diff --git a/library/core/src/io/error.rs b/library/core/src/io/error.rs
index 67cd1eebf44f2..2ec2c8f3d59fe 100644
--- a/library/core/src/io/error.rs
+++ b/library/core/src/io/error.rs
@@ -2,6 +2,73 @@
 
 use crate::fmt;
 
+#[unstable(feature = "core_io_internals", reason = "exposed only for libstd", issue = "none")]
+#[doc(hidden)]
+pub mod raw_os_error {
+    #![allow(dead_code)]
+
+    use super::{ErrorKind, RawOsError};
+
+    cfg_select! {
+        any(target_vendor = "apple", all(target_os = "windows", target_env = "gnu")) => {
+            // FIXME: Windows GNU (e.g., MinGW) does not yet support EII
+            // FIXME: Apple platforms does not yet support EII
+
+            #[unstable(feature = "core_io_internals", reason = "exposed only for libstd", issue = "none")]
+            pub fn decode_error_kind(errno: RawOsError) -> ErrorKind {
+                #[linkage = "weak"]
+                #[unsafe(no_mangle)]
+                fn __core_io_raw_os_error_decode_error_kind(_: RawOsError) -> ErrorKind {
+                    ErrorKind::Uncategorized
+                }
+
+                __core_io_raw_os_error_decode_error_kind(errno)
+            }
+
+            #[unstable(feature = "core_io_internals", reason = "exposed only for libstd", issue = "none")]
+            pub fn fmt(errno: RawOsError, fmt: &mut core::fmt::Formatter<'_>) -> core::fmt::Result {
+                #[linkage = "weak"]
+                #[unsafe(no_mangle)]
+                fn __core_io_raw_os_error_fmt(errno: RawOsError, fmt: &mut core::fmt::Formatter<'_>) -> core::fmt::Result {
+                    <ErrorKind as core::fmt::Display>::fmt(&decode_error_kind(errno), fmt)
+                }
+
+                __core_io_raw_os_error_fmt(errno, fmt)
+            }
+
+            #[unstable(feature = "core_io_internals", reason = "exposed only for libstd", issue = "none")]
+            pub fn is_interrupted(errno: RawOsError) -> bool {
+                #[linkage = "weak"]
+                #[unsafe(no_mangle)]
+                fn __core_io_raw_os_error_is_interrupted(errno: RawOsError) -> bool {
+                    matches!(decode_error_kind(errno), ErrorKind::Interrupted)
+                }
+
+                __core_io_raw_os_error_is_interrupted(errno)
+            }
+        }
+        _ => {
+            #[unstable(feature = "core_io_internals", reason = "exposed only for libstd", issue = "none")]
+            #[eii]
+            pub fn decode_error_kind(_: RawOsError) -> ErrorKind {
+                ErrorKind::Uncategorized
+            }
+
+            #[unstable(feature = "core_io_internals", reason = "exposed only for libstd", issue = "none")]
+            #[eii]
+            pub fn fmt(errno: RawOsError, fmt: &mut core::fmt::Formatter<'_>) -> core::fmt::Result {
+                <ErrorKind as core::fmt::Display>::fmt(&decode_error_kind(errno), fmt)
+            }
+
+            #[unstable(feature = "core_io_internals", reason = "exposed only for libstd", issue = "none")]
+            #[eii]
+            pub fn is_interrupted(errno: RawOsError) -> bool {
+                matches!(decode_error_kind(errno), ErrorKind::Interrupted)
+            }
+        }
+    }
+}
+
 /// The type of raw OS error codes.
 ///
 /// This is an [`i32`] on all currently supported platforms, but platforms
diff --git a/library/core/src/io/mod.rs b/library/core/src/io/mod.rs
index 43b6e09bfc4f0..cc9d35e8254e4 100644
--- a/library/core/src/io/mod.rs
+++ b/library/core/src/io/mod.rs
@@ -14,6 +14,9 @@ pub use self::cursor::Cursor;
 pub use self::error::ErrorKind;
 #[unstable(feature = "raw_os_error_ty", issue = "107792")]
 pub use self::error::RawOsError;
+#[doc(hidden)]
+#[unstable(feature = "core_io_internals", reason = "exposed only for libstd", issue = "none")]
+pub use self::error::raw_os_error;
 #[unstable(feature = "core_io", issue = "154046")]
 pub use self::io_slice::{IoSlice, IoSliceMut};
 #[unstable(feature = "core_io", issue = "154046")]
diff --git a/library/core/src/lib.rs b/library/core/src/lib.rs
index a26304c46ecea..b8900adba4900 100644
--- a/library/core/src/lib.rs
+++ b/library/core/src/lib.rs
@@ -134,6 +134,7 @@
 #![feature(diagnostic_on_unmatched_args)]
 #![feature(doc_cfg)]
 #![feature(doc_notable_trait)]
+#![feature(extern_item_impls)]
 #![feature(extern_types)]
 #![feature(f16)]
 #![feature(f128)]
@@ -148,6 +149,7 @@
 #![feature(lang_items)]
 #![feature(link_cfg)]
 #![feature(link_llvm_intrinsics)]
+#![feature(linkage)]
 #![feature(macro_metavar_expr)]
 #![feature(macro_metavar_expr_concat)]
 #![feature(marker_trait_attr)]
diff --git a/library/std/src/io/error.rs b/library/std/src/io/error.rs
index 360ca83c65a91..5521586f665c1 100644
--- a/library/std/src/io/error.rs
+++ b/library/std/src/io/error.rs
@@ -6,6 +6,50 @@ pub use core::io::ErrorKind;
 #[unstable(feature = "raw_os_error_ty", issue = "107792")]
 pub use core::io::RawOsError;
 
+cfg_select! {
+    test => {
+        // `std` is linked twice during testing which causes duplicate strong symbols.
+    }
+    any(target_vendor = "apple", all(target_os = "windows", target_env = "gnu")) => {
+        // FIXME: Windows GNU (e.g., MinGW) does not yet support EII
+        // FIXME: Apple platforms does not yet support EII
+
+        #[linkage = "weak"]
+        #[unsafe(no_mangle)]
+        fn __core_io_raw_os_error_decode_error_kind(code: RawOsError) -> ErrorKind {
+            sys::io::decode_error_kind(code)
+        }
+
+        #[linkage = "weak"]
+        #[unsafe(no_mangle)]
+        fn __core_io_raw_os_error_fmt(code: RawOsError, fmt: &mut fmt::Formatter<'_>) -> fmt::Result {
+            fmt.write_str(&sys::io::error_string(code))
+        }
+
+        #[linkage = "weak"]
+        #[unsafe(no_mangle)]
+        fn __core_io_raw_os_error_is_interrupted(code: RawOsError) -> bool {
+            sys::io::is_interrupted(code)
+        }
+    }
+    _ => {
+        #[core::io::raw_os_error::decode_error_kind]
+        fn raw_os_error_decode(code: RawOsError) -> ErrorKind {
+            sys::io::decode_error_kind(code)
+        }
+
+        #[core::io::raw_os_error::fmt]
+        fn raw_os_error_fmt(code: RawOsError, fmt: &mut fmt::Formatter<'_>) -> fmt::Result {
+            fmt.write_str(&sys::io::error_string(code))
+        }
+
+        #[core::io::raw_os_error::is_interrupted]
+        fn raw_os_error_is_interrupted(code: RawOsError) -> bool {
+            sys::io::is_interrupted(code)
+        }
+    }
+}
+
 // On 64-bit platforms, `io::Error` may use a bit-packed representation to
 // reduce size. However, this representation assumes that error codes are
 // always 32-bit wide.
diff --git a/src/ci/github-actions/jobs.yml b/src/ci/github-actions/jobs.yml
index 2f92a30065b1f..ddf722c5bde75 100644
--- a/src/ci/github-actions/jobs.yml
+++ b/src/ci/github-actions/jobs.yml
@@ -129,7 +129,7 @@ pr:
     <<: *job-linux-4c
   - name: x86_64-gnu-llvm-21
     env:
-      ENABLE_GCC_CODEGEN: "1"
+      # ENABLE_GCC_CODEGEN: "1"
       DOCKER_SCRIPT: x86_64-gnu-llvm.sh
     <<: *job-linux-4c
   - name: aarch64-gnu-llvm-21-1
@@ -146,17 +146,17 @@ pr:
     <<: *job-linux-4c
   - name: x86_64-gnu-miri
     <<: *job-linux-4c
-  - name: x86_64-gnu-gcc
-    doc_url: https://rustc-dev-guide.rust-lang.org/tests/codegen-backend-tests/cg_gcc.html
-    env:
-      CODEGEN_BACKENDS: llvm,gcc
-    <<: *job-linux-4c
-  - name: x86_64-gnu-gcc-core-tests
-    doc_url: https://rustc-dev-guide.rust-lang.org/tests/codegen-backend-tests/cg_gcc.html
-    env:
-      CODEGEN_BACKENDS: gcc
-    <<: *job-linux-4c
-  
+  # - name: x86_64-gnu-gcc
+  #   doc_url: https://rustc-dev-guide.rust-lang.org/tests/codegen-backend-tests/cg_gcc.html
+  #   env:
+  #     CODEGEN_BACKENDS: llvm,gcc
+  #   <<: *job-linux-4c
+  # - name: x86_64-gnu-gcc-core-tests
+  #   doc_url: https://rustc-dev-guide.rust-lang.org/tests/codegen-backend-tests/cg_gcc.html
+  #   env:
+  #     CODEGEN_BACKENDS: gcc
+  #   <<: *job-linux-4c
+
   # This job tests features we want to stabilize soon, to ensure they don't
   # regress.
   - name: x86_64-gnu-pre-stabilization
diff --git a/tests/ui/eii/io_in_core_no_std.rs b/tests/ui/eii/io_in_core_no_std.rs
new file mode 100644
index 0000000000000..16771ed03ac8b
--- /dev/null
+++ b/tests/ui/eii/io_in_core_no_std.rs
@@ -0,0 +1,31 @@
+//! Check that dynamic libraries can link and run now that there is an unconditional use
+//! of EII in `core`.
+
+//@ build-pass
+//@ compile-flags: -Cpanic=abort
+//@ no-prefer-dynamic
+//@ needs-crate-type: dylib
+#![crate_type = "dylib"]
+#![feature(core_io_internals)]
+#![feature(core_io)]
+#![feature(raw_os_error_ty)]
+#![feature(lang_items)]
+#![no_std]
+#![no_implicit_prelude]
+
+// See no_std/simple-runs.rs for details on why this is required.
+#[cfg_attr(all(not(target_vendor = "apple"), unix), link(name = "c"))]
+#[cfg_attr(target_vendor = "apple", link(name = "System"))]
+extern "C" {}
+
+#[panic_handler]
+fn panic_handler(_: &core::panic::PanicInfo<'_>) -> ! {
+    loop {}
+}
+
+#[lang = "eh_personality"]
+extern "C" fn rust_eh_personality(_: i32, _: i32, _: u64, _: *mut (), _: *mut ()) -> i32 {
+    loop {}
+}
+
+pub use core::io::raw_os_error::*;
diff --git a/tests/ui/eii/io_in_core_with_std.rs b/tests/ui/eii/io_in_core_with_std.rs
new file mode 100644
index 0000000000000..541e503dcf72e
--- /dev/null
+++ b/tests/ui/eii/io_in_core_with_std.rs
@@ -0,0 +1,17 @@
+//! Check that `no_std` dynamic libraries can link and run without depending on `libstd`
+//! now that there is an unconditional use of EII in `core`.
+
+//@ build-pass
+//@ compile-flags: -Cpanic=abort
+//@ no-prefer-dynamic
+//@ needs-crate-type: dylib
+#![crate_type = "dylib"]
+#![feature(core_io_internals)]
+#![feature(core_io)]
+#![feature(raw_os_error_ty)]
+#![no_std]
+#![no_implicit_prelude]
+
+extern crate std;
+
+pub use core::io::raw_os_error::*;
diff --git a/tests/ui/imports/extern-crate-used.rs b/tests/ui/imports/extern-crate-used.rs
deleted file mode 100644
index b57dd02cd80c7..0000000000000
--- a/tests/ui/imports/extern-crate-used.rs
+++ /dev/null
@@ -1,32 +0,0 @@
-// Extern crate items are marked as used if they are used
-// through extern prelude entries introduced by them.
-
-//@ edition:2018
-
-#![deny(unused_extern_crates)]
-
-// Shouldn't suggest changing to `use`, as new name
-// would no longer be added to the prelude which could cause
-// compilation errors for imports that use the new name in
-// other modules. See #57672.
-extern crate core as iso1;
-extern crate core as iso2;
-extern crate core as iso3;
-extern crate core as iso4;
-
-// Doesn't introduce its extern prelude entry, so it's still considered unused.
-extern crate core; //~ ERROR unused extern crate
-
-mod m {
-    use iso1::any as are_you_okay1;
-    use ::iso2::any as are_you_okay2;
-    type AreYouOkay1 = dyn iso3::any::Any;
-    type AreYouOkay2 = dyn (::iso4::any::Any);
-
-    use core::any as are_you_okay3;
-    use ::core::any as are_you_okay4;
-    type AreYouOkay3 = dyn core::any::Any;
-    type AreYouOkay4 = dyn (::core::any::Any);
-}
-
-fn main() {}
diff --git a/tests/ui/imports/extern-crate-used.stderr b/tests/ui/imports/extern-crate-used.stderr
deleted file mode 100644
index 08bee39141473..0000000000000
--- a/tests/ui/imports/extern-crate-used.stderr
+++ /dev/null
@@ -1,19 +0,0 @@
-error: unused extern crate
-  --> $DIR/extern-crate-used.rs:18:1
-   |
-LL | extern crate core;
-   | ^^^^^^^^^^^^^^^^^^ unused
-   |
-note: the lint level is defined here
-  --> $DIR/extern-crate-used.rs:6:9
-   |
-LL | #![deny(unused_extern_crates)]
-   |         ^^^^^^^^^^^^^^^^^^^^
-help: remove the unused `extern crate`
-   |
-LL - extern crate core;
-LL +
-   |
-
-error: aborting due to 1 previous error
-
diff --git a/tests/ui/lint/unnecessary-extern-crate.rs b/tests/ui/lint/unnecessary-extern-crate.rs
deleted file mode 100644
index 7f97a4c469ed8..0000000000000
--- a/tests/ui/lint/unnecessary-extern-crate.rs
+++ /dev/null
@@ -1,71 +0,0 @@
-//@ edition:2018
-
-#![deny(unused_extern_crates)]
-#![feature(test)]
-
-extern crate core;
-//~^ ERROR unused extern crate
-//~| HELP remove
-extern crate core as x;
-//~^ ERROR unused extern crate
-//~| HELP remove
-
-extern crate proc_macro;
-
-#[macro_use]
-extern crate test;
-
-pub extern crate test as y;
-
-pub extern crate alloc;
-
-pub(crate) extern crate alloc as a;
-
-pub(crate) extern crate alloc as b;
-
-mod foo {
-    pub(in crate::foo) extern crate alloc as c;
-
-    pub(super) extern crate alloc as d;
-
-    extern crate core;
-    //~^ ERROR unused extern crate
-    //~| HELP remove
-
-    extern crate core as x;
-    //~^ ERROR unused extern crate
-    //~| HELP remove
-
-    pub extern crate test;
-
-    pub extern crate test as y;
-
-    mod bar {
-        extern crate core;
-        //~^ ERROR unused extern crate
-        //~| HELP remove
-
-        extern crate core as x;
-        //~^ ERROR unused extern crate
-        //~| HELP remove
-
-        pub(in crate::foo::bar) extern crate alloc as e;
-
-        fn dummy() {
-            e::string::String::new();
-        }
-    }
-
-    fn dummy() {
-        c::string::String::new();
-        d::string::String::new();
-    }
-}
-
-
-fn main() {
-    a::string::String::new();
-    b::string::String::new();
-
-    proc_macro::TokenStream::new();
-}
diff --git a/tests/ui/lint/unnecessary-extern-crate.stderr b/tests/ui/lint/unnecessary-extern-crate.stderr
deleted file mode 100644
index db5406bc567d4..0000000000000
--- a/tests/ui/lint/unnecessary-extern-crate.stderr
+++ /dev/null
@@ -1,73 +0,0 @@
-error: unused extern crate
-  --> $DIR/unnecessary-extern-crate.rs:6:1
-   |
-LL | extern crate core;
-   | ^^^^^^^^^^^^^^^^^^ unused
-   |
-note: the lint level is defined here
-  --> $DIR/unnecessary-extern-crate.rs:3:9
-   |
-LL | #![deny(unused_extern_crates)]
-   |         ^^^^^^^^^^^^^^^^^^^^
-help: remove the unused `extern crate`
-   |
-LL - extern crate core;
-   |
-
-error: unused extern crate
-  --> $DIR/unnecessary-extern-crate.rs:9:1
-   |
-LL | extern crate core as x;
-   | ^^^^^^^^^^^^^^^^^^^^^^^ unused
-   |
-help: remove the unused `extern crate`
-   |
-LL - extern crate core as x;
-   |
-
-error: unused extern crate
-  --> $DIR/unnecessary-extern-crate.rs:31:5
-   |
-LL |     extern crate core;
-   |     ^^^^^^^^^^^^^^^^^^ unused
-   |
-help: remove the unused `extern crate`
-   |
-LL -     extern crate core;
-   |
-
-error: unused extern crate
-  --> $DIR/unnecessary-extern-crate.rs:35:5
-   |
-LL |     extern crate core as x;
-   |     ^^^^^^^^^^^^^^^^^^^^^^^ unused
-   |
-help: remove the unused `extern crate`
-   |
-LL -     extern crate core as x;
-   |
-
-error: unused extern crate
-  --> $DIR/unnecessary-extern-crate.rs:44:9
-   |
-LL |         extern crate core;
-   |         ^^^^^^^^^^^^^^^^^^ unused
-   |
-help: remove the unused `extern crate`
-   |
-LL -         extern crate core;
-   |
-
-error: unused extern crate
-  --> $DIR/unnecessary-extern-crate.rs:48:9
-   |
-LL |         extern crate core as x;
-   |         ^^^^^^^^^^^^^^^^^^^^^^^ unused
-   |
-help: remove the unused `extern crate`
-   |
-LL -         extern crate core as x;
-   |
-
-error: aborting due to 6 previous errors
-
diff --git a/tests/ui/rust-2018/remove-extern-crate.fixed b/tests/ui/rust-2018/remove-extern-crate.fixed
deleted file mode 100644
index 19b1dc6fb0130..0000000000000
--- a/tests/ui/rust-2018/remove-extern-crate.fixed
+++ /dev/null
@@ -1,51 +0,0 @@
-//@ run-rustfix
-//@ edition:2018
-//@ check-pass
-//@ aux-build:remove-extern-crate.rs
-//@ compile-flags:--extern remove_extern_crate
-
-#![warn(rust_2018_idioms)]
-#![allow(dropping_copy_types)]
-#![allow(unused_imports)]
-
- //~ WARNING unused extern crate
-// Shouldn't suggest changing to `use`, as `another_name`
-// would no longer be added to the prelude which could cause
-// compilation errors for imports that use `another_name` in other
-// modules. See #57672.
-extern crate core as another_name;
-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();
-    with_visibility::foo();
-    remove_extern_crate::foo!();
-    bar!();
-    alloc::vec![5];
-}
-
-mod another {
-    use core; //~ WARNING `extern crate` is not idiomatic
-    use remove_extern_crate;
-
-    pub fn foo() {
-        core::mem::drop(4);
-        remove_extern_crate::foo!();
-    }
-}
-
-mod with_visibility {
-    pub use core; //~ WARNING `extern crate` is not idiomatic
-
-    pub fn foo() {
-        core::mem::drop(4);
-        remove_extern_crate::foo!();
-    }
-}
diff --git a/tests/ui/rust-2018/remove-extern-crate.rs b/tests/ui/rust-2018/remove-extern-crate.rs
deleted file mode 100644
index 88ef858da147f..0000000000000
--- a/tests/ui/rust-2018/remove-extern-crate.rs
+++ /dev/null
@@ -1,51 +0,0 @@
-//@ run-rustfix
-//@ edition:2018
-//@ check-pass
-//@ aux-build:remove-extern-crate.rs
-//@ compile-flags:--extern remove_extern_crate
-
-#![warn(rust_2018_idioms)]
-#![allow(dropping_copy_types)]
-#![allow(unused_imports)]
-
-extern crate core; //~ WARNING unused extern crate
-// Shouldn't suggest changing to `use`, as `another_name`
-// would no longer be added to the prelude which could cause
-// compilation errors for imports that use `another_name` in other
-// modules. See #57672.
-extern crate core as another_name;
-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();
-    with_visibility::foo();
-    remove_extern_crate::foo!();
-    bar!();
-    alloc::vec![5];
-}
-
-mod another {
-    extern crate core; //~ WARNING `extern crate` is not idiomatic
-    use remove_extern_crate;
-
-    pub fn foo() {
-        core::mem::drop(4);
-        remove_extern_crate::foo!();
-    }
-}
-
-mod with_visibility {
-    pub extern crate core; //~ WARNING `extern crate` is not idiomatic
-
-    pub fn foo() {
-        core::mem::drop(4);
-        remove_extern_crate::foo!();
-    }
-}
diff --git a/tests/ui/rust-2018/remove-extern-crate.stderr b/tests/ui/rust-2018/remove-extern-crate.stderr
deleted file mode 100644
index a530d40188ba2..0000000000000
--- a/tests/ui/rust-2018/remove-extern-crate.stderr
+++ /dev/null
@@ -1,44 +0,0 @@
-warning: unused extern crate
-  --> $DIR/remove-extern-crate.rs:11:1
-   |
-LL | extern crate core;
-   | ^^^^^^^^^^^^^^^^^^ unused
-   |
-note: the lint level is defined here
-  --> $DIR/remove-extern-crate.rs:7:9
-   |
-LL | #![warn(rust_2018_idioms)]
-   |         ^^^^^^^^^^^^^^^^
-   = note: `#[warn(unused_extern_crates)]` implied by `#[warn(rust_2018_idioms)]`
-help: remove the unused `extern crate`
-   |
-LL - extern crate core;
-LL +
-   |
-
-warning: `extern crate` is not idiomatic in the new edition
-  --> $DIR/remove-extern-crate.rs:35:5
-   |
-LL |     extern crate core;
-   |     ^^^^^^^^^^^^^^^^^^
-   |
-help: convert it to a `use`
-   |
-LL -     extern crate core;
-LL +     use core;
-   |
-
-warning: `extern crate` is not idiomatic in the new edition
-  --> $DIR/remove-extern-crate.rs:45:5
-   |
-LL |     pub extern crate core;
-   |     ^^^^^^^^^^^^^^^^^^^^^^
-   |
-help: convert it to a `use`
-   |
-LL -     pub extern crate core;
-LL +     pub use core;
-   |
-
-warning: 3 warnings emitted
-
diff --git a/tests/ui/rust-2018/removing-extern-crate-malformed-cfg.fixed b/tests/ui/rust-2018/removing-extern-crate-malformed-cfg.fixed
deleted file mode 100644
index b4b47dc886bef..0000000000000
--- a/tests/ui/rust-2018/removing-extern-crate-malformed-cfg.fixed
+++ /dev/null
@@ -1,16 +0,0 @@
-//@ edition:2018
-//@ aux-build: remove-extern-crate.rs
-//@ run-rustfix
-//@ rustfix-only-machine-applicable
-
-#![warn(rust_2018_idioms)]
-
- //~ WARNING unused extern crate
- //~ WARNING unused extern crate
-
-mod another {
-     //~ WARNING unused extern crate
-     //~ WARNING unused extern crate
-}
-
-fn main() {}
diff --git a/tests/ui/rust-2018/removing-extern-crate-malformed-cfg.rs b/tests/ui/rust-2018/removing-extern-crate-malformed-cfg.rs
deleted file mode 100644
index f3c591a656adc..0000000000000
--- a/tests/ui/rust-2018/removing-extern-crate-malformed-cfg.rs
+++ /dev/null
@@ -1,18 +0,0 @@
-//@ edition:2018
-//@ aux-build: remove-extern-crate.rs
-//@ run-rustfix
-//@ rustfix-only-machine-applicable
-
-#![warn(rust_2018_idioms)]
-
-#[cfg_attr(test, "macro_use")] //~ ERROR expected
-extern crate remove_extern_crate as foo; //~ WARNING unused extern crate
-extern crate core; //~ WARNING unused extern crate
-
-mod another {
-    #[cfg_attr(test)] //~ ERROR expected
-    extern crate remove_extern_crate as foo; //~ WARNING unused extern crate
-    extern crate core; //~ WARNING unused extern crate
-}
-
-fn main() {}
diff --git a/tests/ui/rust-2018/removing-extern-crate-malformed-cfg.stderr b/tests/ui/rust-2018/removing-extern-crate-malformed-cfg.stderr
deleted file mode 100644
index 20d5e6aebfd06..0000000000000
--- a/tests/ui/rust-2018/removing-extern-crate-malformed-cfg.stderr
+++ /dev/null
@@ -1,84 +0,0 @@
-error: expected identifier, found `"macro_use"`
-  --> $DIR/removing-extern-crate-malformed-cfg.rs:8:18
-   |
-LL | #[cfg_attr(test, "macro_use")]
-   |                  ^^^^^^^^^^^ expected identifier
-   |
-   = note: for more information, visit <https://doc.rust-lang.org/reference/conditional-compilation.html#the-cfg_attr-attribute>
-help: must be of the form
-   |
-LL - #[cfg_attr(test, "macro_use")]
-LL + #[cfg_attr(predicate, attr1, attr2, ...)]
-   |
-
-error: expected one of `(`, `,`, `::`, or `=`, found `<eof>`
-  --> $DIR/removing-extern-crate-malformed-cfg.rs:13:16
-   |
-LL |     #[cfg_attr(test)]
-   |                ^^^^ expected one of `(`, `,`, `::`, or `=`
-   |
-   = note: for more information, visit <https://doc.rust-lang.org/reference/conditional-compilation.html#the-cfg_attr-attribute>
-help: must be of the form
-   |
-LL -     #[cfg_attr(test)]
-LL +     #[cfg_attr(predicate, attr1, attr2, ...)]
-   |
-
-warning: unused extern crate
-  --> $DIR/removing-extern-crate-malformed-cfg.rs:9:1
-   |
-LL | extern crate remove_extern_crate as foo;
-   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ unused
-   |
-note: the lint level is defined here
-  --> $DIR/removing-extern-crate-malformed-cfg.rs:6:9
-   |
-LL | #![warn(rust_2018_idioms)]
-   |         ^^^^^^^^^^^^^^^^
-   = note: `#[warn(unused_extern_crates)]` implied by `#[warn(rust_2018_idioms)]`
-help: remove the unused `extern crate`
-   |
-LL - #[cfg_attr(test, "macro_use")]
-LL - extern crate remove_extern_crate as foo;
-LL +
-   |
-
-warning: unused extern crate
-  --> $DIR/removing-extern-crate-malformed-cfg.rs:10:1
-   |
-LL | extern crate core;
-   | ^^^^^^^^^^^^^^^^^^ unused
-   |
-help: remove the unused `extern crate`
-   |
-LL - extern crate core;
-LL +
-   |
-
-warning: unused extern crate
-  --> $DIR/removing-extern-crate-malformed-cfg.rs:14:5
-   |
-LL |     extern crate remove_extern_crate as foo;
-   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ unused
-   |
-help: remove the unused `extern crate`
-   |
-LL -     #[cfg_attr(test)]
-LL -     extern crate remove_extern_crate as foo;
-LL +
-   |
-
-warning: unused extern crate
-  --> $DIR/removing-extern-crate-malformed-cfg.rs:15:5
-   |
-LL |     extern crate core;
-   |     ^^^^^^^^^^^^^^^^^^ unused
-   |
-help: remove the unused `extern crate`
-   |
-LL -     extern crate core;
-LL +
-   |
-
-error: aborting due to 2 previous errors; 4 warnings emitted
-
diff --git a/tests/ui/rust-2018/removing-extern-crate.fixed b/tests/ui/rust-2018/removing-extern-crate.fixed
deleted file mode 100644
index e88a84cc93e2a..0000000000000
--- a/tests/ui/rust-2018/removing-extern-crate.fixed
+++ /dev/null
@@ -1,16 +0,0 @@
-//@ edition:2018
-//@ aux-build:dummy-crate.rs
-//@ run-rustfix
-//@ check-pass
-
-#![warn(rust_2018_idioms)]
-
- //~ WARNING unused extern crate
- //~ WARNING unused extern crate
-
-mod another {
-     //~ WARNING unused extern crate
-     //~ WARNING unused extern crate
-}
-
-fn main() {}
diff --git a/tests/ui/rust-2018/removing-extern-crate.rs b/tests/ui/rust-2018/removing-extern-crate.rs
deleted file mode 100644
index 844377945e02f..0000000000000
--- a/tests/ui/rust-2018/removing-extern-crate.rs
+++ /dev/null
@@ -1,16 +0,0 @@
-//@ edition:2018
-//@ aux-build:dummy-crate.rs
-//@ run-rustfix
-//@ check-pass
-
-#![warn(rust_2018_idioms)]
-
-extern crate dummy_crate as foo; //~ WARNING unused extern crate
-extern crate core; //~ WARNING unused extern crate
-
-mod another {
-    extern crate dummy_crate as foo; //~ WARNING unused extern crate
-    extern crate core; //~ WARNING unused extern crate
-}
-
-fn main() {}
diff --git a/tests/ui/rust-2018/removing-extern-crate.stderr b/tests/ui/rust-2018/removing-extern-crate.stderr
deleted file mode 100644
index b6f8314ce4b64..0000000000000
--- a/tests/ui/rust-2018/removing-extern-crate.stderr
+++ /dev/null
@@ -1,56 +0,0 @@
-warning: unused extern crate
-  --> $DIR/removing-extern-crate.rs:8:1
-   |
-LL | extern crate dummy_crate as foo;
-   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ unused
-   |
-note: the lint level is defined here
-  --> $DIR/removing-extern-crate.rs:6:9
-   |
-LL | #![warn(rust_2018_idioms)]
-   |         ^^^^^^^^^^^^^^^^
-   = note: `#[warn(unused_extern_crates)]` implied by `#[warn(rust_2018_idioms)]`
-help: remove the unused `extern crate`
-   |
-LL - extern crate dummy_crate as foo;
-LL +
-   |
-
-warning: unused extern crate
-  --> $DIR/removing-extern-crate.rs:9:1
-   |
-LL | extern crate core;
-   | ^^^^^^^^^^^^^^^^^^ unused
-   |
-help: remove the unused `extern crate`
-   |
-LL - extern crate core;
-LL +
-   |
-
-warning: unused extern crate
-  --> $DIR/removing-extern-crate.rs:12:5
-   |
-LL |     extern crate dummy_crate as foo;
-   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ unused
-   |
-help: remove the unused `extern crate`
-   |
-LL -     extern crate dummy_crate as foo;
-LL +
-   |
-
-warning: unused extern crate
-  --> $DIR/removing-extern-crate.rs:13:5
-   |
-LL |     extern crate core;
-   |     ^^^^^^^^^^^^^^^^^^ unused
-   |
-help: remove the unused `extern crate`
-   |
-LL -     extern crate core;
-LL +
-   |
-
-warning: 4 warnings emitted
-