Auto merge of rust-lang#78028 - JohnTitor:rollup-jt3hikb, r=JohnTitor

Rollup of 10 pull requests

Successful merges:

 - rust-lang#75209 (Suggest imports of unresolved macros)
 - rust-lang#77547 (stabilize union with 'ManuallyDrop' fields and 'impl Drop for Union')
 - rust-lang#77827 (Don't link to nightly primitives on stable channel)
 - rust-lang#77855 (resolve: further improvements to "try using the enum's variant" diagnostic)
 - rust-lang#77900 (Use fdatasync for File::sync_data on more OSes)
 - rust-lang#77925 (Suggest minimal subset features in `incomplete_features` lint)
 - rust-lang#77971 (Deny broken intra-doc links in linkchecker)
 - rust-lang#77991 (Bump backtrace-rs)
 - rust-lang#77992 (instrument-coverage: try our best to not ICE)
 - rust-lang#78013 (Fix sidebar scroll on mobile devices)

Failed merges:

r? `@ghost`

Author: bors

Cargo.lock

@@ -1744,6 +1744,10 @@ dependencies = [
 [[package]]
 name = "linkchecker"
 version = "0.1.0"
+dependencies = [
+ "once_cell",
+ "regex",
+]
 
 [[package]]
 name = "linked-hash-map"

compiler/rustc_error_codes/src/error_codes/E0660.md

@@ -9,4 +9,4 @@ llvm_asm!("nop" "nop");
 Considering that this would be a long explanation, we instead recommend you
 take a look at the [`llvm_asm`] chapter of the Unstable book:
 
-[llvm_asm]: https://doc.rust-lang.org/stable/unstable-book/library-features/llvm-asm.html
+[`llvm_asm`]: https://doc.rust-lang.org/stable/unstable-book/library-features/llvm-asm.html

compiler/rustc_error_codes/src/error_codes/E0661.md

@@ -10,4 +10,4 @@ llvm_asm!("nop" : "r"(a));
 Considering that this would be a long explanation, we instead recommend you
 take a look at the [`llvm_asm`] chapter of the Unstable book:
 
-[llvm_asm]: https://doc.rust-lang.org/stable/unstable-book/library-features/llvm-asm.html
+[`llvm_asm`]: https://doc.rust-lang.org/stable/unstable-book/library-features/llvm-asm.html

compiler/rustc_error_codes/src/error_codes/E0662.md

@@ -13,4 +13,4 @@ llvm_asm!("xor %eax, %eax"
 Considering that this would be a long explanation, we instead recommend you
 take a look at the [`llvm_asm`] chapter of the Unstable book:
 
-[llvm_asm]: https://doc.rust-lang.org/stable/unstable-book/library-features/llvm-asm.html
+[`llvm_asm`]: https://doc.rust-lang.org/stable/unstable-book/library-features/llvm-asm.html

compiler/rustc_error_codes/src/error_codes/E0663.md

@@ -13,4 +13,4 @@ llvm_asm!("xor %eax, %eax"
 Considering that this would be a long explanation, we instead recommend you
 take a look at the [`llvm_asm`] chapter of the Unstable book:
 
-[llvm_asm]: https://doc.rust-lang.org/stable/unstable-book/library-features/llvm-asm.html
+[`llvm_asm`]: https://doc.rust-lang.org/stable/unstable-book/library-features/llvm-asm.html

compiler/rustc_error_codes/src/error_codes/E0664.md

@@ -13,4 +13,4 @@ llvm_asm!("mov $$0x200, %eax"
 Considering that this would be a long explanation, we instead recommend you
 take a look at the [`llvm_asm`] chapter of the Unstable book:
 
-[llvm_asm]: https://doc.rust-lang.org/stable/unstable-book/library-features/llvm-asm.html
+[`llvm_asm`]: https://doc.rust-lang.org/stable/unstable-book/library-features/llvm-asm.html

compiler/rustc_lint/src/builtin.rs

@@ -2288,12 +2288,20 @@ impl EarlyLintPass for IncompleteFeatures {
                             n, n,
                         ));
                     }
+                    if HAS_MIN_FEATURES.contains(&name) {
+                        builder.help(&format!(
+                            "consider using `min_{}` instead, which is more stable and complete",
+                            name,
+                        ));
+                    }
                     builder.emit();
                 })
             });
     }
 }
 
+const HAS_MIN_FEATURES: &[Symbol] = &[sym::const_generics, sym::specialization];
+
 declare_lint! {
     /// The `invalid_value` lint detects creating a value that is not valid,
     /// such as a NULL reference.

compiler/rustc_mir/src/transform/instrument_coverage.rs

@@ -22,9 +22,7 @@ use rustc_middle::ty::query::Providers;
 use rustc_middle::ty::TyCtxt;
 use rustc_span::def_id::DefId;
 use rustc_span::source_map::original_sp;
-use rustc_span::{
-    BytePos, CharPos, FileName, Pos, RealFileName, SourceFile, Span, Symbol, SyntaxContext,
-};
+use rustc_span::{BytePos, CharPos, Pos, SourceFile, Span, Symbol, SyntaxContext};
 
 use std::cmp::Ordering;
 
@@ -549,13 +547,7 @@ impl<'a, 'tcx> Instrumentor<'a, 'tcx> {
         let mir_body = &self.mir_body;
         let body_span = self.body_span();
         let source_file = source_map.lookup_source_file(body_span.lo());
-        let file_name = match &source_file.name {
-            FileName::Real(RealFileName::Named(path)) => Symbol::intern(&path.to_string_lossy()),
-            _ => bug!(
-                "source_file.name should be a RealFileName, but it was: {:?}",
-                source_file.name
-            ),
-        };
+        let file_name = Symbol::intern(&source_file.name.to_string());
 
         debug!("instrumenting {:?}, span: {}", def_id, source_map.span_to_string(body_span));
 

compiler/rustc_passes/src/stability.rs

@@ -13,15 +13,13 @@ use rustc_hir::{Generics, HirId, Item, StructField, TraitRef, Ty, TyKind, Varian
 use rustc_middle::hir::map::Map;
 use rustc_middle::middle::privacy::AccessLevels;
 use rustc_middle::middle::stability::{DeprecationEntry, Index};
-use rustc_middle::ty::query::Providers;
-use rustc_middle::ty::TyCtxt;
+use rustc_middle::ty::{self, query::Providers, TyCtxt};
 use rustc_session::lint;
 use rustc_session::lint::builtin::INEFFECTIVE_UNSTABLE_TRAIT_IMPL;
 use rustc_session::parse::feature_err;
 use rustc_session::Session;
 use rustc_span::symbol::{sym, Symbol};
-use rustc_span::Span;
-use rustc_trait_selection::traits::misc::can_type_implement_copy;
+use rustc_span::{Span, DUMMY_SP};
 
 use std::cmp::Ordering;
 use std::mem::replace;
@@ -711,27 +709,35 @@ impl Visitor<'tcx> for Checker<'tcx> {
             // so semi-randomly perform it here in stability.rs
             hir::ItemKind::Union(..) if !self.tcx.features().untagged_unions => {
                 let def_id = self.tcx.hir().local_def_id(item.hir_id);
-                let adt_def = self.tcx.adt_def(def_id);
                 let ty = self.tcx.type_of(def_id);
+                let (adt_def, substs) = match ty.kind() {
+                    ty::Adt(adt_def, substs) => (adt_def, substs),
+                    _ => bug!(),
+                };
 
-                if adt_def.has_dtor(self.tcx) {
-                    feature_err(
-                        &self.tcx.sess.parse_sess,
-                        sym::untagged_unions,
-                        item.span,
-                        "unions with `Drop` implementations are unstable",
-                    )
-                    .emit();
-                } else {
-                    let param_env = self.tcx.param_env(def_id);
-                    if can_type_implement_copy(self.tcx, param_env, ty).is_err() {
-                        feature_err(
-                            &self.tcx.sess.parse_sess,
-                            sym::untagged_unions,
-                            item.span,
-                            "unions with non-`Copy` fields are unstable",
-                        )
-                        .emit();
+                // Non-`Copy` fields are unstable, except for `ManuallyDrop`.
+                let param_env = self.tcx.param_env(def_id);
+                for field in &adt_def.non_enum_variant().fields {
+                    let field_ty = field.ty(self.tcx, substs);
+                    if !field_ty.ty_adt_def().map_or(false, |adt_def| adt_def.is_manually_drop())
+                        && !field_ty.is_copy_modulo_regions(self.tcx.at(DUMMY_SP), param_env)
+                    {
+                        if field_ty.needs_drop(self.tcx, param_env) {
+                            // Avoid duplicate error: This will error later anyway because fields
+                            // that need drop are not allowed.
+                            self.tcx.sess.delay_span_bug(
+                                item.span,
+                                "union should have been rejected due to potentially dropping field",
+                            );
+                        } else {
+                            feature_err(
+                                &self.tcx.sess.parse_sess,
+                                sym::untagged_unions,
+                                self.tcx.def_span(field.did),
+                                "unions with non-`Copy` fields other than `ManuallyDrop<T>` are unstable",
+                            )
+                            .emit();
+                        }
                     }
                 }
             }

compiler/rustc_resolve/src/diagnostics.rs

@@ -922,6 +922,17 @@ impl<'a> Resolver<'a> {
         );
         self.add_typo_suggestion(err, suggestion, ident.span);
 
+        let import_suggestions = self.lookup_import_candidates(
+            ident,
+            Namespace::MacroNS,
+            parent_scope,
+            |res| match res {
+                Res::Def(DefKind::Macro(MacroKind::Bang), _) => true,
+                _ => false,
+            },
+        );
+        show_candidates(err, None, &import_suggestions, false, true);
+
         if macro_kind == MacroKind::Derive && (ident.name == sym::Send || ident.name == sym::Sync) {
             let msg = format!("unsafe traits like `{}` should be implemented explicitly", ident);
             err.span_note(ident.span, &msg);