Auto merge of rust-lang#140282 - matthiaskrgr:rollup-g6ze4jj, r=matthiaskrgr

Rollup of 8 pull requests

Successful merges:

 - rust-lang#137653 (Deprecate the unstable `concat_idents!`)
 - rust-lang#138957 (Update the index of Option to make the summary more comprehensive)
 - rust-lang#140006 (ensure compiler existance of tools on the dist step)
 - rust-lang#140143 (Move `sys::pal::os::Env` into `sys::env`)
 - rust-lang#140202 (Make #![feature(let_chains)] bootstrap conditional in compiler/)
 - rust-lang#140236 (norm nested aliases before evaluating the parent goal)
 - rust-lang#140257 (Some drive-by housecleaning in `rustc_borrowck`)
 - rust-lang#140278 (Don't use item name to look up associated item from trait item)

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

Author: bors

Cargo.lock

@@ -4158,7 +4158,6 @@ dependencies = [
  "rustc_data_structures",
  "rustc_index",
  "rustc_macros",
- "rustc_serialize",
  "rustc_type_ir",
  "rustc_type_ir_macros",
  "tracing",

compiler/rustc_ast/src/lib.rs

@@ -6,6 +6,7 @@
 
 // tidy-alphabetical-start
 #![allow(internal_features)]
+#![cfg_attr(bootstrap, feature(let_chains))]
 #![doc(
     html_root_url = "https://doc.rust-lang.org/nightly/nightly-rustc/",
     test(attr(deny(warnings)))
@@ -14,7 +15,6 @@
 #![feature(associated_type_defaults)]
 #![feature(box_patterns)]
 #![feature(if_let_guard)]
-#![feature(let_chains)]
 #![feature(negative_impls)]
 #![feature(never_type)]
 #![feature(rustdoc_internals)]

compiler/rustc_ast_lowering/src/lib.rs

@@ -32,12 +32,12 @@
 
 // tidy-alphabetical-start
 #![allow(internal_features)]
+#![cfg_attr(bootstrap, feature(let_chains))]
 #![doc(rust_logo)]
 #![feature(assert_matches)]
 #![feature(box_patterns)]
 #![feature(exact_size_is_empty)]
 #![feature(if_let_guard)]
-#![feature(let_chains)]
 #![feature(rustdoc_internals)]
 // tidy-alphabetical-end
 

compiler/rustc_ast_passes/src/lib.rs

@@ -4,11 +4,11 @@
 
 // tidy-alphabetical-start
 #![allow(internal_features)]
+#![cfg_attr(bootstrap, feature(let_chains))]
 #![doc(rust_logo)]
 #![feature(box_patterns)]
 #![feature(if_let_guard)]
 #![feature(iter_is_partitioned)]
-#![feature(let_chains)]
 #![feature(rustdoc_internals)]
 // tidy-alphabetical-end
 

compiler/rustc_attr_data_structures/src/lib.rs

@@ -1,7 +1,7 @@
 // tidy-alphabetical-start
 #![allow(internal_features)]
+#![cfg_attr(bootstrap, feature(let_chains))]
 #![doc(rust_logo)]
-#![feature(let_chains)]
 #![feature(rustdoc_internals)]
 // tidy-alphabetical-end
 

compiler/rustc_attr_parsing/src/lib.rs

@@ -77,8 +77,8 @@
 
 // tidy-alphabetical-start
 #![allow(internal_features)]
+#![cfg_attr(bootstrap, feature(let_chains))]
 #![doc(rust_logo)]
-#![feature(let_chains)]
 #![feature(rustdoc_internals)]
 // tidy-alphabetical-end
 

compiler/rustc_borrowck/src/diagnostics/bound_region_errors.rs

@@ -49,7 +49,7 @@ impl<'tcx> UniverseInfo<'tcx> {
         UniverseInfo::RelateTys { expected, found }
     }
 
-    pub(crate) fn report_error(
+    pub(crate) fn report_erroneous_element(
         &self,
         mbcx: &mut MirBorrowckCtxt<'_, '_, 'tcx>,
         placeholder: ty::PlaceholderRegion,
@@ -68,7 +68,7 @@ impl<'tcx> UniverseInfo<'tcx> {
                 mbcx.buffer_error(err);
             }
             UniverseInfo::TypeOp(ref type_op_info) => {
-                type_op_info.report_error(mbcx, placeholder, error_element, cause);
+                type_op_info.report_erroneous_element(mbcx, placeholder, error_element, cause);
             }
             UniverseInfo::Other => {
                 // FIXME: This error message isn't great, but it doesn't show
@@ -145,8 +145,11 @@ pub(crate) trait TypeOpInfo<'tcx> {
         error_region: Option<ty::Region<'tcx>>,
     ) -> Option<Diag<'infcx>>;
 
+    /// Constraints require that `error_element` appear in the
+    ///  values of `placeholder`, but this cannot be proven to
+    /// hold. Report an error.
     #[instrument(level = "debug", skip(self, mbcx))]
-    fn report_error(
+    fn report_erroneous_element(
         &self,
         mbcx: &mut MirBorrowckCtxt<'_, '_, 'tcx>,
         placeholder: ty::PlaceholderRegion,
@@ -190,12 +193,7 @@ pub(crate) trait TypeOpInfo<'tcx> {
         let nice_error = self.nice_error(mbcx, cause, placeholder_region, error_region);
 
         debug!(?nice_error);
-
-        if let Some(nice_error) = nice_error {
-            mbcx.buffer_error(nice_error);
-        } else {
-            mbcx.buffer_error(self.fallback_error(tcx, span));
-        }
+        mbcx.buffer_error(nice_error.unwrap_or_else(|| self.fallback_error(tcx, span)));
     }
 }
 
@@ -450,7 +448,8 @@ fn try_extract_error_from_region_constraints<'a, 'tcx>(
         ty::ReVar(vid) => universe_of_region(vid),
         _ => ty::UniverseIndex::ROOT,
     };
-    let matches =
+    // Are the two regions the same?
+    let regions_the_same =
         |a_region: Region<'tcx>, b_region: Region<'tcx>| match (a_region.kind(), b_region.kind()) {
             (RePlaceholder(a_p), RePlaceholder(b_p)) => a_p.bound == b_p.bound,
             _ => a_region == b_region,
@@ -459,7 +458,7 @@ fn try_extract_error_from_region_constraints<'a, 'tcx>(
         |constraint: &Constraint<'tcx>, cause: &SubregionOrigin<'tcx>, exact| match *constraint {
             Constraint::RegSubReg(sub, sup)
                 if ((exact && sup == placeholder_region)
-                    || (!exact && matches(sup, placeholder_region)))
+                    || (!exact && regions_the_same(sup, placeholder_region)))
                     && sup != sub =>
             {
                 Some((sub, cause.clone()))
@@ -468,23 +467,21 @@ fn try_extract_error_from_region_constraints<'a, 'tcx>(
                 if (exact
                     && sup == placeholder_region
                     && !universe_of_region(vid).can_name(placeholder_universe))
-                    || (!exact && matches(sup, placeholder_region)) =>
+                    || (!exact && regions_the_same(sup, placeholder_region)) =>
             {
                 Some((ty::Region::new_var(infcx.tcx, vid), cause.clone()))
             }
             _ => None,
         };
-    let mut info = region_constraints
-        .constraints
-        .iter()
-        .find_map(|(constraint, cause)| check(constraint, cause, true));
-    if info.is_none() {
-        info = region_constraints
+
+    let mut find_culprit = |exact_match: bool| {
+        region_constraints
             .constraints
             .iter()
-            .find_map(|(constraint, cause)| check(constraint, cause, false));
-    }
-    let (sub_region, cause) = info?;
+            .find_map(|(constraint, cause)| check(constraint, cause, exact_match))
+    };
+
+    let (sub_region, cause) = find_culprit(true).or_else(|| find_culprit(false))?;
 
     debug!(?sub_region, "cause = {:#?}", cause);
     let error = match (error_region, sub_region.kind()) {

compiler/rustc_borrowck/src/diagnostics/region_errors.rs

@@ -405,7 +405,7 @@ impl<'infcx, 'tcx> MirBorrowckCtxt<'_, 'infcx, 'tcx> {
                     let universe = placeholder.universe;
                     let universe_info = self.regioncx.universe_info(universe);
 
-                    universe_info.report_error(self, placeholder, error_element, cause);
+                    universe_info.report_erroneous_element(self, placeholder, error_element, cause);
                 }
 
                 RegionErrorKind::RegionError { fr_origin, longer_fr, shorter_fr, is_reported } => {

compiler/rustc_borrowck/src/lib.rs

@@ -2,12 +2,12 @@
 
 // tidy-alphabetical-start
 #![allow(internal_features)]
+#![cfg_attr(bootstrap, feature(let_chains))]
 #![doc(rust_logo)]
 #![feature(assert_matches)]
 #![feature(box_patterns)]
 #![feature(file_buffered)]
 #![feature(if_let_guard)]
-#![feature(let_chains)]
 #![feature(negative_impls)]
 #![feature(never_type)]
 #![feature(rustc_attrs)]

compiler/rustc_borrowck/src/region_infer/mod.rs

@@ -1628,30 +1628,23 @@ impl<'tcx> RegionInferenceContext<'tcx> {
         let longer_fr_scc = self.constraint_sccs.scc(longer_fr);
         debug!("check_bound_universal_region: longer_fr_scc={:?}", longer_fr_scc,);
 
-        for error_element in self.scc_values.elements_contained_in(longer_fr_scc) {
-            match error_element {
-                RegionElement::Location(_) | RegionElement::RootUniversalRegion(_) => {}
-                // If we have some bound universal region `'a`, then the only
-                // elements it can contain is itself -- we don't know anything
-                // else about it!
-                RegionElement::PlaceholderRegion(placeholder1) => {
-                    if placeholder == placeholder1 {
-                        continue;
-                    }
-                }
-            }
-
+        // If we have some bound universal region `'a`, then the only
+        // elements it can contain is itself -- we don't know anything
+        // else about it!
+        if let Some(error_element) = self
+            .scc_values
+            .elements_contained_in(longer_fr_scc)
+            .find(|e| *e != RegionElement::PlaceholderRegion(placeholder))
+        {
+            // Stop after the first error, it gets too noisy otherwise, and does not provide more information.
             errors_buffer.push(RegionErrorKind::BoundUniversalRegionError {
                 longer_fr,
                 error_element,
                 placeholder,
             });
-
-            // Stop after the first error, it gets too noisy otherwise, and does not provide more
-            // information.
-            break;
+        } else {
+            debug!("check_bound_universal_region: all bounds satisfied");
         }
-        debug!("check_bound_universal_region: all bounds satisfied");
     }
 
     #[instrument(level = "debug", skip(self, infcx, errors_buffer))]
@@ -2071,7 +2064,7 @@ impl<'tcx> RegionInferenceContext<'tcx> {
                 constraint.category
             };
 
-            match category {
+            let interest = match category {
                 // Returns usually provide a type to blame and have specially written diagnostics,
                 // so prioritize them.
                 ConstraintCategory::Return(_) => 0,
@@ -2123,9 +2116,13 @@ impl<'tcx> RegionInferenceContext<'tcx> {
                 // specific, and are not used for relations that would make sense to blame.
                 ConstraintCategory::BoringNoLocation => 6,
                 // Do not blame internal constraints.
-                ConstraintCategory::Internal => 7,
-                ConstraintCategory::IllegalUniverse => 8,
-            }
+                ConstraintCategory::IllegalUniverse => 7,
+                ConstraintCategory::Internal => 8,
+            };
+
+            debug!("constraint {constraint:?} category: {category:?}, interest: {interest:?}");
+
+            interest
         };
 
         let best_choice = if blame_source {

compiler/rustc_borrowck/src/region_infer/values.rs

@@ -21,7 +21,7 @@ rustc_index::newtype_index! {
 
 /// An individual element in a region value -- the value of a
 /// particular region variable consists of a set of these elements.
-#[derive(Debug, Clone)]
+#[derive(Debug, Clone, PartialEq)]
 pub(crate) enum RegionElement {
     /// A point in the control-flow graph.
     Location(Location),

compiler/rustc_builtin_macros/src/lib.rs

@@ -5,14 +5,14 @@
 #![allow(internal_features)]
 #![allow(rustc::diagnostic_outside_of_impl)]
 #![allow(rustc::untranslatable_diagnostic)]
+#![cfg_attr(bootstrap, feature(let_chains))]
 #![doc(html_root_url = "https://doc.rust-lang.org/nightly/nightly-rustc/")]
 #![doc(rust_logo)]
 #![feature(assert_matches)]
 #![feature(autodiff)]
 #![feature(box_patterns)]
 #![feature(decl_macro)]
 #![feature(if_let_guard)]
-#![feature(let_chains)]
 #![feature(proc_macro_internals)]
 #![feature(proc_macro_quote)]
 #![feature(rustdoc_internals)]

compiler/rustc_codegen_llvm/src/lib.rs

@@ -6,6 +6,7 @@
 
 // tidy-alphabetical-start
 #![allow(internal_features)]
+#![cfg_attr(bootstrap, feature(let_chains))]
 #![doc(html_root_url = "https://doc.rust-lang.org/nightly/nightly-rustc/")]
 #![doc(rust_logo)]
 #![feature(assert_matches)]
@@ -15,7 +16,6 @@
 #![feature(if_let_guard)]
 #![feature(impl_trait_in_assoc_type)]
 #![feature(iter_intersperse)]
-#![feature(let_chains)]
 #![feature(rustdoc_internals)]
 #![feature(slice_as_array)]
 #![feature(try_blocks)]

compiler/rustc_codegen_ssa/src/lib.rs

@@ -2,13 +2,13 @@
 #![allow(internal_features)]
 #![allow(rustc::diagnostic_outside_of_impl)]
 #![allow(rustc::untranslatable_diagnostic)]
+#![cfg_attr(bootstrap, feature(let_chains))]
 #![doc(html_root_url = "https://doc.rust-lang.org/nightly/nightly-rustc/")]
 #![doc(rust_logo)]
 #![feature(assert_matches)]
 #![feature(box_patterns)]
 #![feature(file_buffered)]
 #![feature(if_let_guard)]
-#![feature(let_chains)]
 #![feature(negative_impls)]
 #![feature(rustdoc_internals)]
 #![feature(string_from_utf8_lossy_owned)]

compiler/rustc_const_eval/src/lib.rs

@@ -1,12 +1,12 @@
 // tidy-alphabetical-start
 #![allow(internal_features)]
 #![allow(rustc::diagnostic_outside_of_impl)]
+#![cfg_attr(bootstrap, feature(let_chains))]
 #![doc(rust_logo)]
 #![feature(assert_matches)]
 #![feature(box_patterns)]
 #![feature(decl_macro)]
 #![feature(if_let_guard)]
-#![feature(let_chains)]
 #![feature(never_type)]
 #![feature(rustdoc_internals)]
 #![feature(slice_ptr_get)]

compiler/rustc_data_structures/src/marker.rs

@@ -39,8 +39,15 @@ impls_dyn_send_neg!(
     [std::io::StderrLock<'_>]
 );
 
-#[cfg(any(unix, target_os = "hermit", target_os = "wasi", target_os = "solid_asp3"))]
-// Consistent with `std`, `os_imp::Env` is `!Sync` in these platforms
+#[cfg(any(
+    unix,
+    target_os = "hermit",
+    all(target_vendor = "fortanix", target_env = "sgx"),
+    target_os = "solid_asp3",
+    target_os = "wasi",
+    target_os = "xous"
+))]
+// Consistent with `std`, `env_imp::Env` is `!Sync` in these platforms
 impl !DynSend for std::env::VarsOs {}
 
 macro_rules! already_send {
@@ -106,8 +113,15 @@ impls_dyn_sync_neg!(
     [std::sync::mpsc::Sender<T> where T]
 );
 
-#[cfg(any(unix, target_os = "hermit", target_os = "wasi", target_os = "solid_asp3"))]
-// Consistent with `std`, `os_imp::Env` is `!Sync` in these platforms
+#[cfg(any(
+    unix,
+    target_os = "hermit",
+    all(target_vendor = "fortanix", target_env = "sgx"),
+    target_os = "solid_asp3",
+    target_os = "wasi",
+    target_os = "xous"
+))]
+// Consistent with `std`, `env_imp::Env` is `!Sync` in these platforms
 impl !DynSync for std::env::VarsOs {}
 
 macro_rules! already_sync {

compiler/rustc_driver_impl/src/lib.rs

@@ -7,10 +7,10 @@
 // tidy-alphabetical-start
 #![allow(internal_features)]
 #![allow(rustc::untranslatable_diagnostic)] // FIXME: make this translatable
+#![cfg_attr(bootstrap, feature(let_chains))]
 #![doc(html_root_url = "https://doc.rust-lang.org/nightly/nightly-rustc/")]
 #![doc(rust_logo)]
 #![feature(decl_macro)]
-#![feature(let_chains)]
 #![feature(panic_backtrace_config)]
 #![feature(panic_update_hook)]
 #![feature(result_flattening)]

compiler/rustc_errors/src/lib.rs

@@ -7,6 +7,7 @@
 #![allow(internal_features)]
 #![allow(rustc::diagnostic_outside_of_impl)]
 #![allow(rustc::untranslatable_diagnostic)]
+#![cfg_attr(bootstrap, feature(let_chains))]
 #![doc(html_root_url = "https://doc.rust-lang.org/nightly/nightly-rustc/")]
 #![doc(rust_logo)]
 #![feature(array_windows)]
@@ -17,7 +18,6 @@
 #![feature(default_field_values)]
 #![feature(error_reporter)]
 #![feature(if_let_guard)]
-#![feature(let_chains)]
 #![feature(negative_impls)]
 #![feature(never_type)]
 #![feature(rustc_attrs)]