Auto merge of rust-lang#125976 - compiler-errors:rollup-xt3le7w, r=compiler-errors

Rollup of 8 pull requests

Successful merges:

 - rust-lang#125667 (Silence follow-up errors directly based on error types and regions)
 - rust-lang#125717 (Refactor `#[diagnostic::do_not_recommend]` support)
 - rust-lang#125795 (Improve renaming suggestion for names with leading underscores)
 - rust-lang#125865 (Fix ICE caused by ignoring EffectVars in type inference)
 - rust-lang#125953 (Streamline `nested` calls.)
 - rust-lang#125959 (Reduce `pub` exposure in `rustc_mir_build`)
 - rust-lang#125967 (Split smir `Const` into `TyConst` and `MirConst`)
 - rust-lang#125968 (Store the types of `ty::Expr` arguments in the `ty::Expr`)

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

Author: bors

compiler/rustc_borrowck/src/nll.rs

@@ -125,8 +125,8 @@ pub(crate) fn compute_regions<'cx, 'tcx>(
         placeholder_indices,
         placeholder_index_to_region: _,
         liveness_constraints,
-        outlives_constraints,
-        member_constraints,
+        mut outlives_constraints,
+        mut member_constraints,
         universe_causes,
         type_tests,
     } = constraints;
@@ -144,6 +144,16 @@ pub(crate) fn compute_regions<'cx, 'tcx>(
         &universal_region_relations,
     );
 
+    if let Some(guar) = universal_regions.tainted_by_errors() {
+        // Suppress unhelpful extra errors in `infer_opaque_types` by clearing out all
+        // outlives bounds that we may end up checking.
+        outlives_constraints = Default::default();
+        member_constraints = Default::default();
+
+        // Also taint the entire scope.
+        infcx.set_tainted_by_errors(guar);
+    }
+
     let mut regioncx = RegionInferenceContext::new(
         infcx,
         var_origins,

compiler/rustc_borrowck/src/universal_regions.rs

@@ -29,7 +29,8 @@ use rustc_middle::ty::{self, InlineConstArgs, InlineConstArgsParts, RegionVid, T
 use rustc_middle::ty::{GenericArgs, GenericArgsRef};
 use rustc_middle::{bug, span_bug};
 use rustc_span::symbol::{kw, sym};
-use rustc_span::Symbol;
+use rustc_span::{ErrorGuaranteed, Symbol};
+use std::cell::Cell;
 use std::iter;
 
 use crate::renumber::RegionCtxt;
@@ -186,6 +187,10 @@ struct UniversalRegionIndices<'tcx> {
 
     /// The vid assigned to `'static`. Used only for diagnostics.
     pub fr_static: RegionVid,
+
+    /// Whether we've encountered an error region. If we have, cancel all
+    /// outlives errors, as they are likely bogus.
+    pub tainted_by_errors: Cell<Option<ErrorGuaranteed>>,
 }
 
 #[derive(Debug, PartialEq)]
@@ -408,6 +413,10 @@ impl<'tcx> UniversalRegions<'tcx> {
             }
         }
     }
+
+    pub fn tainted_by_errors(&self) -> Option<ErrorGuaranteed> {
+        self.indices.tainted_by_errors.get()
+    }
 }
 
 struct UniversalRegionsBuilder<'cx, 'tcx> {
@@ -663,7 +672,11 @@ impl<'cx, 'tcx> UniversalRegionsBuilder<'cx, 'tcx> {
         let global_mapping = iter::once((tcx.lifetimes.re_static, fr_static));
         let arg_mapping = iter::zip(identity_args.regions(), fr_args.regions().map(|r| r.as_var()));
 
-        UniversalRegionIndices { indices: global_mapping.chain(arg_mapping).collect(), fr_static }
+        UniversalRegionIndices {
+            indices: global_mapping.chain(arg_mapping).collect(),
+            fr_static,
+            tainted_by_errors: Cell::new(None),
+        }
     }
 
     fn compute_inputs_and_output(
@@ -868,7 +881,8 @@ impl<'tcx> UniversalRegionIndices<'tcx> {
     pub fn to_region_vid(&self, r: ty::Region<'tcx>) -> RegionVid {
         if let ty::ReVar(..) = *r {
             r.as_var()
-        } else if r.is_error() {
+        } else if let ty::ReError(guar) = *r {
+            self.tainted_by_errors.set(Some(guar));
             // We use the `'static` `RegionVid` because `ReError` doesn't actually exist in the
             // `UniversalRegionIndices`. This is fine because 1) it is a fallback only used if
             // errors are being emitted and 2) it leaves the happy path unaffected.

compiler/rustc_driver_impl/src/pretty.rs

@@ -3,7 +3,6 @@
 use rustc_ast as ast;
 use rustc_ast_pretty::pprust as pprust_ast;
 use rustc_errors::FatalError;
-use rustc_hir as hir;
 use rustc_hir_pretty as pprust_hir;
 use rustc_middle::bug;
 use rustc_middle::mir::{write_mir_graphviz, write_mir_pretty};
@@ -70,11 +69,7 @@ struct HirIdentifiedAnn<'tcx> {
 
 impl<'tcx> pprust_hir::PpAnn for HirIdentifiedAnn<'tcx> {
     fn nested(&self, state: &mut pprust_hir::State<'_>, nested: pprust_hir::Nested) {
-        pprust_hir::PpAnn::nested(
-            &(&self.tcx.hir() as &dyn hir::intravisit::Map<'_>),
-            state,
-            nested,
-        )
+        self.tcx.nested(state, nested)
     }
 
     fn pre(&self, s: &mut pprust_hir::State<'_>, node: pprust_hir::AnnNode<'_>) {
@@ -152,8 +147,7 @@ impl<'tcx> pprust_hir::PpAnn for HirTypedAnn<'tcx> {
         if let pprust_hir::Nested::Body(id) = nested {
             self.maybe_typeck_results.set(Some(self.tcx.typeck_body(id)));
         }
-        let pp_ann = &(&self.tcx.hir() as &dyn hir::intravisit::Map<'_>);
-        pprust_hir::PpAnn::nested(pp_ann, state, nested);
+        self.tcx.nested(state, nested);
         self.maybe_typeck_results.set(old_maybe_typeck_results);
     }
 

compiler/rustc_hir_analysis/src/collect/type_of.rs

@@ -502,7 +502,9 @@ pub(super) fn type_of(tcx: TyCtxt<'_>, def_id: LocalDefId) -> ty::EarlyBinder<'_
             bug!("unexpected sort of node in type_of(): {:?}", x);
         }
     };
-    if let Err(e) = icx.check_tainted_by_errors() {
+    if let Err(e) = icx.check_tainted_by_errors()
+        && !output.references_error()
+    {
         ty::EarlyBinder::bind(Ty::new_error(tcx, e))
     } else {
         ty::EarlyBinder::bind(output)

compiler/rustc_infer/src/infer/mod.rs

@@ -587,6 +587,7 @@ pub enum FixupError {
     UnresolvedFloatTy(FloatVid),
     UnresolvedTy(TyVid),
     UnresolvedConst(ConstVid),
+    UnresolvedEffect(EffectVid),
 }
 
 /// See the `region_obligations` field for more information.
@@ -614,6 +615,7 @@ impl fmt::Display for FixupError {
             ),
             UnresolvedTy(_) => write!(f, "unconstrained type"),
             UnresolvedConst(_) => write!(f, "unconstrained const value"),
+            UnresolvedEffect(_) => write!(f, "unconstrained effect value"),
         }
     }
 }

compiler/rustc_infer/src/infer/resolve.rs

@@ -167,6 +167,9 @@ impl<'a, 'tcx> FallibleTypeFolder<TyCtxt<'tcx>> for FullTypeResolver<'a, 'tcx> {
                 ty::ConstKind::Infer(InferConst::Fresh(_)) => {
                     bug!("Unexpected const in full const resolver: {:?}", c);
                 }
+                ty::ConstKind::Infer(InferConst::EffectVar(evid)) => {
+                    return Err(FixupError::UnresolvedEffect(evid));
+                }
                 _ => {}
             }
             c.try_super_fold_with(self)

compiler/rustc_middle/src/ty/consts.rs

@@ -24,7 +24,7 @@ pub type ConstKind<'tcx> = ir::ConstKind<TyCtxt<'tcx>>;
 pub type UnevaluatedConst<'tcx> = ir::UnevaluatedConst<TyCtxt<'tcx>>;
 
 #[cfg(target_pointer_width = "64")]
-rustc_data_structures::static_assert_size!(ConstKind<'_>, 32);
+rustc_data_structures::static_assert_size!(ConstKind<'_>, 24);
 
 /// Use this rather than `ConstData`, whenever possible.
 #[derive(Copy, Clone, PartialEq, Eq, Hash, HashStable)]
@@ -58,7 +58,7 @@ pub struct ConstData<'tcx> {
 }
 
 #[cfg(target_pointer_width = "64")]
-rustc_data_structures::static_assert_size!(ConstData<'_>, 40);
+rustc_data_structures::static_assert_size!(ConstData<'_>, 32);
 
 impl<'tcx> Const<'tcx> {
     #[inline]

compiler/rustc_middle/src/ty/consts/kind.rs

@@ -1,7 +1,7 @@
 use super::Const;
 use crate::mir;
 use crate::ty::abstract_const::CastKind;
-use crate::ty::{self, visit::TypeVisitableExt as _, List, Ty, TyCtxt};
+use crate::ty::{self, visit::TypeVisitableExt as _, Ty, TyCtxt};
 use rustc_macros::{extension, HashStable, TyDecodable, TyEncodable, TypeFoldable, TypeVisitable};
 
 #[extension(pub(crate) trait UnevaluatedConstEvalExt<'tcx>)]
@@ -40,14 +40,125 @@ impl<'tcx> ty::UnevaluatedConst<'tcx> {
     }
 }
 
+#[derive(Copy, Clone, Eq, PartialEq, Hash, Debug)]
+#[derive(HashStable, TyEncodable, TyDecodable, TypeVisitable, TypeFoldable)]
+pub enum ExprKind {
+    Binop(mir::BinOp),
+    UnOp(mir::UnOp),
+    FunctionCall,
+    Cast(CastKind),
+}
 #[derive(Copy, Clone, Eq, PartialEq, Hash)]
 #[derive(HashStable, TyEncodable, TyDecodable, TypeVisitable, TypeFoldable)]
-pub enum Expr<'tcx> {
-    Binop(mir::BinOp, Const<'tcx>, Const<'tcx>),
-    UnOp(mir::UnOp, Const<'tcx>),
-    FunctionCall(Const<'tcx>, &'tcx List<Const<'tcx>>),
-    Cast(CastKind, Const<'tcx>, Ty<'tcx>),
+pub struct Expr<'tcx> {
+    pub kind: ExprKind,
+    args: ty::GenericArgsRef<'tcx>,
+}
+impl<'tcx> Expr<'tcx> {
+    pub fn new_binop(
+        tcx: TyCtxt<'tcx>,
+        binop: mir::BinOp,
+        lhs_ty: Ty<'tcx>,
+        rhs_ty: Ty<'tcx>,
+        lhs_ct: Const<'tcx>,
+        rhs_ct: Const<'tcx>,
+    ) -> Self {
+        let args = tcx.mk_args_from_iter::<_, ty::GenericArg<'tcx>>(
+            [lhs_ty.into(), rhs_ty.into(), lhs_ct.into(), rhs_ct.into()].into_iter(),
+        );
+
+        Self { kind: ExprKind::Binop(binop), args }
+    }
+
+    pub fn binop_args(self) -> (Ty<'tcx>, Ty<'tcx>, Const<'tcx>, Const<'tcx>) {
+        assert!(matches!(self.kind, ExprKind::Binop(_)));
+
+        match self.args().as_slice() {
+            [lhs_ty, rhs_ty, lhs_ct, rhs_ct] => (
+                lhs_ty.expect_ty(),
+                rhs_ty.expect_ty(),
+                lhs_ct.expect_const(),
+                rhs_ct.expect_const(),
+            ),
+            _ => bug!("Invalid args for `Binop` expr {self:?}"),
+        }
+    }
+
+    pub fn new_unop(tcx: TyCtxt<'tcx>, unop: mir::UnOp, ty: Ty<'tcx>, ct: Const<'tcx>) -> Self {
+        let args =
+            tcx.mk_args_from_iter::<_, ty::GenericArg<'tcx>>([ty.into(), ct.into()].into_iter());
+
+        Self { kind: ExprKind::UnOp(unop), args }
+    }
+
+    pub fn unop_args(self) -> (Ty<'tcx>, Const<'tcx>) {
+        assert!(matches!(self.kind, ExprKind::UnOp(_)));
+
+        match self.args().as_slice() {
+            [ty, ct] => (ty.expect_ty(), ct.expect_const()),
+            _ => bug!("Invalid args for `UnOp` expr {self:?}"),
+        }
+    }
+
+    pub fn new_call(
+        tcx: TyCtxt<'tcx>,
+        func_ty: Ty<'tcx>,
+        func_expr: Const<'tcx>,
+        arguments: impl Iterator<Item = Const<'tcx>>,
+    ) -> Self {
+        let args = tcx.mk_args_from_iter::<_, ty::GenericArg<'tcx>>(
+            [func_ty.into(), func_expr.into()].into_iter().chain(arguments.map(|ct| ct.into())),
+        );
+
+        Self { kind: ExprKind::FunctionCall, args }
+    }
+
+    pub fn call_args(self) -> (Ty<'tcx>, Const<'tcx>, impl Iterator<Item = Const<'tcx>>) {
+        assert!(matches!(self.kind, ExprKind::FunctionCall));
+
+        match self.args().as_slice() {
+            [func_ty, func, rest @ ..] => (
+                func_ty.expect_ty(),
+                func.expect_const(),
+                rest.iter().map(|arg| arg.expect_const()),
+            ),
+            _ => bug!("Invalid args for `Call` expr {self:?}"),
+        }
+    }
+
+    pub fn new_cast(
+        tcx: TyCtxt<'tcx>,
+        cast: CastKind,
+        value_ty: Ty<'tcx>,
+        value: Const<'tcx>,
+        to_ty: Ty<'tcx>,
+    ) -> Self {
+        let args = tcx.mk_args_from_iter::<_, ty::GenericArg<'tcx>>(
+            [value_ty.into(), value.into(), to_ty.into()].into_iter(),
+        );
+
+        Self { kind: ExprKind::Cast(cast), args }
+    }
+
+    pub fn cast_args(self) -> (Ty<'tcx>, Const<'tcx>, Ty<'tcx>) {
+        assert!(matches!(self.kind, ExprKind::Cast(_)));
+
+        match self.args().as_slice() {
+            [value_ty, value, to_ty] => {
+                (value_ty.expect_ty(), value.expect_const(), to_ty.expect_ty())
+            }
+            _ => bug!("Invalid args for `Cast` expr {self:?}"),
+        }
+    }
+
+    pub fn new(kind: ExprKind, args: ty::GenericArgsRef<'tcx>) -> Self {
+        Self { kind, args }
+    }
+
+    pub fn args(&self) -> ty::GenericArgsRef<'tcx> {
+        self.args
+    }
 }
 
 #[cfg(target_pointer_width = "64")]
-rustc_data_structures::static_assert_size!(Expr<'_>, 24);
+rustc_data_structures::static_assert_size!(Expr<'_>, 16);

compiler/rustc_middle/src/ty/flags.rs

@@ -374,26 +374,7 @@ impl FlagComputation {
                 self.add_flags(TypeFlags::STILL_FURTHER_SPECIALIZABLE);
             }
             ty::ConstKind::Value(_) => {}
-            ty::ConstKind::Expr(e) => {
-                use ty::Expr;
-                match e {
-                    Expr::Binop(_, l, r) => {
-                        self.add_const(l);
-                        self.add_const(r);
-                    }
-                    Expr::UnOp(_, v) => self.add_const(v),
-                    Expr::FunctionCall(f, args) => {
-                        self.add_const(f);
-                        for arg in args {
-                            self.add_const(arg);
-                        }
-                    }
-                    Expr::Cast(_, c, t) => {
-                        self.add_ty(t);
-                        self.add_const(c);
-                    }
-                }
-            }
+            ty::ConstKind::Expr(e) => self.add_args(e.args()),
             ty::ConstKind::Error(_) => self.add_flags(TypeFlags::HAS_ERROR),
         }
     }

compiler/rustc_middle/src/ty/mod.rs

@@ -87,7 +87,7 @@ pub use self::closure::{
     CAPTURE_STRUCT_LOCAL,
 };
 pub use self::consts::{
-    Const, ConstData, ConstInt, ConstKind, Expr, ScalarInt, UnevaluatedConst, ValTree,
+    Const, ConstData, ConstInt, ConstKind, Expr, ExprKind, ScalarInt, UnevaluatedConst, ValTree,
 };
 pub use self::context::{
     tls, CtxtInterners, CurrentGcx, DeducedParamAttrs, Feed, FreeRegionInfo, GlobalCtxt, Lift,