Auto merge of #107767 - matthiaskrgr:rollup-9m1qfso, r=matthiaskrgr

Rollup of 8 pull requests

Successful merges:

 - #100599 (Add compiler error E0523 long description and test)
 - #107471 (rustdoc: do not include empty default-settings tag in HTML)
 - #107555 (Modify existing bounds if they exist)
 - #107662 (Turn projections into copies in CopyProp.)
 - #107695 (Add test for Future inflating arg size to 3x )
 - #107700 (Run the tools builder on all PRs)
 - #107706 (Mark 'atomic_mut_ptr' methods const)
 - #107709 (Fix problem noticed in PR106859 with char -> u8 suggestion)

Failed merges:

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

compiler/rustc_borrowck/src/diagnostics/conflict_errors.rs

@@ -803,6 +803,7 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
                 predicates
                     .iter()
                     .map(|(param, constraint)| (param.name.as_str(), &**constraint, None)),
+                None,
             );
         }
     }

compiler/rustc_const_eval/src/transform/check_consts/ops.rs

@@ -136,6 +136,7 @@ impl<'tcx> NonConstOp<'tcx> for FnCallNonConst<'tcx> {
                             &param_ty.name.as_str(),
                             &constraint,
                             None,
+                            None,
                         );
                     }
                 }

compiler/rustc_error_codes/src/error_codes.rs

@@ -286,6 +286,7 @@ E0519: include_str!("./error_codes/E0519.md"),
 E0520: include_str!("./error_codes/E0520.md"),
 E0521: include_str!("./error_codes/E0521.md"),
 E0522: include_str!("./error_codes/E0522.md"),
+E0523: include_str!("./error_codes/E0523.md"),
 E0524: include_str!("./error_codes/E0524.md"),
 E0525: include_str!("./error_codes/E0525.md"),
 E0527: include_str!("./error_codes/E0527.md"),
@@ -622,7 +623,6 @@ E0793: include_str!("./error_codes/E0793.md"),
 //  E0488, // lifetime of variable does not enclose its declaration
 //  E0489, // type/lifetime parameter not in scope here
 //  E0490, // removed: unreachable
-    E0523, // two dependencies have same (crate-name, disambiguator) but different SVH
 //  E0526, // shuffle indices are not constant
 //  E0540, // multiple rustc_deprecated attributes
 //  E0548, // replaced with a generic attribute input check

compiler/rustc_error_codes/src/error_codes/E0464.md

@@ -1,6 +1,21 @@
 The compiler found multiple library files with the requested crate name.
 
+```compile_fail
+// aux-build:crateresolve-1.rs
+// aux-build:crateresolve-2.rs
+// aux-build:crateresolve-3.rs
+
+extern crate crateresolve;
+//~^ ERROR multiple candidates for `rlib` dependency `crateresolve` found
+
+fn main() {}
+```
+
 This error can occur in several different cases -- for example, when using
 `extern crate` or passing `--extern` options without crate paths. It can also be
 caused by caching issues with the build directory, in which case `cargo clean`
 may help.
+
+In the above example, there are three different library files, all of which
+define the same crate name. Without providing a full path, there is no way for
+the compiler to know which crate it should use.

compiler/rustc_error_codes/src/error_codes/E0523.md

@@ -0,0 +1,25 @@
+#### Note: this error code is no longer emitted by the compiler.
+
+The compiler found multiple library files with the requested crate name.
+
+```compile_fail
+// aux-build:crateresolve-1.rs
+// aux-build:crateresolve-2.rs
+// aux-build:crateresolve-3.rs
+
+extern crate crateresolve;
+//~^ ERROR multiple candidates for `rlib` dependency `crateresolve` found
+
+fn main() {}
+```
+
+This error can occur in several different cases -- for example, when using
+`extern crate` or passing `--extern` options without crate paths. It can also be
+caused by caching issues with the build directory, in which case `cargo clean`
+may help.
+
+In the above example, there are three different library files, all of which
+define the same crate name. Without providing a full path, there is no way for
+the compiler to know which crate it should use.
+
+*Note that E0523 has been merged into E0464.*

compiler/rustc_hir_analysis/src/coherence/builtin.rs

@@ -176,6 +176,7 @@ fn visit_implementation_of_copy(tcx: TyCtxt<'_>, impl_did: LocalDefId) {
                 bounds.iter().map(|(param, constraint, def_id)| {
                     (param.as_str(), constraint.as_str(), *def_id)
                 }),
+                None,
             );
             err.emit();
         }

compiler/rustc_hir_typeck/src/fn_ctxt/suggestions.rs

@@ -1457,6 +1457,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                     generics,
                     diag,
                     vec![(param.name.as_str(), "Clone", Some(clone_trait_did))].into_iter(),
+                    None,
                 );
             } else {
                 self.suggest_derive(diag, &[(trait_ref.to_predicate(self.tcx), None, None)]);

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

@@ -1922,7 +1922,8 @@ impl<'tcx> TypeErrCtxt<'_, 'tcx> {
                         (ty::Uint(ty::UintTy::U8), ty::Char) => {
                             if let Ok(code) = self.tcx.sess().source_map().span_to_snippet(span)
                                 && let Some(code) = code.strip_prefix('\'').and_then(|s| s.strip_suffix('\''))
-                                && code.chars().next().map_or(false, |c| c.is_ascii())
+                                && !code.starts_with("\\u") // forbid all Unicode escapes
+                                && code.chars().next().map_or(false, |c| c.is_ascii()) // forbids literal Unicode characters beyond ASCII
                             {
                                 err.span_suggestion(
                                     span,

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

@@ -77,49 +77,86 @@ impl<'tcx> TypeErrCtxt<'_, 'tcx> {
                     (ty::Param(p), ty::Alias(ty::Projection, proj)) | (ty::Alias(ty::Projection, proj), ty::Param(p))
                         if tcx.def_kind(proj.def_id) != DefKind::ImplTraitPlaceholder =>
                     {
-                        let generics = tcx.generics_of(body_owner_def_id);
-                        let p_span = tcx.def_span(generics.type_param(p, tcx).def_id);
+                        let p_def_id = tcx
+                            .generics_of(body_owner_def_id)
+                            .type_param(p, tcx)
+                            .def_id;
+                        let p_span = tcx.def_span(p_def_id);
                         if !sp.contains(p_span) {
                             diag.span_label(p_span, "this type parameter");
                         }
                         let hir = tcx.hir();
                         let mut note = true;
-                        if let Some(generics) = generics
-                            .type_param(p, tcx)
-                            .def_id
+                        let parent = p_def_id
                             .as_local()
-                            .map(|id| hir.local_def_id_to_hir_id(id))
-                            .and_then(|id| tcx.hir().find_parent(id))
-                            .as_ref()
-                            .and_then(|node| node.generics())
+                            .and_then(|id| {
+                                let local_id = hir.local_def_id_to_hir_id(id);
+                                let generics = tcx.hir().find_parent(local_id)?.generics()?;
+                                Some((id, generics))
+                            });
+                        if let Some((local_id, generics)) = parent
                         {
                             // Synthesize the associated type restriction `Add<Output = Expected>`.
                             // FIXME: extract this logic for use in other diagnostics.
                             let (trait_ref, assoc_substs) = proj.trait_ref_and_own_substs(tcx);
-                            let path =
-                                tcx.def_path_str_with_substs(trait_ref.def_id, trait_ref.substs);
                             let item_name = tcx.item_name(proj.def_id);
                             let item_args = self.format_generic_args(assoc_substs);
 
-                            let path = if path.ends_with('>') {
-                                format!(
-                                    "{}, {}{} = {}>",
-                                    &path[..path.len() - 1],
-                                    item_name,
-                                    item_args,
-                                    p
-                                )
+                            // Here, we try to see if there's an existing
+                            // trait implementation that matches the one that
+                            // we're suggesting to restrict. If so, find the
+                            // "end", whether it be at the end of the trait
+                            // or the end of the generic arguments.
+                            let mut matching_span = None;
+                            let mut matched_end_of_args = false;
+                            for bound in generics.bounds_for_param(local_id) {
+                                let potential_spans = bound
+                                    .bounds
+                                    .iter()
+                                    .find_map(|bound| {
+                                        let bound_trait_path = bound.trait_ref()?.path;
+                                        let def_id = bound_trait_path.res.opt_def_id()?;
+                                        let generic_args = bound_trait_path.segments.iter().last().map(|path| path.args());
+                                        (def_id == trait_ref.def_id).then_some((bound_trait_path.span, generic_args))
+                                    });
+
+                                if let Some((end_of_trait, end_of_args)) = potential_spans {
+                                    let args_span = end_of_args.and_then(|args| args.span());
+                                    matched_end_of_args = args_span.is_some();
+                                    matching_span = args_span
+                                        .or_else(|| Some(end_of_trait))
+                                        .map(|span| span.shrink_to_hi());
+                                    break;
+                                }
+                            }
+
+                            if matched_end_of_args {
+                                // Append suggestion to the end of our args
+                                let path = format!(", {}{} = {}",item_name, item_args, p);
+                                note = !suggest_constraining_type_param(
+                                    tcx,
+                                    generics,
+                                    diag,
+                                    &format!("{}", proj.self_ty()),
+                                    &path,
+                                    None,
+                                    matching_span,
+                                );
                             } else {
-                                format!("{}<{}{} = {}>", path, item_name, item_args, p)
-                            };
-                            note = !suggest_constraining_type_param(
-                                tcx,
-                                generics,
-                                diag,
-                                &format!("{}", proj.self_ty()),
-                                &path,
-                                None,
-                            );
+                                // Suggest adding a bound to an existing trait
+                                // or if the trait doesn't exist, add the trait
+                                // and the suggested bounds.
+                                let path = format!("<{}{} = {}>", item_name, item_args, p);
+                                note = !suggest_constraining_type_param(
+                                    tcx,
+                                    generics,
+                                    diag,
+                                    &format!("{}", proj.self_ty()),
+                                    &path,
+                                    None,
+                                    matching_span,
+                                );
+                            }
                         }
                         if note {
                             diag.note("you might be missing a type parameter or trait bound");

compiler/rustc_metadata/src/creader.rs

@@ -356,7 +356,12 @@ impl<'a> CrateLoader<'a> {
         for (_, other) in self.cstore.iter_crate_data() {
             // Same stable crate id but different SVH
             if other.stable_crate_id() == root.stable_crate_id() && other.hash() != root.hash() {
-                return Err(CrateError::SymbolConflictsOthers(root.name()));
+                bug!(
+                    "Previously returned E0523 here. \
+                     See https://github.com/rust-lang/rust/pull/100599 for additional discussion.\
+                     root.name() = {}.",
+                    root.name()
+                );
             }
         }
 

compiler/rustc_metadata/src/errors.rs

@@ -511,14 +511,6 @@ pub struct SymbolConflictsCurrent {
     pub crate_name: Symbol,
 }
 
-#[derive(Diagnostic)]
-#[diag(metadata_symbol_conflicts_others, code = "E0523")]
-pub struct SymbolConflictsOthers {
-    #[primary_span]
-    pub span: Span,
-    pub crate_name: Symbol,
-}
-
 #[derive(Diagnostic)]
 #[diag(metadata_stable_crate_id_collision)]
 pub struct StableCrateIdCollision {

compiler/rustc_metadata/src/locator.rs

@@ -945,7 +945,6 @@ pub(crate) enum CrateError {
     ExternLocationNotFile(Symbol, PathBuf),
     MultipleCandidates(Symbol, CrateFlavor, Vec<PathBuf>),
     SymbolConflictsCurrent(Symbol),
-    SymbolConflictsOthers(Symbol),
     StableCrateIdCollision(Symbol, Symbol),
     DlOpen(String),
     DlSym(String),
@@ -989,9 +988,6 @@ impl CrateError {
             CrateError::SymbolConflictsCurrent(root_name) => {
                 sess.emit_err(errors::SymbolConflictsCurrent { span, crate_name: root_name });
             }
-            CrateError::SymbolConflictsOthers(root_name) => {
-                sess.emit_err(errors::SymbolConflictsOthers { span, crate_name: root_name });
-            }
             CrateError::StableCrateIdCollision(crate_name0, crate_name1) => {
                 sess.emit_err(errors::StableCrateIdCollision { span, crate_name0, crate_name1 });
             }

compiler/rustc_middle/src/ty/diagnostics.rs

@@ -193,6 +193,9 @@ fn suggest_removing_unsized_bound(
 }
 
 /// Suggest restricting a type param with a new bound.
+///
+/// If `span_to_replace` is provided, then that span will be replaced with the
+/// `constraint`. If one wasn't provided, then the full bound will be suggested.
 pub fn suggest_constraining_type_param(
     tcx: TyCtxt<'_>,
     generics: &hir::Generics<'_>,
@@ -200,12 +203,14 @@ pub fn suggest_constraining_type_param(
     param_name: &str,
     constraint: &str,
     def_id: Option<DefId>,
+    span_to_replace: Option<Span>,
 ) -> bool {
     suggest_constraining_type_params(
         tcx,
         generics,
         err,
         [(param_name, constraint, def_id)].into_iter(),
+        span_to_replace,
     )
 }
 
@@ -215,6 +220,7 @@ pub fn suggest_constraining_type_params<'a>(
     generics: &hir::Generics<'_>,
     err: &mut Diagnostic,
     param_names_and_constraints: impl Iterator<Item = (&'a str, &'a str, Option<DefId>)>,
+    span_to_replace: Option<Span>,
 ) -> bool {
     let mut grouped = FxHashMap::default();
     param_names_and_constraints.for_each(|(param_name, constraint, def_id)| {
@@ -253,7 +259,9 @@ pub fn suggest_constraining_type_params<'a>(
         let mut suggest_restrict = |span, bound_list_non_empty| {
             suggestions.push((
                 span,
-                if bound_list_non_empty {
+                if span_to_replace.is_some() {
+                    constraint.clone()
+                } else if bound_list_non_empty {
                     format!(" + {}", constraint)
                 } else {
                     format!(" {}", constraint)
@@ -262,6 +270,11 @@ pub fn suggest_constraining_type_params<'a>(
             ))
         };
 
+        if let Some(span) = span_to_replace {
+            suggest_restrict(span, true);
+            continue;
+        }
+
         // When the type parameter has been provided bounds
         //
         //    Message:

compiler/rustc_mir_transform/src/copy_prop.rs

@@ -153,8 +153,9 @@ impl<'tcx> MutVisitor<'tcx> for Replacer<'_, 'tcx> {
 
     fn visit_operand(&mut self, operand: &mut Operand<'tcx>, loc: Location) {
         if let Operand::Move(place) = *operand
-            && let Some(local) = place.as_local()
-            && !self.fully_moved.contains(local)
+            // A move out of a projection of a copy is equivalent to a copy of the original projection.
+            && !place.has_deref()
+            && !self.fully_moved.contains(place.local)
         {
             *operand = Operand::Copy(place);
         }

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

@@ -679,6 +679,7 @@ impl<'tcx> TypeErrCtxtExt<'tcx> for TypeErrCtxt<'_, 'tcx> {
                         &param_name,
                         &constraint,
                         Some(trait_pred.def_id()),
+                        None,
                     ) {
                         return;
                     }
@@ -1087,6 +1088,7 @@ impl<'tcx> TypeErrCtxtExt<'tcx> for TypeErrCtxt<'_, 'tcx> {
                     param.name.as_str(),
                     "Clone",
                     Some(clone_trait),
+                    None,
                 );
             }
             err.span_suggestion_verbose(