Auto merge of #136980 - cuviper:beta-next, r=cuviper

[beta] backports

- Pattern Migration 2024: try to suggest eliding redundant binding modifiers #136577, #136857
- chore: update rustc-hash 2.1.0 to 2.1.1 #136605
- Make `AsyncFnOnce`, `AsyncFnMut`, `AsyncFn` non-`#[fundamental]` #136724
- fix ensure_monomorphic_enough #136839
- Revert "Stabilize `extended_varargs_abi_support`" #136897, #136934

r? cuviper

Author: bors

Diff for: Cargo.lock

@@ -1983,7 +1983,7 @@ dependencies = [
  "anyhow",
  "clap",
  "fs-err",
- "rustc-hash 2.1.0",
+ "rustc-hash 2.1.1",
  "rustdoc-json-types",
  "serde",
  "serde_json",
@@ -3152,7 +3152,7 @@ dependencies = [
  "proc-macro2",
  "quote",
  "rinja_parser",
- "rustc-hash 2.1.0",
+ "rustc-hash 2.1.1",
  "serde",
  "syn 2.0.93",
 ]
@@ -3216,9 +3216,9 @@ checksum = "08d43f7aa6b08d49f382cde6a7982047c3426db949b1424bc4b7ec9ae12c6ce2"
 
 [[package]]
 name = "rustc-hash"
-version = "2.1.0"
+version = "2.1.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "c7fb8039b3032c191086b10f11f319a6e99e1e82889c5cc6046f515c9db1d497"
+checksum = "357703d41365b4b27c590e3ed91eabb1b663f07c4c084095e60cbed4362dff0d"
 
 [[package]]
 name = "rustc-main"
@@ -3620,7 +3620,7 @@ dependencies = [
  "memmap2",
  "parking_lot",
  "portable-atomic",
- "rustc-hash 2.1.0",
+ "rustc-hash 2.1.1",
  "rustc-rayon",
  "rustc-stable-hash",
  "rustc_arena",
@@ -4323,7 +4323,7 @@ dependencies = [
 name = "rustc_pattern_analysis"
 version = "0.0.0"
 dependencies = [
- "rustc-hash 2.1.0",
+ "rustc-hash 2.1.1",
  "rustc_abi",
  "rustc_apfloat",
  "rustc_arena",
@@ -4719,7 +4719,7 @@ name = "rustdoc-json-types"
 version = "0.1.0"
 dependencies = [
  "bincode",
- "rustc-hash 2.1.0",
+ "rustc-hash 2.1.1",
  "serde",
  "serde_json",
 ]
@@ -5363,7 +5363,7 @@ dependencies = [
  "ignore",
  "miropt-test-tools",
  "regex",
- "rustc-hash 2.1.0",
+ "rustc-hash 2.1.1",
  "semver",
  "similar",
  "termcolor",

Diff for: compiler/rustc_const_eval/src/interpret/util.rs

@@ -1,12 +1,8 @@
-use std::ops::ControlFlow;
-
 use rustc_hir::def_id::LocalDefId;
 use rustc_middle::mir;
 use rustc_middle::mir::interpret::{Allocation, InterpResult, Pointer};
 use rustc_middle::ty::layout::TyAndLayout;
-use rustc_middle::ty::{
-    self, Ty, TyCtxt, TypeSuperVisitable, TypeVisitable, TypeVisitableExt, TypeVisitor,
-};
+use rustc_middle::ty::{TyCtxt, TypeVisitable, TypeVisitableExt};
 use tracing::debug;
 
 use super::{InterpCx, MPlaceTy, MemoryKind, interp_ok, throw_inval};
@@ -20,44 +16,10 @@ where
     T: TypeVisitable<TyCtxt<'tcx>>,
 {
     debug!("ensure_monomorphic_enough: ty={:?}", ty);
-    if !ty.has_param() {
-        return interp_ok(());
-    }
-
-    struct FoundParam;
-    struct UsedParamsNeedInstantiationVisitor {}
-
-    impl<'tcx> TypeVisitor<TyCtxt<'tcx>> for UsedParamsNeedInstantiationVisitor {
-        type Result = ControlFlow<FoundParam>;
-
-        fn visit_ty(&mut self, ty: Ty<'tcx>) -> Self::Result {
-            if !ty.has_param() {
-                return ControlFlow::Continue(());
-            }
-
-            match *ty.kind() {
-                ty::Param(_) => ControlFlow::Break(FoundParam),
-                ty::Closure(..) | ty::CoroutineClosure(..) | ty::Coroutine(..) | ty::FnDef(..) => {
-                    ControlFlow::Continue(())
-                }
-                _ => ty.super_visit_with(self),
-            }
-        }
-
-        fn visit_const(&mut self, c: ty::Const<'tcx>) -> Self::Result {
-            match c.kind() {
-                ty::ConstKind::Param(..) => ControlFlow::Break(FoundParam),
-                _ => c.super_visit_with(self),
-            }
-        }
-    }
-
-    let mut vis = UsedParamsNeedInstantiationVisitor {};
-    if matches!(ty.visit_with(&mut vis), ControlFlow::Break(FoundParam)) {
+    if ty.has_param() {
         throw_inval!(TooGeneric);
-    } else {
-        interp_ok(())
     }
+    interp_ok(())
 }
 
 impl<'tcx> InterpretationResult<'tcx> for mir::interpret::ConstAllocation<'tcx> {

Diff for: compiler/rustc_feature/src/accepted.rs

@@ -197,9 +197,6 @@ declare_features! (
     (accepted, expr_fragment_specifier_2024, "1.83.0", Some(123742)),
     /// Allows arbitrary expressions in key-value attributes at parse time.
     (accepted, extended_key_value_attributes, "1.54.0", Some(78835)),
-    /// Allows using `efiapi`, `aapcs`, `sysv64` and `win64` as calling
-    /// convention for functions with varargs.
-    (accepted, extended_varargs_abi_support, "1.85.0", Some(100189)),
     /// Allows resolving absolute paths as paths from other crates.
     (accepted, extern_absolute_paths, "1.30.0", Some(44660)),
     /// Allows `extern crate foo as bar;`. This puts `bar` into extern prelude.

Diff for: compiler/rustc_feature/src/unstable.rs

@@ -479,6 +479,9 @@ declare_features! (
     (unstable, exhaustive_patterns, "1.13.0", Some(51085)),
     /// Allows explicit tail calls via `become` expression.
     (incomplete, explicit_tail_calls, "1.72.0", Some(112788)),
+    /// Allows using `efiapi`, `sysv64` and `win64` as calling convention
+    /// for functions with varargs.
+    (unstable, extended_varargs_abi_support, "1.65.0", Some(100189)),
     /// Allows defining `extern type`s.
     (unstable, extern_types, "1.23.0", Some(43467)),
     /// Allow using 128-bit (quad precision) floating point numbers.

Diff for: compiler/rustc_hir_analysis/messages.ftl

@@ -602,7 +602,7 @@ hir_analysis_value_of_associated_struct_already_specified =
     .label = re-bound here
     .previous_bound_label = `{$item_name}` bound here first
 
-hir_analysis_variadic_function_compatible_convention = C-variadic function must have a compatible calling convention, like `C`, `cdecl`, `system`, `aapcs`, `win64`, `sysv64` or `efiapi`
+hir_analysis_variadic_function_compatible_convention = C-variadic function must have a compatible calling convention, like {$conventions}
     .label = C-variadic function must have a compatible calling convention
 
 hir_analysis_variances_of = {$variances}

Diff for: compiler/rustc_hir_analysis/src/errors.rs

@@ -688,10 +688,11 @@ pub(crate) struct MainFunctionGenericParameters {
 
 #[derive(Diagnostic)]
 #[diag(hir_analysis_variadic_function_compatible_convention, code = E0045)]
-pub(crate) struct VariadicFunctionCompatibleConvention {
+pub(crate) struct VariadicFunctionCompatibleConvention<'a> {
     #[primary_span]
     #[label]
     pub span: Span,
+    pub conventions: &'a str,
 }
 
 #[derive(Diagnostic)]

Diff for: compiler/rustc_hir_analysis/src/lib.rs

@@ -100,6 +100,8 @@ use rustc_middle::middle;
 use rustc_middle::mir::interpret::GlobalId;
 use rustc_middle::query::Providers;
 use rustc_middle::ty::{self, Const, Ty, TyCtxt};
+use rustc_session::parse::feature_err;
+use rustc_span::symbol::sym;
 use rustc_span::Span;
 use rustc_trait_selection::traits;
 
@@ -113,9 +115,34 @@ fn require_c_abi_if_c_variadic(
     abi: ExternAbi,
     span: Span,
 ) {
-    if decl.c_variadic && !abi.supports_varargs() {
-        tcx.dcx().emit_err(errors::VariadicFunctionCompatibleConvention { span });
+    const CONVENTIONS_UNSTABLE: &str =
+        "`C`, `cdecl`, `system`, `aapcs`, `win64`, `sysv64` or `efiapi`";
+    const CONVENTIONS_STABLE: &str = "`C` or `cdecl`";
+    const UNSTABLE_EXPLAIN: &str =
+        "using calling conventions other than `C` or `cdecl` for varargs functions is unstable";
+
+    if !decl.c_variadic || matches!(abi, ExternAbi::C { .. } | ExternAbi::Cdecl { .. }) {
+        return;
     }
+
+    let extended_abi_support = tcx.features().extended_varargs_abi_support();
+    let conventions = match (extended_abi_support, abi.supports_varargs()) {
+        // User enabled additional ABI support for varargs and function ABI matches those ones.
+        (true, true) => return,
+
+        // Using this ABI would be ok, if the feature for additional ABI support was enabled.
+        // Return CONVENTIONS_STABLE, because we want the other error to look the same.
+        (false, true) => {
+            feature_err(&tcx.sess, sym::extended_varargs_abi_support, span, UNSTABLE_EXPLAIN)
+                .emit();
+            CONVENTIONS_STABLE
+        }
+
+        (false, false) => CONVENTIONS_STABLE,
+        (true, false) => CONVENTIONS_UNSTABLE,
+    };
+
+    tcx.dcx().emit_err(errors::VariadicFunctionCompatibleConvention { span, conventions });
 }
 
 pub fn provide(providers: &mut Providers) {

Diff for: compiler/rustc_hir_typeck/src/pat.rs

@@ -699,7 +699,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
 
         // Determine the binding mode...
         let bm = match user_bind_annot {
-            BindingMode(ByRef::No, Mutability::Mut) if matches!(def_br, ByRef::Yes(_)) => {
+            BindingMode(ByRef::No, Mutability::Mut) if let ByRef::Yes(def_br_mutbl) = def_br => {
                 if pat.span.at_least_rust_2024()
                     && (self.tcx.features().ref_pat_eat_one_layer_2024()
                         || self.tcx.features().ref_pat_eat_one_layer_2024_structural())
@@ -719,22 +719,22 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                     // `mut` resets the binding mode on edition <= 2021
                     self.add_rust_2024_migration_desugared_pat(
                         pat_info.top_info.hir_id,
-                        pat.span,
+                        pat,
                         ident.span,
-                        "requires binding by-value, but the implicit default is by-reference",
+                        def_br_mutbl,
                     );
                     BindingMode(ByRef::No, Mutability::Mut)
                 }
             }
             BindingMode(ByRef::No, mutbl) => BindingMode(def_br, mutbl),
             BindingMode(ByRef::Yes(_), _) => {
-                if matches!(def_br, ByRef::Yes(_)) {
+                if let ByRef::Yes(def_br_mutbl) = def_br {
                     // `ref`/`ref mut` overrides the binding mode on edition <= 2021
                     self.add_rust_2024_migration_desugared_pat(
                         pat_info.top_info.hir_id,
-                        pat.span,
+                        pat,
                         ident.span,
-                        "cannot override to bind by-reference when that is the implicit default",
+                        def_br_mutbl,
                     );
                 }
                 user_bind_annot
@@ -2263,13 +2263,13 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
             }
         } else {
             // Reset binding mode on old editions
-            if pat_info.binding_mode != ByRef::No {
+            if let ByRef::Yes(inh_mut) = pat_info.binding_mode {
                 pat_info.binding_mode = ByRef::No;
                 self.add_rust_2024_migration_desugared_pat(
                     pat_info.top_info.hir_id,
-                    pat.span,
+                    pat,
                     inner.span,
-                    "cannot implicitly match against multiple layers of reference",
+                    inh_mut,
                 )
             }
         }
@@ -2635,33 +2635,65 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
     fn add_rust_2024_migration_desugared_pat(
         &self,
         pat_id: HirId,
-        subpat_span: Span,
+        subpat: &'tcx Pat<'tcx>,
         cutoff_span: Span,
-        detailed_label: &str,
+        def_br_mutbl: Mutability,
     ) {
         // Try to trim the span we're labeling to just the `&` or binding mode that's an issue.
         // If the subpattern's span is is from an expansion, the emitted label will not be trimmed.
         let source_map = self.tcx.sess.source_map();
         let cutoff_span = source_map
-            .span_extend_prev_while(cutoff_span, char::is_whitespace)
+            .span_extend_prev_while(cutoff_span, |c| c.is_whitespace() || c == '(')
             .unwrap_or(cutoff_span);
-        // Ensure we use the syntax context and thus edition of `subpat_span`; this will be a hard
+        // Ensure we use the syntax context and thus edition of `subpat.span`; this will be a hard
         // error if the subpattern is of edition >= 2024.
-        let trimmed_span = subpat_span.until(cutoff_span).with_ctxt(subpat_span.ctxt());
+        let trimmed_span = subpat.span.until(cutoff_span).with_ctxt(subpat.span.ctxt());
+
+        let mut typeck_results = self.typeck_results.borrow_mut();
+        let mut table = typeck_results.rust_2024_migration_desugared_pats_mut();
+        // FIXME(ref_pat_eat_one_layer_2024): The migration diagnostic doesn't know how to track the
+        // default binding mode in the presence of Rule 3 or Rule 5. As a consequence, the labels it
+        // gives for default binding modes are wrong, as well as suggestions based on the default
+        // binding mode. This keeps it from making those suggestions, as doing so could panic.
+        let info = table.entry(pat_id).or_insert_with(|| ty::Rust2024IncompatiblePatInfo {
+            primary_labels: Vec::new(),
+            bad_modifiers: false,
+            bad_ref_pats: false,
+            suggest_eliding_modes: !self.tcx.features().ref_pat_eat_one_layer_2024()
+                && !self.tcx.features().ref_pat_eat_one_layer_2024_structural(),
+        });
 
         // Only provide a detailed label if the problematic subpattern isn't from an expansion.
         // In the case that it's from a macro, we'll add a more detailed note in the emitter.
-        let desc = if subpat_span.from_expansion() {
-            "default binding mode is reset within expansion"
+        let from_expansion = subpat.span.from_expansion();
+        let primary_label = if from_expansion {
+            // NB: This wording assumes the only expansions that can produce problematic reference
+            // patterns and bindings are macros. If a desugaring or AST pass is added that can do
+            // so, we may want to inspect the span's source callee or macro backtrace.
+            "occurs within macro expansion".to_owned()
         } else {
-            detailed_label
+            let pat_kind = if let PatKind::Binding(user_bind_annot, _, _, _) = subpat.kind {
+                info.bad_modifiers |= true;
+                // If the user-provided binding modifier doesn't match the default binding mode, we'll
+                // need to suggest reference patterns, which can affect other bindings.
+                // For simplicity, we opt to suggest making the pattern fully explicit.
+                info.suggest_eliding_modes &=
+                    user_bind_annot == BindingMode(ByRef::Yes(def_br_mutbl), Mutability::Not);
+                "binding modifier"
+            } else {
+                info.bad_ref_pats |= true;
+                // For simplicity, we don't try to suggest eliding reference patterns. Thus, we'll
+                // suggest adding them instead, which can affect the types assigned to bindings.
+                // As such, we opt to suggest making the pattern fully explicit.
+                info.suggest_eliding_modes = false;
+                "reference pattern"
+            };
+            let dbm_str = match def_br_mutbl {
+                Mutability::Not => "ref",
+                Mutability::Mut => "ref mut",
+            };
+            format!("{pat_kind} not allowed under `{dbm_str}` default binding mode")
         };
-
-        self.typeck_results
-            .borrow_mut()
-            .rust_2024_migration_desugared_pats_mut()
-            .entry(pat_id)
-            .or_default()
-            .push((trimmed_span, desc.to_owned()));
+        info.primary_labels.push((trimmed_span, primary_label));
     }
 }

Diff for: compiler/rustc_middle/src/ty/mod.rs

@@ -95,7 +95,7 @@ pub use self::sty::{
 pub use self::trait_def::TraitDef;
 pub use self::typeck_results::{
     CanonicalUserType, CanonicalUserTypeAnnotation, CanonicalUserTypeAnnotations, IsIdentity,
-    TypeckResults, UserType, UserTypeAnnotationIndex, UserTypeKind,
+    Rust2024IncompatiblePatInfo, TypeckResults, UserType, UserTypeAnnotationIndex, UserTypeKind,
 };
 pub use self::visit::{TypeSuperVisitable, TypeVisitable, TypeVisitableExt, TypeVisitor};
 use crate::error::{OpaqueHiddenTypeMismatch, TypeMismatchReason};