Auto merge of #52481 - Mark-Simulacrum:stable-next, r=alexcrichton

1.27.2 stable release

This is essentially a backport of #52232. I've set the release date for Friday, July 20th.

r? @alexcrichton

Author: bors

RELEASES.md

@@ -1,3 +1,14 @@
+Version 1.27.2 (2018-07-20)
+===========================
+
+Compatibility Notes
+-------------------
+
+- The borrow checker was fixed to avoid potential unsoundness when using
+  match ergonomics: [#52213][52213].
+
+[52213]: https://github.com/rust-lang/rust/issues/52213
+
 Version 1.27.1 (2018-07-10)
 ===========================
 

src/bootstrap/channel.rs

@@ -24,7 +24,7 @@ use Build;
 use config::Config;
 
 // The version number
-pub const CFG_RELEASE_NUM: &str = "1.27.1";
+pub const CFG_RELEASE_NUM: &str = "1.27.2";
 
 pub struct GitInfo {
     inner: Option<Info>,

src/librustc/middle/mem_categorization.rs

@@ -1325,7 +1325,7 @@ impl<'a, 'gcx, 'tcx> MemCategorizationContext<'a, 'gcx, 'tcx> {
                 ref ty => span_bug!(pat.span, "tuple pattern unexpected type {:?}", ty),
             };
             for (i, subpat) in subpats.iter().enumerate_and_adjust(expected_len, ddpos) {
-                let subpat_ty = self.pat_ty_unadjusted(&subpat)?; // see (*2)
+                let subpat_ty = self.pat_ty_adjusted(&subpat)?; // see (*2)
                 let interior = InteriorField(FieldIndex(i, Name::intern(&i.to_string())));
                 let subcmt = Rc::new(self.cat_imm_interior(pat, cmt.clone(), subpat_ty, interior));
                 self.cat_pattern_(subcmt, &subpat, op)?;

src/librustc_typeck/check/regionck.rs

@@ -105,7 +105,10 @@ use rustc::hir::{self, PatKind};
 
 // a variation on try that just returns unit
 macro_rules! ignore_err {
-    ($e:expr) => (match $e { Ok(e) => e, Err(_) => return () })
+    ($e:expr) => (match $e { Ok(e) => e, Err(_) => {
+        debug!("ignoring mem-categorization error!");
+        return ()
+    }})
 }
 
 ///////////////////////////////////////////////////////////////////////////
@@ -1036,7 +1039,7 @@ impl<'a, 'gcx, 'tcx> RegionCtxt<'a, 'gcx, 'tcx> {
         debug!("link_pattern(discr_cmt={:?}, root_pat={:?})",
                discr_cmt,
                root_pat);
-        let _ = self.with_mc(|mc| {
+        ignore_err!(self.with_mc(|mc| {
             mc.cat_pattern(discr_cmt, root_pat, |sub_cmt, sub_pat| {
                 match sub_pat.node {
                     // `ref x` pattern
@@ -1051,7 +1054,7 @@ impl<'a, 'gcx, 'tcx> RegionCtxt<'a, 'gcx, 'tcx> {
                     _ => {}
                 }
             })
-        });
+        }));
     }
 
     /// Link lifetime of borrowed pointer resulting from autoref to lifetimes in the value being

src/test/compile-fail/issue-52213.rs

@@ -0,0 +1,24 @@
+// Copyright 2017 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+fn transmute_lifetime<'a, 'b, T>(t: &'a (T,)) -> &'b T {
+    match (&t,) { //~ ERROR cannot infer an appropriate lifetime
+        ((u,),) => u,
+    }
+}
+
+fn main() {
+    let x = {
+        let y = Box::new((42,));
+        transmute_lifetime(&y)
+    };
+
+    println!("{}", x);
+}