Auto merge of rust-lang#128048 - workingjubilee:rollup-gehtjxd, r=workingjubilee

Rollup of 6 pull requests

Successful merges:

 - rust-lang#127583 (Deal with invalid UTF-8 from `gai_strerror`)
 - rust-lang#128014 (Fix stab display in doc blocks)
 - rust-lang#128020 (Just totally fully deny late-bound consts)
 - rust-lang#128023 (rustdoc: short descriptions cause word-breaks in tables)
 - rust-lang#128033 (Explain why we require `_` for empty patterns)
 - rust-lang#128038 (Don't output incremental test artifacts into working directory)

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

Author: bors

.gitignore

@@ -50,7 +50,6 @@ build/
 /target
 /src/bootstrap/target
 /src/tools/x/target
-/inc-fat/
 # Created by default with `src/ci/docker/run.sh`
 /obj/
 /rustc-ice*

compiler/rustc_ast_passes/messages.ftl

@@ -120,6 +120,9 @@ ast_passes_fn_without_body =
 ast_passes_forbidden_bound =
     bounds cannot be used in this context
 
+ast_passes_forbidden_const_param =
+    late-bound const parameters cannot be used currently
+
 ast_passes_forbidden_default =
     `default` is only allowed on items in trait impls
     .label = `default` because of this

compiler/rustc_ast_passes/src/errors.rs

@@ -69,6 +69,13 @@ pub struct ForbiddenBound {
     pub spans: Vec<Span>,
 }
 
+#[derive(Diagnostic)]
+#[diag(ast_passes_forbidden_const_param)]
+pub struct ForbiddenConstParam {
+    #[primary_span]
+    pub const_param_spans: Vec<Span>,
+}
+
 #[derive(Diagnostic)]
 #[diag(ast_passes_fn_param_too_many)]
 pub struct FnParamTooMany {

compiler/rustc_ast_passes/src/feature_gate.rs

@@ -162,6 +162,22 @@ impl<'a> PostExpansionVisitor<'a> {
             crate::fluent_generated::ast_passes_forbidden_non_lifetime_param
         );
 
+        // FIXME(non_lifetime_binders): Const bound params are pretty broken.
+        // Let's keep users from using this feature accidentally.
+        if self.features.non_lifetime_binders {
+            let const_param_spans: Vec<_> = params
+                .iter()
+                .filter_map(|param| match param.kind {
+                    ast::GenericParamKind::Const { .. } => Some(param.ident.span),
+                    _ => None,
+                })
+                .collect();
+
+            if !const_param_spans.is_empty() {
+                self.sess.dcx().emit_err(errors::ForbiddenConstParam { const_param_spans });
+            }
+        }
+
         for param in params {
             if !param.bounds.is_empty() {
                 let spans: Vec<_> = param.bounds.iter().map(|b| b.span()).collect();

compiler/rustc_hir_analysis/src/collect/resolve_bound_vars.rs

@@ -2094,11 +2094,7 @@ pub fn deny_non_region_late_bound(
             format!("late-bound {what} parameter not allowed on {where_}"),
         );
 
-        let guar = if tcx.features().non_lifetime_binders && first {
-            diag.emit()
-        } else {
-            diag.delay_as_bug()
-        };
+        let guar = diag.emit_unless(!tcx.features().non_lifetime_binders || !first);
 
         first = false;
         *arg = ResolvedArg::Error(guar);

compiler/rustc_mir_build/src/thir/pattern/check_match.rs

@@ -16,8 +16,8 @@ use rustc_middle::ty::print::with_no_trimmed_paths;
 use rustc_middle::ty::{self, AdtDef, Ty, TyCtxt};
 use rustc_pattern_analysis::errors::Uncovered;
 use rustc_pattern_analysis::rustc::{
-    Constructor, DeconstructedPat, MatchArm, RustcPatCtxt as PatCtxt, Usefulness, UsefulnessReport,
-    WitnessPat,
+    Constructor, DeconstructedPat, MatchArm, RevealedTy, RustcPatCtxt as PatCtxt, Usefulness,
+    UsefulnessReport, WitnessPat,
 };
 use rustc_session::lint::builtin::{
     BINDINGS_WITH_VARIANT_NAME, IRREFUTABLE_LET_PATTERNS, UNREACHABLE_PATTERNS,
@@ -998,27 +998,31 @@ fn report_non_exhaustive_match<'p, 'tcx>(
     err.note(format!("the matched value is of type `{}`", scrut_ty));
 
     if !is_empty_match {
-        let mut non_exhaustive_tys = FxIndexSet::default();
+        let mut special_tys = FxIndexSet::default();
         // Look at the first witness.
-        collect_non_exhaustive_tys(cx, &witnesses[0], &mut non_exhaustive_tys);
+        collect_special_tys(cx, &witnesses[0], &mut special_tys);
 
-        for ty in non_exhaustive_tys {
+        for ty in special_tys {
             if ty.is_ptr_sized_integral() {
-                if ty == cx.tcx.types.usize {
+                if ty.inner() == cx.tcx.types.usize {
                     err.note(format!(
                         "`{ty}` does not have a fixed maximum value, so half-open ranges are necessary to match \
                              exhaustively",
                     ));
-                } else if ty == cx.tcx.types.isize {
+                } else if ty.inner() == cx.tcx.types.isize {
                     err.note(format!(
                         "`{ty}` does not have fixed minimum and maximum values, so half-open ranges are necessary to match \
                              exhaustively",
                     ));
                 }
-            } else if ty == cx.tcx.types.str_ {
+            } else if ty.inner() == cx.tcx.types.str_ {
                 err.note("`&str` cannot be matched exhaustively, so a wildcard `_` is necessary");
-            } else if cx.is_foreign_non_exhaustive_enum(cx.reveal_opaque_ty(ty)) {
+            } else if cx.is_foreign_non_exhaustive_enum(ty) {
                 err.note(format!("`{ty}` is marked as non-exhaustive, so a wildcard `_` is necessary to match exhaustively"));
+            } else if cx.is_uninhabited(ty.inner()) && cx.tcx.features().min_exhaustive_patterns {
+                // The type is uninhabited yet there is a witness: we must be in the `MaybeInvalid`
+                // case.
+                err.note(format!("`{ty}` is uninhabited but is not being matched by value, so a wildcard `_` is required"));
             }
         }
     }
@@ -1168,22 +1172,22 @@ fn joined_uncovered_patterns<'p, 'tcx>(
     }
 }
 
-fn collect_non_exhaustive_tys<'tcx>(
+/// Collect types that require specific explanations when they show up in witnesses.
+fn collect_special_tys<'tcx>(
     cx: &PatCtxt<'_, 'tcx>,
     pat: &WitnessPat<'_, 'tcx>,
-    non_exhaustive_tys: &mut FxIndexSet<Ty<'tcx>>,
+    special_tys: &mut FxIndexSet<RevealedTy<'tcx>>,
 ) {
-    if matches!(pat.ctor(), Constructor::NonExhaustive) {
-        non_exhaustive_tys.insert(pat.ty().inner());
+    if matches!(pat.ctor(), Constructor::NonExhaustive | Constructor::Never) {
+        special_tys.insert(*pat.ty());
     }
     if let Constructor::IntRange(range) = pat.ctor() {
         if cx.is_range_beyond_boundaries(range, *pat.ty()) {
             // The range denotes the values before `isize::MIN` or the values after `usize::MAX`/`isize::MAX`.
-            non_exhaustive_tys.insert(pat.ty().inner());
+            special_tys.insert(*pat.ty());
         }
     }
-    pat.iter_fields()
-        .for_each(|field_pat| collect_non_exhaustive_tys(cx, field_pat, non_exhaustive_tys))
+    pat.iter_fields().for_each(|field_pat| collect_special_tys(cx, field_pat, special_tys))
 }
 
 fn report_adt_defined_here<'tcx>(

compiler/rustc_pattern_analysis/src/rustc.rs

@@ -40,9 +40,15 @@ pub type WitnessPat<'p, 'tcx> = crate::pat::WitnessPat<RustcPatCtxt<'p, 'tcx>>;
 ///
 /// Use `.inner()` or deref to get to the `Ty<'tcx>`.
 #[repr(transparent)]
-#[derive(Clone, Copy)]
+#[derive(Clone, Copy, PartialEq, Eq, Hash)]
 pub struct RevealedTy<'tcx>(Ty<'tcx>);
 
+impl<'tcx> fmt::Display for RevealedTy<'tcx> {
+    fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result {
+        self.0.fmt(fmt)
+    }
+}
+
 impl<'tcx> fmt::Debug for RevealedTy<'tcx> {
     fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result {
         self.0.fmt(fmt)

compiler/rustc_resolve/src/late.rs

@@ -2763,7 +2763,11 @@ impl<'a: 'ast, 'b, 'ast, 'tcx> LateResolutionVisitor<'a, 'b, 'ast, 'tcx> {
             let res = match kind {
                 RibKind::Item(..) | RibKind::AssocItem => Res::Def(def_kind, def_id.to_def_id()),
                 RibKind::Normal => {
-                    if self.r.tcx.features().non_lifetime_binders {
+                    // FIXME(non_lifetime_binders): Stop special-casing
+                    // const params to error out here.
+                    if self.r.tcx.features().non_lifetime_binders
+                        && matches!(param.kind, GenericParamKind::Type { .. })
+                    {
                         Res::Def(def_kind, def_id.to_def_id())
                     } else {
                         Res::Err

library/std/src/sys/pal/unix/net.rs

@@ -4,7 +4,6 @@ use crate::io::{self, BorrowedBuf, BorrowedCursor, IoSlice, IoSliceMut};
 use crate::mem;
 use crate::net::{Shutdown, SocketAddr};
 use crate::os::unix::io::{AsFd, AsRawFd, BorrowedFd, FromRawFd, IntoRawFd, RawFd};
-use crate::str;
 use crate::sys::fd::FileDesc;
 use crate::sys::pal::unix::IsMinusOne;
 use crate::sys_common::net::{getsockopt, setsockopt, sockaddr_to_addr};
@@ -47,7 +46,9 @@ pub fn cvt_gai(err: c_int) -> io::Result<()> {
 
     #[cfg(not(target_os = "espidf"))]
     let detail = unsafe {
-        str::from_utf8(CStr::from_ptr(libc::gai_strerror(err)).to_bytes()).unwrap().to_owned()
+        // We can't always expect a UTF-8 environment. When we don't get that luxury,
+        // it's better to give a low-quality error message than none at all.
+        CStr::from_ptr(libc::gai_strerror(err)).to_string_lossy()
     };
 
     #[cfg(target_os = "espidf")]

src/librustdoc/html/static/css/rustdoc.css

@@ -831,6 +831,10 @@ pre, .rustdoc.src .example-wrap {
 	background: var(--table-alt-row-background-color);
 }
 
+.docblock .stab, .docblock-short .stab {
+	display: inline-block;
+}
+
 /* "where ..." clauses with block display are also smaller */
 div.where {
 	white-space: pre-wrap;
@@ -953,6 +957,7 @@ table,
 	display: table;
 	padding: 0;
 	margin: 0;
+	width: 100%;
 }
 .item-table > li {
 	display: table-row;