Auto merge of rust-lang#134878 - Zalathar:rollup-ebqmxw7, r=Zalathar

Rollup of 4 pull requests

Successful merges:

 - rust-lang#122565 (Try to write the panic message with a single `write_all` call)
 - rust-lang#133460 (Use `check-run-results` for `run-fail` test stderr)
 - rust-lang#134627 (Avoid ICE in borrowck)
 - rust-lang#134799 (nits: Cleanups in `librustdoc::clean`)

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

Author: bors

compiler/rustc_borrowck/src/region_infer/mod.rs

@@ -1950,8 +1950,14 @@ impl<'tcx> RegionInferenceContext<'tcx> {
         target_test: impl Fn(RegionVid) -> bool,
     ) -> (BlameConstraint<'tcx>, Vec<ExtraConstraintInfo>) {
         // Find all paths
-        let (path, target_region) =
-            self.find_constraint_paths_between_regions(from_region, target_test).unwrap();
+        let (path, target_region) = self
+            .find_constraint_paths_between_regions(from_region, target_test)
+            .or_else(|| {
+                self.find_constraint_paths_between_regions(from_region, |r| {
+                    self.cannot_name_placeholder(from_region, r)
+                })
+            })
+            .unwrap();
         debug!(
             "path={:#?}",
             path.iter()

library/std/src/panicking.rs

@@ -266,7 +266,23 @@ fn default_hook(info: &PanicHookInfo<'_>) {
         // Use a lock to prevent mixed output in multithreading context.
         // Some platforms also require it when printing a backtrace, like `SymFromAddr` on Windows.
         let mut lock = backtrace::lock();
-        let _ = writeln!(err, "thread '{name}' panicked at {location}:\n{msg}");
+        // Try to write the panic message to a buffer first to prevent other concurrent outputs
+        // interleaving with it.
+        let mut buffer = [0u8; 512];
+        let mut cursor = crate::io::Cursor::new(&mut buffer[..]);
+
+        let write_msg = |dst: &mut dyn crate::io::Write| {
+            // We add a newline to ensure the panic message appears at the start of a line.
+            writeln!(dst, "\nthread '{name}' panicked at {location}:\n{msg}")
+        };
+
+        if write_msg(&mut cursor).is_ok() {
+            let pos = cursor.position() as usize;
+            let _ = err.write_all(&buffer[0..pos]);
+        } else {
+            // The message did not fit into the buffer, write it directly instead.
+            let _ = write_msg(err);
+        };
 
         static FIRST_PANIC: AtomicBool = AtomicBool::new(true);
 

src/librustdoc/clean/mod.rs

@@ -268,7 +268,7 @@ fn clean_poly_trait_ref_with_constraints<'tcx>(
     )
 }
 
-fn clean_lifetime(lifetime: &hir::Lifetime, cx: &mut DocContext<'_>) -> Lifetime {
+fn clean_lifetime(lifetime: &hir::Lifetime, cx: &DocContext<'_>) -> Lifetime {
     if let Some(
         rbv::ResolvedArg::EarlyBound(did)
         | rbv::ResolvedArg::LateBound(_, _, did)
@@ -362,9 +362,9 @@ pub(crate) fn clean_predicate<'tcx>(
     let bound_predicate = predicate.kind();
     match bound_predicate.skip_binder() {
         ty::ClauseKind::Trait(pred) => clean_poly_trait_predicate(bound_predicate.rebind(pred), cx),
-        ty::ClauseKind::RegionOutlives(pred) => clean_region_outlives_predicate(pred),
+        ty::ClauseKind::RegionOutlives(pred) => Some(clean_region_outlives_predicate(pred)),
         ty::ClauseKind::TypeOutlives(pred) => {
-            clean_type_outlives_predicate(bound_predicate.rebind(pred), cx)
+            Some(clean_type_outlives_predicate(bound_predicate.rebind(pred), cx))
         }
         ty::ClauseKind::Projection(pred) => {
             Some(clean_projection_predicate(bound_predicate.rebind(pred), cx))
@@ -396,32 +396,30 @@ fn clean_poly_trait_predicate<'tcx>(
     })
 }
 
-fn clean_region_outlives_predicate(
-    pred: ty::RegionOutlivesPredicate<'_>,
-) -> Option<WherePredicate> {
+fn clean_region_outlives_predicate(pred: ty::RegionOutlivesPredicate<'_>) -> WherePredicate {
     let ty::OutlivesPredicate(a, b) = pred;
 
-    Some(WherePredicate::RegionPredicate {
+    WherePredicate::RegionPredicate {
         lifetime: clean_middle_region(a).expect("failed to clean lifetime"),
         bounds: vec![GenericBound::Outlives(
             clean_middle_region(b).expect("failed to clean bounds"),
         )],
-    })
+    }
 }
 
 fn clean_type_outlives_predicate<'tcx>(
     pred: ty::Binder<'tcx, ty::TypeOutlivesPredicate<'tcx>>,
     cx: &mut DocContext<'tcx>,
-) -> Option<WherePredicate> {
+) -> WherePredicate {
     let ty::OutlivesPredicate(ty, lt) = pred.skip_binder();
 
-    Some(WherePredicate::BoundPredicate {
+    WherePredicate::BoundPredicate {
         ty: clean_middle_ty(pred.rebind(ty), cx, None, None),
         bounds: vec![GenericBound::Outlives(
             clean_middle_region(lt).expect("failed to clean lifetimes"),
         )],
         bound_params: Vec::new(),
-    })
+    }
 }
 
 fn clean_middle_term<'tcx>(
@@ -1860,7 +1858,7 @@ pub(crate) fn clean_ty<'tcx>(ty: &hir::Ty<'tcx>, cx: &mut DocContext<'tcx>) -> T
 
 /// Returns `None` if the type could not be normalized
 fn normalize<'tcx>(
-    cx: &mut DocContext<'tcx>,
+    cx: &DocContext<'tcx>,
     ty: ty::Binder<'tcx, Ty<'tcx>>,
 ) -> Option<ty::Binder<'tcx, Ty<'tcx>>> {
     // HACK: low-churn fix for #79459 while we wait for a trait normalization fix

src/tools/miri/tests/fail/function_calls/exported_symbol_bad_unwind1.stderr

@@ -1,3 +1,4 @@
+
 thread 'main' panicked at tests/fail/function_calls/exported_symbol_bad_unwind1.rs:LL:CC:
 explicit panic
 note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace

src/tools/miri/tests/fail/function_calls/exported_symbol_bad_unwind2.both.stderr

@@ -1,7 +1,9 @@
+
 thread 'main' panicked at tests/fail/function_calls/exported_symbol_bad_unwind2.rs:LL:CC:
 explicit panic
 note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace
 note: in Miri, you may have to set `MIRIFLAGS=-Zmiri-env-forward=RUST_BACKTRACE` for the environment variable to have an effect
+
 thread 'main' panicked at RUSTLIB/core/src/panicking.rs:LL:CC:
 panic in a function that cannot unwind
 stack backtrace:

src/tools/miri/tests/fail/function_calls/exported_symbol_bad_unwind2.definition.stderr

@@ -1,7 +1,9 @@
+
 thread 'main' panicked at tests/fail/function_calls/exported_symbol_bad_unwind2.rs:LL:CC:
 explicit panic
 note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace
 note: in Miri, you may have to set `MIRIFLAGS=-Zmiri-env-forward=RUST_BACKTRACE` for the environment variable to have an effect
+
 thread 'main' panicked at RUSTLIB/core/src/panicking.rs:LL:CC:
 panic in a function that cannot unwind
 stack backtrace:

src/tools/miri/tests/fail/function_calls/exported_symbol_bad_unwind2.extern_block.stderr

@@ -1,3 +1,4 @@
+
 thread 'main' panicked at tests/fail/function_calls/exported_symbol_bad_unwind2.rs:LL:CC:
 explicit panic
 note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace

src/tools/miri/tests/fail/function_calls/return_pointer_on_unwind.stderr

@@ -1,3 +1,4 @@
+
 thread 'main' panicked at tests/fail/function_calls/return_pointer_on_unwind.rs:LL:CC:
 explicit panic
 note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace

src/tools/miri/tests/fail/intrinsics/uninit_uninhabited_type.stderr

@@ -1,3 +1,4 @@
+
 thread 'main' panicked at RUSTLIB/core/src/panicking.rs:LL:CC:
 aborted execution: attempted to instantiate uninhabited type `!`
 note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace

src/tools/miri/tests/fail/intrinsics/zero_fn_ptr.stderr

@@ -1,3 +1,4 @@
+
 thread 'main' panicked at RUSTLIB/core/src/panicking.rs:LL:CC:
 aborted execution: attempted to zero-initialize type `fn()`, which is invalid
 note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace