Auto merge of #93119 - matthiaskrgr:rollup-ku3cn5j, r=matthiaskrgr

Rollup of 13 pull requests

Successful merges:

 - #89747 (Add MaybeUninit::(slice_)as_bytes(_mut))
 - #89764 (Fix variant index / discriminant confusion in uninhabited enum branching)
 - #91606 (Stabilize `-Z print-link-args` as `--print link-args`)
 - #91694 (rustdoc: decouple stability and const-stability)
 - #92183 (Point at correct argument when async fn output type lifetime disagrees with signature)
 - #92582 (improve `_` constants in item signature handling)
 - #92680 (intra-doc: Use the impl's assoc item where possible)
 - #92704 (Change lint message to be stronger for &T -> &mut T transmute)
 - #92861 (Rustdoc mobile: put out-of-band info on its own line)
 - #92992 (Help optimize out backtraces when disabled)
 - #93038 (Fix star handling in block doc comments)
 - #93108 (:arrow_up: rust-analyzer)
 - #93112 (Fix CVE-2022-21658)

Failed merges:

r? `@ghost`
`@rustbot` modify labels: rollup

compiler/rustc_ast/src/attr/mod.rs

@@ -242,6 +242,17 @@ impl Attribute {
         }
     }
 
+    pub fn doc_str_and_comment_kind(&self) -> Option<(Symbol, CommentKind)> {
+        match self.kind {
+            AttrKind::DocComment(kind, data) => Some((data, kind)),
+            AttrKind::Normal(ref item, _) if item.path == sym::doc => item
+                .meta_kind()
+                .and_then(|kind| kind.value_str())
+                .map(|data| (data, CommentKind::Line)),
+            _ => None,
+        }
+    }
+
     pub fn doc_str(&self) -> Option<Symbol> {
         match self.kind {
             AttrKind::DocComment(.., data) => Some(data),

compiler/rustc_ast/src/util/comments.rs

@@ -1,3 +1,4 @@
+use crate::token::CommentKind;
 use rustc_span::source_map::SourceMap;
 use rustc_span::{BytePos, CharPos, FileName, Pos, Symbol};
 
@@ -25,7 +26,7 @@ pub struct Comment {
 
 /// Makes a doc string more presentable to users.
 /// Used by rustdoc and perhaps other tools, but not by rustc.
-pub fn beautify_doc_string(data: Symbol) -> Symbol {
+pub fn beautify_doc_string(data: Symbol, kind: CommentKind) -> Symbol {
     fn get_vertical_trim(lines: &[&str]) -> Option<(usize, usize)> {
         let mut i = 0;
         let mut j = lines.len();
@@ -42,10 +43,28 @@ pub fn beautify_doc_string(data: Symbol) -> Symbol {
         if i != 0 || j != lines.len() { Some((i, j)) } else { None }
     }
 
-    fn get_horizontal_trim(lines: &[&str]) -> Option<usize> {
+    fn get_horizontal_trim(lines: &[&str], kind: CommentKind) -> Option<usize> {
         let mut i = usize::MAX;
         let mut first = true;
 
+        // In case we have doc comments like `/**` or `/*!`, we want to remove stars if they are
+        // present. However, we first need to strip the empty lines so they don't get in the middle
+        // when we try to compute the "horizontal trim".
+        let lines = if kind == CommentKind::Block {
+            let mut i = 0;
+            let mut j = lines.len();
+
+            while i < j && lines[i].trim().is_empty() {
+                i += 1;
+            }
+            while j > i && lines[j - 1].trim().is_empty() {
+                j -= 1;
+            }
+            &lines[i..j]
+        } else {
+            lines
+        };
+
         for line in lines {
             for (j, c) in line.chars().enumerate() {
                 if j > i || !"* \t".contains(c) {
@@ -79,11 +98,13 @@ pub fn beautify_doc_string(data: Symbol) -> Symbol {
         } else {
             &mut lines
         };
-        if let Some(horizontal) = get_horizontal_trim(&lines) {
+        if let Some(horizontal) = get_horizontal_trim(&lines, kind) {
             changes = true;
             // remove a "[ \t]*\*" block from each line, if possible
             for line in lines.iter_mut() {
-                *line = &line[horizontal + 1..];
+                if horizontal + 1 < line.len() {
+                    *line = &line[horizontal + 1..];
+                }
             }
         }
         if changes {

compiler/rustc_ast/src/util/comments/tests.rs

@@ -5,7 +5,7 @@ use rustc_span::create_default_session_globals_then;
 fn test_block_doc_comment_1() {
     create_default_session_globals_then(|| {
         let comment = "\n * Test \n **  Test\n *   Test\n";
-        let stripped = beautify_doc_string(Symbol::intern(comment));
+        let stripped = beautify_doc_string(Symbol::intern(comment), CommentKind::Block);
         assert_eq!(stripped.as_str(), " Test \n*  Test\n   Test");
     })
 }
@@ -14,7 +14,7 @@ fn test_block_doc_comment_1() {
 fn test_block_doc_comment_2() {
     create_default_session_globals_then(|| {
         let comment = "\n * Test\n *  Test\n";
-        let stripped = beautify_doc_string(Symbol::intern(comment));
+        let stripped = beautify_doc_string(Symbol::intern(comment), CommentKind::Block);
         assert_eq!(stripped.as_str(), " Test\n  Test");
     })
 }
@@ -23,21 +23,21 @@ fn test_block_doc_comment_2() {
 fn test_block_doc_comment_3() {
     create_default_session_globals_then(|| {
         let comment = "\n let a: *i32;\n *a = 5;\n";
-        let stripped = beautify_doc_string(Symbol::intern(comment));
+        let stripped = beautify_doc_string(Symbol::intern(comment), CommentKind::Block);
         assert_eq!(stripped.as_str(), " let a: *i32;\n *a = 5;");
     })
 }
 
 #[test]
 fn test_line_doc_comment() {
     create_default_session_globals_then(|| {
-        let stripped = beautify_doc_string(Symbol::intern(" test"));
+        let stripped = beautify_doc_string(Symbol::intern(" test"), CommentKind::Line);
         assert_eq!(stripped.as_str(), " test");
-        let stripped = beautify_doc_string(Symbol::intern("! test"));
+        let stripped = beautify_doc_string(Symbol::intern("! test"), CommentKind::Line);
         assert_eq!(stripped.as_str(), "! test");
-        let stripped = beautify_doc_string(Symbol::intern("test"));
+        let stripped = beautify_doc_string(Symbol::intern("test"), CommentKind::Line);
         assert_eq!(stripped.as_str(), "test");
-        let stripped = beautify_doc_string(Symbol::intern("!test"));
+        let stripped = beautify_doc_string(Symbol::intern("!test"), CommentKind::Line);
         assert_eq!(stripped.as_str(), "!test");
     })
 }

compiler/rustc_codegen_ssa/src/back/link.rs

@@ -667,7 +667,7 @@ fn link_natively<'a, B: ArchiveBuilder<'a>>(
         cmd.env_remove(k);
     }
 
-    if sess.opts.debugging_opts.print_link_args {
+    if sess.opts.prints.contains(&PrintRequest::LinkArgs) {
         println!("{:?}", &cmd);
     }
 

compiler/rustc_driver/src/lib.rs

@@ -645,9 +645,9 @@ impl RustcDefaultCalls {
         temps_dir: &Option<PathBuf>,
     ) -> Compilation {
         use rustc_session::config::PrintRequest::*;
-        // PrintRequest::NativeStaticLibs is special - printed during linking
+        // NativeStaticLibs and LinkArgs are special - printed during linking
         // (empty iterator returns true)
-        if sess.opts.prints.iter().all(|&p| p == PrintRequest::NativeStaticLibs) {
+        if sess.opts.prints.iter().all(|&p| p == NativeStaticLibs || p == LinkArgs) {
             return Compilation::Continue;
         }
 
@@ -738,7 +738,8 @@ impl RustcDefaultCalls {
                     codegen_backend.print(*req, sess);
                 }
                 // Any output here interferes with Cargo's parsing of other printed output
-                PrintRequest::NativeStaticLibs => {}
+                NativeStaticLibs => {}
+                LinkArgs => {}
             }
         }
         Compilation::Stop

compiler/rustc_hir/src/hir.rs

@@ -2726,6 +2726,10 @@ pub struct FnHeader {
 }
 
 impl FnHeader {
+    pub fn is_async(&self) -> bool {
+        matches!(&self.asyncness, IsAsync::Async)
+    }
+
     pub fn is_const(&self) -> bool {
         matches!(&self.constness, Constness::Const)
     }
@@ -3169,7 +3173,7 @@ impl<'hir> Node<'hir> {
         }
     }
 
-    pub fn fn_decl(&self) -> Option<&FnDecl<'hir>> {
+    pub fn fn_decl(&self) -> Option<&'hir FnDecl<'hir>> {
         match self {
             Node::TraitItem(TraitItem { kind: TraitItemKind::Fn(fn_sig, _), .. })
             | Node::ImplItem(ImplItem { kind: ImplItemKind::Fn(fn_sig, _), .. })
@@ -3181,6 +3185,15 @@ impl<'hir> Node<'hir> {
         }
     }
 
+    pub fn fn_sig(&self) -> Option<&'hir FnSig<'hir>> {
+        match self {
+            Node::TraitItem(TraitItem { kind: TraitItemKind::Fn(fn_sig, _), .. })
+            | Node::ImplItem(ImplItem { kind: ImplItemKind::Fn(fn_sig, _), .. })
+            | Node::Item(Item { kind: ItemKind::Fn(fn_sig, _, _), .. }) => Some(fn_sig),
+            _ => None,
+        }
+    }
+
     pub fn body_id(&self) -> Option<BodyId> {
         match self {
             Node::TraitItem(TraitItem {

compiler/rustc_infer/src/infer/error_reporting/mod.rs

@@ -65,11 +65,11 @@ use rustc_hir::def_id::DefId;
 use rustc_hir::lang_items::LangItem;
 use rustc_hir::{Item, ItemKind, Node};
 use rustc_middle::dep_graph::DepContext;
-use rustc_middle::ty::error::TypeError;
 use rustc_middle::ty::{
     self,
+    error::TypeError,
     subst::{GenericArgKind, Subst, SubstsRef},
-    Region, Ty, TyCtxt, TypeFoldable,
+    Binder, Region, Ty, TyCtxt, TypeFoldable,
 };
 use rustc_span::{sym, BytePos, DesugaringKind, MultiSpan, Pos, Span};
 use rustc_target::spec::abi;
@@ -1765,7 +1765,7 @@ impl<'a, 'tcx> InferCtxt<'a, 'tcx> {
         self.note_error_origin(diag, cause, exp_found, terr);
     }
 
-    pub fn get_impl_future_output_ty(&self, ty: Ty<'tcx>) -> Option<Ty<'tcx>> {
+    pub fn get_impl_future_output_ty(&self, ty: Ty<'tcx>) -> Option<Binder<'tcx, Ty<'tcx>>> {
         if let ty::Opaque(def_id, substs) = ty.kind() {
             let future_trait = self.tcx.require_lang_item(LangItem::Future, None);
             // Future::Output
@@ -1775,13 +1775,20 @@ impl<'a, 'tcx> InferCtxt<'a, 'tcx> {
 
             for (predicate, _) in bounds {
                 let predicate = predicate.subst(self.tcx, substs);
-                if let ty::PredicateKind::Projection(projection_predicate) =
-                    predicate.kind().skip_binder()
-                {
-                    if projection_predicate.projection_ty.item_def_id == item_def_id {
-                        // We don't account for multiple `Future::Output = Ty` contraints.
-                        return projection_predicate.term.ty();
-                    }
+                let output = predicate
+                    .kind()
+                    .map_bound(|kind| match kind {
+                        ty::PredicateKind::Projection(projection_predicate)
+                            if projection_predicate.projection_ty.item_def_id == item_def_id =>
+                        {
+                            projection_predicate.term.ty()
+                        }
+                        _ => None,
+                    })
+                    .transpose();
+                if output.is_some() {
+                    // We don't account for multiple `Future::Output = Ty` contraints.
+                    return output;
                 }
             }
         }
@@ -1823,8 +1830,8 @@ impl<'a, 'tcx> InferCtxt<'a, 'tcx> {
         }
 
         match (
-            self.get_impl_future_output_ty(exp_found.expected),
-            self.get_impl_future_output_ty(exp_found.found),
+            self.get_impl_future_output_ty(exp_found.expected).map(Binder::skip_binder),
+            self.get_impl_future_output_ty(exp_found.found).map(Binder::skip_binder),
         ) {
             (Some(exp), Some(found)) if same_type_modulo_infer(exp, found) => match cause.code() {
                 ObligationCauseCode::IfExpression(box IfExpressionCause { then, .. }) => {

compiler/rustc_infer/src/infer/error_reporting/nice_region_error/different_lifetimes.rs

@@ -106,90 +106,47 @@ impl<'a, 'tcx> NiceRegionError<'a, 'tcx> {
             None => String::new(),
         };
 
-        let (span_1, span_2, main_label, span_label, future_return_type) =
-            match (sup_is_ret_type, sub_is_ret_type) {
-                (None, None) => {
-                    let (main_label_1, span_label_1) = if ty_sup.hir_id == ty_sub.hir_id {
-                        (
-                            "this type is declared with multiple lifetimes...".to_owned(),
-                            "...but data with one lifetime flows into the other here".to_owned(),
-                        )
-                    } else {
-                        (
-                            "these two types are declared with different lifetimes...".to_owned(),
-                            format!("...but data{} flows{} here", span_label_var1, span_label_var2),
-                        )
-                    };
-                    (ty_sup.span, ty_sub.span, main_label_1, span_label_1, None)
-                }
+        debug!(
+            "try_report_anon_anon_conflict: sub_is_ret_type={:?} sup_is_ret_type={:?}",
+            sub_is_ret_type, sup_is_ret_type
+        );
 
-                (Some(ret_span), _) => {
-                    let sup_future = self.future_return_type(scope_def_id_sup);
-                    let (return_type, action) = if sup_future.is_some() {
-                        ("returned future", "held across an await point")
-                    } else {
-                        ("return type", "returned")
-                    };
+        let mut err = struct_span_err!(self.tcx().sess, span, E0623, "lifetime mismatch");
 
-                    (
-                        ty_sub.span,
-                        ret_span,
-                        format!(
-                            "this parameter and the {} are declared with different lifetimes...",
-                            return_type
-                        ),
-                        format!("...but data{} is {} here", span_label_var1, action),
-                        sup_future,
-                    )
-                }
-                (_, Some(ret_span)) => {
-                    let sub_future = self.future_return_type(scope_def_id_sub);
-                    let (return_type, action) = if sub_future.is_some() {
-                        ("returned future", "held across an await point")
-                    } else {
-                        ("return type", "returned")
-                    };
+        match (sup_is_ret_type, sub_is_ret_type) {
+            (ret_capture @ Some(ret_span), _) | (_, ret_capture @ Some(ret_span)) => {
+                let param_span =
+                    if sup_is_ret_type == ret_capture { ty_sub.span } else { ty_sup.span };
+
+                err.span_label(
+                    param_span,
+                    "this parameter and the return type are declared with different lifetimes...",
+                );
+                err.span_label(ret_span, "");
+                err.span_label(span, format!("...but data{} is returned here", span_label_var1));
+            }
 
-                    (
+            (None, None) => {
+                if ty_sup.hir_id == ty_sub.hir_id {
+                    err.span_label(ty_sup.span, "this type is declared with multiple lifetimes...");
+                    err.span_label(ty_sub.span, "");
+                    err.span_label(span, "...but data with one lifetime flows into the other here");
+                } else {
+                    err.span_label(
                         ty_sup.span,
-                        ret_span,
-                        format!(
-                            "this parameter and the {} are declared with different lifetimes...",
-                            return_type
-                        ),
-                        format!("...but data{} is {} here", span_label_var1, action),
-                        sub_future,
-                    )
+                        "these two types are declared with different lifetimes...",
+                    );
+                    err.span_label(ty_sub.span, "");
+                    err.span_label(
+                        span,
+                        format!("...but data{} flows{} here", span_label_var1, span_label_var2),
+                    );
                 }
-            };
-
-        let mut err = struct_span_err!(self.tcx().sess, span, E0623, "lifetime mismatch");
-
-        err.span_label(span_1, main_label);
-        err.span_label(span_2, String::new());
-        err.span_label(span, span_label);
+            }
+        }
 
         self.suggest_adding_lifetime_params(sub, ty_sup, ty_sub, &mut err);
 
-        if let Some(t) = future_return_type {
-            let snip = self
-                .tcx()
-                .sess
-                .source_map()
-                .span_to_snippet(t.span)
-                .ok()
-                .and_then(|s| match (&t.kind, s.as_str()) {
-                    (rustc_hir::TyKind::Tup(&[]), "") => Some("()".to_string()),
-                    (_, "") => None,
-                    _ => Some(s),
-                })
-                .unwrap_or_else(|| "{unnamed_type}".to_string());
-
-            err.span_label(
-                t.span,
-                &format!("this `async fn` implicitly returns an `impl Future<Output = {}>`", snip),
-            );
-        }
         err.emit();
         Some(ErrorReported)
     }