Rollup of 8 pull requests

compiler/rustc_abi/src/lib.rs

@@ -802,12 +802,9 @@ impl Integer {
     pub fn for_align<C: HasDataLayout>(cx: &C, wanted: Align) -> Option<Integer> {
         let dl = cx.data_layout();
 
-        for candidate in [I8, I16, I32, I64, I128] {
-            if wanted == candidate.align(dl).abi && wanted.bytes() == candidate.size().bytes() {
-                return Some(candidate);
-            }
-        }
-        None
+        [I8, I16, I32, I64, I128].into_iter().find(|&candidate| {
+            wanted == candidate.align(dl).abi && wanted.bytes() == candidate.size().bytes()
+        })
     }
 
     /// Find the largest integer with the given alignment or less.

compiler/rustc_ast/src/token.rs

@@ -114,7 +114,7 @@ impl Lit {
                 if let NtExpr(expr) | NtLiteral(expr) = &**nt
                 && let ast::ExprKind::Lit(token_lit) = expr.kind =>
             {
-                Some(token_lit.clone())
+                Some(token_lit)
             }
             _ => None,
         }

compiler/rustc_ast_passes/src/feature_gate.rs

@@ -630,7 +630,7 @@ fn check_incompatible_features(sess: &Session) {
             {
                 let spans = vec![f1_span, f2_span];
                 sess.struct_span_err(
-                    spans.clone(),
+                    spans,
                     &format!(
                         "features `{}` and `{}` are incompatible, using them at the same time \
                         is not allowed",

compiler/rustc_borrowck/src/diagnostics/conflict_errors.rs

@@ -745,7 +745,7 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
             err.span_suggestion_verbose(
                 span.shrink_to_hi(),
                 "consider cloning the value if the performance cost is acceptable",
-                ".clone()".to_string(),
+                ".clone()",
                 Applicability::MachineApplicable,
             );
         }

compiler/rustc_builtin_macros/src/alloc_error_handler.rs

@@ -32,7 +32,7 @@ pub fn expand(
             (item, true, ecx.with_def_site_ctxt(fn_kind.sig.span))
         } else {
             ecx.sess.parse_sess.span_diagnostic.span_err(item.span(), "alloc_error_handler must be a function");
-            return vec![orig_item.clone()];
+            return vec![orig_item];
         };
 
     // Generate a bunch of new items using the AllocFnFactory

compiler/rustc_builtin_macros/src/concat_bytes.rs

@@ -196,7 +196,7 @@ pub fn expand_concat_bytes(
         }
     }
     if !missing_literals.is_empty() {
-        let mut err = cx.struct_span_err(missing_literals.clone(), "expected a byte literal");
+        let mut err = cx.struct_span_err(missing_literals, "expected a byte literal");
         err.note("only byte literals (like `b\"foo\"`, `b's'`, and `[3, 4, 5]`) can be passed to `concat_bytes!()`");
         err.emit();
         return base::MacEager::expr(DummyResult::raw_expr(sp, true));

compiler/rustc_codegen_llvm/src/back/lto.rs

@@ -210,7 +210,7 @@ pub(crate) fn run_thin(
 }
 
 pub(crate) fn prepare_thin(module: ModuleCodegen<ModuleLlvm>) -> (String, ThinBuffer) {
-    let name = module.name.clone();
+    let name = module.name;
     let buffer = ThinBuffer::new(module.module_llvm.llmod(), true);
     (name, buffer)
 }

compiler/rustc_data_structures/src/base_n.rs

@@ -9,7 +9,7 @@ pub const MAX_BASE: usize = 64;
 pub const ALPHANUMERIC_ONLY: usize = 62;
 pub const CASE_INSENSITIVE: usize = 36;
 
-const BASE_64: &[u8; MAX_BASE as usize] =
+const BASE_64: &[u8; MAX_BASE] =
     b"0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ@$";
 
 #[inline]

compiler/rustc_errors/src/diagnostic.rs

@@ -370,7 +370,11 @@ impl Diagnostic {
         self.set_span(after);
         for span_label in before.span_labels() {
             if let Some(label) = span_label.label {
-                self.span.push_span_label(after, label);
+                if span_label.is_primary {
+                    self.span.push_span_label(after, label);
+                } else {
+                    self.span.push_span_label(span_label.span, label);
+                }
             }
         }
         self
@@ -802,7 +806,7 @@ impl Diagnostic {
         debug_assert!(
             !(suggestions
                 .iter()
-                .flat_map(|suggs| suggs)
+                .flatten()
                 .any(|(sp, suggestion)| sp.is_empty() && suggestion.is_empty())),
             "Span must not be empty and have no suggestion"
         );

compiler/rustc_errors/src/emitter.rs

@@ -1308,7 +1308,7 @@ impl EmitterWriter {
         //                see how it *looks* with
         //                very *weird* formats
         //                see?
-        for &(ref text, ref style) in msg.iter() {
+        for (text, style) in msg.iter() {
             let text = self.translate_message(text, args);
             let lines = text.split('\n').collect::<Vec<_>>();
             if lines.len() > 1 {
@@ -1370,7 +1370,7 @@ impl EmitterWriter {
                 buffer.append(0, ": ", header_style);
                 label_width += 2;
             }
-            for &(ref text, _) in msg.iter() {
+            for (text, _) in msg.iter() {
                 let text = self.translate_message(text, args);
                 // Account for newlines to align output to its label.
                 for (line, text) in normalize_whitespace(&text).lines().enumerate() {

compiler/rustc_hir/src/hir.rs

@@ -548,12 +548,7 @@ impl<'hir> Generics<'hir> {
     }
 
     pub fn get_named(&self, name: Symbol) -> Option<&GenericParam<'hir>> {
-        for param in self.params {
-            if name == param.name.ident().name {
-                return Some(param);
-            }
-        }
-        None
+        self.params.iter().find(|&param| name == param.name.ident().name)
     }
 
     pub fn spans(&self) -> MultiSpan {

compiler/rustc_index/src/bit_set.rs

@@ -209,7 +209,7 @@ impl<T: Idx> BitSet<T> {
             self.words[start_word_index] |= !(start_mask - 1);
             // And all trailing bits (i.e. from 0..=end) in the end word,
             // including the end.
-            self.words[end_word_index] |= end_mask | end_mask - 1;
+            self.words[end_word_index] |= end_mask | (end_mask - 1);
         } else {
             self.words[start_word_index] |= end_mask | (end_mask - start_mask);
         }

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

@@ -330,7 +330,7 @@ pub fn suggest_new_region_bound(
                             Applicability::MaybeIncorrect,
                         );
                     }
-                    if let Some((param_span, param_ty)) = param.clone() {
+                    if let Some((param_span, ref param_ty)) = param {
                         err.span_suggestion_verbose(
                             param_span,
                             add_static_bound,

compiler/rustc_lexer/src/unescape.rs

@@ -204,14 +204,13 @@ fn scan_escape(chars: &mut Chars<'_>, is_byte: bool) -> Result<char, EscapeError
                         })?;
                     }
                     Some(c) => {
-                        let digit =
+                        let digit: u32 =
                             c.to_digit(16).ok_or(EscapeError::InvalidCharInUnicodeEscape)?;
                         n_digits += 1;
                         if n_digits > 6 {
                             // Stop updating value since we're sure that it's incorrect already.
                             continue;
                         }
-                        let digit = digit as u32;
                         value = value * 16 + digit;
                     }
                 };

compiler/rustc_resolve/src/late.rs

@@ -566,6 +566,9 @@ struct LateResolutionVisitor<'a, 'b, 'ast> {
     /// FIXME #4948: Reuse ribs to avoid allocation.
     ribs: PerNS<Vec<Rib<'a>>>,
 
+    /// Previous poped `rib`, only used for diagnostic.
+    last_block_rib: Option<Rib<'a>>,
+
     /// The current set of local scopes, for labels.
     label_ribs: Vec<Rib<'a, NodeId>>,
 
@@ -873,6 +876,8 @@ impl<'a: 'ast, 'ast> Visitor<'ast> for LateResolutionVisitor<'a, '_, 'ast> {
                             // Ignore errors in function bodies if this is rustdoc
                             // Be sure not to set this until the function signature has been resolved.
                             let previous_state = replace(&mut this.in_func_body, true);
+                            // We only care block in the same function
+                            this.last_block_rib = None;
                             // Resolve the function body, potentially inside the body of an async closure
                             this.with_lifetime_rib(
                                 LifetimeRibKind::Elided(LifetimeRes::Infer),
@@ -1168,6 +1173,7 @@ impl<'a: 'ast, 'b, 'ast> LateResolutionVisitor<'a, 'b, 'ast> {
                 type_ns: vec![Rib::new(start_rib_kind)],
                 macro_ns: vec![Rib::new(start_rib_kind)],
             },
+            last_block_rib: None,
             label_ribs: Vec::new(),
             lifetime_ribs: Vec::new(),
             lifetime_elision_candidates: None,
@@ -3769,7 +3775,7 @@ impl<'a: 'ast, 'b, 'ast> LateResolutionVisitor<'a, 'b, 'ast> {
             self.ribs[ValueNS].pop();
             self.label_ribs.pop();
         }
-        self.ribs[ValueNS].pop();
+        self.last_block_rib = self.ribs[ValueNS].pop();
         if anonymous_module.is_some() {
             self.ribs[TypeNS].pop();
         }

compiler/rustc_resolve/src/late/diagnostics.rs

@@ -623,6 +623,22 @@ impl<'a: 'ast, 'ast> LateResolutionVisitor<'a, '_, 'ast> {
                 return (true, candidates);
             }
         }
+
+        // Try to find in last block rib
+        if let Some(rib) = &self.last_block_rib && let RibKind::NormalRibKind = rib.kind {
+            for (ident, &res) in &rib.bindings {
+                if let Res::Local(_) = res && path.len() == 1 &&
+                    ident.span.eq_ctxt(path[0].ident.span) &&
+                    ident.name == path[0].ident.name {
+                    err.span_help(
+                        ident.span,
+                        &format!("the binding `{}` is available in a different scope in the same function", path_str),
+                    );
+                    return (true, candidates);
+                }
+            }
+        }
+
         return (false, candidates);
     }
 

compiler/rustc_span/src/source_map.rs

@@ -1150,7 +1150,7 @@ impl FilePathMapping {
             // NOTE: We are iterating over the mapping entries from last to first
             //       because entries specified later on the command line should
             //       take precedence.
-            for &(ref from, ref to) in mapping.iter().rev() {
+            for (from, to) in mapping.iter().rev() {
                 debug!("Trying to apply {from:?} => {to:?}");
 
                 if let Ok(rest) = path.strip_prefix(from) {

compiler/rustc_trait_selection/src/traits/error_reporting/method_chain.rs

@@ -0,0 +1,74 @@
+use crate::infer::InferCtxt;
+
+use rustc_middle::ty::error::TypeError;
+use rustc_middle::ty::relate::{self, Relate, RelateResult, TypeRelation};
+use rustc_middle::ty::{self, Ty, TyCtxt};
+
+pub struct CollectAllMismatches<'a, 'tcx> {
+    pub infcx: &'a InferCtxt<'tcx>,
+    pub param_env: ty::ParamEnv<'tcx>,
+    pub errors: Vec<TypeError<'tcx>>,
+}
+
+impl<'a, 'tcx> TypeRelation<'tcx> for CollectAllMismatches<'a, 'tcx> {
+    fn tag(&self) -> &'static str {
+        "CollectAllMismatches"
+    }
+    fn tcx(&self) -> TyCtxt<'tcx> {
+        self.infcx.tcx
+    }
+    fn intercrate(&self) -> bool {
+        false
+    }
+    fn param_env(&self) -> ty::ParamEnv<'tcx> {
+        self.param_env
+    }
+    fn a_is_expected(&self) -> bool {
+        true
+    } // irrelevant
+    fn mark_ambiguous(&mut self) {
+        bug!()
+    }
+    fn relate_with_variance<T: Relate<'tcx>>(
+        &mut self,
+        _: ty::Variance,
+        _: ty::VarianceDiagInfo<'tcx>,
+        a: T,
+        b: T,
+    ) -> RelateResult<'tcx, T> {
+        self.relate(a, b)
+    }
+    fn regions(
+        &mut self,
+        a: ty::Region<'tcx>,
+        _b: ty::Region<'tcx>,
+    ) -> RelateResult<'tcx, ty::Region<'tcx>> {
+        Ok(a)
+    }
+    fn tys(&mut self, a: Ty<'tcx>, b: Ty<'tcx>) -> RelateResult<'tcx, Ty<'tcx>> {
+        if a == b || matches!(a.kind(), ty::Infer(_)) || matches!(b.kind(), ty::Infer(_)) {
+            return Ok(a);
+        }
+        relate::super_relate_tys(self, a, b).or_else(|e| {
+            self.errors.push(e);
+            Ok(a)
+        })
+    }
+    fn consts(
+        &mut self,
+        a: ty::Const<'tcx>,
+        b: ty::Const<'tcx>,
+    ) -> RelateResult<'tcx, ty::Const<'tcx>> {
+        if a == b {
+            return Ok(a);
+        }
+        relate::super_relate_consts(self, a, b) // could do something similar here for constants!
+    }
+    fn binders<T: Relate<'tcx>>(
+        &mut self,
+        a: ty::Binder<'tcx, T>,
+        b: ty::Binder<'tcx, T>,
+    ) -> RelateResult<'tcx, ty::Binder<'tcx, T>> {
+        Ok(a.rebind(self.relate(a.skip_binder(), b.skip_binder())?))
+    }
+}

compiler/rustc_trait_selection/src/traits/error_reporting/mod.rs

@@ -1,4 +1,5 @@
 mod ambiguity;
+pub mod method_chain;
 pub mod on_unimplemented;
 pub mod suggestions;
 
@@ -536,7 +537,7 @@ impl<'tcx> TypeErrCtxtExt<'tcx> for TypeErrCtxt<'_, 'tcx> {
             |err| {
                 self.note_obligation_cause_code(
                     err,
-                    &predicate,
+                    predicate,
                     obligation.param_env,
                     obligation.cause.code(),
                     &mut vec![],
@@ -1587,7 +1588,7 @@ impl<'tcx> InferCtxtPrivExt<'tcx> for TypeErrCtxt<'_, 'tcx> {
                 {
                     self.note_obligation_cause_code(
                         &mut diag,
-                        &error.obligation.predicate,
+                        error.obligation.predicate,
                         error.obligation.param_env,
                         code,
                         &mut vec![],
@@ -2602,7 +2603,7 @@ impl<'tcx> InferCtxtPrivExt<'tcx> for TypeErrCtxt<'_, 'tcx> {
         if !self.maybe_note_obligation_cause_for_async_await(err, obligation) {
             self.note_obligation_cause_code(
                 err,
-                &obligation.predicate,
+                obligation.predicate,
                 obligation.param_env,
                 obligation.cause.code(),
                 &mut vec![],