Auto merge of #127377 - cuviper:beta-next, r=cuviper

[beta] backports

- Properly gate `safe` keyword in pre-expansion #126757
- Switch back `non_local_definitions` lint to allow-by-default #127015
- Stall computing instance for drop shim until it has no unsubstituted const params #127068
- Update LLVM submodule #127190

r? cuviper

Author: bors

compiler/rustc_ast_passes/src/feature_gate.rs

@@ -562,6 +562,10 @@ pub fn check_crate(krate: &ast::Crate, sess: &Session, features: &Features) {
     gate_all!(precise_capturing, "precise captures on `impl Trait` are experimental");
     gate_all!(global_registration, "global registration is experimental");
     gate_all!(unsafe_attributes, "`#[unsafe()]` markers for attributes are experimental");
+    gate_all!(
+        unsafe_extern_blocks,
+        "`unsafe extern {}` blocks and `safe` keyword are experimental"
+    );
 
     if !visitor.features.never_patterns {
         if let Some(spans) = spans.get(&sym::never_patterns) {

compiler/rustc_lint/src/non_local_def.rs

@@ -50,7 +50,7 @@ declare_lint! {
     /// All nested bodies (functions, enum discriminant, array length, consts) (expect for
     /// `const _: Ty = { ... }` in top-level module, which is still undecided) are checked.
     pub NON_LOCAL_DEFINITIONS,
-    Warn,
+    Allow,
     "checks for non-local definitions",
     report_in_external_macro
 }

compiler/rustc_mir_transform/src/inline.rs

@@ -10,7 +10,7 @@ use rustc_middle::middle::codegen_fn_attrs::{CodegenFnAttrFlags, CodegenFnAttrs}
 use rustc_middle::mir::visit::*;
 use rustc_middle::mir::*;
 use rustc_middle::ty::TypeVisitableExt;
-use rustc_middle::ty::{self, Instance, InstanceDef, ParamEnv, Ty, TyCtxt};
+use rustc_middle::ty::{self, Instance, InstanceDef, ParamEnv, Ty, TyCtxt, TypeFlags};
 use rustc_session::config::{DebugInfo, OptLevel};
 use rustc_span::source_map::Spanned;
 use rustc_span::sym;
@@ -320,6 +320,16 @@ impl<'tcx> Inliner<'tcx> {
             InstanceDef::Intrinsic(_) | InstanceDef::Virtual(..) => {
                 return Err("instance without MIR (intrinsic / virtual)");
             }
+
+            // FIXME(#127030): `ConstParamHasTy` has bad interactions with
+            // the drop shim builder, which does not evaluate predicates in
+            // the correct param-env for types being dropped. Stall resolving
+            // the MIR for this instance until all of its const params are
+            // substituted.
+            InstanceDef::DropGlue(_, Some(ty)) if ty.has_type_flags(TypeFlags::HAS_CT_PARAM) => {
+                return Err("still needs substitution");
+            }
+
             // This cannot result in an immediate cycle since the callee MIR is a shim, which does
             // not get any optimizations run on it. Any subsequent inlining may cause cycles, but we
             // do not need to catch this here, we can wait until the inliner decides to continue

compiler/rustc_parse/src/parser/mod.rs

@@ -1221,6 +1221,9 @@ impl<'a> Parser<'a> {
         if self.eat_keyword_case(kw::Unsafe, case) {
             Safety::Unsafe(self.prev_token.uninterpolated_span())
         } else if self.eat_keyword_case(kw::Safe, case) {
+            self.psess
+                .gated_spans
+                .gate(sym::unsafe_extern_blocks, self.prev_token.uninterpolated_span());
             Safety::Safe(self.prev_token.uninterpolated_span())
         } else {
             Safety::Default

src/llvm-project

@@ -4,6 +4,8 @@
 //@ normalize-stderr-test: "tests/rustdoc-ui/doctest" -> "$$DIR"
 //@ normalize-stdout-test "finished in \d+\.\d+s" -> "finished in $$TIME"
 
+#![doc(test(attr(warn(non_local_definitions))))]
+
 //! ```
 //! #[macro_export]
 //! macro_rules! a_macro { () => {} }

tests/rustdoc-ui/doctest/non_local_defs.rs

@@ -1,13 +1,17 @@
 warning: non-local `macro_rules!` definition, `#[macro_export]` macro should be written at top level module
-  --> $DIR/non_local_defs.rs:9:1
+  --> $DIR/non_local_defs.rs:11:1
    |
 LL | macro_rules! a_macro { () => {} }
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    |
    = help: remove the `#[macro_export]` or make this doc-test a standalone test with its own `fn main() { ... }`
    = note: a `macro_rules!` definition is non-local if it is nested inside an item and has a `#[macro_export]` attribute
    = note: this lint may become deny-by-default in the edition 2024 and higher, see the tracking issue <https://github.com/rust-lang/rust/issues/120363>
-   = note: `#[warn(non_local_definitions)]` on by default
+note: the lint level is defined here
+  --> $DIR/non_local_defs.rs:8:9
+   |
+LL | #![warn(non_local_definitions)]
+   |         ^^^^^^^^^^^^^^^^^^^^^
 
 warning: 1 warning emitted
 

tests/rustdoc-ui/doctest/non_local_defs.stderr

@@ -1,6 +1,6 @@
 
 running 1 test
-test $DIR/non_local_defs.rs - (line 7) ... ok
+test $DIR/non_local_defs.rs - (line 9) ... ok
 
 test result: ok. 1 passed; 0 failed; 0 ignored; 0 measured; 0 filtered out; finished in $TIME
 

tests/rustdoc-ui/doctest/non_local_defs.stdout

@@ -0,0 +1,18 @@
+//@ compile-flags: -Zinline-mir=yes --crate-type=lib
+//@ build-pass
+
+use std::mem::ManuallyDrop;
+
+pub struct Foo<T, const N: usize>([T; N]);
+
+pub struct Dorp {}
+
+impl Drop for Dorp {
+    fn drop(&mut self) {}
+}
+
+#[inline]
+// SAFETY: call this with a valid allocation idk
+pub unsafe fn drop<const M: usize>(x: *mut Foo<Dorp, M>) {
+    std::ptr::drop_in_place(x);
+}

tests/ui/const-generics/polymorphic-drop-shim.rs

@@ -2,4 +2,12 @@ unsafe extern "C" {
     //~^ ERROR extern block cannot be declared unsafe
 }
 
+// We can't gate `unsafe extern` blocks themselves since they were previously
+// allowed, but we should gate the `safe` soft keyword.
+#[cfg(any())]
+unsafe extern "C" {
+    safe fn foo();
+    //~^ ERROR `unsafe extern {}` blocks and `safe` keyword are experimental
+}
+
 fn main() {}