---

yaml
---
r: 183634
b: refs/heads/beta
c: d0ef166
h: refs/heads/master
v: v3

Author: nikomatsakis

[refs]

@@ -31,7 +31,7 @@ refs/heads/automation-fail: 1bf06495443584539b958873e04cc2f864ab10e4
 refs/heads/issue-18208-method-dispatch-3-quick-reject: 2009f85b9f99dedcec4404418eda9ddba90258a2
 refs/heads/batch: b7fd822592a4fb577552d93010c4a4e14f314346
 refs/heads/building: 126db549b038c84269a1e4fe46f051b2c15d6970
-refs/heads/beta: f58a1bfa981eee4ba4d4c3c801f94772e4ab0019
+refs/heads/beta: d0ef1664ca9bc885724e3a42d3194079ad0cf582
 refs/heads/windistfix: 7608dbad651f02e837ed05eef3d74a6662a6e928
 refs/tags/1.0.0-alpha: e42bd6d93a1d3433c486200587f8f9e12590a4d7
 refs/heads/tmp: eb836bf767aa1d8d4cba488a9091cde3c0ab4b2f

branches/beta/src/librustc_typeck/check/mod.rs

@@ -1891,12 +1891,13 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
 
 impl<'a, 'tcx> RegionScope for FnCtxt<'a, 'tcx> {
     fn object_lifetime_default(&self, span: Span) -> Option<ty::Region> {
-        // TODO. RFC #599 specifies that object lifetime defaults take
-        // precedence over other defaults. *However,* within a fn
-        // body, we typically use inference to allow users to elide
-        // lifetimes whenever they like, and then just infer it to
-        // whatever it must be. So I interpret that as applying only
-        // to fn sigs.
+        // RFC #599 specifies that object lifetime defaults take
+        // precedence over other defaults. But within a fn body we
+        // don't have a *default* region, rather we use inference to
+        // find the *correct* region, which is strictly more general
+        // (and anyway, within a fn body the right region may not even
+        // be something the user can write explicitly, since it might
+        // be some expression).
         Some(self.infcx().next_region_var(infer::MiscVariable(span)))
     }