                 // these: so, if one of these scopes is a subscope of the
                 // other, return it.  Otherwise fail.
@@ -2385,7 +2386,6 @@ fn regions(a: ty::region, b: ty::region) -> cres<ty::region> {
 
               // For these types, we cannot define any additional
               // relationship:
-              (ty::re_free(_, _), ty::re_free(_, _)) |
               (ty::re_bound(_), ty::re_bound(_)) |
               (ty::re_bound(_), ty::re_free(_, _)) |
               (ty::re_bound(_), ty::re_scope(_)) |
diff --git a/src/test/compile-fail/regions-infer-call-3.rs b/src/test/compile-fail/regions-infer-call-3.rs
new file mode 100644
index 000000000000..4a2be378d425
--- /dev/null
+++ b/src/test/compile-fail/regions-infer-call-3.rs
@@ -0,0 +1,14 @@
+fn select(x: &int, y: &int) -> &int { x }
+
+fn with<T>(f: fn(x: &int) -> T) -> T {
+    f(&20)
+}
+
+fn manip(x: &a/int) -> int {
+    let z = do with |y| { select(x, y) };
+    //~^ ERROR reference is not valid outside of its lifetime
+    *z
+}
+
+fn main() {
+}
\ No newline at end of file
diff --git a/src/test/run-pass/regions-infer-call-2.rs b/src/test/run-pass/regions-infer-call-2.rs
new file mode 100644
index 000000000000..9e4000f05993
--- /dev/null
+++ b/src/test/run-pass/regions-infer-call-2.rs
@@ -0,0 +1,13 @@
+fn takes_two(x: &int, y: &int) -> int { *x + *y }
+
+fn with<T>(f: fn(x: &int) -> T) -> T {
+    f(&20)
+}
+
+fn has_one(x: &a/int) -> int {
+    do with |y| { takes_two(x, y) }
+}
+
+fn main() {
+    assert has_one(&2) == 22;
+}
\ No newline at end of file
diff --git a/src/test/run-pass/regions-infer-call.rs b/src/test/run-pass/regions-infer-call.rs
new file mode 100644
index 000000000000..f3f14d0250c6
--- /dev/null
+++ b/src/test/run-pass/regions-infer-call.rs
@@ -0,0 +1,9 @@
+fn takes_two(x: &int, y: &int) -> int { *x + *y }
+
+fn has_two(x: &a/int, y: &b/int) -> int {
+    takes_two(x, y)
+}
+
+fn main() {
+    assert has_two(&20, &2) == 22;
+}
\ No newline at end of file