Rollup of 8 pull requests

compiler/rustc_ast/src/ast.rs

@@ -2466,20 +2466,14 @@ pub enum ModKind {
     Unloaded,
 }
 
-#[derive(Copy, Clone, Encodable, Decodable, Debug)]
+#[derive(Copy, Clone, Encodable, Decodable, Debug, Default)]
 pub struct ModSpans {
     /// `inner_span` covers the body of the module; for a file module, its the whole file.
     /// For an inline module, its the span inside the `{ ... }`, not including the curly braces.
     pub inner_span: Span,
     pub inject_use_span: Span,
 }
 
-impl Default for ModSpans {
-    fn default() -> ModSpans {
-        ModSpans { inner_span: Default::default(), inject_use_span: Default::default() }
-    }
-}
-
 /// Foreign module declaration.
 ///
 /// E.g., `extern { .. }` or `extern "C" { .. }`.

compiler/rustc_data_structures/src/sorted_map.rs

@@ -126,13 +126,13 @@ impl<K: Ord, V> SortedMap<K, V> {
     /// Iterate over the keys, sorted
     #[inline]
     pub fn keys(&self) -> impl Iterator<Item = &K> + ExactSizeIterator + DoubleEndedIterator {
-        self.data.iter().map(|&(ref k, _)| k)
+        self.data.iter().map(|(k, _)| k)
     }
 
     /// Iterate over values, sorted by key
     #[inline]
     pub fn values(&self) -> impl Iterator<Item = &V> + ExactSizeIterator + DoubleEndedIterator {
-        self.data.iter().map(|&(_, ref v)| v)
+        self.data.iter().map(|(_, v)| v)
     }
 
     #[inline]
@@ -222,7 +222,7 @@ impl<K: Ord, V> SortedMap<K, V> {
         K: Borrow<Q>,
         Q: Ord + ?Sized,
     {
-        self.data.binary_search_by(|&(ref x, _)| x.borrow().cmp(key))
+        self.data.binary_search_by(|(x, _)| x.borrow().cmp(key))
     }
 
     #[inline]
@@ -300,7 +300,7 @@ impl<K: Ord, V> FromIterator<(K, V)> for SortedMap<K, V> {
     fn from_iter<T: IntoIterator<Item = (K, V)>>(iter: T) -> Self {
         let mut data: Vec<(K, V)> = iter.into_iter().collect();
 
-        data.sort_unstable_by(|&(ref k1, _), &(ref k2, _)| k1.cmp(k2));
+        data.sort_unstable_by(|(k1, _), (k2, _)| k1.cmp(k2));
         data.dedup_by(|&mut (ref k1, _), &mut (ref k2, _)| k1.cmp(k2) == Ordering::Equal);
 
         SortedMap { data }

compiler/rustc_error_messages/locales/en-US/hir_analysis.ftl

@@ -20,6 +20,10 @@ hir_analysis_lifetimes_or_bounds_mismatch_on_trait =
     .where_label = this `where` clause might not match the one in the trait
     .bounds_label = this bound might be missing in the impl
 
+hir_analysis_async_trait_impl_should_be_async =
+    method `{$method_name}` should be async because the method from the trait is async
+    .trait_item_label = required because the trait method is async
+
 hir_analysis_drop_impl_on_wrong_item =
     the `Drop` trait may only be implemented for local structs, enums, and unions
     .label = must be a struct, enum, or union in the current crate

compiler/rustc_errors/src/emitter.rs

@@ -2313,7 +2313,7 @@ impl FileWithAnnotatedLines {
         }
 
         // Find overlapping multiline annotations, put them at different depths
-        multiline_annotations.sort_by_key(|&(_, ref ml)| (ml.line_start, usize::MAX - ml.line_end));
+        multiline_annotations.sort_by_key(|(_, ml)| (ml.line_start, usize::MAX - ml.line_end));
         for (_, ann) in multiline_annotations.clone() {
             for (_, a) in multiline_annotations.iter_mut() {
                 // Move all other multiline annotations overlapping with this one

compiler/rustc_errors/src/lib.rs

@@ -324,7 +324,7 @@ impl CodeSuggestion {
                         // Account for the difference between the width of the current code and the
                         // snippet being suggested, so that the *later* suggestions are correctly
                         // aligned on the screen.
-                        acc += len as isize - (cur_hi.col.0 - cur_lo.col.0) as isize;
+                        acc += len - (cur_hi.col.0 - cur_lo.col.0) as isize;
                     }
                     prev_hi = cur_hi;
                     prev_line = sf.get_line(prev_hi.line - 1);

compiler/rustc_hir_analysis/src/check/compare_method.rs

@@ -67,6 +67,10 @@ pub(crate) fn compare_impl_method<'tcx>(
         return;
     }
 
+    if let Err(_) = compare_asyncness(tcx, impl_m, impl_m_span, trait_m, trait_item_span) {
+        return;
+    }
+
     if let Err(_) = compare_predicate_entailment(tcx, impl_m, impl_m_span, trait_m, impl_trait_ref)
     {
         return;
@@ -323,6 +327,34 @@ fn compare_predicate_entailment<'tcx>(
     Ok(())
 }
 
+fn compare_asyncness<'tcx>(
+    tcx: TyCtxt<'tcx>,
+    impl_m: &ty::AssocItem,
+    impl_m_span: Span,
+    trait_m: &ty::AssocItem,
+    trait_item_span: Option<Span>,
+) -> Result<(), ErrorGuaranteed> {
+    if tcx.asyncness(trait_m.def_id) == hir::IsAsync::Async {
+        match tcx.fn_sig(impl_m.def_id).skip_binder().output().kind() {
+            ty::Alias(ty::Opaque, ..) => {
+                // allow both `async fn foo()` and `fn foo() -> impl Future`
+            }
+            ty::Error(rustc_errors::ErrorGuaranteed { .. }) => {
+                // We don't know if it's ok, but at least it's already an error.
+            }
+            _ => {
+                return Err(tcx.sess.emit_err(crate::errors::AsyncTraitImplShouldBeAsync {
+                    span: impl_m_span,
+                    method_name: trait_m.name,
+                    trait_item_span,
+                }));
+            }
+        };
+    }
+
+    Ok(())
+}
+
 #[instrument(skip(tcx), level = "debug", ret)]
 pub fn collect_trait_impl_trait_tys<'tcx>(
     tcx: TyCtxt<'tcx>,

compiler/rustc_hir_analysis/src/errors.rs

@@ -51,6 +51,17 @@ pub struct LifetimesOrBoundsMismatchOnTrait {
     pub ident: Ident,
 }
 
+#[derive(Diagnostic)]
+#[diag(hir_analysis_async_trait_impl_should_be_async)]
+pub struct AsyncTraitImplShouldBeAsync {
+    #[primary_span]
+    // #[label]
+    pub span: Span,
+    #[label(trait_item_label)]
+    pub trait_item_span: Option<Span>,
+    pub method_name: Symbol,
+}
+
 #[derive(Diagnostic)]
 #[diag(hir_analysis_drop_impl_on_wrong_item, code = "E0120")]
 pub struct DropImplOnWrongItem {

compiler/rustc_hir_pretty/src/lib.rs

@@ -1757,7 +1757,6 @@ impl<'a> State<'a> {
                 self.print_qpath(qpath, true);
                 self.popen();
                 if let Some(ddpos) = ddpos.as_opt_usize() {
-                    let ddpos = ddpos as usize;
                     self.commasep(Inconsistent, &elts[..ddpos], |s, p| s.print_pat(p));
                     if ddpos != 0 {
                         self.word_space(",");

compiler/rustc_macros/src/diagnostics/diagnostic.rs

@@ -192,7 +192,7 @@ impl Mismatch {
         let crate_name = std::env::var("CARGO_CRATE_NAME").ok()?;
 
         // If we're not in a "rustc_" crate, bail.
-        let Some(("rustc", slug_prefix)) = crate_name.split_once("_") else { return None };
+        let Some(("rustc", slug_prefix)) = crate_name.split_once('_') else { return None };
 
         let slug_name = slug.segments.first()?.ident.to_string();
         if !slug_name.starts_with(slug_prefix) {

compiler/rustc_middle/src/ty/diagnostics.rs

@@ -3,8 +3,8 @@
 use std::ops::ControlFlow;
 
 use crate::ty::{
-    visit::TypeVisitable, AliasTy, Const, ConstKind, DefIdTree, ExistentialPredicate, InferConst,
-    InferTy, Opaque, PolyTraitPredicate, Ty, TyCtxt, TypeSuperVisitable, TypeVisitor,
+    visit::TypeVisitable, AliasTy, Const, ConstKind, DefIdTree, InferConst, InferTy, Opaque,
+    PolyTraitPredicate, Ty, TyCtxt, TypeSuperVisitable, TypeVisitor,
 };
 
 use rustc_data_structures::fx::FxHashMap;
@@ -469,17 +469,6 @@ impl<'tcx> TypeVisitor<'tcx> for IsSuggestableVisitor<'tcx> {
                 }
             }
 
-            Dynamic(dty, _, _) => {
-                for pred in *dty {
-                    match pred.skip_binder() {
-                        ExistentialPredicate::Trait(_) | ExistentialPredicate::Projection(_) => {
-                            // Okay
-                        }
-                        _ => return ControlFlow::Break(()),
-                    }
-                }
-            }
-
             Param(param) => {
                 // FIXME: It would be nice to make this not use string manipulation,
                 // but it's pretty hard to do this, since `ty::ParamTy` is missing

compiler/rustc_session/src/config.rs

@@ -875,18 +875,12 @@ pub struct PacRet {
     pub key: PAuthKey,
 }
 
-#[derive(Clone, Copy, Hash, Debug, PartialEq)]
+#[derive(Clone, Copy, Hash, Debug, PartialEq, Default)]
 pub struct BranchProtection {
     pub bti: bool,
     pub pac_ret: Option<PacRet>,
 }
 
-impl Default for BranchProtection {
-    fn default() -> Self {
-        BranchProtection { bti: false, pac_ret: None }
-    }
-}
-
 pub const fn default_lib_output() -> CrateType {
     CrateType::Rlib
 }
@@ -1875,7 +1869,7 @@ fn parse_opt_level(
         .into_iter()
         .flat_map(|(i, s)| {
             // NB: This can match a string without `=`.
-            if let Some("opt-level") = s.splitn(2, '=').next() { Some(i) } else { None }
+            if let Some("opt-level") = s.split('=').next() { Some(i) } else { None }
         })
         .max();
     if max_o > max_c {
@@ -1912,7 +1906,7 @@ fn select_debuginfo(
         .into_iter()
         .flat_map(|(i, s)| {
             // NB: This can match a string without `=`.
-            if let Some("debuginfo") = s.splitn(2, '=').next() { Some(i) } else { None }
+            if let Some("debuginfo") = s.split('=').next() { Some(i) } else { None }
         })
         .max();
     if max_g > max_c {

compiler/rustc_span/src/analyze_source_file.rs

@@ -175,7 +175,7 @@ cfg_if::cfg_if! {
             // There might still be a tail left to analyze
             let tail_start = chunk_count * CHUNK_SIZE + intra_chunk_offset;
             if tail_start < src.len() {
-                analyze_source_file_generic(&src[tail_start as usize ..],
+                analyze_source_file_generic(&src[tail_start ..],
                                         src.len() - tail_start,
                                         output_offset + BytePos::from_usize(tail_start),
                                         lines,
@@ -219,7 +219,7 @@ fn analyze_source_file_generic(
     while i < scan_len {
         let byte = unsafe {
             // We verified that i < scan_len <= src.len()
-            *src_bytes.get_unchecked(i as usize)
+            *src_bytes.get_unchecked(i)
         };
 
         // How much to advance in order to get to the next UTF-8 char in the

compiler/rustc_span/src/lib.rs

@@ -1381,7 +1381,7 @@ impl<S: Encoder> Encodable<S> for SourceFile {
                     4 => {
                         raw_diffs = Vec::with_capacity(bytes_per_diff * num_diffs);
                         for diff in diff_iter {
-                            raw_diffs.extend_from_slice(&(diff.0 as u32).to_le_bytes());
+                            raw_diffs.extend_from_slice(&(diff.0).to_le_bytes());
                         }
                     }
                     _ => unreachable!(),

compiler/rustc_span/src/source_map.rs

@@ -941,7 +941,7 @@ impl SourceMap {
     /// Otherwise, the span reached to limit is returned.
     pub fn span_look_ahead(&self, span: Span, expect: Option<&str>, limit: Option<usize>) -> Span {
         let mut sp = span;
-        for _ in 0..limit.unwrap_or(100 as usize) {
+        for _ in 0..limit.unwrap_or(100_usize) {
             sp = self.next_point(sp);
             if let Ok(ref snippet) = self.span_to_snippet(sp) {
                 if expect.map_or(false, |es| snippet == es) {

compiler/rustc_target/src/spec/apple_base.rs

@@ -81,7 +81,7 @@ fn pre_link_args(os: &'static str, arch: Arch, abi: &'static str) -> LinkArgs {
         _ => os.into(),
     };
 
-    let platform_version: StaticCow<str> = match os.as_ref() {
+    let platform_version: StaticCow<str> = match os {
         "ios" => ios_lld_platform_version(),
         "tvos" => tvos_lld_platform_version(),
         "watchos" => watchos_lld_platform_version(),

compiler/rustc_target/src/spec/powerpc64_ibm_aix.rs

@@ -5,12 +5,7 @@ pub fn target() -> Target {
     base.max_atomic_width = Some(64);
     base.add_pre_link_args(
         LinkerFlavor::Unix(Cc::No),
-        &[
-            "-b64".into(),
-            "-bpT:0x100000000".into(),
-            "-bpD:0x110000000".into(),
-            "-bcdtors:all:0:s".into(),
-        ],
+        &["-b64", "-bpT:0x100000000", "-bpD:0x110000000", "-bcdtors:all:0:s"],
     );
 
     Target {