Correctly handle path stability for 'use tree' items

PR #5956 started checking the stability of path segments.
However, this was not applied to 'use tree' items
(e.g. 'use some::path::{ItemOne, ItemTwo}') due to the way
that we desugar these items in HIR lowering.

This PR modifies 'use tree' lowering to preserve resolution
information, which is needed by stability checking.

4 files changed, 38 insertions, 3 deletions

diff --git a/src/test/ui/lint/lint-output-format.rs b/src/test/ui/lint/lint-output-format.rs
index 169a98c9483..67e8ec8f13b 100644
--- a/src/test/ui/lint/lint-output-format.rs
+++ b/src/test/ui/lint/lint-output-format.rs
@@ -5,6 +5,7 @@
 
 extern crate lint_output_format; //~ ERROR use of unstable library feature
 use lint_output_format::{foo, bar}; //~ ERROR use of unstable library feature
+//~| ERROR use of unstable library feature
 
 fn main() {
     let _x = foo();
diff --git a/src/test/ui/lint/lint-output-format.stderr b/src/test/ui/lint/lint-output-format.stderr
index 3bc1d6fc135..0db79a1564f 100644
--- a/src/test/ui/lint/lint-output-format.stderr
+++ b/src/test/ui/lint/lint-output-format.stderr
@@ -7,6 +7,14 @@ LL | extern crate lint_output_format;
    = help: add `#![feature(unstable_test_feature)]` to the crate attributes to enable
 
 error[E0658]: use of unstable library feature 'unstable_test_feature'
+  --> $DIR/lint-output-format.rs:7:26
+   |
+LL | use lint_output_format::{foo, bar};
+   |                          ^^^
+   |
+   = help: add `#![feature(unstable_test_feature)]` to the crate attributes to enable
+
+error[E0658]: use of unstable library feature 'unstable_test_feature'
   --> $DIR/lint-output-format.rs:7:31
    |
 LL | use lint_output_format::{foo, bar};
@@ -15,13 +23,13 @@ LL | use lint_output_format::{foo, bar};
    = help: add `#![feature(unstable_test_feature)]` to the crate attributes to enable
 
 error[E0658]: use of unstable library feature 'unstable_test_feature'
-  --> $DIR/lint-output-format.rs:11:14
+  --> $DIR/lint-output-format.rs:12:14
    |
 LL |     let _y = bar();
    |              ^^^
    |
    = help: add `#![feature(unstable_test_feature)]` to the crate attributes to enable
 
-error: aborting due to 3 previous errors
+error: aborting due to 4 previous errors
 
 For more information about this error, try `rustc --explain E0658`.
diff --git a/src/test/ui/stability-attribute/stable-in-unstable.rs b/src/test/ui/stability-attribute/stable-in-unstable.rs
index 272a1a97234..226367c3992 100644
--- a/src/test/ui/stability-attribute/stable-in-unstable.rs
+++ b/src/test/ui/stability-attribute/stable-in-unstable.rs
@@ -44,3 +44,11 @@ mod isolated5 {
 
     impl stable_in_unstable_std::old_stable_module::OldTrait for LocalType {}
 }
+
+mod isolated6 {
+    use stable_in_unstable_core::new_unstable_module::{OldTrait}; //~ ERROR use of unstable library feature 'unstable_test_feature'
+}
+
+mod isolated7 {
+    use stable_in_unstable_core::new_unstable_module::*; //~ ERROR use of unstable library feature 'unstable_test_feature'
+}
diff --git a/src/test/ui/stability-attribute/stable-in-unstable.stderr b/src/test/ui/stability-attribute/stable-in-unstable.stderr
index e123d83584c..b5e3e5f1202 100644
--- a/src/test/ui/stability-attribute/stable-in-unstable.stderr
+++ b/src/test/ui/stability-attribute/stable-in-unstable.stderr
@@ -34,6 +34,24 @@ LL |     impl stable_in_unstable_core::new_unstable_module::OldTrait for LocalTy
    = note: see issue #1 <https://github.com/rust-lang/rust/issues/1> for more information
    = help: add `#![feature(unstable_test_feature)]` to the crate attributes to enable
 
-error: aborting due to 4 previous errors
+error[E0658]: use of unstable library feature 'unstable_test_feature'
+  --> $DIR/stable-in-unstable.rs:49:56
+   |
+LL |     use stable_in_unstable_core::new_unstable_module::{OldTrait};
+   |                                                        ^^^^^^^^
+   |
+   = note: see issue #1 <https://github.com/rust-lang/rust/issues/1> for more information
+   = help: add `#![feature(unstable_test_feature)]` to the crate attributes to enable
+
+error[E0658]: use of unstable library feature 'unstable_test_feature'
+  --> $DIR/stable-in-unstable.rs:53:9
+   |
+LL |     use stable_in_unstable_core::new_unstable_module::*;
+   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = note: see issue #1 <https://github.com/rust-lang/rust/issues/1> for more information
+   = help: add `#![feature(unstable_test_feature)]` to the crate attributes to enable
+
+error: aborting due to 6 previous errors
 
 For more information about this error, try `rustc --explain E0658`.