Auto merge of #71201 - Dylan-DPC:rollup-23202uf, r=Dylan-DPC

Rollup of 5 pull requests

Successful merges:

 - #70566 (Don't bail out before linting in generic contexts.)
 - #71141 (Provide better compiler output when using `?` on `Option` in fn returning `Result` and vice-versa)
 - #71149 (remove an impossible branch from check_consts)
 - #71179 (fix more clippy warnings)
 - #71191 (Clean up E0520 explanation)

Failed merges:

r? @ghost

src/liballoc/vec.rs

@@ -971,7 +971,7 @@ impl<T> Vec<T> {
         }
 
         let len = self.len();
-        if !(index < len) {
+        if index >= len {
             assert_failed(index, len);
         }
         unsafe {
@@ -1010,7 +1010,7 @@ impl<T> Vec<T> {
         }
 
         let len = self.len();
-        if !(index <= len) {
+        if index > len {
             assert_failed(index, len);
         }
 
@@ -1058,7 +1058,7 @@ impl<T> Vec<T> {
         }
 
         let len = self.len();
-        if !(index < len) {
+        if index >= len {
             assert_failed(index, len);
         }
         unsafe {
@@ -1331,10 +1331,10 @@ impl<T> Vec<T> {
             panic!("end drain index (is {}) should be <= len (is {})", end, len);
         }
 
-        if !(start <= end) {
+        if start > end {
             start_assert_failed(start, end);
         }
-        if !(end <= len) {
+        if end > len {
             end_assert_failed(end, len);
         }
 
@@ -1432,7 +1432,7 @@ impl<T> Vec<T> {
             panic!("`at` split index (is {}) should be <= len (is {})", at, len);
         }
 
-        if !(at <= self.len()) {
+        if at > self.len() {
             assert_failed(at, self.len());
         }
 

src/librustc_builtin_macros/deriving/debug.rs

@@ -63,7 +63,7 @@ fn show_substructure(cx: &mut ExtCtxt<'_>, span: Span, substr: &Substructure<'_>
     let span = cx.with_def_site_ctxt(span);
     let name = cx.expr_lit(span, ast::LitKind::Str(ident.name, ast::StrStyle::Cooked));
     let builder = cx.ident_of("debug_trait_builder", span);
-    let builder_expr = cx.expr_ident(span, builder.clone());
+    let builder_expr = cx.expr_ident(span, builder);
 
     let fmt = substr.nonself_args[0].clone();
 

src/librustc_error_codes/error_codes/E0520.md

@@ -1,5 +1,7 @@
 A non-default implementation was already made on this type so it cannot be
-specialized further. Erroneous code example:
+specialized further.
+
+Erroneous code example:
 
 ```compile_fail,E0520
 #![feature(specialization)]

src/librustc_errors/emitter.rs

@@ -2005,7 +2005,7 @@ fn emit_to_destination(
     let _buffer_lock = lock::acquire_global_lock("rustc_errors");
     for (pos, line) in rendered_buffer.iter().enumerate() {
         for part in line {
-            dst.apply_style(lvl.clone(), part.style)?;
+            dst.apply_style(*lvl, part.style)?;
             write!(dst, "{}", part.text)?;
             dst.reset()?;
         }

src/librustc_infer/infer/error_reporting/mod.rs

@@ -871,7 +871,7 @@ impl<'a, 'tcx> InferCtxt<'a, 'tcx> {
                 return Some(());
             }
             if let &ty::Adt(def, _) = &ta.kind {
-                let path_ = self.tcx.def_path_str(def.did.clone());
+                let path_ = self.tcx.def_path_str(def.did);
                 if path_ == other_path {
                     self.highlight_outer(&mut t1_out, &mut t2_out, path, sub, i, &other_ty);
                     return Some(());
@@ -1091,8 +1091,8 @@ impl<'a, 'tcx> InferCtxt<'a, 'tcx> {
                 let sub_no_defaults_1 = self.strip_generic_default_params(def1.did, sub1);
                 let sub_no_defaults_2 = self.strip_generic_default_params(def2.did, sub2);
                 let mut values = (DiagnosticStyledString::new(), DiagnosticStyledString::new());
-                let path1 = self.tcx.def_path_str(def1.did.clone());
-                let path2 = self.tcx.def_path_str(def2.did.clone());
+                let path1 = self.tcx.def_path_str(def1.did);
+                let path2 = self.tcx.def_path_str(def2.did);
                 if def1.did == def2.did {
                     // Easy case. Replace same types with `_` to shorten the output and highlight
                     // the differing ones.

src/librustc_infer/infer/outlives/obligations.rs

@@ -452,7 +452,7 @@ where
         // even though a satisfactory solution exists.
         let generic = GenericKind::Projection(projection_ty);
         let verify_bound = self.verify_bound.generic_bound(generic);
-        self.delegate.push_verify(origin, generic.clone(), region, verify_bound);
+        self.delegate.push_verify(origin, generic, region, verify_bound);
     }
 }
 

src/librustc_infer/infer/outlives/verify.rs

@@ -297,7 +297,6 @@ impl<'cx, 'tcx> VerifyBoundCx<'cx, 'tcx> {
         self.collect_outlives_from_predicate_list(
             move |ty| ty == identity_proj,
             traits::elaborate_predicates(tcx, trait_predicates)
-                .into_iter()
                 .map(|o| o.predicate)
                 .collect::<Vec<_>>(),
         )

src/librustc_mir/borrow_check/mod.rs

@@ -1056,7 +1056,7 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
                                  place: {:?}",
                                 place_span.0
                             );
-                            this.reservation_error_reported.insert(place_span.0.clone());
+                            this.reservation_error_reported.insert(place_span.0);
                         }
                         Activation(_, activating) => {
                             debug!(

src/librustc_mir/borrow_check/region_infer/mod.rs

@@ -495,7 +495,7 @@ impl<'tcx> RegionInferenceContext<'tcx> {
         // to store those. Otherwise, we'll pass in `None` to the
         // functions below, which will trigger them to report errors
         // eagerly.
-        let mut outlives_requirements = infcx.tcx.is_closure(mir_def_id).then(|| vec![]);
+        let mut outlives_requirements = infcx.tcx.is_closure(mir_def_id).then(Vec::new);
 
         self.check_type_tests(infcx, body, outlives_requirements.as_mut(), &mut errors_buffer);
 

src/librustc_mir/dataflow/move_paths/builder.rs

@@ -286,7 +286,7 @@ impl<'b, 'a, 'tcx> Gatherer<'b, 'a, 'tcx> {
                     // Box starts out uninitialized - need to create a separate
                     // move-path for the interior so it will be separate from
                     // the exterior.
-                    self.create_move_path(self.builder.tcx.mk_place_deref(place.clone()));
+                    self.create_move_path(self.builder.tcx.mk_place_deref(*place));
                     self.gather_init(place.as_ref(), InitKind::Shallow);
                 } else {
                     self.gather_init(place.as_ref(), InitKind::Deep);
@@ -458,9 +458,8 @@ impl<'b, 'a, 'tcx> Gatherer<'b, 'a, 'tcx> {
             for offset in from..to {
                 let elem =
                     ProjectionElem::ConstantIndex { offset, min_length: len, from_end: false };
-                let path = self.add_move_path(base_path, &elem, |tcx| {
-                    tcx.mk_place_elem(base_place.clone(), elem)
-                });
+                let path =
+                    self.add_move_path(base_path, &elem, |tcx| tcx.mk_place_elem(base_place, elem));
                 self.record_move(place, path);
             }
         } else {

src/librustc_mir/interpret/place.rs

@@ -549,7 +549,7 @@ where
                 let n = base.len(self)?;
                 if n < u64::from(min_length) {
                     // This can only be reached in ConstProp and non-rustc-MIR.
-                    throw_ub!(BoundsCheckFailed { len: min_length.into(), index: n.into() });
+                    throw_ub!(BoundsCheckFailed { len: min_length.into(), index: n });
                 }
 
                 let index = if from_end {

src/librustc_mir/monomorphize/collector.rs

@@ -335,7 +335,7 @@ fn collect_items_rec<'tcx>(
     recursion_depths: &mut DefIdMap<usize>,
     inlining_map: MTRef<'_, MTLock<InliningMap<'tcx>>>,
 ) {
-    if !visited.lock_mut().insert(starting_point.clone()) {
+    if !visited.lock_mut().insert(starting_point) {
         // We've been here already, no need to search again.
         return;
     }

src/librustc_mir/shim.rs

@@ -538,7 +538,7 @@ impl CloneShimBuilder<'tcx> {
         // BB #2
         // `dest[i] = Clone::clone(src[beg])`;
         // Goto #3 if ok, #5 if unwinding happens.
-        let dest_field = self.tcx.mk_place_index(dest.clone(), beg);
+        let dest_field = self.tcx.mk_place_index(dest, beg);
         let src_field = self.tcx.mk_place_index(src, beg);
         self.make_clone_call(dest_field, src_field, ty, BasicBlock::new(3), BasicBlock::new(5));
 
@@ -620,9 +620,9 @@ impl CloneShimBuilder<'tcx> {
         let mut previous_field = None;
         for (i, ity) in tys.enumerate() {
             let field = Field::new(i);
-            let src_field = self.tcx.mk_place_field(src.clone(), field, ity);
+            let src_field = self.tcx.mk_place_field(src, field, ity);
 
-            let dest_field = self.tcx.mk_place_field(dest.clone(), field, ity);
+            let dest_field = self.tcx.mk_place_field(dest, field, ity);
 
             // #(2i + 1) is the cleanup block for the previous clone operation
             let cleanup_block = self.block_index_offset(1);
@@ -633,7 +633,7 @@ impl CloneShimBuilder<'tcx> {
             // BB #(2i)
             // `dest.i = Clone::clone(&src.i);`
             // Goto #(2i + 2) if ok, #(2i + 1) if unwinding happens.
-            self.make_clone_call(dest_field.clone(), src_field, ity, next_block, cleanup_block);
+            self.make_clone_call(dest_field, src_field, ity, next_block, cleanup_block);
 
             // BB #(2i + 1) (cleanup)
             if let Some((previous_field, previous_cleanup)) = previous_field.take() {

src/librustc_mir/transform/check_consts/ops.rs

@@ -90,16 +90,6 @@ impl NonConstOp for FnCallNonConst {
     }
 }
 
-/// A function call where the callee is not a function definition or function pointer, e.g. a
-/// closure.
-///
-/// This can be subdivided in the future to produce a better error message.
-#[derive(Debug)]
-pub struct FnCallOther;
-impl NonConstOp for FnCallOther {
-    const IS_SUPPORTED_IN_MIRI: bool = false;
-}
-
 /// A call to a `#[unstable]` const fn or `#[rustc_const_unstable]` function.
 ///
 /// Contains the name of the feature that would allow the use of this function.

src/librustc_mir/transform/check_consts/validation.rs

@@ -495,11 +495,11 @@ impl Visitor<'tcx> for Validator<'_, 'mir, 'tcx> {
         }
     }
 
-    fn visit_terminator_kind(&mut self, kind: &TerminatorKind<'tcx>, location: Location) {
-        trace!("visit_terminator_kind: kind={:?} location={:?}", kind, location);
-        self.super_terminator_kind(kind, location);
+    fn visit_terminator(&mut self, terminator: &Terminator<'tcx>, location: Location) {
+        trace!("visit_terminator: terminator={:?} location={:?}", terminator, location);
+        self.super_terminator(terminator, location);
 
-        match kind {
+        match &terminator.kind {
             TerminatorKind::Call { func, .. } => {
                 let fn_ty = func.ty(*self.body, self.tcx);
 
@@ -511,8 +511,7 @@ impl Visitor<'tcx> for Validator<'_, 'mir, 'tcx> {
                         return;
                     }
                     _ => {
-                        self.check_op(ops::FnCallOther);
-                        return;
+                        span_bug!(terminator.source_info.span, "invalid callee of type {:?}", fn_ty)
                     }
                 };
 

src/librustc_mir/transform/const_prop.rs

@@ -581,11 +581,6 @@ impl<'mir, 'tcx> ConstPropagator<'mir, 'tcx> {
             return None;
         }
 
-        // FIXME we need to revisit this for #67176
-        if rvalue.needs_subst() {
-            return None;
-        }
-
         // Perform any special handling for specific Rvalue types.
         // Generally, checks here fall into one of two categories:
         //   1. Additional checking to provide useful lints to the user
@@ -626,6 +621,11 @@ impl<'mir, 'tcx> ConstPropagator<'mir, 'tcx> {
             _ => {}
         }
 
+        // FIXME we need to revisit this for #67176
+        if rvalue.needs_subst() {
+            return None;
+        }
+
         self.use_ecx(|this| {
             trace!("calling eval_rvalue_into_place(rvalue = {:?}, place = {:?})", rvalue, place);
             this.ecx.eval_rvalue_into_place(rvalue, place)?;

src/librustc_mir/transform/inline.rs

@@ -582,7 +582,7 @@ impl Inliner<'tcx> {
             let tuple_tmp_args = tuple_tys.iter().enumerate().map(|(i, ty)| {
                 // This is e.g., `tuple_tmp.0` in our example above.
                 let tuple_field =
-                    Operand::Move(tcx.mk_place_field(tuple.clone(), Field::new(i), ty.expect_ty()));
+                    Operand::Move(tcx.mk_place_field(tuple, Field::new(i), ty.expect_ty()));
 
                 // Spill to a local to make e.g., `tmp0`.
                 self.create_temp_if_necessary(tuple_field, callsite, caller_body)

src/librustc_mir/util/aggregate.rs

@@ -56,7 +56,7 @@ pub fn expand_aggregate<'tcx>(
                 let offset = i as u32;
                 assert_eq!(offset as usize, i);
                 tcx.mk_place_elem(
-                    lhs.clone(),
+                    lhs,
                     ProjectionElem::ConstantIndex {
                         offset,
                         // FIXME(eddyb) `min_length` doesn't appear to be used.
@@ -66,7 +66,7 @@ pub fn expand_aggregate<'tcx>(
                 )
             } else {
                 let field = Field::new(active_field_index.unwrap_or(i));
-                tcx.mk_place_field(lhs.clone(), field, ty)
+                tcx.mk_place_field(lhs, field, ty)
             };
             Statement { source_info, kind: StatementKind::Assign(box (lhs_field, Rvalue::Use(op))) }
         })

src/librustc_mir/util/elaborate_drops.rs

@@ -212,7 +212,7 @@ where
                 assert_eq!(self.elaborator.param_env().reveal, Reveal::All);
                 let field_ty =
                     tcx.normalize_erasing_regions(self.elaborator.param_env(), f.ty(tcx, substs));
-                (tcx.mk_place_field(base_place.clone(), field, field_ty), subpath)
+                (tcx.mk_place_field(base_place, field, field_ty), subpath)
             })
             .collect()
     }
@@ -340,7 +340,7 @@ where
             .enumerate()
             .map(|(i, &ty)| {
                 (
-                    self.tcx().mk_place_field(self.place.clone(), Field::new(i), ty),
+                    self.tcx().mk_place_field(self.place, Field::new(i), ty),
                     self.elaborator.field_subpath(self.path, Field::new(i)),
                 )
             })
@@ -353,7 +353,7 @@ where
     fn open_drop_for_box(&mut self, adt: &'tcx ty::AdtDef, substs: SubstsRef<'tcx>) -> BasicBlock {
         debug!("open_drop_for_box({:?}, {:?}, {:?})", self, adt, substs);
 
-        let interior = self.tcx().mk_place_deref(self.place.clone());
+        let interior = self.tcx().mk_place_deref(self.place);
         let interior_path = self.elaborator.deref_subpath(self.path);
 
         let succ = self.succ; // FIXME(#43234)
@@ -434,7 +434,7 @@ where
 
             if let Some(variant_path) = subpath {
                 let base_place = tcx.mk_place_elem(
-                    self.place.clone(),
+                    self.place,
                     ProjectionElem::Downcast(Some(variant.ident.name), variant_index),
                 );
                 let fields = self.move_paths_for_fields(base_place, variant_path, &variant, substs);
@@ -622,7 +622,7 @@ where
             (Rvalue::Use(copy(cur.into())), Rvalue::BinaryOp(BinOp::Offset, move_(cur.into()), one))
         } else {
             (
-                Rvalue::AddressOf(Mutability::Mut, tcx.mk_place_index(self.place.clone(), cur)),
+                Rvalue::AddressOf(Mutability::Mut, tcx.mk_place_index(self.place, cur)),
                 Rvalue::BinaryOp(BinOp::Add, move_(cur.into()), one),
             )
         };
@@ -654,7 +654,7 @@ where
         self.elaborator.patch().patch_terminator(
             drop_block,
             TerminatorKind::Drop {
-                location: tcx.mk_place_deref(ptr.clone()),
+                location: tcx.mk_place_deref(ptr),
                 target: loop_block,
                 unwind: unwind.into_option(),
             },
@@ -682,7 +682,7 @@ where
                 .map(|i| {
                     (
                         tcx.mk_place_elem(
-                            self.place.clone(),
+                            self.place,
                             ProjectionElem::ConstantIndex {
                                 offset: i,
                                 min_length: size,
@@ -719,8 +719,8 @@ where
                     switch_ty: tcx.types.usize,
                     values: From::from(USIZE_SWITCH_ZERO),
                     targets: vec![
-                        self.drop_loop_pair(ety, false, len.clone()),
-                        self.drop_loop_pair(ety, true, len.clone()),
+                        self.drop_loop_pair(ety, false, len),
+                        self.drop_loop_pair(ety, true, len),
                     ],
                 },
             }),
@@ -912,7 +912,7 @@ where
             .map(|(i, f)| {
                 let field = Field::new(i);
                 let field_ty = f.ty(tcx, substs);
-                Operand::Move(tcx.mk_place_field(self.place.clone(), field, field_ty))
+                Operand::Move(tcx.mk_place_field(self.place, field, field_ty))
             })
             .collect();
 

src/librustc_mir_build/build/block.rs

@@ -2,8 +2,8 @@ use crate::build::matches::ArmHasGuard;
 use crate::build::ForGuard::OutsideGuard;
 use crate::build::{BlockAnd, BlockAndExtension, BlockFrame, Builder};
 use crate::hair::*;
-use rustc_middle::mir::*;
 use rustc_hir as hir;
+use rustc_middle::mir::*;
 use rustc_span::Span;
 
 impl<'a, 'tcx> Builder<'a, 'tcx> {
@@ -29,7 +29,7 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
                     // This is a `break`-able block
                     let exit_block = this.cfg.start_new_block();
                     let block_exit =
-                        this.in_breakable_scope(None, exit_block, destination.clone(), |this| {
+                        this.in_breakable_scope(None, exit_block, destination, |this| {
                             this.ast_block_stmts(destination, block, span, stmts, expr, safety_mode)
                         });
                     this.cfg.goto(unpack!(block_exit), source_info, exit_block);