Auto merge of #138523 - fmease:rollup-j2j5h59, r=fmease

Rollup of 9 pull requests

Successful merges:

 - #138056 (rustc_target: Add target features for LoongArch v1.1)
 - #138451 (Build GCC on CI with GCC, not Clang)
 - #138454 (Improve post-merge workflow)
 - #138460 (Pass struct field HirId when check_expr_struct_fields)
 - #138474 (Refactor is_snake_case.)
 - #138482 (Fix HIR printing of parameters)
 - #138507 (Mirror NetBSD sources)
 - #138511 (Make `Parser::parse_expr_cond` public)
 - #138518 (Fix typo in hir lowering lint diag)

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

11 files changed, 63 insertions, 41 deletions

diff --git a/compiler/rustc_ast_lowering/src/lib.rs b/compiler/rustc_ast_lowering/src/lib.rs
index c7d37e2704d..df671cf4b86 100644
--- a/compiler/rustc_ast_lowering/src/lib.rs
+++ b/compiler/rustc_ast_lowering/src/lib.rs
@@ -1516,7 +1516,14 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
     fn lower_fn_params_to_names(&mut self, decl: &FnDecl) -> &'hir [Ident] {
         self.arena.alloc_from_iter(decl.inputs.iter().map(|param| match param.pat.kind {
             PatKind::Ident(_, ident, _) => self.lower_ident(ident),
-            _ => Ident::new(kw::Empty, self.lower_span(param.pat.span)),
+            PatKind::Wild => Ident::new(kw::Underscore, self.lower_span(param.pat.span)),
+            _ => {
+                self.dcx().span_delayed_bug(
+                    param.pat.span,
+                    "non-ident/wild param pat must trigger an error",
+                );
+                Ident::new(kw::Empty, self.lower_span(param.pat.span))
+            }
         }))
     }
 
diff --git a/compiler/rustc_hir_analysis/src/hir_ty_lowering/lint.rs b/compiler/rustc_hir_analysis/src/hir_ty_lowering/lint.rs
index e78801dd601..be726c042da 100644
--- a/compiler/rustc_hir_analysis/src/hir_ty_lowering/lint.rs
+++ b/compiler/rustc_hir_analysis/src/hir_ty_lowering/lint.rs
@@ -411,14 +411,16 @@ impl<'tcx> dyn HirTyLowerer<'tcx> + '_ {
                 Applicability::MachineApplicable,
             );
             if !is_dyn_compatible {
-                diag.note(format!("`{trait_name}` it is dyn-incompatible, so it can't be `dyn`"));
+                diag.note(format!(
+                    "`{trait_name}` is dyn-incompatible, otherwise a trait object could be used"
+                ));
             } else {
                 // No ampersand in suggestion if it's borrowed already
                 let (dyn_str, paren_dyn_str) =
                     if borrowed { ("dyn ", "(dyn ") } else { ("&dyn ", "&(dyn ") };
 
                 let sugg = if let hir::TyKind::TraitObject([_, _, ..], _) = self_ty.kind {
-                    // There are more than one trait bound, we need surrounding parentheses.
+                    // There is more than one trait bound, we need surrounding parentheses.
                     vec![
                         (self_ty.span.shrink_to_lo(), paren_dyn_str.to_string()),
                         (self_ty.span.shrink_to_hi(), ")".to_string()),
diff --git a/compiler/rustc_hir_pretty/src/lib.rs b/compiler/rustc_hir_pretty/src/lib.rs
index 3067766fb4d..1409310339a 100644
--- a/compiler/rustc_hir_pretty/src/lib.rs
+++ b/compiler/rustc_hir_pretty/src/lib.rs
@@ -2148,9 +2148,11 @@ impl<'a> State<'a> {
                 s.print_implicit_self(&decl.implicit_self);
             } else {
                 if let Some(arg_name) = arg_names.get(i) {
-                    s.word(arg_name.to_string());
-                    s.word(":");
-                    s.space();
+                    if arg_name.name != kw::Empty {
+                        s.word(arg_name.to_string());
+                        s.word(":");
+                        s.space();
+                    }
                 } else if let Some(body_id) = body_id {
                     s.ann.nested(s, Nested::BodyParamPat(body_id, i));
                     s.word(":");
diff --git a/compiler/rustc_hir_typeck/src/expr.rs b/compiler/rustc_hir_typeck/src/expr.rs
index 7c6bb495be3..7e8e4e3a561 100644
--- a/compiler/rustc_hir_typeck/src/expr.rs
+++ b/compiler/rustc_hir_typeck/src/expr.rs
@@ -2060,7 +2060,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                 // struct-like enums (yet...), but it's definitely not
                 // a bug to have constructed one.
                 if adt_kind != AdtKind::Enum {
-                    tcx.check_stability(v_field.did, Some(expr.hir_id), field.span, None);
+                    tcx.check_stability(v_field.did, Some(field.hir_id), field.span, None);
                 }
 
                 self.field_ty(field.span, v_field, args)
diff --git a/compiler/rustc_hir_typeck/src/fn_ctxt/checks.rs b/compiler/rustc_hir_typeck/src/fn_ctxt/checks.rs
index b8517701667..96d0a0fc6de 100644
--- a/compiler/rustc_hir_typeck/src/fn_ctxt/checks.rs
+++ b/compiler/rustc_hir_typeck/src/fn_ctxt/checks.rs
@@ -19,7 +19,7 @@ use rustc_middle::ty::visit::TypeVisitableExt;
 use rustc_middle::ty::{self, IsSuggestable, Ty, TyCtxt};
 use rustc_middle::{bug, span_bug};
 use rustc_session::Session;
-use rustc_span::{DUMMY_SP, Ident, Span, Symbol, kw, sym};
+use rustc_span::{DUMMY_SP, Ident, Span, kw, sym};
 use rustc_trait_selection::error_reporting::infer::{FailureCode, ObligationCauseExt};
 use rustc_trait_selection::infer::InferCtxtExt;
 use rustc_trait_selection::traits::{self, ObligationCauseCode, ObligationCtxt, SelectionContext};
@@ -2679,7 +2679,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                     params.get(is_method as usize..params.len() - sig.decl.c_variadic as usize)?;
                 debug_assert_eq!(params.len(), fn_inputs.len());
                 Some((
-                    fn_inputs.zip(params.iter().map(|param| FnParam::Name(param))).collect(),
+                    fn_inputs.zip(params.iter().map(|&param| FnParam::Name(param))).collect(),
                     generics,
                 ))
             }
@@ -2710,23 +2710,14 @@ impl<'tcx> Visitor<'tcx> for FindClosureArg<'tcx> {
 #[derive(Clone, Copy)]
 enum FnParam<'hir> {
     Param(&'hir hir::Param<'hir>),
-    Name(&'hir Ident),
+    Name(Ident),
 }
+
 impl FnParam<'_> {
     fn span(&self) -> Span {
         match self {
-            Self::Param(x) => x.span,
-            Self::Name(x) => x.span,
-        }
-    }
-
-    fn name(&self) -> Option<Symbol> {
-        match self {
-            Self::Param(x) if let hir::PatKind::Binding(_, _, ident, _) = x.pat.kind => {
-                Some(ident.name)
-            }
-            Self::Name(x) if x.name != kw::Empty => Some(x.name),
-            _ => None,
+            Self::Param(param) => param.span,
+            Self::Name(ident) => ident.span,
         }
     }
 
@@ -2734,8 +2725,23 @@ impl FnParam<'_> {
         struct D<'a>(FnParam<'a>, usize);
         impl fmt::Display for D<'_> {
             fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
-                if let Some(name) = self.0.name() {
-                    write!(f, "`{name}`")
+                // A "unique" param name is one that (a) exists, and (b) is guaranteed to be unique
+                // among the parameters, i.e. `_` does not count.
+                let unique_name = match self.0 {
+                    FnParam::Param(param)
+                        if let hir::PatKind::Binding(_, _, ident, _) = param.pat.kind =>
+                    {
+                        Some(ident.name)
+                    }
+                    FnParam::Name(ident)
+                        if ident.name != kw::Empty && ident.name != kw::Underscore =>
+                    {
+                        Some(ident.name)
+                    }
+                    _ => None,
+                };
+                if let Some(unique_name) = unique_name {
+                    write!(f, "`{unique_name}`")
                 } else {
                     write!(f, "parameter #{}", self.1 + 1)
                 }
diff --git a/compiler/rustc_hir_typeck/src/pat.rs b/compiler/rustc_hir_typeck/src/pat.rs
index 7e6973259fe..3d1c61a9c34 100644
--- a/compiler/rustc_hir_typeck/src/pat.rs
+++ b/compiler/rustc_hir_typeck/src/pat.rs
@@ -1422,7 +1422,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
 
                 self.tcx.check_stability(
                     variant.fields[FieldIdx::from_usize(i)].did,
-                    Some(pat.hir_id),
+                    Some(subpat.hir_id),
                     subpat.span,
                     None,
                 );
@@ -1686,7 +1686,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                         .get(&ident)
                         .map(|(i, f)| {
                             self.write_field_index(field.hir_id, *i);
-                            self.tcx.check_stability(f.did, Some(pat.hir_id), span, None);
+                            self.tcx.check_stability(f.did, Some(field.hir_id), span, None);
                             self.field_ty(span, f, args)
                         })
                         .unwrap_or_else(|| {
diff --git a/compiler/rustc_lint/src/nonstandard_style.rs b/compiler/rustc_lint/src/nonstandard_style.rs
index 722779d3268..9e4fdd2b3ce 100644
--- a/compiler/rustc_lint/src/nonstandard_style.rs
+++ b/compiler/rustc_lint/src/nonstandard_style.rs
@@ -274,18 +274,13 @@ impl NonSnakeCase {
             let ident = ident.trim_start_matches('\'');
             let ident = ident.trim_matches('_');
 
-            let mut allow_underscore = true;
-            ident.chars().all(|c| {
-                allow_underscore = match c {
-                    '_' if !allow_underscore => return false,
-                    '_' => false,
-                    // It would be more obvious to use `c.is_lowercase()`,
-                    // but some characters do not have a lowercase form
-                    c if !c.is_uppercase() => true,
-                    _ => return false,
-                };
-                true
-            })
+            if ident.contains("__") {
+                return false;
+            }
+
+            // This correctly handles letters in languages with and without
+            // cases, as well as numbers and underscores.
+            !ident.chars().any(char::is_uppercase)
         }
 
         let name = ident.name.as_str();
diff --git a/compiler/rustc_middle/src/hir/map.rs b/compiler/rustc_middle/src/hir/map.rs
index 73c0af84a9f..c61c7a4fb02 100644
--- a/compiler/rustc_middle/src/hir/map.rs
+++ b/compiler/rustc_middle/src/hir/map.rs
@@ -281,8 +281,9 @@ impl<'tcx> TyCtxt<'tcx> {
     }
 
     pub fn hir_body_param_names(self, id: BodyId) -> impl Iterator<Item = Ident> {
-        self.hir_body(id).params.iter().map(|arg| match arg.pat.kind {
+        self.hir_body(id).params.iter().map(|param| match param.pat.kind {
             PatKind::Binding(_, _, ident, _) => ident,
+            PatKind::Wild => Ident::new(kw::Underscore, param.pat.span),
             _ => Ident::empty(),
         })
     }
diff --git a/compiler/rustc_parse/src/parser/expr.rs b/compiler/rustc_parse/src/parser/expr.rs
index 9b2d562a69e..0774324eae7 100644
--- a/compiler/rustc_parse/src/parser/expr.rs
+++ b/compiler/rustc_parse/src/parser/expr.rs
@@ -2588,7 +2588,8 @@ impl<'a> Parser<'a> {
     }
 
     /// Parses the condition of a `if` or `while` expression.
-    fn parse_expr_cond(&mut self) -> PResult<'a, P<Expr>> {
+    // Public because it is used in rustfmt forks such as https://github.com/tucant/rustfmt/blob/30c83df9e1db10007bdd16dafce8a86b404329b2/src/parse/macros/html.rs#L57 for custom if expressions.
+    pub fn parse_expr_cond(&mut self) -> PResult<'a, P<Expr>> {
         let attrs = self.parse_outer_attributes()?;
         let (mut cond, _) =
             self.parse_expr_res(Restrictions::NO_STRUCT_LITERAL | Restrictions::ALLOW_LET, attrs)?;
diff --git a/compiler/rustc_target/src/target_features.rs b/compiler/rustc_target/src/target_features.rs
index 6d3b6608ea2..a32b42a6fe3 100644
--- a/compiler/rustc_target/src/target_features.rs
+++ b/compiler/rustc_target/src/target_features.rs
@@ -603,13 +603,18 @@ static CSKY_FEATURES: &[(&str, Stability, ImpliedFeatures)] = &[
 static LOONGARCH_FEATURES: &[(&str, Stability, ImpliedFeatures)] = &[
     // tidy-alphabetical-start
     ("d", Unstable(sym::loongarch_target_feature), &["f"]),
+    ("div32", Unstable(sym::loongarch_target_feature), &[]),
     ("f", Unstable(sym::loongarch_target_feature), &[]),
     ("frecipe", Unstable(sym::loongarch_target_feature), &[]),
+    ("lam-bh", Unstable(sym::loongarch_target_feature), &[]),
+    ("lamcas", Unstable(sym::loongarch_target_feature), &[]),
     ("lasx", Unstable(sym::loongarch_target_feature), &["lsx"]),
     ("lbt", Unstable(sym::loongarch_target_feature), &[]),
+    ("ld-seq-sa", Unstable(sym::loongarch_target_feature), &[]),
     ("lsx", Unstable(sym::loongarch_target_feature), &["d"]),
     ("lvz", Unstable(sym::loongarch_target_feature), &[]),
     ("relax", Unstable(sym::loongarch_target_feature), &[]),
+    ("scq", Unstable(sym::loongarch_target_feature), &[]),
     ("ual", Unstable(sym::loongarch_target_feature), &[]),
     // tidy-alphabetical-end
 ];
diff --git a/compiler/rustc_trait_selection/src/error_reporting/traits/suggestions.rs b/compiler/rustc_trait_selection/src/error_reporting/traits/suggestions.rs
index dce85b43df1..9383b82ff3c 100644
--- a/compiler/rustc_trait_selection/src/error_reporting/traits/suggestions.rs
+++ b/compiler/rustc_trait_selection/src/error_reporting/traits/suggestions.rs
@@ -1998,7 +1998,10 @@ impl<'a, 'tcx> TypeErrCtxt<'a, 'tcx> {
                 .iter()
                 .enumerate()
                 .map(|(i, ident)| {
-                    if ident.name.is_empty() || ident.name == kw::SelfLower {
+                    if ident.name.is_empty()
+                        || ident.name == kw::Underscore
+                        || ident.name == kw::SelfLower
+                    {
                         format!("arg{i}")
                     } else {
                         format!("{ident}")