Auto merge of #41862 - GuillaumeGomez:improve-e0477, r=nagisa

Improve E0477 error message

Part of #41816.

r? @nagisa

Author: bors

src/librustc/infer/error_reporting/note.rs

@@ -9,7 +9,7 @@
 // except according to those terms.
 
 use infer::{self, InferCtxt, SubregionOrigin};
-use ty::Region;
+use ty::{self, Region};
 use ty::error::TypeError;
 use errors::DiagnosticBuilder;
 
@@ -262,7 +262,14 @@ impl<'a, 'gcx, 'tcx> InferCtxt<'a, 'gcx, 'tcx> {
                                                "the type `{}` does not fulfill the required \
                                                 lifetime",
                                                self.ty_to_string(ty));
-                self.tcx.note_and_explain_region(&mut err, "type must outlive ", sub, "");
+                match *sub {
+                    ty::ReStatic => {
+                        self.tcx.note_and_explain_region(&mut err, "type must satisfy ", sub, "")
+                    }
+                    _ => {
+                        self.tcx.note_and_explain_region(&mut err, "type must outlive ", sub, "")
+                    }
+                }
                 err
             }
             infer::RelateRegionParamBound(span) => {

src/test/ui/static-lifetime.rs

@@ -0,0 +1,16 @@
+// Copyright 2016 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.
+
+pub trait Arbitrary: Sized + 'static {}
+
+impl<'a, A: Clone> Arbitrary for ::std::borrow::Cow<'a, A> {}
+
+fn main() {
+}

src/test/ui/static-lifetime.stderr

@@ -0,0 +1,10 @@
+error[E0477]: the type `std::borrow::Cow<'a, A>` does not fulfill the required lifetime
+  --> $DIR/static-lifetime.rs:13:20
+   |
+13 | impl<'a, A: Clone> Arbitrary for ::std::borrow::Cow<'a, A> {}
+   |                    ^^^^^^^^^
+   |
+   = note: type must satisfy the static lifetime
+
+error: aborting due to previous error
+