diff --git a/.travis.yml b/.travis.yml
index 966b7d7bac4..d699bd842ee 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -47,6 +47,8 @@ matrix:
 script:
   - |
     if [ -z ${INTEGRATION} ]; then
+      export CFG_RELEASE_CHANNEL=nightly
+      export CFG_RELEASE=nightly
       cargo build
       cargo test
       cargo test -- --ignored
diff --git a/Cargo.lock b/Cargo.lock
index 7864cf47314..81b56b87605 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -294,7 +294,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 
 [[package]]
 name = "ena"
-version = "0.13.1"
+version = "0.14.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "log 0.4.8 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -608,6 +608,14 @@ dependencies = [
  "unicode-xid 0.2.0 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
+[[package]]
+name = "psm"
+version = "0.1.8"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "cc 1.0.46 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
 [[package]]
 name = "quick-error"
 version = "1.2.2"
@@ -699,89 +707,88 @@ dependencies = [
 
 [[package]]
 name = "rustc-ap-arena"
-version = "654.0.0"
+version = "659.0.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
- "rustc-ap-rustc_data_structures 654.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "rustc-ap-rustc_data_structures 659.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "smallvec 1.2.0 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
 name = "rustc-ap-graphviz"
-version = "654.0.0"
+version = "659.0.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 
 [[package]]
 name = "rustc-ap-rustc_ast"
-version = "654.0.0"
+version = "659.0.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "log 0.4.8 (registry+https://github.com/rust-lang/crates.io-index)",
- "rustc-ap-rustc_data_structures 654.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "rustc-ap-rustc_index 654.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "rustc-ap-rustc_lexer 654.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "rustc-ap-rustc_macros 654.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "rustc-ap-rustc_span 654.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "rustc-ap-serialize 654.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "rustc-ap-rustc_data_structures 659.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "rustc-ap-rustc_index 659.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "rustc-ap-rustc_lexer 659.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "rustc-ap-rustc_macros 659.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "rustc-ap-rustc_span 659.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "rustc-ap-serialize 659.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "scoped-tls 1.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "smallvec 1.2.0 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
 name = "rustc-ap-rustc_ast_passes"
-version = "654.0.0"
+version = "659.0.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "itertools 0.8.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "log 0.4.8 (registry+https://github.com/rust-lang/crates.io-index)",
- "rustc-ap-rustc_ast 654.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "rustc-ap-rustc_ast_pretty 654.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "rustc-ap-rustc_attr 654.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "rustc-ap-rustc_data_structures 654.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "rustc-ap-rustc_errors 654.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "rustc-ap-rustc_feature 654.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "rustc-ap-rustc_parse 654.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "rustc-ap-rustc_session 654.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "rustc-ap-rustc_span 654.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "rustc-ap-rustc_ast 659.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "rustc-ap-rustc_ast_pretty 659.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "rustc-ap-rustc_attr 659.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "rustc-ap-rustc_data_structures 659.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "rustc-ap-rustc_errors 659.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "rustc-ap-rustc_feature 659.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "rustc-ap-rustc_parse 659.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "rustc-ap-rustc_session 659.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "rustc-ap-rustc_span 659.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
 name = "rustc-ap-rustc_ast_pretty"
-version = "654.0.0"
+version = "659.0.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "log 0.4.8 (registry+https://github.com/rust-lang/crates.io-index)",
- "rustc-ap-rustc_ast 654.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "rustc-ap-rustc_data_structures 654.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "rustc-ap-rustc_span 654.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "rustc-ap-rustc_ast 659.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "rustc-ap-rustc_span 659.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
 name = "rustc-ap-rustc_attr"
-version = "654.0.0"
+version = "659.0.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
- "rustc-ap-rustc_ast 654.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "rustc-ap-rustc_ast_pretty 654.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "rustc-ap-rustc_data_structures 654.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "rustc-ap-rustc_errors 654.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "rustc-ap-rustc_feature 654.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "rustc-ap-rustc_macros 654.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "rustc-ap-rustc_session 654.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "rustc-ap-rustc_span 654.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "rustc-ap-serialize 654.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "smallvec 1.2.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "rustc-ap-rustc_ast 659.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "rustc-ap-rustc_ast_pretty 659.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "rustc-ap-rustc_data_structures 659.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "rustc-ap-rustc_errors 659.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "rustc-ap-rustc_feature 659.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "rustc-ap-rustc_macros 659.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "rustc-ap-rustc_session 659.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "rustc-ap-rustc_span 659.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "rustc-ap-serialize 659.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "version_check 0.9.1 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
 name = "rustc-ap-rustc_data_structures"
-version = "654.0.0"
+version = "659.0.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "bitflags 1.2.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "cfg-if 0.1.10 (registry+https://github.com/rust-lang/crates.io-index)",
  "crossbeam-utils 0.7.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "ena 0.13.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "ena 0.14.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "indexmap 1.3.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "jobserver 0.1.17 (registry+https://github.com/rust-lang/crates.io-index)",
  "lazy_static 1.4.0 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -789,28 +796,29 @@ dependencies = [
  "log 0.4.8 (registry+https://github.com/rust-lang/crates.io-index)",
  "measureme 0.7.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "parking_lot 0.10.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "rustc-ap-graphviz 654.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "rustc-ap-rustc_index 654.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "rustc-ap-serialize 654.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "rustc-ap-graphviz 659.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "rustc-ap-rustc_index 659.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "rustc-ap-serialize 659.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "rustc-hash 1.0.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "rustc-rayon 0.3.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "rustc-rayon-core 0.3.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "smallvec 1.2.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "stable_deref_trait 1.1.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "stacker 0.1.9 (registry+https://github.com/rust-lang/crates.io-index)",
  "winapi 0.3.8 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
 name = "rustc-ap-rustc_errors"
-version = "654.0.0"
+version = "659.0.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "annotate-snippets 0.6.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "atty 0.2.13 (registry+https://github.com/rust-lang/crates.io-index)",
  "log 0.4.8 (registry+https://github.com/rust-lang/crates.io-index)",
- "rustc-ap-rustc_data_structures 654.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "rustc-ap-rustc_span 654.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "rustc-ap-serialize 654.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "rustc-ap-rustc_data_structures 659.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "rustc-ap-rustc_span 659.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "rustc-ap-serialize 659.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "termcolor 1.0.5 (registry+https://github.com/rust-lang/crates.io-index)",
  "termize 0.1.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "unicode-width 0.1.6 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -819,52 +827,52 @@ dependencies = [
 
 [[package]]
 name = "rustc-ap-rustc_expand"
-version = "654.0.0"
+version = "659.0.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "log 0.4.8 (registry+https://github.com/rust-lang/crates.io-index)",
- "rustc-ap-rustc_ast 654.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "rustc-ap-rustc_ast_passes 654.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "rustc-ap-rustc_ast_pretty 654.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "rustc-ap-rustc_attr 654.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "rustc-ap-rustc_data_structures 654.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "rustc-ap-rustc_errors 654.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "rustc-ap-rustc_feature 654.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "rustc-ap-rustc_lexer 654.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "rustc-ap-rustc_parse 654.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "rustc-ap-rustc_session 654.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "rustc-ap-rustc_span 654.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "rustc-ap-serialize 654.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "rustc-ap-rustc_ast 659.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "rustc-ap-rustc_ast_passes 659.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "rustc-ap-rustc_ast_pretty 659.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "rustc-ap-rustc_attr 659.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "rustc-ap-rustc_data_structures 659.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "rustc-ap-rustc_errors 659.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "rustc-ap-rustc_feature 659.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "rustc-ap-rustc_lexer 659.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "rustc-ap-rustc_parse 659.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "rustc-ap-rustc_session 659.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "rustc-ap-rustc_span 659.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "rustc-ap-serialize 659.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "smallvec 1.2.0 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
 name = "rustc-ap-rustc_feature"
-version = "654.0.0"
+version = "659.0.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "lazy_static 1.4.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "rustc-ap-rustc_data_structures 654.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "rustc-ap-rustc_span 654.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "rustc-ap-rustc_data_structures 659.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "rustc-ap-rustc_span 659.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
 name = "rustc-ap-rustc_fs_util"
-version = "654.0.0"
+version = "659.0.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 
 [[package]]
 name = "rustc-ap-rustc_index"
-version = "654.0.0"
+version = "659.0.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
- "rustc-ap-serialize 654.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "rustc-ap-serialize 659.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "smallvec 1.2.0 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
 name = "rustc-ap-rustc_lexer"
-version = "654.0.0"
+version = "659.0.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "unicode-xid 0.2.0 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -872,7 +880,7 @@ dependencies = [
 
 [[package]]
 name = "rustc-ap-rustc_macros"
-version = "654.0.0"
+version = "659.0.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "proc-macro2 1.0.6 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -883,55 +891,54 @@ dependencies = [
 
 [[package]]
 name = "rustc-ap-rustc_parse"
-version = "654.0.0"
+version = "659.0.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "bitflags 1.2.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "log 0.4.8 (registry+https://github.com/rust-lang/crates.io-index)",
- "rustc-ap-rustc_ast 654.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "rustc-ap-rustc_ast_pretty 654.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "rustc-ap-rustc_data_structures 654.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "rustc-ap-rustc_errors 654.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "rustc-ap-rustc_feature 654.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "rustc-ap-rustc_lexer 654.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "rustc-ap-rustc_session 654.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "rustc-ap-rustc_span 654.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "smallvec 1.2.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "rustc-ap-rustc_ast 659.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "rustc-ap-rustc_ast_pretty 659.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "rustc-ap-rustc_data_structures 659.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "rustc-ap-rustc_errors 659.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "rustc-ap-rustc_feature 659.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "rustc-ap-rustc_lexer 659.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "rustc-ap-rustc_session 659.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "rustc-ap-rustc_span 659.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "unicode-normalization 0.1.12 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
 name = "rustc-ap-rustc_session"
-version = "654.0.0"
+version = "659.0.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "getopts 0.2.21 (registry+https://github.com/rust-lang/crates.io-index)",
  "log 0.4.8 (registry+https://github.com/rust-lang/crates.io-index)",
  "num_cpus 1.10.1 (registry+https://github.com/rust-lang/crates.io-index)",
- "rustc-ap-rustc_ast 654.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "rustc-ap-rustc_data_structures 654.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "rustc-ap-rustc_errors 654.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "rustc-ap-rustc_feature 654.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "rustc-ap-rustc_fs_util 654.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "rustc-ap-rustc_index 654.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "rustc-ap-rustc_span 654.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "rustc-ap-rustc_target 654.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "rustc-ap-serialize 654.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "rustc-ap-rustc_ast 659.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "rustc-ap-rustc_data_structures 659.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "rustc-ap-rustc_errors 659.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "rustc-ap-rustc_feature 659.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
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@@ -1146,6 +1154,18 @@ name = "stable_deref_trait"
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+ "winapi 0.3.8 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
 [[package]]
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@@ -1289,6 +1309,11 @@ name = "vec_map"
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 source = "registry+https://github.com/rust-lang/crates.io-index"
 
+[[package]]
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+version = "0.9.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+
 [[package]]
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@@ -1414,6 +1439,7 @@ dependencies = [
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@@ -1463,6 +1489,7 @@ dependencies = [
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 "checksum structopt-derive 0.3.3 (registry+https://github.com/rust-lang/crates.io-index)" = "8fe0c13e476b4e21ff7f5c4ace3818b6d7bdc16897c31c73862471bc1663acae"
@@ -1482,6 +1509,7 @@ dependencies = [
 "checksum unicode-xid 0.2.0 (registry+https://github.com/rust-lang/crates.io-index)" = "826e7639553986605ec5979c7dd957c7895e93eabed50ab2ffa7f6128a75097c"
 "checksum unicode_categories 0.1.1 (registry+https://github.com/rust-lang/crates.io-index)" = "39ec24b3121d976906ece63c9daad25b85969647682eee313cb5779fdd69e14e"
 "checksum vec_map 0.8.1 (registry+https://github.com/rust-lang/crates.io-index)" = "05c78687fb1a80548ae3250346c3db86a80a7cdd77bda190189f2d0a0987c81a"
+"checksum version_check 0.9.1 (registry+https://github.com/rust-lang/crates.io-index)" = "078775d0255232fb988e6fccf26ddc9d1ac274299aaedcedce21c6f72cc533ce"
 "checksum walkdir 2.2.9 (registry+https://github.com/rust-lang/crates.io-index)" = "9658c94fa8b940eab2250bd5a457f9c48b748420d71293b165c8cdbe2f55f71e"
 "checksum wasi 0.7.0 (registry+https://github.com/rust-lang/crates.io-index)" = "b89c3ce4ce14bdc6fb6beaf9ec7928ca331de5df7e5ea278375642a2f478570d"
 "checksum winapi 0.3.8 (registry+https://github.com/rust-lang/crates.io-index)" = "8093091eeb260906a183e6ae1abdba2ef5ef2257a21801128899c3fc699229c6"
diff --git a/Cargo.toml b/Cargo.toml
index bfffe94c505..b0e13269f0b 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -65,32 +65,36 @@ rustc-workspace-hack = "1.0.0"
 
 [dependencies.rustc_ast]
 package = "rustc-ap-rustc_ast"
-version = "654.0.0"
+version = "659.0.0"
 
 [dependencies.rustc_ast_pretty]
 package = "rustc-ap-rustc_ast_pretty"
-version = "654.0.0"
+version = "659.0.0"
+
+[dependencies.rustc_attr]
+package = "rustc-ap-rustc_attr"
+version = "659.0.0"
 
 [dependencies.rustc_data_structures]
 package = "rustc-ap-rustc_data_structures"
-version = "654.0.0"
+version = "659.0.0"
 
 [dependencies.rustc_errors]
 package = "rustc-ap-rustc_errors"
-version = "654.0.0"
+version = "659.0.0"
 
 [dependencies.rustc_expand]
 package = "rustc-ap-rustc_expand"
-version = "654.0.0"
+version = "659.0.0"
 
 [dependencies.rustc_parse]
 package = "rustc-ap-rustc_parse"
-version = "654.0.0"
+version = "659.0.0"
 
 [dependencies.rustc_session]
 package = "rustc-ap-rustc_session"
-version = "654.0.0"
+version = "659.0.0"
 
 [dependencies.rustc_span]
 package = "rustc-ap-rustc_span"
-version = "654.0.0"
+version = "659.0.0"
diff --git a/appveyor.yml b/appveyor.yml
index 1d3b06152a9..7bfe696009f 100644
--- a/appveyor.yml
+++ b/appveyor.yml
@@ -48,6 +48,8 @@ install:
 build: false
 
 test_script:
+  - set CFG_RELEASE_CHANNEL=nightly
+  - set CFG_RELEASE=nightly
   - cargo build --verbose
   - cargo test
   - cargo test -- --ignored
diff --git a/ci/integration.sh b/ci/integration.sh
index 4d5498b6ec7..13a3ecaa196 100755
--- a/ci/integration.sh
+++ b/ci/integration.sh
@@ -15,7 +15,7 @@ set -ex
 # it again.
 #
 #which cargo-fmt || cargo install --force
-cargo install --path . --force 
+CFG_RELEASE=nightly CFG_RELEASE_CHANNEL=nightly cargo install --path . --force 
 
 echo "Integration tests for: ${INTEGRATION}"
 cargo fmt -- --version
diff --git a/src/chains.rs b/src/chains.rs
index 40e4d483993..ebf562c093d 100644
--- a/src/chains.rs
+++ b/src/chains.rs
@@ -59,7 +59,7 @@ use std::borrow::Cow;
 use std::cmp::min;
 
 use rustc_ast::{ast, ptr};
-use rustc_span::{BytePos, Span};
+use rustc_span::{symbol, BytePos, Span};
 
 use crate::comment::{rewrite_comment, CharClasses, FullCodeCharKind, RichChar};
 use crate::config::IndentStyle;
@@ -116,8 +116,8 @@ enum ChainItemKind {
         Vec<ast::GenericArg>,
         Vec<ptr::P<ast::Expr>>,
     ),
-    StructField(ast::Ident),
-    TupleField(ast::Ident, bool),
+    StructField(symbol::Ident),
+    TupleField(symbol::Ident, bool),
     Await,
     Comment(String, CommentPosition),
 }
@@ -234,7 +234,7 @@ impl ChainItem {
     }
 
     fn rewrite_method_call(
-        method_name: ast::Ident,
+        method_name: symbol::Ident,
         types: &[ast::GenericArg],
         args: &[ptr::P<ast::Expr>],
         span: Span,
diff --git a/src/imports.rs b/src/imports.rs
index d8f963e1ec3..914b91a46ca 100644
--- a/src/imports.rs
+++ b/src/imports.rs
@@ -3,7 +3,11 @@ use std::cmp::Ordering;
 use std::fmt;
 
 use rustc_ast::ast::{self, UseTreeKind};
-use rustc_span::{source_map, symbol::sym, BytePos, Span, DUMMY_SP};
+use rustc_span::{
+    source_map,
+    symbol::{self, sym},
+    BytePos, Span, DUMMY_SP,
+};
 
 use crate::comment::combine_strs_with_missing_comments;
 use crate::config::lists::*;
@@ -20,7 +24,7 @@ use crate::visitor::FmtVisitor;
 
 /// Returns a name imported by a `use` declaration.
 /// E.g., returns `Ordering` for `std::cmp::Ordering` and `self` for `std::cmp::self`.
-pub(crate) fn path_to_imported_ident(path: &ast::Path) -> ast::Ident {
+pub(crate) fn path_to_imported_ident(path: &ast::Path) -> symbol::Ident {
     path.segments.last().unwrap().ident
 }
 
diff --git a/src/items.rs b/src/items.rs
index baa993590ca..4a1af8e09a1 100644
--- a/src/items.rs
+++ b/src/items.rs
@@ -311,7 +311,7 @@ impl<'a> FmtVisitor<'a> {
     pub(crate) fn rewrite_fn_before_block(
         &mut self,
         indent: Indent,
-        ident: ast::Ident,
+        ident: symbol::Ident,
         fn_sig: &FnSig<'_>,
         span: Span,
     ) -> Option<(String, FnBraceStyle)> {
@@ -335,7 +335,7 @@ impl<'a> FmtVisitor<'a> {
     pub(crate) fn rewrite_required_fn(
         &mut self,
         indent: Indent,
-        ident: ast::Ident,
+        ident: symbol::Ident,
         sig: &ast::FnSig,
         generics: &ast::Generics,
         span: Span,
@@ -411,7 +411,7 @@ impl<'a> FmtVisitor<'a> {
 
     pub(crate) fn visit_enum(
         &mut self,
-        ident: ast::Ident,
+        ident: symbol::Ident,
         vis: &ast::Visibility,
         enum_def: &ast::EnumDef,
         generics: &ast::Generics,
@@ -967,7 +967,7 @@ fn rewrite_trait_ref(
 
 pub(crate) struct StructParts<'a> {
     prefix: &'a str,
-    ident: ast::Ident,
+    ident: symbol::Ident,
     vis: &'a ast::Visibility,
     def: &'a ast::VariantData,
     generics: Option<&'a ast::Generics>,
@@ -1234,7 +1234,7 @@ impl<'a> Rewrite for TraitAliasBounds<'a> {
 
 pub(crate) fn format_trait_alias(
     context: &RewriteContext<'_>,
-    ident: ast::Ident,
+    ident: symbol::Ident,
     vis: &ast::Visibility,
     generics: &ast::Generics,
     generic_bounds: &ast::GenericBounds,
@@ -1513,7 +1513,7 @@ fn rewrite_type_prefix(
     context: &RewriteContext<'_>,
     indent: Indent,
     prefix: &str,
-    ident: ast::Ident,
+    ident: symbol::Ident,
     generics: &ast::Generics,
 ) -> Option<String> {
     let mut result = String::with_capacity(128);
@@ -1554,7 +1554,7 @@ fn rewrite_type_item<R: Rewrite>(
     indent: Indent,
     prefix: &str,
     suffix: &str,
-    ident: ast::Ident,
+    ident: symbol::Ident,
     rhs: &R,
     generics: &ast::Generics,
     vis: &ast::Visibility,
@@ -1583,7 +1583,7 @@ fn rewrite_type_item<R: Rewrite>(
 pub(crate) fn rewrite_type_alias(
     context: &RewriteContext<'_>,
     indent: Indent,
-    ident: ast::Ident,
+    ident: symbol::Ident,
     ty: &ast::Ty,
     generics: &ast::Generics,
     vis: &ast::Visibility,
@@ -1594,7 +1594,7 @@ pub(crate) fn rewrite_type_alias(
 pub(crate) fn rewrite_opaque_type(
     context: &RewriteContext<'_>,
     indent: Indent,
-    ident: ast::Ident,
+    ident: symbol::Ident,
     generic_bounds: &ast::GenericBounds,
     generics: &ast::Generics,
     vis: &ast::Visibility,
@@ -1709,7 +1709,7 @@ pub(crate) fn rewrite_struct_field(
 pub(crate) struct StaticParts<'a> {
     prefix: &'a str,
     vis: &'a ast::Visibility,
-    ident: ast::Ident,
+    ident: symbol::Ident,
     ty: &'a ast::Ty,
     mutability: ast::Mutability,
     expr_opt: Option<&'a ptr::P<ast::Expr>>,
@@ -1830,7 +1830,7 @@ fn rewrite_static(
 }
 
 pub(crate) fn rewrite_associated_type(
-    ident: ast::Ident,
+    ident: symbol::Ident,
     ty_opt: Option<&ptr::P<ast::Ty>>,
     generics: &ast::Generics,
     generic_bounds_opt: Option<&ast::GenericBounds>,
@@ -1880,7 +1880,7 @@ impl<'a> Rewrite for OpaqueType<'a> {
 
 pub(crate) fn rewrite_opaque_impl_type(
     context: &RewriteContext<'_>,
-    ident: ast::Ident,
+    ident: symbol::Ident,
     generics: &ast::Generics,
     generic_bounds: &ast::GenericBounds,
     indent: Indent,
@@ -1904,7 +1904,7 @@ pub(crate) fn rewrite_opaque_impl_type(
 }
 
 pub(crate) fn rewrite_associated_impl_type(
-    ident: ast::Ident,
+    ident: symbol::Ident,
     defaultness: ast::Defaultness,
     ty_opt: Option<&ptr::P<ast::Ty>>,
     generics: &ast::Generics,
@@ -2141,7 +2141,7 @@ pub(crate) enum FnBraceStyle {
 fn rewrite_fn_base(
     context: &RewriteContext<'_>,
     indent: Indent,
-    ident: ast::Ident,
+    ident: symbol::Ident,
     fn_sig: &FnSig<'_>,
     span: Span,
     fn_brace_style: FnBraceStyle,
@@ -2969,7 +2969,7 @@ fn rewrite_comments_before_after_where(
 fn format_header(
     context: &RewriteContext<'_>,
     item_name: &str,
-    ident: ast::Ident,
+    ident: symbol::Ident,
     vis: &ast::Visibility,
 ) -> String {
     format!(
diff --git a/src/lib.rs b/src/lib.rs
index ecf19ebb586..831eac8dc7e 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -20,6 +20,7 @@ use std::rc::Rc;
 use failure::Fail;
 use ignore;
 use rustc_ast::ast;
+use rustc_span::symbol;
 
 use crate::comment::LineClasses;
 use crate::emitter::Emitter;
@@ -524,7 +525,7 @@ impl Input {
                 let file_stem = file.file_stem()?;
                 if file.parent()?.to_path_buf().join(file_stem).is_dir() {
                     Some(DirectoryOwnership::Owned {
-                        relative: file_stem.to_str().map(ast::Ident::from_str),
+                        relative: file_stem.to_str().map(symbol::Ident::from_str),
                     })
                 } else {
                     None
diff --git a/src/macros.rs b/src/macros.rs
index 400daa6a5aa..cec5d873693 100644
--- a/src/macros.rs
+++ b/src/macros.rs
@@ -17,7 +17,10 @@ use rustc_ast::tokenstream::{Cursor, TokenStream, TokenTree};
 use rustc_ast::{ast, ptr};
 use rustc_ast_pretty::pprust;
 use rustc_parse::{new_parser_from_tts, parser::Parser};
-use rustc_span::{symbol::kw, BytePos, Span, Symbol, DUMMY_SP};
+use rustc_span::{
+    symbol::{self, kw},
+    BytePos, Span, Symbol, DUMMY_SP,
+};
 
 use crate::comment::{
     contains_comment, CharClasses, FindUncommented, FullCodeCharKind, LineClasses,
@@ -52,7 +55,7 @@ pub(crate) enum MacroArg {
     Ty(ptr::P<ast::Ty>),
     Pat(ptr::P<ast::Pat>),
     Item(ptr::P<ast::Item>),
-    Keyword(ast::Ident, Span),
+    Keyword(symbol::Ident, Span),
 }
 
 impl MacroArg {
@@ -137,7 +140,7 @@ fn parse_macro_arg<'a, 'b: 'a>(parser: &'a mut Parser<'b>) -> Option<MacroArg> {
 fn rewrite_macro_name(
     context: &RewriteContext<'_>,
     path: &ast::Path,
-    extra_ident: Option<ast::Ident>,
+    extra_ident: Option<symbol::Ident>,
 ) -> String {
     let name = if path.segments.len() == 1 {
         // Avoid using pretty-printer in the common case.
@@ -188,7 +191,7 @@ fn return_macro_parse_failure_fallback(
 
 pub(crate) fn rewrite_macro(
     mac: &ast::MacCall,
-    extra_ident: Option<ast::Ident>,
+    extra_ident: Option<symbol::Ident>,
     context: &RewriteContext<'_>,
     shape: Shape,
     position: MacroPosition,
@@ -230,9 +233,10 @@ fn check_keyword<'a, 'b: 'a>(parser: &'a mut Parser<'b>) -> Option<MacroArg> {
             })
         {
             parser.bump();
-            let macro_arg =
-                MacroArg::Keyword(ast::Ident::with_dummy_span(keyword), parser.prev_token.span);
-            return Some(macro_arg);
+            return Some(MacroArg::Keyword(
+                symbol::Ident::with_dummy_span(keyword),
+                parser.prev_token.span,
+            ));
         }
     }
     None
@@ -240,7 +244,7 @@ fn check_keyword<'a, 'b: 'a>(parser: &'a mut Parser<'b>) -> Option<MacroArg> {
 
 fn rewrite_macro_inner(
     mac: &ast::MacCall,
-    extra_ident: Option<ast::Ident>,
+    extra_ident: Option<symbol::Ident>,
     context: &RewriteContext<'_>,
     shape: Shape,
     position: MacroPosition,
@@ -479,7 +483,7 @@ pub(crate) fn rewrite_macro_def(
     shape: Shape,
     indent: Indent,
     def: &ast::MacroDef,
-    ident: ast::Ident,
+    ident: symbol::Ident,
     vis: &ast::Visibility,
     span: Span,
 ) -> Option<String> {
@@ -620,7 +624,7 @@ fn replace_names(input: &str) -> Option<(String, HashMap<String, String>)> {
 #[derive(Debug, Clone)]
 enum MacroArgKind {
     /// e.g., `$x: expr`.
-    MetaVariable(ast::Name, String),
+    MetaVariable(Symbol, String),
     /// e.g., `$($foo: expr),*`
     Repeat(
         /// `()`, `[]` or `{}`.
diff --git a/src/modules.rs b/src/modules.rs
index 9f8dabbfaf4..747b186dae3 100644
--- a/src/modules.rs
+++ b/src/modules.rs
@@ -4,7 +4,7 @@ use std::path::{Path, PathBuf};
 
 use rustc_ast::ast;
 use rustc_ast::visit::Visitor;
-use rustc_span::symbol::{sym, Symbol};
+use rustc_span::symbol::{self, sym, Symbol};
 
 use crate::attr::MetaVisitor;
 use crate::config::FileName;
@@ -239,7 +239,7 @@ impl<'ast, 'sess, 'c> ModResolver<'ast, 'sess> {
     /// Find a file path in the filesystem which corresponds to the given module.
     fn find_external_module(
         &self,
-        mod_name: ast::Ident,
+        mod_name: symbol::Ident,
         attrs: &[ast::Attribute],
         sub_mod: &Cow<'ast, ast::Mod>,
     ) -> Result<Option<SubModKind<'c, 'ast>>, String> {
@@ -326,7 +326,7 @@ impl<'ast, 'sess, 'c> ModResolver<'ast, 'sess> {
         }
     }
 
-    fn push_inline_mod_directory(&mut self, id: ast::Ident, attrs: &[ast::Attribute]) {
+    fn push_inline_mod_directory(&mut self, id: symbol::Ident, attrs: &[ast::Attribute]) {
         if let Some(path) = find_path_value(attrs) {
             self.directory.path.push(&*path.as_str());
             self.directory.ownership = DirectoryOwnership::Owned { relative: None };
diff --git a/src/syntux/session.rs b/src/syntux/session.rs
index da8741c84e5..00f12b32237 100644
--- a/src/syntux/session.rs
+++ b/src/syntux/session.rs
@@ -2,14 +2,13 @@ use std::cell::RefCell;
 use std::path::Path;
 use std::rc::Rc;
 
-use rustc_ast::ast;
 use rustc_data_structures::sync::{Lrc, Send};
 use rustc_errors::emitter::{Emitter, EmitterWriter};
 use rustc_errors::{ColorConfig, Diagnostic, Handler, Level as DiagnosticLevel};
 use rustc_session::parse::ParseSess as RawParseSess;
 use rustc_span::{
     source_map::{FilePathMapping, SourceMap},
-    BytePos, Span,
+    symbol, BytePos, Span,
 };
 
 use crate::config::file_lines::LineRange;
@@ -147,8 +146,8 @@ impl ParseSess {
 
     pub(crate) fn default_submod_path(
         &self,
-        id: ast::Ident,
-        relative: Option<ast::Ident>,
+        id: symbol::Ident,
+        relative: Option<symbol::Ident>,
         dir_path: &Path,
     ) -> rustc_expand::module::ModulePath<'_> {
         rustc_expand::module::default_submod_path(
diff --git a/src/utils.rs b/src/utils.rs
index e029aa435c0..f82bdd501cf 100644
--- a/src/utils.rs
+++ b/src/utils.rs
@@ -6,7 +6,7 @@ use rustc_ast::ast::{
 };
 use rustc_ast::ptr;
 use rustc_ast_pretty::pprust;
-use rustc_span::{sym, BytePos, ExpnId, Span, Symbol, SyntaxContext};
+use rustc_span::{sym, symbol, BytePos, ExpnId, Span, Symbol, SyntaxContext};
 use unicode_width::UnicodeWidthStr;
 
 use crate::comment::{filter_normal_code, CharClasses, FullCodeCharKind, LineClasses};
@@ -24,7 +24,7 @@ pub(crate) fn skip_annotation() -> Symbol {
     Symbol::intern("rustfmt::skip")
 }
 
-pub(crate) fn rewrite_ident<'a>(context: &'a RewriteContext<'_>, ident: ast::Ident) -> &'a str {
+pub(crate) fn rewrite_ident<'a>(context: &'a RewriteContext<'_>, ident: symbol::Ident) -> &'a str {
     context.snippet(ident.span)
 }
 
diff --git a/src/visitor.rs b/src/visitor.rs
index 346628c0b89..ef6a7ff7ba6 100644
--- a/src/visitor.rs
+++ b/src/visitor.rs
@@ -1,9 +1,8 @@
 use std::cell::{Cell, RefCell};
 use std::rc::Rc;
 
-use rustc_ast::token::DelimToken;
-use rustc_ast::{ast, visit};
-use rustc_span::{BytePos, Pos, Span};
+use rustc_ast::{ast, token::DelimToken, visit};
+use rustc_span::{symbol, BytePos, Pos, Span};
 
 use crate::attr::*;
 use crate::comment::{rewrite_comment, CodeCharKind, CommentCodeSlices};
@@ -691,7 +690,7 @@ impl<'b, 'a: 'b> FmtVisitor<'a> {
         }
     }
 
-    fn visit_mac(&mut self, mac: &ast::MacCall, ident: Option<ast::Ident>, pos: MacroPosition) {
+    fn visit_mac(&mut self, mac: &ast::MacCall, ident: Option<symbol::Ident>, pos: MacroPosition) {
         skip_out_of_file_lines_range_visitor!(self, mac.span());
 
         // 1 = ;
@@ -897,7 +896,7 @@ impl<'b, 'a: 'b> FmtVisitor<'a> {
         m: &ast::Mod,
         vis: &ast::Visibility,
         s: Span,
-        ident: ast::Ident,
+        ident: symbol::Ident,
         attrs: &[ast::Attribute],
         is_internal: bool,
     ) {