Rollup of 10 pull requests

compiler/rustc_builtin_macros/src/test.rs

@@ -112,7 +112,7 @@ pub fn expand_test_or_bench(
     };
 
     // Note: non-associated fn items are already handled by `expand_test_or_bench`
-    if !matches!(item.kind, ast::ItemKind::Fn(_)) {
+    let ast::ItemKind::Fn(fn_) = &item.kind else {
         let diag = &cx.sess.parse_sess.span_diagnostic;
         let msg = "the `#[test]` attribute may only be used on a non-associated function";
         let mut err = match item.kind {
@@ -130,7 +130,7 @@ pub fn expand_test_or_bench(
             .emit();
 
         return vec![Annotatable::Item(item)];
-    }
+    };
 
     // has_*_signature will report any errors in the type so compilation
     // will fail. We shouldn't try to expand in this case because the errors
@@ -141,12 +141,14 @@ pub fn expand_test_or_bench(
         return vec![Annotatable::Item(item)];
     }
 
-    let (sp, attr_sp) = (cx.with_def_site_ctxt(item.span), cx.with_def_site_ctxt(attr_sp));
+    let sp = cx.with_def_site_ctxt(item.span);
+    let ret_ty_sp = cx.with_def_site_ctxt(fn_.sig.decl.output.span());
+    let attr_sp = cx.with_def_site_ctxt(attr_sp);
 
     let test_id = Ident::new(sym::test, attr_sp);
 
     // creates test::$name
-    let test_path = |name| cx.path(sp, vec![test_id, Ident::from_str_and_span(name, sp)]);
+    let test_path = |name| cx.path(ret_ty_sp, vec![test_id, Ident::from_str_and_span(name, sp)]);
 
     // creates test::ShouldPanic::$name
     let should_panic_path = |name| {
@@ -192,7 +194,7 @@ pub fn expand_test_or_bench(
                         vec![
                             // super::$test_fn(b)
                             cx.expr_call(
-                                sp,
+                                ret_ty_sp,
                                 cx.expr_path(cx.path(sp, vec![item.ident])),
                                 vec![cx.expr_ident(sp, b)],
                             ),
@@ -216,7 +218,11 @@ pub fn expand_test_or_bench(
                         cx.expr_path(test_path("assert_test_result")),
                         vec![
                             // $test_fn()
-                            cx.expr_call(sp, cx.expr_path(cx.path(sp, vec![item.ident])), vec![]), // )
+                            cx.expr_call(
+                                ret_ty_sp,
+                                cx.expr_path(cx.path(sp, vec![item.ident])),
+                                vec![],
+                            ), // )
                         ],
                     ), // }
                 ), // )

compiler/rustc_codegen_llvm/src/intrinsic.rs

@@ -340,17 +340,26 @@ impl<'ll, 'tcx> IntrinsicCallMethods<'tcx> for Builder<'_, 'll, 'tcx> {
 
             sym::black_box => {
                 args[0].val.store(self, result);
-
+                let result_val_span = [result.llval];
                 // We need to "use" the argument in some way LLVM can't introspect, and on
                 // targets that support it we can typically leverage inline assembly to do
                 // this. LLVM's interpretation of inline assembly is that it's, well, a black
                 // box. This isn't the greatest implementation since it probably deoptimizes
                 // more than we want, but it's so far good enough.
+                //
+                // For zero-sized types, the location pointed to by the result may be
+                // uninitialized. Do not "use" the result in this case; instead just clobber
+                // the memory.
+                let (constraint, inputs): (&str, &[_]) = if result.layout.is_zst() {
+                    ("~{memory}", &[])
+                } else {
+                    ("r,~{memory}", &result_val_span)
+                };
                 crate::asm::inline_asm_call(
                     self,
                     "",
-                    "r,~{memory}",
-                    &[result.llval],
+                    constraint,
+                    inputs,
                     self.type_void(),
                     true,
                     false,

compiler/rustc_codegen_ssa/src/back/linker.rs

@@ -1260,11 +1260,11 @@ impl<'a> Linker for WasmLd<'a> {
     }
 
     fn link_whole_staticlib(&mut self, lib: &str, _verbatim: bool, _search_path: &[PathBuf]) {
-        self.cmd.arg("-l").arg(lib);
+        self.cmd.arg("--whole-archive").arg("-l").arg(lib).arg("--no-whole-archive");
     }
 
     fn link_whole_rlib(&mut self, lib: &Path) {
-        self.cmd.arg(lib);
+        self.cmd.arg("--whole-archive").arg(lib).arg("--no-whole-archive");
     }
 
     fn gc_sections(&mut self, _keep_metadata: bool) {

compiler/rustc_error_codes/src/error_codes/E0706.md

@@ -56,4 +56,4 @@ You might be interested in visiting the [async book] for further information.
 [`async-trait` crate]: https://crates.io/crates/async-trait
 [async-is-hard]: https://smallcultfollowing.com/babysteps/blog/2019/10/26/async-fn-in-traits-are-hard/
 [Generic Associated Types]: https://github.com/rust-lang/rust/issues/44265
-[async book]: https://rust-lang.github.io/async-book/07_workarounds/06_async_in_traits.html
+[async book]: https://rust-lang.github.io/async-book/07_workarounds/05_async_in_traits.html

compiler/rustc_lint/src/unused.rs

@@ -9,7 +9,7 @@ use rustc_hir::def::{DefKind, Res};
 use rustc_hir::def_id::DefId;
 use rustc_infer::traits::util::elaborate_predicates_with_span;
 use rustc_middle::ty::adjustment;
-use rustc_middle::ty::{self, Ty};
+use rustc_middle::ty::{self, DefIdTree, Ty};
 use rustc_span::symbol::Symbol;
 use rustc_span::symbol::{kw, sym};
 use rustc_span::{BytePos, Span};
@@ -87,17 +87,33 @@ declare_lint_pass!(UnusedResults => [UNUSED_MUST_USE, UNUSED_RESULTS]);
 
 impl<'tcx> LateLintPass<'tcx> for UnusedResults {
     fn check_stmt(&mut self, cx: &LateContext<'_>, s: &hir::Stmt<'_>) {
-        let expr = match s.kind {
-            hir::StmtKind::Semi(ref expr) => &**expr,
-            _ => return,
-        };
+        let hir::StmtKind::Semi(expr) = s.kind else { return; };
 
         if let hir::ExprKind::Ret(..) = expr.kind {
             return;
         }
 
+        if let hir::ExprKind::Match(await_expr, _arms, hir::MatchSource::AwaitDesugar) = expr.kind
+            && let ty = cx.typeck_results().expr_ty(&await_expr)
+            && let ty::Opaque(future_def_id, _) = ty.kind()
+            && cx.tcx.ty_is_opaque_future(ty)
+            // FIXME: This also includes non-async fns that return `impl Future`.
+            && let async_fn_def_id = cx.tcx.parent(*future_def_id)
+            && check_must_use_def(
+                cx,
+                async_fn_def_id,
+                expr.span,
+                "output of future returned by ",
+                "",
+            )
+        {
+            // We have a bare `foo().await;` on an opaque type from an async function that was
+            // annotated with `#[must_use]`.
+            return;
+        }
+
         let ty = cx.typeck_results().expr_ty(&expr);
-        let type_permits_lack_of_use = check_must_use_ty(cx, ty, &expr, s.span, "", "", 1);
+        let type_permits_lack_of_use = check_must_use_ty(cx, ty, &expr, expr.span, "", "", 1);
 
         let mut fn_warned = false;
         let mut op_warned = false;
@@ -119,7 +135,7 @@ impl<'tcx> LateLintPass<'tcx> for UnusedResults {
             _ => None,
         };
         if let Some(def_id) = maybe_def_id {
-            fn_warned = check_must_use_def(cx, def_id, s.span, "return value of ", "");
+            fn_warned = check_must_use_def(cx, def_id, expr.span, "return value of ", "");
         } else if type_permits_lack_of_use {
             // We don't warn about unused unit or uninhabited types.
             // (See https://github.com/rust-lang/rust/issues/43806 for details.)
@@ -565,10 +581,24 @@ trait UnusedDelimLint {
             lint.set_arg("delim", Self::DELIM_STR);
             lint.set_arg("item", msg);
             if let Some((lo, hi)) = spans {
-                let replacement = vec![
-                    (lo, if keep_space.0 { " ".into() } else { "".into() }),
-                    (hi, if keep_space.1 { " ".into() } else { "".into() }),
-                ];
+                let sm = cx.sess().source_map();
+                let lo_replace =
+                    if keep_space.0 &&
+                        let Ok(snip) = sm.span_to_prev_source(lo) && !snip.ends_with(" ") {
+                        " ".to_string()
+                        } else {
+                            "".to_string()
+                        };
+
+                let hi_replace =
+                    if keep_space.1 &&
+                        let Ok(snip) = sm.span_to_next_source(hi) && !snip.starts_with(" ") {
+                        " ".to_string()
+                        } else {
+                            "".to_string()
+                        };
+
+                let replacement = vec![(lo, lo_replace), (hi, hi_replace)];
                 lint.multipart_suggestion(
                     fluent::suggestion,
                     replacement,
@@ -765,6 +795,7 @@ impl UnusedParens {
         value: &ast::Pat,
         avoid_or: bool,
         avoid_mut: bool,
+        keep_space: (bool, bool),
     ) {
         use ast::{BindingAnnotation, PatKind};
 
@@ -789,7 +820,7 @@ impl UnusedParens {
             } else {
                 None
             };
-            self.emit_unused_delims(cx, value.span, spans, "pattern", (false, false));
+            self.emit_unused_delims(cx, value.span, spans, "pattern", keep_space);
         }
     }
 }
@@ -798,7 +829,7 @@ impl EarlyLintPass for UnusedParens {
     fn check_expr(&mut self, cx: &EarlyContext<'_>, e: &ast::Expr) {
         match e.kind {
             ExprKind::Let(ref pat, _, _) | ExprKind::ForLoop(ref pat, ..) => {
-                self.check_unused_parens_pat(cx, pat, false, false);
+                self.check_unused_parens_pat(cx, pat, false, false, (true, true));
             }
             // We ignore parens in cases like `if (((let Some(0) = Some(1))))` because we already
             // handle a hard error for them during AST lowering in `lower_expr_mut`, but we still
@@ -842,40 +873,41 @@ impl EarlyLintPass for UnusedParens {
 
     fn check_pat(&mut self, cx: &EarlyContext<'_>, p: &ast::Pat) {
         use ast::{Mutability, PatKind::*};
+        let keep_space = (false, false);
         match &p.kind {
             // Do not lint on `(..)` as that will result in the other arms being useless.
             Paren(_)
             // The other cases do not contain sub-patterns.
             | Wild | Rest | Lit(..) | MacCall(..) | Range(..) | Ident(.., None) | Path(..) => {},
             // These are list-like patterns; parens can always be removed.
             TupleStruct(_, _, ps) | Tuple(ps) | Slice(ps) | Or(ps) => for p in ps {
-                self.check_unused_parens_pat(cx, p, false, false);
+                self.check_unused_parens_pat(cx, p, false, false, keep_space);
             },
             Struct(_, _, fps, _) => for f in fps {
-                self.check_unused_parens_pat(cx, &f.pat, false, false);
+                self.check_unused_parens_pat(cx, &f.pat, false, false, keep_space);
             },
             // Avoid linting on `i @ (p0 | .. | pn)` and `box (p0 | .. | pn)`, #64106.
-            Ident(.., Some(p)) | Box(p) => self.check_unused_parens_pat(cx, p, true, false),
+            Ident(.., Some(p)) | Box(p) => self.check_unused_parens_pat(cx, p, true, false, keep_space),
             // Avoid linting on `&(mut x)` as `&mut x` has a different meaning, #55342.
             // Also avoid linting on `& mut? (p0 | .. | pn)`, #64106.
-            Ref(p, m) => self.check_unused_parens_pat(cx, p, true, *m == Mutability::Not),
+            Ref(p, m) => self.check_unused_parens_pat(cx, p, true, *m == Mutability::Not, keep_space),
         }
     }
 
     fn check_stmt(&mut self, cx: &EarlyContext<'_>, s: &ast::Stmt) {
         if let StmtKind::Local(ref local) = s.kind {
-            self.check_unused_parens_pat(cx, &local.pat, true, false);
+            self.check_unused_parens_pat(cx, &local.pat, true, false, (false, false));
         }
 
         <Self as UnusedDelimLint>::check_stmt(self, cx, s)
     }
 
     fn check_param(&mut self, cx: &EarlyContext<'_>, param: &ast::Param) {
-        self.check_unused_parens_pat(cx, &param.pat, true, false);
+        self.check_unused_parens_pat(cx, &param.pat, true, false, (false, false));
     }
 
     fn check_arm(&mut self, cx: &EarlyContext<'_>, arm: &ast::Arm) {
-        self.check_unused_parens_pat(cx, &arm.pat, false, false);
+        self.check_unused_parens_pat(cx, &arm.pat, false, false, (false, false));
     }
 
     fn check_ty(&mut self, cx: &EarlyContext<'_>, ty: &ast::Ty) {

compiler/rustc_parse/src/errors.rs

@@ -1165,10 +1165,12 @@ pub(crate) struct ParenthesesInForHead {
 #[derive(Subdiagnostic)]
 #[multipart_suggestion(suggestion, applicability = "machine-applicable")]
 pub(crate) struct ParenthesesInForHeadSugg {
-    #[suggestion_part(code = "")]
+    #[suggestion_part(code = "{left_snippet}")]
     pub left: Span,
-    #[suggestion_part(code = "")]
+    pub left_snippet: String,
+    #[suggestion_part(code = "{right_snippet}")]
     pub right: Span,
+    pub right_snippet: String,
 }
 
 #[derive(Diagnostic)]

compiler/rustc_parse/src/parser/diagnostics.rs

@@ -1653,15 +1653,29 @@ impl<'a> Parser<'a> {
             (token::CloseDelim(Delimiter::Parenthesis), Some(begin_par_sp)) => {
                 self.bump();
 
+                let sm = self.sess.source_map();
+                let left = begin_par_sp;
+                let right = self.prev_token.span;
+                let left_snippet = if let Ok(snip) = sm.span_to_prev_source(left) &&
+                        !snip.ends_with(" ") {
+                                " ".to_string()
+                            } else {
+                                "".to_string()
+                            };
+
+                let right_snippet = if let Ok(snip) = sm.span_to_next_source(right) &&
+                        !snip.starts_with(" ") {
+                                " ".to_string()
+                            } else {
+                                "".to_string()
+                        };
+
                 self.sess.emit_err(ParenthesesInForHead {
-                    span: vec![begin_par_sp, self.prev_token.span],
+                    span: vec![left, right],
                     // With e.g. `for (x) in y)` this would replace `(x) in y)`
                     // with `x) in y)` which is syntactically invalid.
                     // However, this is prevented before we get here.
-                    sugg: ParenthesesInForHeadSugg {
-                        left: begin_par_sp,
-                        right: self.prev_token.span,
-                    },
+                    sugg: ParenthesesInForHeadSugg { left, right, left_snippet, right_snippet },
                 });
 
                 // Unwrap `(pat)` into `pat` to avoid the `unused_parens` lint.

compiler/rustc_passes/src/check_attr.rs

@@ -139,7 +139,7 @@ impl CheckAttrVisitor<'_> {
                 sym::collapse_debuginfo => self.check_collapse_debuginfo(attr, span, target),
                 sym::const_trait => self.check_const_trait(attr, span, target),
                 sym::must_not_suspend => self.check_must_not_suspend(&attr, span, target),
-                sym::must_use => self.check_must_use(hir_id, &attr, span, target),
+                sym::must_use => self.check_must_use(hir_id, &attr, target),
                 sym::rustc_pass_by_value => self.check_pass_by_value(&attr, span, target),
                 sym::rustc_allow_incoherent_impl => {
                     self.check_allow_incoherent_impl(&attr, span, target)
@@ -1163,17 +1163,7 @@ impl CheckAttrVisitor<'_> {
     }
 
     /// Warns against some misuses of `#[must_use]`
-    fn check_must_use(&self, hir_id: HirId, attr: &Attribute, span: Span, target: Target) -> bool {
-        let node = self.tcx.hir().get(hir_id);
-        if let Some(kind) = node.fn_kind() && let rustc_hir::IsAsync::Async = kind.asyncness() {
-            self.tcx.emit_spanned_lint(
-                UNUSED_ATTRIBUTES,
-                hir_id,
-                attr.span,
-                errors::MustUseAsync { span }
-            );
-        }
-
+    fn check_must_use(&self, hir_id: HirId, attr: &Attribute, target: Target) -> bool {
         if !matches!(
             target,
             Target::Fn