Auto merge of #146160 - Zalathar:rollup-qxphx7g, r=Zalathar

Rollup of 8 pull requests

Successful merges:

 - rust-lang/rust#145279 (Constify conversion traits (part 1))
 - rust-lang/rust#145414 (unicode-table-generator refactors)
 - rust-lang/rust#145823 (editorconfig: don't use nonexistent syntax)
 - rust-lang/rust#145944 (std: Start supporting WASIp2 natively )
 - rust-lang/rust#145961 (resolve: Avoid a regression from splitting prelude into two scopes)
 - rust-lang/rust#146032 (Explicity disable LSX feature for `loongarch64-unknown-none` target)
 - rust-lang/rust#146106 (fix(lexer): Only allow horizontal whitespace in frontmatter )
 - rust-lang/rust#146154 (CI: rfl: move job forward to Linux v6.17-rc3 plus 2 commits)

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

4 files changed, 52 insertions, 22 deletions

diff --git a/compiler/rustc_lexer/src/lib.rs b/compiler/rustc_lexer/src/lib.rs
index d10b1920343..c29ab569f47 100644
--- a/compiler/rustc_lexer/src/lib.rs
+++ b/compiler/rustc_lexer/src/lib.rs
@@ -331,24 +331,37 @@ pub fn is_whitespace(c: char) -> bool {
 
     matches!(
         c,
-        // Usual ASCII suspects
-        '\u{0009}'   // \t
-        | '\u{000A}' // \n
+        // End-of-line characters
+        | '\u{000A}' // line feed (\n)
         | '\u{000B}' // vertical tab
         | '\u{000C}' // form feed
-        | '\u{000D}' // \r
-        | '\u{0020}' // space
-
-        // NEXT LINE from latin1
-        | '\u{0085}'
+        | '\u{000D}' // carriage return (\r)
+        | '\u{0085}' // next line (from latin1)
+        | '\u{2028}' // LINE SEPARATOR
+        | '\u{2029}' // PARAGRAPH SEPARATOR
 
-        // Bidi markers
+        // `Default_Ignorable_Code_Point` characters
         | '\u{200E}' // LEFT-TO-RIGHT MARK
         | '\u{200F}' // RIGHT-TO-LEFT MARK
 
-        // Dedicated whitespace characters from Unicode
-        | '\u{2028}' // LINE SEPARATOR
-        | '\u{2029}' // PARAGRAPH SEPARATOR
+        // Horizontal space characters
+        | '\u{0009}'   // tab (\t)
+        | '\u{0020}' // space
+    )
+}
+
+/// True if `c` is considered horizontal whitespace according to Rust language definition.
+pub fn is_horizontal_whitespace(c: char) -> bool {
+    // This is Pattern_White_Space.
+    //
+    // Note that this set is stable (ie, it doesn't change with different
+    // Unicode versions), so it's ok to just hard-code the values.
+
+    matches!(
+        c,
+        // Horizontal space characters
+        '\u{0009}'   // tab (\t)
+        | '\u{0020}' // space
     )
 }
 
@@ -538,7 +551,7 @@ impl Cursor<'_> {
         debug_assert!(length_opening >= 3);
 
         // whitespace between the opening and the infostring.
-        self.eat_while(|ch| ch != '\n' && is_whitespace(ch));
+        self.eat_while(|ch| ch != '\n' && is_horizontal_whitespace(ch));
 
         // copied from `eat_identifier`, but allows `-` and `.` in infostring to allow something like
         // `---Cargo.toml` as a valid opener
@@ -547,7 +560,7 @@ impl Cursor<'_> {
             self.eat_while(|c| is_id_continue(c) || c == '-' || c == '.');
         }
 
-        self.eat_while(|ch| ch != '\n' && is_whitespace(ch));
+        self.eat_while(|ch| ch != '\n' && is_horizontal_whitespace(ch));
         let invalid_infostring = self.first() != '\n';
 
         let mut found = false;
@@ -588,7 +601,7 @@ impl Cursor<'_> {
                 // on a standalone line. Might be wrong.
                 while let Some(closing) = rest.find("---") {
                     let preceding_chars_start = rest[..closing].rfind("\n").map_or(0, |i| i + 1);
-                    if rest[preceding_chars_start..closing].chars().all(is_whitespace) {
+                    if rest[preceding_chars_start..closing].chars().all(is_horizontal_whitespace) {
                         // candidate found
                         potential_closing = Some(closing);
                         break;
diff --git a/compiler/rustc_parse/src/lexer/mod.rs b/compiler/rustc_parse/src/lexer/mod.rs
index 9792240a548..e3bd6a9a327 100644
--- a/compiler/rustc_parse/src/lexer/mod.rs
+++ b/compiler/rustc_parse/src/lexer/mod.rs
@@ -6,7 +6,7 @@ use rustc_ast::util::unicode::{TEXT_FLOW_CONTROL_CHARS, contains_text_flow_contr
 use rustc_errors::codes::*;
 use rustc_errors::{Applicability, Diag, DiagCtxtHandle, StashKey};
 use rustc_lexer::{
-    Base, Cursor, DocStyle, FrontmatterAllowed, LiteralKind, RawStrError, is_whitespace,
+    Base, Cursor, DocStyle, FrontmatterAllowed, LiteralKind, RawStrError, is_horizontal_whitespace,
 };
 use rustc_literal_escaper::{EscapeError, Mode, check_for_errors};
 use rustc_session::lint::BuiltinLintDiag;
@@ -597,7 +597,7 @@ impl<'psess, 'src> Lexer<'psess, 'src> {
 
         let last_line_start = within.rfind('\n').map_or(0, |i| i + 1);
         let last_line = &within[last_line_start..];
-        let last_line_trimmed = last_line.trim_start_matches(is_whitespace);
+        let last_line_trimmed = last_line.trim_start_matches(is_horizontal_whitespace);
         let last_line_start_pos = frontmatter_opening_end_pos + BytePos(last_line_start as u32);
 
         let frontmatter_span = self.mk_sp(frontmatter_opening_pos, self.pos);
@@ -640,7 +640,7 @@ impl<'psess, 'src> Lexer<'psess, 'src> {
             });
         }
 
-        if !rest.trim_matches(is_whitespace).is_empty() {
+        if !rest.trim_matches(is_horizontal_whitespace).is_empty() {
             let span = self.mk_sp(last_line_start_pos, self.pos);
             self.dcx().emit_err(errors::FrontmatterExtraCharactersAfterClose { span });
         }
diff --git a/compiler/rustc_resolve/src/ident.rs b/compiler/rustc_resolve/src/ident.rs
index dae42645bec..bc06a227571 100644
--- a/compiler/rustc_resolve/src/ident.rs
+++ b/compiler/rustc_resolve/src/ident.rs
@@ -422,6 +422,8 @@ impl<'ra, 'tcx> Resolver<'ra, 'tcx> {
         // to detect potential ambiguities.
         let mut innermost_result: Option<(NameBinding<'_>, Flags)> = None;
         let mut determinacy = Determinacy::Determined;
+        let mut extern_prelude_item_binding = None;
+        let mut extern_prelude_flag_binding = None;
         // Shadowed bindings don't need to be marked as used or non-speculatively loaded.
         macro finalize_scope() {
             if innermost_result.is_none() { finalize } else { None }
@@ -558,7 +560,10 @@ impl<'ra, 'tcx> Resolver<'ra, 'tcx> {
                     Scope::ExternPreludeItems => {
                         // FIXME: use `finalize_scope` here.
                         match this.reborrow().extern_prelude_get_item(ident, finalize.is_some()) {
-                            Some(binding) => Ok((binding, Flags::empty())),
+                            Some(binding) => {
+                                extern_prelude_item_binding = Some(binding);
+                                Ok((binding, Flags::empty()))
+                            }
                             None => Err(Determinacy::determined(
                                 this.graph_root.unexpanded_invocations.borrow().is_empty(),
                             )),
@@ -566,7 +571,10 @@ impl<'ra, 'tcx> Resolver<'ra, 'tcx> {
                     }
                     Scope::ExternPreludeFlags => {
                         match this.extern_prelude_get_flag(ident, finalize_scope!().is_some()) {
-                            Some(binding) => Ok((binding, Flags::empty())),
+                            Some(binding) => {
+                                extern_prelude_flag_binding = Some(binding);
+                                Ok((binding, Flags::empty()))
+                            }
                             None => Err(Determinacy::Determined),
                         }
                     }
@@ -686,7 +694,16 @@ impl<'ra, 'tcx> Resolver<'ra, 'tcx> {
                                 } else {
                                     None
                                 };
-                                if let Some(kind) = ambiguity_error_kind {
+                                // Skip ambiguity errors for extern flag bindings "overridden"
+                                // by extern item bindings.
+                                // FIXME: Remove with lang team approval.
+                                let issue_145575_hack = Some(binding)
+                                    == extern_prelude_flag_binding
+                                    && extern_prelude_item_binding.is_some()
+                                    && extern_prelude_item_binding != Some(innermost_binding);
+                                if let Some(kind) = ambiguity_error_kind
+                                    && !issue_145575_hack
+                                {
                                     let misc = |f: Flags| {
                                         if f.contains(Flags::MISC_SUGGEST_CRATE) {
                                             AmbiguityErrorMisc::SuggestCrate
diff --git a/compiler/rustc_target/src/spec/targets/loongarch64_unknown_none.rs b/compiler/rustc_target/src/spec/targets/loongarch64_unknown_none.rs
index 91e3064aaed..b6a08958284 100644
--- a/compiler/rustc_target/src/spec/targets/loongarch64_unknown_none.rs
+++ b/compiler/rustc_target/src/spec/targets/loongarch64_unknown_none.rs
@@ -17,7 +17,7 @@ pub(crate) fn target() -> Target {
         arch: "loongarch64".into(),
         options: TargetOptions {
             cpu: "generic".into(),
-            features: "+f,+d".into(),
+            features: "+f,+d,-lsx".into(),
             linker_flavor: LinkerFlavor::Gnu(Cc::No, Lld::Yes),
             linker: Some("rust-lld".into()),
             llvm_abiname: "lp64d".into(),