Allow unsafe extern on all editions

Author: spastorino

compiler/rustc_ast_passes/src/ast_validation.rs

@@ -1021,15 +1021,12 @@ impl<'a> Visitor<'a> for AstValidator<'a> {
                 walk_list!(self, visit_attribute, &item.attrs);
                 return; // Avoid visiting again.
             }
-            ItemKind::ForeignMod(ForeignMod { abi, unsafety, .. }) => {
+            ItemKind::ForeignMod(ForeignMod { abi, .. }) => {
                 let old_item = mem::replace(&mut self.extern_mod, Some(item));
                 self.visibility_not_permitted(
                     &item.vis,
                     errors::VisibilityNotPermittedNote::IndividualForeignItems,
                 );
-                if let &Unsafe::Yes(span) = unsafety {
-                    self.dcx().emit_err(errors::UnsafeItem { span, kind: "extern block" });
-                }
                 if abi.is_none() {
                     self.maybe_lint_missing_abi(item.span, item.id);
                 }

compiler/rustc_codegen_llvm/src/llvm/ffi.rs

@@ -1,5 +1,6 @@
 #![allow(non_camel_case_types)]
 #![allow(non_upper_case_globals)]
+#![cfg_attr(not(bootstrap), allow(missing_unsafe_on_extern))]
 
 use super::debuginfo::{
     DIArray, DIBasicType, DIBuilder, DICompositeType, DIDerivedType, DIDescriptor, DIEnumerator,

compiler/rustc_driver_impl/src/signal_handler.rs

@@ -1,6 +1,8 @@
 //! Signal handler for rustc
 //! Primarily used to extract a backtrace from stack overflow
 
+#![cfg_attr(not(bootstrap), allow(missing_unsafe_on_extern))]
+
 use rustc_interface::util::{DEFAULT_STACK_SIZE, STACK_SIZE};
 use std::alloc::{alloc, Layout};
 use std::{fmt, mem, ptr};

compiler/rustc_llvm/src/lib.rs

@@ -2,6 +2,7 @@
 #![doc(rust_logo)]
 #![feature(rustdoc_internals)]
 #![allow(internal_features)]
+#![cfg_attr(not(bootstrap), allow(missing_unsafe_on_extern))]
 
 // NOTE: This crate only exists to allow linking on mingw targets.
 

compiler/rustc_middle/src/ty/list.rs

@@ -1,3 +1,5 @@
+#![cfg_attr(not(bootstrap), allow(missing_unsafe_on_extern))]
+
 use super::flags::FlagComputation;
 use super::{DebruijnIndex, DebugWithInfcx, InferCtxtLike, TyCtxt, TypeFlags, WithInfcx};
 use crate::arena::Arena;

tests/ui/parser/unsafe-foreign-mod-2.rs

@@ -1,8 +1,7 @@
 extern "C" unsafe {
-               //~^ ERROR expected `{`, found keyword `unsafe`
-               //~| ERROR extern block cannot be declared unsafe
+    //~^ ERROR expected `{`, found keyword `unsafe`
     unsafe fn foo();
-        //~^ ERROR functions in `extern` blocks cannot have qualifiers
+    //~^ ERROR functions in `extern` blocks cannot have qualifiers
 }
 
 fn main() {}

tests/ui/parser/unsafe-foreign-mod-2.stderr

@@ -4,20 +4,14 @@ error: expected `{`, found keyword `unsafe`
 LL | extern "C" unsafe {
    |            ^^^^^^ expected `{`
 
-error: extern block cannot be declared unsafe
-  --> $DIR/unsafe-foreign-mod-2.rs:1:12
-   |
-LL | extern "C" unsafe {
-   |            ^^^^^^
-
 error: functions in `extern` blocks cannot have qualifiers
-  --> $DIR/unsafe-foreign-mod-2.rs:4:5
+  --> $DIR/unsafe-foreign-mod-2.rs:3:5
    |
 LL | extern "C" unsafe {
    | ----------------- in this `extern` block
-...
+LL |
 LL |     unsafe fn foo();
    |     ^^^^^^ help: remove this qualifier
 
-error: aborting due to 3 previous errors
+error: aborting due to 2 previous errors
 

tests/ui/parser/unsafe-foreign-mod.rs

@@ -1,5 +1,5 @@
-unsafe extern "C" {
-    //~^ ERROR extern block cannot be declared unsafe
-}
+//@ build-pass
+
+unsafe extern "C" {}
 
 fn main() {}

tests/ui/parser/unsafe-foreign-mod.stderr

@@ -1,10 +1,11 @@
+//@ build-pass
+
 extern "C" {
     static TEST1: i32;
     fn test1(i: i32);
 }
 
 unsafe extern "C" {
-    //~^ ERROR: extern block cannot be declared unsafe
     static TEST2: i32;
     fn test2(i: i32);
 }