rustc_typeck: don't lint non-extern-prelude extern crate's in Rust 2018.

5 files changed, 25 insertions, 81 deletions

diff --git a/src/test/ui-fulldeps/unnecessary-extern-crate.rs b/src/test/ui-fulldeps/unnecessary-extern-crate.rs
index df723ddf590..1cdc9229d07 100644
--- a/src/test/ui-fulldeps/unnecessary-extern-crate.rs
+++ b/src/test/ui-fulldeps/unnecessary-extern-crate.rs
@@ -20,33 +20,23 @@ extern crate alloc as x;
 //~^ ERROR unused extern crate
 //~| HELP remove
 
+extern crate proc_macro;
+
 #[macro_use]
 extern crate test;
 
 pub extern crate test as y;
-//~^ ERROR `extern crate` is not idiomatic in the new edition
-//~| HELP convert it to a `pub use`
 
 pub extern crate libc;
-//~^ ERROR `extern crate` is not idiomatic in the new edition
-//~| HELP convert it to a `pub use`
 
 pub(crate) extern crate libc as a;
-//~^ ERROR `extern crate` is not idiomatic in the new edition
-//~| HELP convert it to a `pub(crate) use`
 
 crate extern crate libc as b;
-//~^ ERROR `extern crate` is not idiomatic in the new edition
-//~| HELP convert it to a `crate use`
 
 mod foo {
     pub(in crate::foo) extern crate libc as c;
-    //~^ ERROR `extern crate` is not idiomatic in the new edition
-    //~| HELP convert it to a `pub(in crate::foo) use`
 
     pub(super) extern crate libc as d;
-    //~^ ERROR `extern crate` is not idiomatic in the new edition
-    //~| HELP convert it to a `pub(super) use`
 
     extern crate alloc;
     //~^ ERROR unused extern crate
@@ -57,12 +47,8 @@ mod foo {
     //~| HELP remove
 
     pub extern crate test;
-    //~^ ERROR `extern crate` is not idiomatic in the new edition
-    //~| HELP convert it
 
     pub extern crate test as y;
-    //~^ ERROR `extern crate` is not idiomatic in the new edition
-    //~| HELP convert it
 
     mod bar {
         extern crate alloc;
@@ -74,8 +60,6 @@ mod foo {
         //~| HELP remove
 
         pub(in crate::foo::bar) extern crate libc as e;
-        //~^ ERROR `extern crate` is not idiomatic in the new edition
-        //~| HELP convert it to a `pub(in crate::foo::bar) use`
 
         fn dummy() {
             unsafe {
@@ -96,4 +80,6 @@ mod foo {
 fn main() {
     unsafe { a::getpid(); }
     unsafe { b::getpid(); }
+
+    proc_macro::TokenStream::new();
 }
diff --git a/src/test/ui-fulldeps/unnecessary-extern-crate.stderr b/src/test/ui-fulldeps/unnecessary-extern-crate.stderr
index a4307112157..58ec5901585 100644
--- a/src/test/ui-fulldeps/unnecessary-extern-crate.stderr
+++ b/src/test/ui-fulldeps/unnecessary-extern-crate.stderr
@@ -16,83 +16,29 @@ error: unused extern crate
 LL | extern crate alloc as x;
    | ^^^^^^^^^^^^^^^^^^^^^^^^ help: remove it
 
-error: `extern crate` is not idiomatic in the new edition
-  --> $DIR/unnecessary-extern-crate.rs:26:1
-   |
-LL | pub extern crate test as y;
-   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: convert it to a `pub use`
-
-error: `extern crate` is not idiomatic in the new edition
-  --> $DIR/unnecessary-extern-crate.rs:30:1
-   |
-LL | pub extern crate libc;
-   | ^^^^^^^^^^^^^^^^^^^^^^ help: convert it to a `pub use`
-
-error: `extern crate` is not idiomatic in the new edition
-  --> $DIR/unnecessary-extern-crate.rs:34:1
-   |
-LL | pub(crate) extern crate libc as a;
-   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: convert it to a `pub(crate) use`
-
-error: `extern crate` is not idiomatic in the new edition
-  --> $DIR/unnecessary-extern-crate.rs:38:1
-   |
-LL | crate extern crate libc as b;
-   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: convert it to a `crate use`
-
-error: `extern crate` is not idiomatic in the new edition
-  --> $DIR/unnecessary-extern-crate.rs:43:5
-   |
-LL |     pub(in crate::foo) extern crate libc as c;
-   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: convert it to a `pub(in crate::foo) use`
-
-error: `extern crate` is not idiomatic in the new edition
-  --> $DIR/unnecessary-extern-crate.rs:47:5
-   |
-LL |     pub(super) extern crate libc as d;
-   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: convert it to a `pub(super) use`
-
 error: unused extern crate
-  --> $DIR/unnecessary-extern-crate.rs:51:5
+  --> $DIR/unnecessary-extern-crate.rs:41:5
    |
 LL |     extern crate alloc;
    |     ^^^^^^^^^^^^^^^^^^^ help: remove it
 
 error: unused extern crate
-  --> $DIR/unnecessary-extern-crate.rs:55:5
+  --> $DIR/unnecessary-extern-crate.rs:45:5
    |
 LL |     extern crate alloc as x;
    |     ^^^^^^^^^^^^^^^^^^^^^^^^ help: remove it
 
-error: `extern crate` is not idiomatic in the new edition
-  --> $DIR/unnecessary-extern-crate.rs:59:5
-   |
-LL |     pub extern crate test;
-   |     ^^^^^^^^^^^^^^^^^^^^^^ help: convert it to a `pub use`
-
-error: `extern crate` is not idiomatic in the new edition
-  --> $DIR/unnecessary-extern-crate.rs:63:5
-   |
-LL |     pub extern crate test as y;
-   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: convert it to a `pub use`
-
 error: unused extern crate
-  --> $DIR/unnecessary-extern-crate.rs:68:9
+  --> $DIR/unnecessary-extern-crate.rs:54:9
    |
 LL |         extern crate alloc;
    |         ^^^^^^^^^^^^^^^^^^^ help: remove it
 
 error: unused extern crate
-  --> $DIR/unnecessary-extern-crate.rs:72:9
+  --> $DIR/unnecessary-extern-crate.rs:58:9
    |
 LL |         extern crate alloc as x;
    |         ^^^^^^^^^^^^^^^^^^^^^^^^ help: remove it
 
-error: `extern crate` is not idiomatic in the new edition
-  --> $DIR/unnecessary-extern-crate.rs:76:9
-   |
-LL |         pub(in crate::foo::bar) extern crate libc as e;
-   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: convert it to a `pub(in crate::foo::bar) use`
-
-error: aborting due to 15 previous errors
+error: aborting due to 6 previous errors
 
diff --git a/src/test/ui/rust-2018/remove-extern-crate.fixed b/src/test/ui/rust-2018/remove-extern-crate.fixed
index cdae815b200..34c7266b637 100644
--- a/src/test/ui/rust-2018/remove-extern-crate.fixed
+++ b/src/test/ui/rust-2018/remove-extern-crate.fixed
@@ -14,6 +14,7 @@
 // aux-build:remove-extern-crate.rs
 // compile-flags:--extern remove_extern_crate
 
+#![feature(alloc)]
 #![warn(rust_2018_idioms)]
 
 
@@ -22,11 +23,16 @@ use remove_extern_crate;
 #[macro_use]
 extern crate remove_extern_crate as something_else;
 
+// Shouldn't suggest changing to `use`, as the `alloc`
+// crate is not in the extern prelude - see #54381.
+extern crate alloc;
+
 fn main() {
     another_name::mem::drop(3);
     another::foo();
     remove_extern_crate::foo!();
     bar!();
+    alloc::vec![5];
 }
 
 mod another {
diff --git a/src/test/ui/rust-2018/remove-extern-crate.rs b/src/test/ui/rust-2018/remove-extern-crate.rs
index 4984da802c0..570bbb02f72 100644
--- a/src/test/ui/rust-2018/remove-extern-crate.rs
+++ b/src/test/ui/rust-2018/remove-extern-crate.rs
@@ -14,6 +14,7 @@
 // aux-build:remove-extern-crate.rs
 // compile-flags:--extern remove_extern_crate
 
+#![feature(alloc)]
 #![warn(rust_2018_idioms)]
 
 extern crate core;
@@ -22,11 +23,16 @@ use remove_extern_crate;
 #[macro_use]
 extern crate remove_extern_crate as something_else;
 
+// Shouldn't suggest changing to `use`, as the `alloc`
+// crate is not in the extern prelude - see #54381.
+extern crate alloc;
+
 fn main() {
     another_name::mem::drop(3);
     another::foo();
     remove_extern_crate::foo!();
     bar!();
+    alloc::vec![5];
 }
 
 mod another {
diff --git a/src/test/ui/rust-2018/remove-extern-crate.stderr b/src/test/ui/rust-2018/remove-extern-crate.stderr
index 064a853625f..847ba5f3544 100644
--- a/src/test/ui/rust-2018/remove-extern-crate.stderr
+++ b/src/test/ui/rust-2018/remove-extern-crate.stderr
@@ -1,24 +1,24 @@
 warning: unused extern crate
-  --> $DIR/remove-extern-crate.rs:19:1
+  --> $DIR/remove-extern-crate.rs:20:1
    |
 LL | extern crate core;
    | ^^^^^^^^^^^^^^^^^^ help: remove it
    |
 note: lint level defined here
-  --> $DIR/remove-extern-crate.rs:17:9
+  --> $DIR/remove-extern-crate.rs:18:9
    |
 LL | #![warn(rust_2018_idioms)]
    |         ^^^^^^^^^^^^^^^^
    = note: #[warn(unused_extern_crates)] implied by #[warn(rust_2018_idioms)]
 
 warning: `extern crate` is not idiomatic in the new edition
-  --> $DIR/remove-extern-crate.rs:20:1
+  --> $DIR/remove-extern-crate.rs:21:1
    |
 LL | extern crate core as another_name;
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: convert it to a `use`
 
 warning: `extern crate` is not idiomatic in the new edition
-  --> $DIR/remove-extern-crate.rs:33:5
+  --> $DIR/remove-extern-crate.rs:39:5
    |
 LL |     extern crate core;
    |     ^^^^^^^^^^^^^^^^^^ help: convert it to a `use`