Rollup of 8 pull requests

compiler/rustc_ast_lowering/src/asm.rs

@@ -20,8 +20,8 @@ use super::errors::{
 };
 use super::LoweringContext;
 use crate::{
-    fluent_generated as fluent, ImplTraitContext, ImplTraitPosition, ParamMode,
-    ResolverAstLoweringExt,
+    fluent_generated as fluent, AllowReturnTypeNotation, ImplTraitContext, ImplTraitPosition,
+    ParamMode, ResolverAstLoweringExt,
 };
 
 impl<'a, 'hir> LoweringContext<'a, 'hir> {
@@ -201,6 +201,7 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
                                 &sym.qself,
                                 &sym.path,
                                 ParamMode::Optional,
+                                AllowReturnTypeNotation::No,
                                 ImplTraitContext::Disallowed(ImplTraitPosition::Path),
                                 None,
                             );

compiler/rustc_ast_lowering/src/delegation.rs

@@ -52,7 +52,7 @@ use rustc_target::spec::abi;
 use {rustc_ast as ast, rustc_hir as hir};
 
 use super::{GenericArgsMode, ImplTraitContext, LoweringContext, ParamMode};
-use crate::{ImplTraitPosition, ResolverAstLoweringExt};
+use crate::{AllowReturnTypeNotation, ImplTraitPosition, ResolverAstLoweringExt};
 
 pub(crate) struct DelegationResults<'hir> {
     pub body_id: hir::BodyId,
@@ -340,6 +340,7 @@ impl<'hir> LoweringContext<'_, 'hir> {
                 &delegation.qself,
                 &delegation.path,
                 ParamMode::Optional,
+                AllowReturnTypeNotation::No,
                 ImplTraitContext::Disallowed(ImplTraitPosition::Path),
                 None,
             );

compiler/rustc_ast_lowering/src/expr.rs

@@ -23,7 +23,7 @@ use super::{
     GenericArgsMode, ImplTraitContext, LoweringContext, ParamMode, ResolverAstLoweringExt,
 };
 use crate::errors::YieldInClosure;
-use crate::{fluent_generated, FnDeclKind, ImplTraitPosition};
+use crate::{fluent_generated, AllowReturnTypeNotation, FnDeclKind, ImplTraitPosition};
 
 impl<'hir> LoweringContext<'_, 'hir> {
     fn lower_exprs(&mut self, exprs: &[AstP<Expr>]) -> &'hir [hir::Expr<'hir>] {
@@ -281,6 +281,7 @@ impl<'hir> LoweringContext<'_, 'hir> {
                         qself,
                         path,
                         ParamMode::Optional,
+                        AllowReturnTypeNotation::No,
                         ImplTraitContext::Disallowed(ImplTraitPosition::Path),
                         None,
                     );
@@ -328,6 +329,7 @@ impl<'hir> LoweringContext<'_, 'hir> {
                             &se.qself,
                             &se.path,
                             ParamMode::Optional,
+                            AllowReturnTypeNotation::No,
                             ImplTraitContext::Disallowed(ImplTraitPosition::Path),
                             None,
                         )),
@@ -1291,6 +1293,7 @@ impl<'hir> LoweringContext<'_, 'hir> {
                         qself,
                         path,
                         ParamMode::Optional,
+                        AllowReturnTypeNotation::No,
                         ImplTraitContext::Disallowed(ImplTraitPosition::Path),
                         None,
                     );
@@ -1311,6 +1314,7 @@ impl<'hir> LoweringContext<'_, 'hir> {
                         qself,
                         path,
                         ParamMode::Optional,
+                        AllowReturnTypeNotation::No,
                         ImplTraitContext::Disallowed(ImplTraitPosition::Path),
                         None,
                     );
@@ -1336,6 +1340,7 @@ impl<'hir> LoweringContext<'_, 'hir> {
                     &se.qself,
                     &se.path,
                     ParamMode::Optional,
+                    AllowReturnTypeNotation::No,
                     ImplTraitContext::Disallowed(ImplTraitPosition::Path),
                     None,
                 );

compiler/rustc_ast_lowering/src/lib.rs

@@ -485,9 +485,23 @@ enum ParamMode {
     Optional,
 }
 
+#[derive(Copy, Clone, Debug)]
+enum AllowReturnTypeNotation {
+    /// Only in types, since RTN is denied later during HIR lowering.
+    Yes,
+    /// All other positions (path expr, method, use tree).
+    No,
+}
+
 enum GenericArgsMode {
+    /// Allow paren sugar, don't allow RTN.
     ParenSugar,
+    /// Allow RTN, don't allow paren sugar.
+    ReturnTypeNotation,
+    // Error if parenthesized generics or RTN are encountered.
     Err,
+    /// Silence errors when lowering generics. Only used with `Res::Err`.
+    Silence,
 }
 
 impl<'a, 'hir> LoweringContext<'a, 'hir> {
@@ -1226,7 +1240,15 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
         }
 
         let id = self.lower_node_id(t.id);
-        let qpath = self.lower_qpath(t.id, qself, path, param_mode, itctx, None);
+        let qpath = self.lower_qpath(
+            t.id,
+            qself,
+            path,
+            param_mode,
+            AllowReturnTypeNotation::Yes,
+            itctx,
+            None,
+        );
         self.ty_path(id, t.span, qpath)
     }
 
@@ -2203,6 +2225,7 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
             &None,
             &p.path,
             ParamMode::Explicit,
+            AllowReturnTypeNotation::No,
             itctx,
             Some(modifiers),
         ) {
@@ -2341,6 +2364,7 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
                     &None,
                     path,
                     ParamMode::Optional,
+                    AllowReturnTypeNotation::No,
                     ImplTraitContext::Disallowed(ImplTraitPosition::Path),
                     None,
                 );
@@ -2419,6 +2443,7 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
                 qself,
                 path,
                 ParamMode::Optional,
+                AllowReturnTypeNotation::No,
                 ImplTraitContext::Disallowed(ImplTraitPosition::Path),
                 None,
             );

compiler/rustc_ast_lowering/src/pat.rs

@@ -11,7 +11,7 @@ use super::errors::{
     ArbitraryExpressionInPattern, ExtraDoubleDot, MisplacedDoubleDot, SubTupleBinding,
 };
 use super::{ImplTraitContext, LoweringContext, ParamMode, ResolverAstLoweringExt};
-use crate::ImplTraitPosition;
+use crate::{AllowReturnTypeNotation, ImplTraitPosition};
 
 impl<'a, 'hir> LoweringContext<'a, 'hir> {
     pub(crate) fn lower_pat(&mut self, pattern: &Pat) -> &'hir hir::Pat<'hir> {
@@ -38,6 +38,7 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
                             qself,
                             path,
                             ParamMode::Optional,
+                            AllowReturnTypeNotation::No,
                             ImplTraitContext::Disallowed(ImplTraitPosition::Path),
                             None,
                         );
@@ -55,6 +56,7 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
                             qself,
                             path,
                             ParamMode::Optional,
+                            AllowReturnTypeNotation::No,
                             ImplTraitContext::Disallowed(ImplTraitPosition::Path),
                             None,
                         );
@@ -66,6 +68,7 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
                             qself,
                             path,
                             ParamMode::Optional,
+                            AllowReturnTypeNotation::No,
                             ImplTraitContext::Disallowed(ImplTraitPosition::Path),
                             None,
                         );

compiler/rustc_ast_lowering/src/path.rs

@@ -5,6 +5,7 @@ use rustc_hir::def::{DefKind, PartialRes, Res};
 use rustc_hir::def_id::DefId;
 use rustc_hir::GenericArg;
 use rustc_middle::span_bug;
+use rustc_session::parse::add_feature_diagnostics;
 use rustc_span::symbol::{kw, sym, Ident};
 use rustc_span::{BytePos, DesugaringKind, Span, Symbol, DUMMY_SP};
 use smallvec::{smallvec, SmallVec};
@@ -15,10 +16,9 @@ use super::errors::{
     GenericTypeWithParentheses, UseAngleBrackets,
 };
 use super::{
-    GenericArgsCtor, GenericArgsMode, ImplTraitContext, LifetimeRes, LoweringContext, ParamMode,
-    ResolverAstLoweringExt,
+    AllowReturnTypeNotation, GenericArgsCtor, GenericArgsMode, ImplTraitContext, ImplTraitPosition,
+    LifetimeRes, LoweringContext, ParamMode, ResolverAstLoweringExt,
 };
-use crate::ImplTraitPosition;
 
 impl<'a, 'hir> LoweringContext<'a, 'hir> {
     #[instrument(level = "trace", skip(self))]
@@ -28,6 +28,7 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
         qself: &Option<ptr::P<QSelf>>,
         p: &Path,
         param_mode: ParamMode,
+        allow_return_type_notation: AllowReturnTypeNotation,
         itctx: ImplTraitContext,
         // modifiers of the impl/bound if this is a trait path
         modifiers: Option<ast::TraitBoundModifiers>,
@@ -103,8 +104,14 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
                         {
                             GenericArgsMode::ParenSugar
                         }
+                        Res::Def(DefKind::AssocFn, _) if i + 1 == proj_start => {
+                            match allow_return_type_notation {
+                                AllowReturnTypeNotation::Yes => GenericArgsMode::ReturnTypeNotation,
+                                AllowReturnTypeNotation::No => GenericArgsMode::Err,
+                            }
+                        }
                         // Avoid duplicated errors.
-                        Res::Err => GenericArgsMode::ParenSugar,
+                        Res::Err => GenericArgsMode::Silence,
                         // An error
                         _ => GenericArgsMode::Err,
                     };
@@ -164,11 +171,20 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
         //   3. `<<std::vec::Vec<T>>::IntoIter>::Item`
         // * final path is `<<<std::vec::Vec<T>>::IntoIter>::Item>::clone`
         for (i, segment) in p.segments.iter().enumerate().skip(proj_start) {
+            // If this is a type-dependent `T::method(..)`.
+            let generic_args_mode = if i + 1 == p.segments.len()
+                && matches!(allow_return_type_notation, AllowReturnTypeNotation::Yes)
+            {
+                GenericArgsMode::ReturnTypeNotation
+            } else {
+                GenericArgsMode::Err
+            };
+
             let hir_segment = self.arena.alloc(self.lower_path_segment(
                 p.span,
                 segment,
                 param_mode,
-                GenericArgsMode::Err,
+                generic_args_mode,
                 itctx,
                 None,
             ));
@@ -238,11 +254,46 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
                     self.lower_angle_bracketed_parameter_data(data, param_mode, itctx)
                 }
                 GenericArgs::Parenthesized(data) => match generic_args_mode {
-                    GenericArgsMode::ParenSugar => self.lower_parenthesized_parameter_data(
-                        data,
-                        itctx,
-                        bound_modifier_allowed_features,
-                    ),
+                    GenericArgsMode::ReturnTypeNotation => {
+                        let mut err = if !data.inputs.is_empty() {
+                            self.dcx().create_err(BadReturnTypeNotation::Inputs {
+                                span: data.inputs_span,
+                            })
+                        } else if let FnRetTy::Ty(ty) = &data.output {
+                            self.dcx().create_err(BadReturnTypeNotation::Output {
+                                span: data.inputs_span.shrink_to_hi().to(ty.span),
+                            })
+                        } else {
+                            self.dcx().create_err(BadReturnTypeNotation::NeedsDots {
+                                span: data.inputs_span,
+                            })
+                        };
+                        if !self.tcx.features().return_type_notation
+                            && self.tcx.sess.is_nightly_build()
+                        {
+                            add_feature_diagnostics(
+                                &mut err,
+                                &self.tcx.sess,
+                                sym::return_type_notation,
+                            );
+                        }
+                        err.emit();
+                        (
+                            GenericArgsCtor {
+                                args: Default::default(),
+                                constraints: &[],
+                                parenthesized: hir::GenericArgsParentheses::ReturnTypeNotation,
+                                span: path_span,
+                            },
+                            false,
+                        )
+                    }
+                    GenericArgsMode::ParenSugar | GenericArgsMode::Silence => self
+                        .lower_parenthesized_parameter_data(
+                            data,
+                            itctx,
+                            bound_modifier_allowed_features,
+                        ),
                     GenericArgsMode::Err => {
                         // Suggest replacing parentheses with angle brackets `Trait(params...)` to `Trait<params...>`
                         let sub = if !data.inputs.is_empty() {
@@ -279,7 +330,14 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
                     }
                 },
                 GenericArgs::ParenthesizedElided(span) => {
-                    self.dcx().emit_err(BadReturnTypeNotation::Position { span: *span });
+                    match generic_args_mode {
+                        GenericArgsMode::ReturnTypeNotation | GenericArgsMode::Silence => {
+                            // Ok
+                        }
+                        GenericArgsMode::ParenSugar | GenericArgsMode::Err => {
+                            self.dcx().emit_err(BadReturnTypeNotation::Position { span: *span });
+                        }
+                    }
                     (
                         GenericArgsCtor {
                             args: Default::default(),

compiler/rustc_codegen_cranelift/src/abi/mod.rs

@@ -61,6 +61,9 @@ pub(crate) fn conv_to_call_conv(sess: &Session, c: Conv, default_call_conv: Call
         Conv::CCmseNonSecureCall => {
             sess.dcx().fatal("C-cmse-nonsecure-call call conv is not yet implemented");
         }
+        Conv::CCmseNonSecureEntry => {
+            sess.dcx().fatal("C-cmse-nonsecure-entry call conv is not yet implemented");
+        }
 
         Conv::Msp430Intr | Conv::PtxKernel | Conv::AvrInterrupt | Conv::AvrNonBlockingInterrupt => {
             unreachable!("tried to use {c:?} call conv which only exists on an unsupported target");

compiler/rustc_codegen_llvm/src/abi.rs

@@ -422,6 +422,9 @@ impl<'ll, 'tcx> FnAbiLlvmExt<'ll, 'tcx> for FnAbi<'tcx, Ty<'tcx>> {
         if let Conv::RiscvInterrupt { kind } = self.conv {
             func_attrs.push(llvm::CreateAttrStringValue(cx.llcx, "interrupt", kind.as_str()));
         }
+        if let Conv::CCmseNonSecureEntry = self.conv {
+            func_attrs.push(llvm::CreateAttrString(cx.llcx, "cmse_nonsecure_entry"))
+        }
         attributes::apply_to_llfn(llfn, llvm::AttributePlace::Function, &{ func_attrs });
 
         let mut i = 0;
@@ -659,9 +662,11 @@ impl<'tcx> AbiBuilderMethods<'tcx> for Builder<'_, '_, 'tcx> {
 impl From<Conv> for llvm::CallConv {
     fn from(conv: Conv) -> Self {
         match conv {
-            Conv::C | Conv::Rust | Conv::CCmseNonSecureCall | Conv::RiscvInterrupt { .. } => {
-                llvm::CCallConv
-            }
+            Conv::C
+            | Conv::Rust
+            | Conv::CCmseNonSecureCall
+            | Conv::CCmseNonSecureEntry
+            | Conv::RiscvInterrupt { .. } => llvm::CCallConv,
             Conv::Cold => llvm::ColdCallConv,
             Conv::PreserveMost => llvm::PreserveMost,
             Conv::PreserveAll => llvm::PreserveAll,

compiler/rustc_codegen_llvm/src/attributes.rs

@@ -483,9 +483,6 @@ pub(crate) fn llfn_attrs_from_instance<'ll, 'tcx>(
         let allocated_pointer = AttributeKind::AllocatedPointer.create_attr(cx.llcx);
         attributes::apply_to_llfn(llfn, AttributePlace::Argument(0), &[allocated_pointer]);
     }
-    if codegen_fn_attrs.flags.contains(CodegenFnAttrFlags::CMSE_NONSECURE_ENTRY) {
-        to_add.push(llvm::CreateAttrString(cx.llcx, "cmse_nonsecure_entry"));
-    }
     if let Some(align) = codegen_fn_attrs.alignment {
         llvm::set_alignment(llfn, align);
     }

compiler/rustc_codegen_ssa/src/codegen_attrs.rs

@@ -195,24 +195,6 @@ fn codegen_fn_attrs(tcx: TyCtxt<'_>, did: LocalDefId) -> CodegenFnAttrs {
                     }
                 }
             }
-            sym::cmse_nonsecure_entry => {
-                if let Some(fn_sig) = fn_sig()
-                    && !matches!(fn_sig.skip_binder().abi(), abi::Abi::C { .. })
-                {
-                    struct_span_code_err!(
-                        tcx.dcx(),
-                        attr.span,
-                        E0776,
-                        "`#[cmse_nonsecure_entry]` requires C ABI"
-                    )
-                    .emit();
-                }
-                if !tcx.sess.target.llvm_target.contains("thumbv8m") {
-                    struct_span_code_err!(tcx.dcx(), attr.span, E0775, "`#[cmse_nonsecure_entry]` is only valid for targets with the TrustZone-M extension")
-                    .emit();
-                }
-                codegen_fn_attrs.flags |= CodegenFnAttrFlags::CMSE_NONSECURE_ENTRY
-            }
             sym::thread_local => codegen_fn_attrs.flags |= CodegenFnAttrFlags::THREAD_LOCAL,
             sym::track_caller => {
                 let is_closure = tcx.is_closure_like(did.to_def_id());