Auto merge of #98781 - GuillaumeGomez:rollup-798kb8u, r=GuillaumeGomez

Rollup of 5 pull requests

Successful merges:

 - #97249 (`<details>`/`<summary>` UI fixes)
 - #98418 (Allow macOS to build LLVM as shared library)
 - #98460 (Use CSS variables to handle theming)
 - #98497 (Improve some inference diagnostics)
 - #98708 (rustdoc: fix 98690 Panic if invalid path for -Z persist-doctests)

Failed merges:

 - #98761 (more `need_type_info` improvements)

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

Author: bors

Diff for: compiler/rustc_infer/src/infer/error_reporting/need_type_info.rs

@@ -313,11 +313,12 @@ impl<'a, 'tcx> InferCtxt<'a, 'tcx> {
     pub fn emit_inference_failure_err(
         &self,
         body_id: Option<hir::BodyId>,
-        span: Span,
+        failure_span: Span,
         arg: GenericArg<'tcx>,
         // FIXME(#94483): Either use this or remove it.
         _impl_candidates: Vec<ty::TraitRef<'tcx>>,
         error_code: TypeAnnotationNeeded,
+        should_label_span: bool,
     ) -> DiagnosticBuilder<'tcx, ErrorGuaranteed> {
         let arg = self.resolve_vars_if_possible(arg);
         let arg_data = self.extract_inference_diagnostics_data(arg, None);
@@ -326,7 +327,7 @@ impl<'a, 'tcx> InferCtxt<'a, 'tcx> {
             // If we don't have any typeck results we're outside
             // of a body, so we won't be able to get better info
             // here.
-            return self.bad_inference_failure_err(span, arg_data, error_code);
+            return self.bad_inference_failure_err(failure_span, arg_data, error_code);
         };
         let typeck_results = typeck_results.borrow();
         let typeck_results = &typeck_results;
@@ -338,7 +339,7 @@ impl<'a, 'tcx> InferCtxt<'a, 'tcx> {
         }
 
         let Some(InferSource { span, kind }) = local_visitor.infer_source else {
-            return self.bad_inference_failure_err(span, arg_data, error_code)
+            return self.bad_inference_failure_err(failure_span, arg_data, error_code)
         };
 
         let error_code = error_code.into();
@@ -347,6 +348,11 @@ impl<'a, 'tcx> InferCtxt<'a, 'tcx> {
             &format!("type annotations needed{}", kind.ty_msg(self)),
             error_code,
         );
+
+        if should_label_span && !failure_span.overlaps(span) {
+            err.span_label(failure_span, "type must be known at this point");
+        }
+
         match kind {
             InferSourceKind::LetBinding { insert_span, pattern_name, ty } => {
                 let suggestion_msg = if let Some(name) = pattern_name {

Diff for: compiler/rustc_middle/src/ty/mod.rs

@@ -914,9 +914,17 @@ impl<'tcx> Term<'tcx> {
     pub fn ty(&self) -> Option<Ty<'tcx>> {
         if let Term::Ty(ty) = self { Some(*ty) } else { None }
     }
+
     pub fn ct(&self) -> Option<Const<'tcx>> {
         if let Term::Const(c) = self { Some(*c) } else { None }
     }
+
+    pub fn into_arg(self) -> GenericArg<'tcx> {
+        match self {
+            Term::Ty(ty) => ty.into(),
+            Term::Const(c) => c.into(),
+        }
+    }
 }
 
 /// This kind of predicate has no *direct* correspondent in the

Diff for: compiler/rustc_trait_selection/src/traits/error_reporting/mod.rs

@@ -1958,26 +1958,6 @@ impl<'a, 'tcx> InferCtxtPrivExt<'a, 'tcx> for InferCtxt<'a, 'tcx> {
                 if predicate.references_error() {
                     return;
                 }
-                // Typically, this ambiguity should only happen if
-                // there are unresolved type inference variables
-                // (otherwise it would suggest a coherence
-                // failure). But given #21974 that is not necessarily
-                // the case -- we can have multiple where clauses that
-                // are only distinguished by a region, which results
-                // in an ambiguity even when all types are fully
-                // known, since we don't dispatch based on region
-                // relationships.
-
-                // Pick the first substitution that still contains inference variables as the one
-                // we're going to emit an error for. If there are none (see above), fall back to
-                // the substitution for `Self`.
-                let subst = {
-                    let substs = data.trait_ref.substs;
-                    substs
-                        .iter()
-                        .find(|s| s.has_infer_types_or_consts())
-                        .unwrap_or_else(|| substs[0])
-                };
 
                 // This is kind of a hack: it frequently happens that some earlier
                 // error prevents types from being fully inferred, and then we get
@@ -1999,27 +1979,54 @@ impl<'a, 'tcx> InferCtxtPrivExt<'a, 'tcx> for InferCtxt<'a, 'tcx> {
                         self.emit_inference_failure_err(
                             body_id,
                             span,
-                            subst,
+                            trait_ref.self_ty().skip_binder().into(),
                             vec![],
                             ErrorCode::E0282,
+                            false,
                         )
                         .emit();
                     }
                     return;
                 }
 
-                let impl_candidates = self
-                    .find_similar_impl_candidates(trait_ref)
-                    .into_iter()
-                    .map(|candidate| candidate.trait_ref)
-                    .collect();
-                let mut err = self.emit_inference_failure_err(
-                    body_id,
-                    span,
-                    subst,
-                    impl_candidates,
-                    ErrorCode::E0283,
-                );
+                // Typically, this ambiguity should only happen if
+                // there are unresolved type inference variables
+                // (otherwise it would suggest a coherence
+                // failure). But given #21974 that is not necessarily
+                // the case -- we can have multiple where clauses that
+                // are only distinguished by a region, which results
+                // in an ambiguity even when all types are fully
+                // known, since we don't dispatch based on region
+                // relationships.
+
+                // Pick the first substitution that still contains inference variables as the one
+                // we're going to emit an error for. If there are none (see above), fall back to
+                // a more general error.
+                let subst = data.trait_ref.substs.iter().find(|s| s.has_infer_types_or_consts());
+
+                let mut err = if let Some(subst) = subst {
+                    let impl_candidates = self
+                        .find_similar_impl_candidates(trait_ref)
+                        .into_iter()
+                        .map(|candidate| candidate.trait_ref)
+                        .collect();
+                    self.emit_inference_failure_err(
+                        body_id,
+                        span,
+                        subst,
+                        impl_candidates,
+                        ErrorCode::E0283,
+                        true,
+                    )
+                } else {
+                    struct_span_err!(
+                        self.tcx.sess,
+                        span,
+                        E0283,
+                        "type annotations needed: cannot satisfy `{}`",
+                        predicate,
+                    )
+                };
 
                 let obligation = Obligation::new(
                     obligation.cause.clone(),
@@ -2110,7 +2117,7 @@ impl<'a, 'tcx> InferCtxtPrivExt<'a, 'tcx> for InferCtxt<'a, 'tcx> {
                     return;
                 }
 
-                self.emit_inference_failure_err(body_id, span, arg, vec![], ErrorCode::E0282)
+                self.emit_inference_failure_err(body_id, span, arg, vec![], ErrorCode::E0282, false)
             }
 
             ty::PredicateKind::Subtype(data) => {
@@ -2124,26 +2131,38 @@ impl<'a, 'tcx> InferCtxtPrivExt<'a, 'tcx> for InferCtxt<'a, 'tcx> {
                 let SubtypePredicate { a_is_expected: _, a, b } = data;
                 // both must be type variables, or the other would've been instantiated
                 assert!(a.is_ty_var() && b.is_ty_var());
-                self.emit_inference_failure_err(body_id, span, a.into(), vec![], ErrorCode::E0282)
+                self.emit_inference_failure_err(
+                    body_id,
+                    span,
+                    a.into(),
+                    vec![],
+                    ErrorCode::E0282,
+                    true,
+                )
             }
             ty::PredicateKind::Projection(data) => {
-                let self_ty = data.projection_ty.self_ty();
-                let term = data.term;
                 if predicate.references_error() || self.is_tainted_by_errors() {
                     return;
                 }
-                if self_ty.needs_infer() && term.needs_infer() {
-                    // We do this for the `foo.collect()?` case to produce a suggestion.
+                let subst = data
+                    .projection_ty
+                    .substs
+                    .iter()
+                    .chain(Some(data.term.into_arg()))
+                    .find(|g| g.has_infer_types_or_consts());
+                if let Some(subst) = subst {
                     let mut err = self.emit_inference_failure_err(
                         body_id,
                         span,
-                        self_ty.into(),
+                        subst,
                         vec![],
                         ErrorCode::E0284,
+                        true,
                     );
                     err.note(&format!("cannot satisfy `{}`", predicate));
                     err
                 } else {
+                    // If we can't find a substitution, just print a generic error
                     let mut err = struct_span_err!(
                         self.tcx.sess,
                         span,

Diff for: compiler/rustc_typeck/src/check/fn_ctxt/_impl.rs

@@ -1538,9 +1538,15 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
             ty
         } else {
             if !self.is_tainted_by_errors() {
-                self.emit_inference_failure_err((**self).body_id, sp, ty.into(), vec![], E0282)
-                    .note("type must be known at this point")
-                    .emit();
+                self.emit_inference_failure_err(
+                    (**self).body_id,
+                    sp,
+                    ty.into(),
+                    vec![],
+                    E0282,
+                    true,
+                )
+                .emit();
             }
             let err = self.tcx.ty_error();
             self.demand_suptype(sp, err, ty);

Diff for: compiler/rustc_typeck/src/check/writeback.rs

@@ -694,6 +694,7 @@ impl<'cx, 'tcx> Resolver<'cx, 'tcx> {
                     t.into(),
                     vec![],
                     E0282,
+                    false,
                 )
                 .emit();
         }
@@ -708,6 +709,7 @@ impl<'cx, 'tcx> Resolver<'cx, 'tcx> {
                     c.into(),
                     vec![],
                     E0282,
+                    false,
                 )
                 .emit();
         }

Diff for: src/bootstrap/lib.rs

@@ -107,15 +107,11 @@ use std::cell::{Cell, RefCell};
 use std::collections::{HashMap, HashSet};
 use std::env;
 use std::fs::{self, File};
+use std::io;
 use std::path::{Path, PathBuf};
 use std::process::{self, Command};
 use std::str;
 
-#[cfg(unix)]
-use std::os::unix::fs::symlink as symlink_file;
-#[cfg(windows)]
-use std::os::windows::fs::symlink_file;
-
 use filetime::FileTime;
 use once_cell::sync::OnceCell;
 
@@ -1460,7 +1456,7 @@ impl Build {
                 src = t!(fs::canonicalize(src));
             } else {
                 let link = t!(fs::read_link(src));
-                t!(symlink_file(link, dst));
+                t!(self.symlink_file(link, dst));
                 return;
             }
         }
@@ -1585,6 +1581,14 @@ impl Build {
         iter.map(|e| t!(e)).collect::<Vec<_>>().into_iter()
     }
 
+    fn symlink_file<P: AsRef<Path>, Q: AsRef<Path>>(&self, src: P, link: Q) -> io::Result<()> {
+        #[cfg(unix)]
+        use std::os::unix::fs::symlink as symlink_file;
+        #[cfg(windows)]
+        use std::os::windows::fs::symlink_file;
+        if !self.config.dry_run { symlink_file(src.as_ref(), link.as_ref()) } else { Ok(()) }
+    }
+
     fn remove(&self, f: &Path) {
         if self.config.dry_run {
             return;

Diff for: src/bootstrap/native.rs

@@ -251,9 +251,7 @@ impl Step for Llvm {
             };
 
         builder.update_submodule(&Path::new("src").join("llvm-project"));
-        if builder.llvm_link_shared()
-            && (target.contains("windows") || target.contains("apple-darwin"))
-        {
+        if builder.llvm_link_shared() && target.contains("windows") {
             panic!("shared linking to LLVM is not currently supported on {}", target.triple);
         }
 
@@ -359,7 +357,9 @@ impl Step for Llvm {
         //
         // If we're not linking rustc to a dynamic LLVM, though, then don't link
         // tools to it.
-        if builder.llvm_link_tools_dynamically(target) && builder.llvm_link_shared() {
+        let llvm_link_shared =
+            builder.llvm_link_tools_dynamically(target) && builder.llvm_link_shared();
+        if llvm_link_shared {
             cfg.define("LLVM_LINK_LLVM_DYLIB", "ON");
         }
 
@@ -438,18 +438,18 @@ impl Step for Llvm {
             );
         }
 
-        if let Some(ref suffix) = builder.config.llvm_version_suffix {
+        let llvm_version_suffix = if let Some(ref suffix) = builder.config.llvm_version_suffix {
             // Allow version-suffix="" to not define a version suffix at all.
-            if !suffix.is_empty() {
-                cfg.define("LLVM_VERSION_SUFFIX", suffix);
-            }
+            if !suffix.is_empty() { Some(suffix.to_string()) } else { None }
         } else if builder.config.channel == "dev" {
             // Changes to a version suffix require a complete rebuild of the LLVM.
             // To avoid rebuilds during a time of version bump, don't include rustc
             // release number on the dev channel.
-            cfg.define("LLVM_VERSION_SUFFIX", "-rust-dev");
+            Some("-rust-dev".to_string())
         } else {
-            let suffix = format!("-rust-{}-{}", builder.version, builder.config.channel);
+            Some(format!("-rust-{}-{}", builder.version, builder.config.channel))
+        };
+        if let Some(ref suffix) = llvm_version_suffix {
             cfg.define("LLVM_VERSION_SUFFIX", suffix);
         }
 
@@ -478,6 +478,27 @@ impl Step for Llvm {
 
         cfg.build();
 
+        // When building LLVM with LLVM_LINK_LLVM_DYLIB for macOS, an unversioned
+        // libLLVM.dylib will be built. However, llvm-config will still look
+        // for a versioned path like libLLVM-14.dylib. Manually create a symbolic
+        // link to make llvm-config happy.
+        if llvm_link_shared && target.contains("apple-darwin") {
+            let mut cmd = Command::new(&build_llvm_config);
+            let version = output(cmd.arg("--version"));
+            let major = version.split('.').next().unwrap();
+            let lib_name = match llvm_version_suffix {
+                Some(s) => format!("lib/libLLVM-{}{}.dylib", major, s),
+                None => format!("lib/libLLVM-{}.dylib", major),
+            };
+
+            // The reason why we build the library path from llvm-config is because
+            // the output of llvm-config depends on its location in the file system.
+            // Make sure we create the symlink exactly where it's needed.
+            let llvm_base = build_llvm_config.parent().unwrap().parent().unwrap();
+            let lib_llvm = llvm_base.join(lib_name);
+            t!(builder.symlink_file("libLLVM.dylib", &lib_llvm));
+        }
+
         t!(stamp.write());
 
         build_llvm_config

Diff for: src/librustdoc/doctest.rs

@@ -1003,8 +1003,10 @@ impl Tester for Collector {
         let outdir = if let Some(mut path) = rustdoc_options.persist_doctests.clone() {
             path.push(&test_id);
 
-            std::fs::create_dir_all(&path)
-                .expect("Couldn't create directory for doctest executables");
+            if let Err(err) = std::fs::create_dir_all(&path) {
+                eprintln!("Couldn't create directory for doctest executables: {}", err);
+                panic::resume_unwind(box ());
+            }
 
             DirState::Perm(path)
         } else {