Auto merge of rust-lang#119156 - matthiaskrgr:rollup-482ow65, r=matthiaskrgr

Rollup of 7 pull requests

Successful merges:

 - rust-lang#118691 (Add check for possible CStr literals in pre-2021)
 - rust-lang#118973 (rustc_codegen_ssa: Don't drop `IncorrectCguReuseType` , make `rustc_expected_cgu_reuse` attr work)
 - rust-lang#119071 (-Znext-solver: adapt overflow rules to avoid breakage)
 - rust-lang#119089 (effects: fix a comment)
 - rust-lang#119094 (Add function ABI and type layout to StableMIR)
 - rust-lang#119102 (Add arm-none-eabi and armv7r-none-eabi platform-support documentation.)
 - rust-lang#119107 (subtype_predicate: remove unnecessary probe)

Failed merges:

 - rust-lang#119135 (Fix crash due to `CrateItem::kind()` not handling constructors)
 - rust-lang#119141 (Add method to get instance instantiation arguments)

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

Author: bors

Diff for: compiler/rustc_codegen_ssa/src/assert_module_sources.rs

@@ -278,13 +278,13 @@ impl CguReuseTracker {
 
                     if error {
                         let at_least = if at_least { 1 } else { 0 };
-                        errors::IncorrectCguReuseType {
+                        sess.emit_err(errors::IncorrectCguReuseType {
                             span: *error_span,
                             cgu_user_name,
                             actual_reuse,
                             expected_reuse,
                             at_least,
-                        };
+                        });
                     }
                 } else {
                     sess.emit_fatal(errors::CguNotRecorded { cgu_user_name, cgu_name });

Diff for: compiler/rustc_hir_analysis/src/astconv/generics.rs

@@ -262,7 +262,7 @@ pub fn create_args_for_parent_generic_args<'tcx, 'a>(
                             // impl const PartialEq for () {}
                             // ```
                             //
-                            // Since this is a const impl, we need to insert `<false>` at the end of
+                            // Since this is a const impl, we need to insert a host arg at the end of
                             // `PartialEq`'s generics, but this errors since `Rhs` isn't specified.
                             // To work around this, we infer all arguments until we reach the host param.
                             args.push(ctx.inferred_kind(Some(&args), param, infer_args));

Diff for: compiler/rustc_infer/src/infer/mod.rs

@@ -713,10 +713,6 @@ impl<'tcx> InferCtxtBuilder<'tcx> {
 }
 
 impl<'tcx, T> InferOk<'tcx, T> {
-    pub fn unit(self) -> InferOk<'tcx, ()> {
-        InferOk { value: (), obligations: self.obligations }
-    }
-
     /// Extracts `value`, registering any obligations into `fulfill_cx`.
     pub fn into_value_registering_obligations(
         self,
@@ -1025,15 +1021,10 @@ impl<'tcx> InferCtxt<'tcx> {
             _ => {}
         }
 
-        Ok(self.commit_if_ok(|_snapshot| {
-            let ty::SubtypePredicate { a_is_expected, a, b } =
-                self.instantiate_binder_with_placeholders(predicate);
-
-            let ok =
-                self.at(cause, param_env).sub_exp(DefineOpaqueTypes::No, a_is_expected, a, b)?;
+        let ty::SubtypePredicate { a_is_expected, a, b } =
+            self.instantiate_binder_with_placeholders(predicate);
 
-            Ok(ok.unit())
-        }))
+        Ok(self.at(cause, param_env).sub_exp(DefineOpaqueTypes::No, a_is_expected, a, b))
     }
 
     pub fn region_outlives_predicate(

Diff for: compiler/rustc_middle/src/traits/solve.rs

@@ -233,6 +233,27 @@ impl<'tcx> TypeVisitable<TyCtxt<'tcx>> for PredefinedOpaques<'tcx> {
     }
 }
 
+/// Why a specific goal has to be proven.
+///
+/// This is necessary as we treat nested goals different depending on
+/// their source.
+#[derive(Copy, Clone, Debug, PartialEq, Eq)]
+pub enum GoalSource {
+    Misc,
+    /// We're proving a where-bound of an impl.
+    ///
+    /// FIXME(-Znext-solver=coinductive): Explain how and why this
+    /// changes whether cycles are coinductive.
+    ///
+    /// This also impacts whether we erase constraints on overflow.
+    /// Erasing constraints is generally very useful for perf and also
+    /// results in better error messages by avoiding spurious errors.
+    /// We do not erase overflow constraints in `normalizes-to` goals unless
+    /// they are from an impl where-clause. This is necessary due to
+    /// backwards compatability, cc trait-system-refactor-initiatitive#70.
+    ImplWhereBound,
+}
+
 #[derive(Debug, Copy, Clone, PartialEq, Eq, Hash, HashStable)]
 pub enum IsNormalizesToHack {
     Yes,

Diff for: compiler/rustc_middle/src/traits/solve/inspect.rs

@@ -19,8 +19,8 @@
 //! [canonicalized]: https://rustc-dev-guide.rust-lang.org/solve/canonicalization.html
 
 use super::{
-    CandidateSource, Canonical, CanonicalInput, Certainty, Goal, IsNormalizesToHack, NoSolution,
-    QueryInput, QueryResult,
+    CandidateSource, Canonical, CanonicalInput, Certainty, Goal, GoalSource, IsNormalizesToHack,
+    NoSolution, QueryInput, QueryResult,
 };
 use crate::{infer::canonical::CanonicalVarValues, ty};
 use format::ProofTreeFormatter;
@@ -115,7 +115,7 @@ impl Debug for Probe<'_> {
 pub enum ProbeStep<'tcx> {
     /// We added a goal to the `EvalCtxt` which will get proven
     /// the next time `EvalCtxt::try_evaluate_added_goals` is called.
-    AddGoal(CanonicalState<'tcx, Goal<'tcx, ty::Predicate<'tcx>>>),
+    AddGoal(GoalSource, CanonicalState<'tcx, Goal<'tcx, ty::Predicate<'tcx>>>),
     /// The inside of a `EvalCtxt::try_evaluate_added_goals` call.
     EvaluateGoals(AddedGoalsEvaluation<'tcx>),
     /// A call to `probe` while proving the current goal. This is

Diff for: compiler/rustc_middle/src/traits/solve/inspect/format.rs

@@ -123,7 +123,13 @@ impl<'a, 'b> ProofTreeFormatter<'a, 'b> {
         self.nested(|this| {
             for step in &probe.steps {
                 match step {
-                    ProbeStep::AddGoal(goal) => writeln!(this.f, "ADDED GOAL: {goal:?}")?,
+                    ProbeStep::AddGoal(source, goal) => {
+                        let source = match source {
+                            GoalSource::Misc => "misc",
+                            GoalSource::ImplWhereBound => "impl where-bound",
+                        };
+                        writeln!(this.f, "ADDED GOAL ({source}): {goal:?}")?
+                    }
                     ProbeStep::EvaluateGoals(eval) => this.format_added_goals_evaluation(eval)?,
                     ProbeStep::NestedProbe(probe) => this.format_probe(probe)?,
                     ProbeStep::CommitIfOkStart => writeln!(this.f, "COMMIT_IF_OK START")?,

Diff for: compiler/rustc_parse/src/parser/diagnostics.rs

@@ -10,13 +10,13 @@ use crate::errors::{
     ConstGenericWithoutBracesSugg, DocCommentDoesNotDocumentAnything, DocCommentOnParamType,
     DoubleColonInBound, ExpectedIdentifier, ExpectedSemi, ExpectedSemiSugg,
     GenericParamsWithoutAngleBrackets, GenericParamsWithoutAngleBracketsSugg,
-    HelpIdentifierStartsWithNumber, InInTypo, IncorrectAwait, IncorrectSemicolon,
-    IncorrectUseOfAwait, PatternMethodParamWithoutBody, QuestionMarkInType, QuestionMarkInTypeSugg,
-    SelfParamNotFirst, StructLiteralBodyWithoutPath, StructLiteralBodyWithoutPathSugg,
-    StructLiteralNeedingParens, StructLiteralNeedingParensSugg, SuggAddMissingLetStmt,
-    SuggEscapeIdentifier, SuggRemoveComma, TernaryOperator, UnexpectedConstInGenericParam,
-    UnexpectedConstParamDeclaration, UnexpectedConstParamDeclarationSugg, UnmatchedAngleBrackets,
-    UseEqInstead, WrapType,
+    HelpIdentifierStartsWithNumber, HelpUseLatestEdition, InInTypo, IncorrectAwait,
+    IncorrectSemicolon, IncorrectUseOfAwait, PatternMethodParamWithoutBody, QuestionMarkInType,
+    QuestionMarkInTypeSugg, SelfParamNotFirst, StructLiteralBodyWithoutPath,
+    StructLiteralBodyWithoutPathSugg, StructLiteralNeedingParens, StructLiteralNeedingParensSugg,
+    SuggAddMissingLetStmt, SuggEscapeIdentifier, SuggRemoveComma, TernaryOperator,
+    UnexpectedConstInGenericParam, UnexpectedConstParamDeclaration,
+    UnexpectedConstParamDeclarationSugg, UnmatchedAngleBrackets, UseEqInstead, WrapType,
 };
 use crate::fluent_generated as fluent;
 use crate::parser;
@@ -640,6 +640,28 @@ impl<'a> Parser<'a> {
             }
         }
 
+        // Try to detect an intended c-string literal while using a pre-2021 edition. The heuristic
+        // here is to identify a cooked, uninterpolated `c` id immediately followed by a string, or
+        // a cooked, uninterpolated `cr` id immediately followed by a string or a `#`, in an edition
+        // where c-string literals are not allowed. There is the very slight possibility of a false
+        // positive for a `cr#` that wasn't intended to start a c-string literal, but identifying
+        // that in the parser requires unbounded lookahead, so we only add a hint to the existing
+        // error rather than replacing it entirely.
+        if ((self.prev_token.kind == TokenKind::Ident(sym::c, false)
+            && matches!(&self.token.kind, TokenKind::Literal(token::Lit { kind: token::Str, .. })))
+            || (self.prev_token.kind == TokenKind::Ident(sym::cr, false)
+                && matches!(
+                    &self.token.kind,
+                    TokenKind::Literal(token::Lit { kind: token::Str, .. }) | token::Pound
+                )))
+            && self.prev_token.span.hi() == self.token.span.lo()
+            && !self.token.span.at_least_rust_2021()
+        {
+            err.note("you may be trying to write a c-string literal");
+            err.note("c-string literals require Rust 2021 or later");
+            HelpUseLatestEdition::new().add_to_diagnostic(&mut err);
+        }
+
         // `pub` may be used for an item or `pub(crate)`
         if self.prev_token.is_ident_named(sym::public)
             && (self.token.can_begin_item()

Diff for: compiler/rustc_smir/src/rustc_internal/internal.rs

@@ -7,6 +7,7 @@
 use crate::rustc_smir::Tables;
 use rustc_middle::ty::{self as rustc_ty, Ty as InternalTy};
 use rustc_span::Symbol;
+use stable_mir::abi::Layout;
 use stable_mir::mir::alloc::AllocId;
 use stable_mir::mir::mono::{Instance, MonoItem, StaticDef};
 use stable_mir::mir::{Mutability, Safety};
@@ -460,6 +461,14 @@ impl<'tcx> RustcInternal<'tcx> for Span {
     }
 }
 
+impl<'tcx> RustcInternal<'tcx> for Layout {
+    type T = rustc_target::abi::Layout<'tcx>;
+
+    fn internal(&self, tables: &mut Tables<'tcx>) -> Self::T {
+        tables.layouts[*self]
+    }
+}
+
 impl<'tcx, T> RustcInternal<'tcx> for &T
 where
     T: RustcInternal<'tcx>,

Diff for: compiler/rustc_smir/src/rustc_internal/mod.rs

@@ -12,6 +12,7 @@ use rustc_middle::ty::TyCtxt;
 use rustc_span::def_id::{CrateNum, DefId};
 use rustc_span::Span;
 use scoped_tls::scoped_thread_local;
+use stable_mir::abi::Layout;
 use stable_mir::ty::IndexedVal;
 use stable_mir::Error;
 use std::cell::Cell;
@@ -136,6 +137,10 @@ impl<'tcx> Tables<'tcx> {
     pub(crate) fn static_def(&mut self, did: DefId) -> stable_mir::mir::mono::StaticDef {
         stable_mir::mir::mono::StaticDef(self.create_def_id(did))
     }
+
+    pub(crate) fn layout_id(&mut self, layout: rustc_target::abi::Layout<'tcx>) -> Layout {
+        self.layouts.create_or_fetch(layout)
+    }
 }
 
 pub fn crate_num(item: &stable_mir::Crate) -> CrateNum {
@@ -180,6 +185,7 @@ where
         types: IndexMap::default(),
         instances: IndexMap::default(),
         constants: IndexMap::default(),
+        layouts: IndexMap::default(),
     }));
     stable_mir::compiler_interface::run(&tables, || init(&tables, f))
 }

Diff for: compiler/rustc_smir/src/rustc_smir/context.rs

@@ -3,12 +3,19 @@
 //! This trait is currently the main interface between the Rust compiler,
 //! and the `stable_mir` crate.
 
+#![allow(rustc::usage_of_qualified_ty)]
+
+use rustc_abi::HasDataLayout;
 use rustc_middle::ty;
+use rustc_middle::ty::layout::{
+    FnAbiOf, FnAbiOfHelpers, HasParamEnv, HasTyCtxt, LayoutOf, LayoutOfHelpers,
+};
 use rustc_middle::ty::print::{with_forced_trimmed_paths, with_no_trimmed_paths};
 use rustc_middle::ty::{
-    GenericPredicates, Instance, ParamEnv, ScalarInt, TypeVisitableExt, ValTree,
+    GenericPredicates, Instance, List, ParamEnv, ScalarInt, TyCtxt, TypeVisitableExt, ValTree,
 };
 use rustc_span::def_id::LOCAL_CRATE;
+use stable_mir::abi::{FnAbi, Layout, LayoutShape};
 use stable_mir::compiler_interface::Context;
 use stable_mir::mir::alloc::GlobalAlloc;
 use stable_mir::mir::mono::{InstanceDef, StaticDef};
@@ -280,7 +287,6 @@ impl<'tcx> Context for TablesWrapper<'tcx> {
         tables.tcx.mk_ty_from_kind(internal_kind).stable(&mut *tables)
     }
 
-    #[allow(rustc::usage_of_qualified_ty)]
     fn new_box_ty(&self, ty: stable_mir::ty::Ty) -> stable_mir::ty::Ty {
         let mut tables = self.0.borrow_mut();
         let inner = ty.internal(&mut *tables);
@@ -335,6 +341,12 @@ impl<'tcx> Context for TablesWrapper<'tcx> {
         instance.ty(tables.tcx, ParamEnv::reveal_all()).stable(&mut *tables)
     }
 
+    fn instance_abi(&self, def: InstanceDef) -> Result<FnAbi, Error> {
+        let mut tables = self.0.borrow_mut();
+        let instance = tables.instances[def];
+        Ok(tables.fn_abi_of_instance(instance, List::empty())?.stable(&mut *tables))
+    }
+
     fn instance_def_id(&self, def: InstanceDef) -> stable_mir::DefId {
         let mut tables = self.0.borrow_mut();
         let def_id = tables.instances[def].def_id();
@@ -473,6 +485,65 @@ impl<'tcx> Context for TablesWrapper<'tcx> {
             )
         }
     }
+
+    fn ty_layout(&self, ty: Ty) -> Result<Layout, Error> {
+        let mut tables = self.0.borrow_mut();
+        let ty = ty.internal(&mut *tables);
+        let layout = tables.layout_of(ty)?.layout;
+        Ok(layout.stable(&mut *tables))
+    }
+
+    fn layout_shape(&self, id: Layout) -> LayoutShape {
+        let mut tables = self.0.borrow_mut();
+        id.internal(&mut *tables).0.stable(&mut *tables)
+    }
 }
 
 pub struct TablesWrapper<'tcx>(pub RefCell<Tables<'tcx>>);
+
+/// Implement error handling for extracting function ABI information.
+impl<'tcx> FnAbiOfHelpers<'tcx> for Tables<'tcx> {
+    type FnAbiOfResult = Result<&'tcx rustc_target::abi::call::FnAbi<'tcx, ty::Ty<'tcx>>, Error>;
+
+    #[inline]
+    fn handle_fn_abi_err(
+        &self,
+        err: ty::layout::FnAbiError<'tcx>,
+        _span: rustc_span::Span,
+        fn_abi_request: ty::layout::FnAbiRequest<'tcx>,
+    ) -> Error {
+        Error::new(format!("Failed to get ABI for `{fn_abi_request:?}`: {err:?}"))
+    }
+}
+
+impl<'tcx> LayoutOfHelpers<'tcx> for Tables<'tcx> {
+    type LayoutOfResult = Result<ty::layout::TyAndLayout<'tcx>, Error>;
+
+    #[inline]
+    fn handle_layout_err(
+        &self,
+        err: ty::layout::LayoutError<'tcx>,
+        _span: rustc_span::Span,
+        ty: ty::Ty<'tcx>,
+    ) -> Error {
+        Error::new(format!("Failed to get layout for `{ty}`: {err}"))
+    }
+}
+
+impl<'tcx> HasParamEnv<'tcx> for Tables<'tcx> {
+    fn param_env(&self) -> ty::ParamEnv<'tcx> {
+        ty::ParamEnv::reveal_all()
+    }
+}
+
+impl<'tcx> HasTyCtxt<'tcx> for Tables<'tcx> {
+    fn tcx(&self) -> TyCtxt<'tcx> {
+        self.tcx
+    }
+}
+
+impl<'tcx> HasDataLayout for Tables<'tcx> {
+    fn data_layout(&self) -> &rustc_abi::TargetDataLayout {
+        self.tcx.data_layout()
+    }
+}