Auto merge of rust-lang#119243 - matthiaskrgr:rollup-xszboqi, r=matthiaskrgr

Rollup of 2 pull requests

Successful merges:

 - rust-lang#119072 (Clean up `check_consts` and misc fixes)
 - rust-lang#119231 (Clairify `ast::PatKind::Struct` presese of `..` by using an enum instead of a bool)

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

Author: bors

compiler/rustc_ast/src/ast.rs

@@ -754,8 +754,7 @@ pub enum PatKind {
     Ident(BindingAnnotation, Ident, Option<P<Pat>>),
 
     /// A struct or struct variant pattern (e.g., `Variant {x, y, ..}`).
-    /// The `bool` is `true` in the presence of a `..`.
-    Struct(Option<P<QSelf>>, Path, ThinVec<PatField>, /* recovered */ bool),
+    Struct(Option<P<QSelf>>, Path, ThinVec<PatField>, PatFieldsRest),
 
     /// A tuple struct/variant pattern (`Variant(x, y, .., z)`).
     TupleStruct(Option<P<QSelf>>, Path, ThinVec<P<Pat>>),
@@ -812,6 +811,15 @@ pub enum PatKind {
     MacCall(P<MacCall>),
 }
 
+/// Whether the `..` is present in a struct fields pattern.
+#[derive(Clone, Copy, Encodable, Decodable, Debug, PartialEq)]
+pub enum PatFieldsRest {
+    /// `module::StructName { field, ..}`
+    Rest,
+    /// `module::StructName { field }`
+    None,
+}
+
 /// The kind of borrow in an `AddrOf` expression,
 /// e.g., `&place` or `&raw const place`.
 #[derive(Clone, Copy, PartialEq, Eq, Debug)]

compiler/rustc_ast_lowering/src/pat.rs

@@ -82,7 +82,7 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
                                 span: self.lower_span(f.span),
                             }
                         }));
-                        break hir::PatKind::Struct(qpath, fs, *etc);
+                        break hir::PatKind::Struct(qpath, fs, *etc == ast::PatFieldsRest::Rest);
                     }
                     PatKind::Tuple(pats) => {
                         let (pats, ddpos) = self.lower_pat_tuple(pats, "tuple");

compiler/rustc_ast_pretty/src/pprust/state.rs

@@ -1427,7 +1427,7 @@ impl<'a> State<'a> {
                 }
                 self.nbsp();
                 self.word("{");
-                let empty = fields.is_empty() && !etc;
+                let empty = fields.is_empty() && *etc == ast::PatFieldsRest::None;
                 if !empty {
                     self.space();
                 }
@@ -1445,7 +1445,7 @@ impl<'a> State<'a> {
                     },
                     |f| f.pat.span,
                 );
-                if *etc {
+                if *etc == ast::PatFieldsRest::Rest {
                     if !fields.is_empty() {
                         self.word_space(",");
                     }

compiler/rustc_const_eval/src/transform/check_consts/check.rs

@@ -5,17 +5,15 @@ use rustc_hir as hir;
 use rustc_hir::def_id::DefId;
 use rustc_index::bit_set::BitSet;
 use rustc_infer::infer::TyCtxtInferExt;
-use rustc_infer::traits::{ImplSource, Obligation, ObligationCause};
+use rustc_infer::traits::ObligationCause;
 use rustc_middle::mir::visit::{MutatingUseContext, NonMutatingUseContext, PlaceContext, Visitor};
 use rustc_middle::mir::*;
-use rustc_middle::traits::BuiltinImplSource;
-use rustc_middle::ty::GenericArgs;
-use rustc_middle::ty::{self, adjustment::PointerCoercion, Instance, InstanceDef, Ty, TyCtxt};
-use rustc_middle::ty::{TraitRef, TypeVisitableExt};
+use rustc_middle::ty::{self, adjustment::PointerCoercion, Ty, TyCtxt};
+use rustc_middle::ty::{Instance, InstanceDef, TypeVisitableExt};
 use rustc_mir_dataflow::Analysis;
 use rustc_span::{sym, Span, Symbol};
 use rustc_trait_selection::traits::error_reporting::TypeErrCtxtExt as _;
-use rustc_trait_selection::traits::{self, ObligationCauseCode, ObligationCtxt, SelectionContext};
+use rustc_trait_selection::traits::{self, ObligationCauseCode, ObligationCtxt};
 use rustc_type_ir::visit::{TypeSuperVisitable, TypeVisitor};
 
 use std::mem;
@@ -756,143 +754,43 @@ impl<'tcx> Visitor<'tcx> for Checker<'_, 'tcx> {
                     infcx.err_ctxt().report_fulfillment_errors(errors);
                 }
 
+                let mut is_trait = false;
                 // Attempting to call a trait method?
-                // FIXME(effects) do we need this?
-                if let Some(trait_id) = tcx.trait_of_item(callee) {
+                if tcx.trait_of_item(callee).is_some() {
                     trace!("attempting to call a trait method");
-                    if !self.tcx.features().const_trait_impl {
+                    // trait method calls are only permitted when `effects` is enabled.
+                    // we don't error, since that is handled by typeck. We try to resolve
+                    // the trait into the concrete method, and uses that for const stability
+                    // checks.
+                    // FIXME(effects) we might consider moving const stability checks to typeck as well.
+                    if tcx.features().effects {
+                        is_trait = true;
+
+                        if let Ok(Some(instance)) =
+                            Instance::resolve(tcx, param_env, callee, fn_args)
+                            && let InstanceDef::Item(def) = instance.def
+                        {
+                            // Resolve a trait method call to its concrete implementation, which may be in a
+                            // `const` trait impl. This is only used for the const stability check below, since
+                            // we want to look at the concrete impl's stability.
+                            fn_args = instance.args;
+                            callee = def;
+                        }
+                    } else {
                         self.check_op(ops::FnCallNonConst {
                             caller,
                             callee,
                             args: fn_args,
                             span: *fn_span,
                             call_source: *call_source,
-                            feature: Some(sym::const_trait_impl),
+                            feature: Some(if tcx.features().const_trait_impl {
+                                sym::effects
+                            } else {
+                                sym::const_trait_impl
+                            }),
                         });
                         return;
                     }
-
-                    let trait_ref = TraitRef::from_method(tcx, trait_id, fn_args);
-                    let obligation =
-                        Obligation::new(tcx, ObligationCause::dummy(), param_env, trait_ref);
-
-                    let implsrc = {
-                        let infcx = tcx.infer_ctxt().build();
-                        let mut selcx = SelectionContext::new(&infcx);
-                        selcx.select(&obligation)
-                    };
-
-                    match implsrc {
-                        Ok(Some(ImplSource::Param(_))) if tcx.features().effects => {
-                            debug!(
-                                "const_trait_impl: provided {:?} via where-clause in {:?}",
-                                trait_ref, param_env
-                            );
-                            return;
-                        }
-                        // Closure: Fn{Once|Mut}
-                        Ok(Some(ImplSource::Builtin(BuiltinImplSource::Misc, _)))
-                            if trait_ref.self_ty().is_closure()
-                                && tcx.fn_trait_kind_from_def_id(trait_id).is_some() =>
-                        {
-                            let ty::Closure(closure_def_id, fn_args) = *trait_ref.self_ty().kind()
-                            else {
-                                unreachable!()
-                            };
-                            if !tcx.is_const_fn_raw(closure_def_id) {
-                                self.check_op(ops::FnCallNonConst {
-                                    caller,
-                                    callee,
-                                    args: fn_args,
-                                    span: *fn_span,
-                                    call_source: *call_source,
-                                    feature: None,
-                                });
-
-                                return;
-                            }
-                        }
-                        Ok(Some(ImplSource::UserDefined(data))) => {
-                            let callee_name = tcx.item_name(callee);
-
-                            if let hir::Constness::NotConst = tcx.constness(data.impl_def_id) {
-                                self.check_op(ops::FnCallNonConst {
-                                    caller,
-                                    callee,
-                                    args: fn_args,
-                                    span: *fn_span,
-                                    call_source: *call_source,
-                                    feature: None,
-                                });
-                                return;
-                            }
-
-                            if let Some(&did) = tcx
-                                .associated_item_def_ids(data.impl_def_id)
-                                .iter()
-                                .find(|did| tcx.item_name(**did) == callee_name)
-                            {
-                                // using internal args is ok here, since this is only
-                                // used for the `resolve` call below
-                                fn_args = GenericArgs::identity_for_item(tcx, did);
-                                callee = did;
-                            }
-                        }
-                        _ if !tcx.is_const_fn_raw(callee) => {
-                            // At this point, it is only legal when the caller is in a trait
-                            // marked with #[const_trait], and the callee is in the same trait.
-                            let mut nonconst_call_permission = false;
-                            if let Some(callee_trait) = tcx.trait_of_item(callee)
-                                && tcx.has_attr(callee_trait, sym::const_trait)
-                                && Some(callee_trait) == tcx.trait_of_item(caller.to_def_id())
-                                // Can only call methods when it's `<Self as TheTrait>::f`.
-                                && tcx.types.self_param == fn_args.type_at(0)
-                            {
-                                nonconst_call_permission = true;
-                            }
-
-                            if !nonconst_call_permission {
-                                let obligation = Obligation::new(
-                                    tcx,
-                                    ObligationCause::dummy_with_span(*fn_span),
-                                    param_env,
-                                    trait_ref,
-                                );
-
-                                // improve diagnostics by showing what failed. Our requirements are stricter this time
-                                // as we are going to error again anyways.
-                                let infcx = tcx.infer_ctxt().build();
-                                if let Err(e) = implsrc {
-                                    infcx.err_ctxt().report_selection_error(
-                                        obligation.clone(),
-                                        &obligation,
-                                        &e,
-                                    );
-                                }
-
-                                self.check_op(ops::FnCallNonConst {
-                                    caller,
-                                    callee,
-                                    args: fn_args,
-                                    span: *fn_span,
-                                    call_source: *call_source,
-                                    feature: None,
-                                });
-                                return;
-                            }
-                        }
-                        _ => {}
-                    }
-
-                    // Resolve a trait method call to its concrete implementation, which may be in a
-                    // `const` trait impl.
-                    let instance = Instance::resolve(tcx, param_env, callee, fn_args);
-                    debug!("Resolving ({:?}) -> {:?}", callee, instance);
-                    if let Ok(Some(func)) = instance {
-                        if let InstanceDef::Item(def) = func.def {
-                            callee = def;
-                        }
-                    }
                 }
 
                 // At this point, we are calling a function, `callee`, whose `DefId` is known...
@@ -925,21 +823,16 @@ impl<'tcx> Visitor<'tcx> for Checker<'_, 'tcx> {
                     return;
                 }
 
-                if !tcx.is_const_fn_raw(callee) {
-                    if !tcx.is_const_default_method(callee) {
-                        // To get to here we must have already found a const impl for the
-                        // trait, but for it to still be non-const can be that the impl is
-                        // using default method bodies.
-                        self.check_op(ops::FnCallNonConst {
-                            caller,
-                            callee,
-                            args: fn_args,
-                            span: *fn_span,
-                            call_source: *call_source,
-                            feature: None,
-                        });
-                        return;
-                    }
+                if !tcx.is_const_fn_raw(callee) && !is_trait {
+                    self.check_op(ops::FnCallNonConst {
+                        caller,
+                        callee,
+                        args: fn_args,
+                        span: *fn_span,
+                        call_source: *call_source,
+                        feature: None,
+                    });
+                    return;
                 }
 
                 // If the `const fn` we are trying to call is not const-stable, ensure that we have

compiler/rustc_expand/src/build.rs

@@ -491,7 +491,7 @@ impl<'a> ExtCtxt<'a> {
         path: ast::Path,
         field_pats: ThinVec<ast::PatField>,
     ) -> P<ast::Pat> {
-        self.pat(span, PatKind::Struct(None, path, field_pats, false))
+        self.pat(span, PatKind::Struct(None, path, field_pats, ast::PatFieldsRest::None))
     }
     pub fn pat_tuple(&self, span: Span, pats: ThinVec<P<ast::Pat>>) -> P<ast::Pat> {
         self.pat(span, PatKind::Tuple(pats))

compiler/rustc_hir_analysis/src/astconv/mod.rs

@@ -378,7 +378,7 @@ impl<'o, 'tcx> dyn AstConv<'tcx> + 'o {
             assert!(self_ty.is_none());
         }
 
-        let arg_count = check_generic_arg_count(
+        let mut arg_count = check_generic_arg_count(
             tcx,
             span,
             def_id,
@@ -560,6 +560,14 @@ impl<'o, 'tcx> dyn AstConv<'tcx> + 'o {
             inferred_params: vec![],
             infer_args,
         };
+        if let ty::BoundConstness::ConstIfConst = constness
+            && generics.has_self
+            && !tcx.has_attr(def_id, sym::const_trait)
+        {
+            let e = tcx.sess.emit_err(crate::errors::ConstBoundForNonConstTrait { span });
+            arg_count.correct =
+                Err(GenericArgCountMismatch { reported: Some(e), invalid_args: vec![] });
+        }
         let args = create_args_for_parent_generic_args(
             tcx,
             def_id,
@@ -570,13 +578,6 @@ impl<'o, 'tcx> dyn AstConv<'tcx> + 'o {
             &mut args_ctx,
         );
 
-        if let ty::BoundConstness::ConstIfConst = constness
-            && generics.has_self
-            && !tcx.has_attr(def_id, sym::const_trait)
-        {
-            tcx.sess.emit_err(crate::errors::ConstBoundForNonConstTrait { span });
-        }
-
         (args, arg_count)
     }
 

compiler/rustc_parse/src/parser/pat.rs

@@ -15,7 +15,7 @@ use rustc_ast::ptr::P;
 use rustc_ast::token::{self, Delimiter};
 use rustc_ast::{
     self as ast, AttrVec, BindingAnnotation, ByRef, Expr, ExprKind, MacCall, Mutability, Pat,
-    PatField, PatKind, Path, QSelf, RangeEnd, RangeSyntax,
+    PatField, PatFieldsRest, PatKind, Path, QSelf, RangeEnd, RangeSyntax,
 };
 use rustc_ast_pretty::pprust;
 use rustc_errors::{Applicability, DiagnosticBuilder, PResult};
@@ -891,7 +891,8 @@ impl<'a> Parser<'a> {
             e.span_label(path.span, "while parsing the fields for this pattern");
             e.emit();
             self.recover_stmt();
-            (ThinVec::new(), true)
+            // When recovering, pretend we had `Foo { .. }`, to avoid cascading errors.
+            (ThinVec::new(), PatFieldsRest::Rest)
         });
         self.bump();
         Ok(PatKind::Struct(qself, path, fields, etc))
@@ -965,9 +966,9 @@ impl<'a> Parser<'a> {
     }
 
     /// Parses the fields of a struct-like pattern.
-    fn parse_pat_fields(&mut self) -> PResult<'a, (ThinVec<PatField>, bool)> {
+    fn parse_pat_fields(&mut self) -> PResult<'a, (ThinVec<PatField>, PatFieldsRest)> {
         let mut fields = ThinVec::new();
-        let mut etc = false;
+        let mut etc = PatFieldsRest::None;
         let mut ate_comma = true;
         let mut delayed_err: Option<DiagnosticBuilder<'a>> = None;
         let mut first_etc_and_maybe_comma_span = None;
@@ -1001,7 +1002,7 @@ impl<'a> Parser<'a> {
                 || self.check_noexpect(&token::DotDotDot)
                 || self.check_keyword(kw::Underscore)
             {
-                etc = true;
+                etc = PatFieldsRest::Rest;
                 let mut etc_sp = self.token.span;
                 if first_etc_and_maybe_comma_span.is_none() {
                     if let Some(comma_tok) = self

src/tools/clippy/clippy_lints/src/unnested_or_patterns.rs

@@ -293,7 +293,7 @@ fn extend_with_struct_pat(
     qself1: &Option<P<ast::QSelf>>,
     path1: &ast::Path,
     fps1: &mut [ast::PatField],
-    rest1: bool,
+    rest1: ast::PatFieldsRest,
     start: usize,
     alternatives: &mut ThinVec<P<Pat>>,
 ) -> bool {

src/tools/rustfmt/src/patterns.rs

@@ -259,9 +259,15 @@ impl Rewrite for Pat {
                 None,
                 None,
             ),
-            PatKind::Struct(ref qself, ref path, ref fields, ellipsis) => {
-                rewrite_struct_pat(qself, path, fields, ellipsis, self.span, context, shape)
-            }
+            PatKind::Struct(ref qself, ref path, ref fields, rest) => rewrite_struct_pat(
+                qself,
+                path,
+                fields,
+                rest == ast::PatFieldsRest::Rest,
+                self.span,
+                context,
+                shape,
+            ),
             PatKind::MacCall(ref mac) => {
                 rewrite_macro(mac, None, context, shape, MacroPosition::Pat)
             }

tests/ui/consts/auxiliary/closure-in-foreign-crate.rs

@@ -1,5 +1,5 @@
 #![crate_type = "lib"]
-#![feature(const_closures, const_trait_impl)]
+#![feature(const_closures, const_trait_impl, effects)]
 #![allow(incomplete_features)]
 
 pub const fn test() {