Rollup of 8 pull requests

compiler/rustc_codegen_ssa/src/mir/mod.rs

@@ -188,8 +188,10 @@ pub fn codegen_mir<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>>(
 
     fx.per_local_var_debug_info = fx.compute_per_local_var_debug_info(&mut bx);
 
+    let mut all_consts_ok = true;
     for const_ in &mir.required_consts {
         if let Err(err) = fx.eval_mir_constant(const_) {
+            all_consts_ok = false;
             match err {
                 // errored or at least linted
                 ErrorHandled::Reported(ErrorReported) | ErrorHandled::Linted => {}
@@ -199,6 +201,25 @@ pub fn codegen_mir<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>>(
             }
         }
     }
+    if !all_consts_ok {
+        // There is no delay_span_bug here, we just have to rely on a hard error actually having
+        // been raised.
+        bx.abort();
+        // `abort` does not terminate the block, so we still need to generate
+        // an `unreachable` terminator after it.
+        bx.unreachable();
+        // We also have to delete all the other basic blocks again...
+        for bb in mir.basic_blocks().indices() {
+            if bb != mir::START_BLOCK {
+                unsafe {
+                    bx.delete_basic_block(fx.blocks[bb]);
+                }
+            }
+        }
+        // FIXME: Can we somehow avoid all this by evaluating the consts before creating the basic
+        // blocks? The tricky part is doing that without duplicating `fx.eval_mir_constant`.
+        return;
+    }
 
     let memory_locals = analyze::non_ssa_locals(&fx);
 

compiler/rustc_codegen_ssa/src/mir/operand.rs

@@ -6,9 +6,8 @@ use crate::glue;
 use crate::traits::*;
 use crate::MemFlags;
 
-use rustc_errors::ErrorReported;
 use rustc_middle::mir;
-use rustc_middle::mir::interpret::{ConstValue, ErrorHandled, Pointer, Scalar};
+use rustc_middle::mir::interpret::{ConstValue, Pointer, Scalar};
 use rustc_middle::ty::layout::TyAndLayout;
 use rustc_middle::ty::Ty;
 use rustc_target::abi::{Abi, Align, LayoutOf, Size};
@@ -439,25 +438,9 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
             }
 
             mir::Operand::Constant(ref constant) => {
-                self.eval_mir_constant_to_operand(bx, constant).unwrap_or_else(|err| {
-                    match err {
-                        // errored or at least linted
-                        ErrorHandled::Reported(ErrorReported) | ErrorHandled::Linted => {}
-                        ErrorHandled::TooGeneric => {
-                            bug!("codegen encountered polymorphic constant")
-                        }
-                    }
-                    // Allow RalfJ to sleep soundly knowing that even refactorings that remove
-                    // the above error (or silence it under some conditions) will not cause UB.
-                    bx.abort();
-                    // We still have to return an operand but it doesn't matter,
-                    // this code is unreachable.
-                    let ty = self.monomorphize(constant.literal.ty);
-                    let layout = bx.cx().layout_of(ty);
-                    bx.load_operand(PlaceRef::new_sized(
-                        bx.cx().const_undef(bx.cx().type_ptr_to(bx.cx().backend_type(layout))),
-                        layout,
-                    ))
+                // This cannot fail because we checked all required_consts in advance.
+                self.eval_mir_constant_to_operand(bx, constant).unwrap_or_else(|_err| {
+                    span_bug!(constant.span, "erroneous constant not captured by required_consts")
                 })
             }
         }

compiler/rustc_mir/src/borrow_check/diagnostics/mutability_errors.rs

@@ -1,9 +1,12 @@
 use rustc_hir as hir;
 use rustc_hir::Node;
 use rustc_index::vec::Idx;
-use rustc_middle::mir::{self, ClearCrossCrate, Local, LocalDecl, LocalInfo, Location};
 use rustc_middle::mir::{Mutability, Place, PlaceRef, ProjectionElem};
 use rustc_middle::ty::{self, Ty, TyCtxt};
+use rustc_middle::{
+    hir::place::PlaceBase,
+    mir::{self, ClearCrossCrate, Local, LocalDecl, LocalInfo, Location},
+};
 use rustc_span::source_map::DesugaringKind;
 use rustc_span::symbol::{kw, Symbol};
 use rustc_span::Span;
@@ -241,6 +244,10 @@ impl<'a, 'tcx> MirBorrowckCtxt<'a, 'tcx> {
                     format!("mut {}", self.local_names[local].unwrap()),
                     Applicability::MachineApplicable,
                 );
+                let tcx = self.infcx.tcx;
+                if let ty::Closure(id, _) = the_place_err.ty(self.body, tcx).ty.kind() {
+                    self.show_mutating_upvar(tcx, id, the_place_err, &mut err);
+                }
             }
 
             // Also suggest adding mut for upvars
@@ -271,6 +278,14 @@ impl<'a, 'tcx> MirBorrowckCtxt<'a, 'tcx> {
                         );
                     }
                 }
+
+                let tcx = self.infcx.tcx;
+                if let ty::Ref(_, ty, Mutability::Mut) = the_place_err.ty(self.body, tcx).ty.kind()
+                {
+                    if let ty::Closure(id, _) = ty.kind() {
+                        self.show_mutating_upvar(tcx, id, the_place_err, &mut err);
+                    }
+                }
             }
 
             // complete hack to approximate old AST-borrowck
@@ -463,6 +478,45 @@ impl<'a, 'tcx> MirBorrowckCtxt<'a, 'tcx> {
         err.buffer(&mut self.errors_buffer);
     }
 
+    // point to span of upvar making closure call require mutable borrow
+    fn show_mutating_upvar(
+        &self,
+        tcx: TyCtxt<'_>,
+        id: &hir::def_id::DefId,
+        the_place_err: PlaceRef<'tcx>,
+        err: &mut DiagnosticBuilder<'_>,
+    ) {
+        let id = id.expect_local();
+        let tables = tcx.typeck(id);
+        let hir_id = tcx.hir().local_def_id_to_hir_id(id);
+        let (span, place) = &tables.closure_kind_origins()[hir_id];
+        let reason = if let PlaceBase::Upvar(upvar_id) = place.base {
+            let upvar = ty::place_to_string_for_capture(tcx, place);
+            match tables.upvar_capture(upvar_id) {
+                ty::UpvarCapture::ByRef(ty::UpvarBorrow {
+                    kind: ty::BorrowKind::MutBorrow,
+                    ..
+                }) => {
+                    format!("mutable borrow of `{}`", upvar)
+                }
+                ty::UpvarCapture::ByValue(_) => {
+                    format!("possible mutation of `{}`", upvar)
+                }
+                _ => bug!("upvar `{}` borrowed, but not mutably", upvar),
+            }
+        } else {
+            bug!("not an upvar")
+        };
+        err.span_label(
+            *span,
+            format!(
+                "calling `{}` requires mutable binding due to {}",
+                self.describe_place(the_place_err).unwrap(),
+                reason
+            ),
+        );
+    }
+
     /// Targeted error when encountering an `FnMut` closure where an `Fn` closure was expected.
     fn expected_fn_found_fn_mut_call(&self, err: &mut DiagnosticBuilder<'_>, sp: Span, act: &str) {
         err.span_label(sp, format!("cannot {}", act));

compiler/rustc_mir/src/interpret/operand.rs

@@ -511,6 +511,10 @@ impl<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
             Constant(ref constant) => {
                 let val =
                     self.subst_from_current_frame_and_normalize_erasing_regions(constant.literal);
+                // This can still fail:
+                // * During ConstProp, with `TooGeneric` or since the `requried_consts` were not all
+                //   checked yet.
+                // * During CTFE, since promoteds in `const`/`static` initializer bodies can fail.
                 self.const_to_op(val, layout)?
             }
         };

compiler/rustc_mir/src/interpret/validity.rs

@@ -515,7 +515,11 @@ impl<'rt, 'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> ValidityVisitor<'rt, 'mir, '
                 Ok(true)
             }
             ty::Float(_) | ty::Int(_) | ty::Uint(_) => {
-                let value = self.ecx.read_scalar(value)?;
+                let value = try_validation!(
+                    self.ecx.read_scalar(value),
+                    self.path,
+                    err_unsup!(ReadPointerAsBytes) => { "read of part of a pointer" },
+                );
                 // NOTE: Keep this in sync with the array optimization for int/float
                 // types below!
                 if self.ctfe_mode.is_some() {

compiler/rustc_span/src/symbol.rs

@@ -622,6 +622,7 @@ symbols! {
         intel,
         into_iter,
         into_result,
+        into_trait,
         intra_doc_pointers,
         intrinsics,
         irrefutable_let_patterns,
@@ -1159,6 +1160,8 @@ symbols! {
         truncf32,
         truncf64,
         try_blocks,
+        try_from_trait,
+        try_into_trait,
         try_trait,
         tt,
         tuple,

compiler/rustc_trait_selection/src/traits/error_reporting/suggestions.rs

@@ -286,21 +286,32 @@ fn suggest_restriction(
         );
     } else {
         // Trivial case: `T` needs an extra bound: `T: Bound`.
-        let (sp, suggestion) = match super_traits {
-            None => predicate_constraint(
+        let (sp, suggestion) = match (
+            generics
+                .params
+                .iter()
+                .filter(
+                    |p| !matches!(p.kind, hir::GenericParamKind::Type { synthetic: Some(_), ..}),
+                )
+                .next(),
+            super_traits,
+        ) {
+            (_, None) => predicate_constraint(
                 generics,
                 trait_ref.without_const().to_predicate(tcx).to_string(),
             ),
-            Some((ident, bounds)) => match bounds {
-                [.., bound] => (
-                    bound.span().shrink_to_hi(),
-                    format!(" + {}", trait_ref.print_only_trait_path().to_string()),
-                ),
-                [] => (
-                    ident.span.shrink_to_hi(),
-                    format!(": {}", trait_ref.print_only_trait_path().to_string()),
-                ),
-            },
+            (None, Some((ident, []))) => (
+                ident.span.shrink_to_hi(),
+                format!(": {}", trait_ref.print_only_trait_path().to_string()),
+            ),
+            (_, Some((_, [.., bounds]))) => (
+                bounds.span().shrink_to_hi(),
+                format!(" + {}", trait_ref.print_only_trait_path().to_string()),
+            ),
+            (Some(_), Some((_, []))) => (
+                generics.span.shrink_to_hi(),
+                format!(": {}", trait_ref.print_only_trait_path().to_string()),
+            ),
         };
 
         err.span_suggestion_verbose(

library/core/src/convert/mod.rs

@@ -267,6 +267,7 @@ pub trait AsMut<T: ?Sized> {
 ///
 /// [`String`]: ../../std/string/struct.String.html
 /// [`Vec`]: ../../std/vec/struct.Vec.html
+#[rustc_diagnostic_item = "into_trait"]
 #[stable(feature = "rust1", since = "1.0.0")]
 pub trait Into<T>: Sized {
     /// Performs the conversion.
@@ -382,6 +383,7 @@ pub trait From<T>: Sized {
 ///
 /// This suffers the same restrictions and reasoning as implementing
 /// [`Into`], see there for details.
+#[rustc_diagnostic_item = "try_into_trait"]
 #[stable(feature = "try_from", since = "1.34.0")]
 pub trait TryInto<T>: Sized {
     /// The type returned in the event of a conversion error.
@@ -462,6 +464,7 @@ pub trait TryInto<T>: Sized {
 ///
 /// [`try_from`]: TryFrom::try_from
 /// [`!`]: ../../std/primitive.never.html
+#[rustc_diagnostic_item = "try_from_trait"]
 #[stable(feature = "try_from", since = "1.34.0")]
 pub trait TryFrom<T>: Sized {
     /// The type returned in the event of a conversion error.

library/core/src/option.rs

@@ -428,6 +428,40 @@ impl<T> Option<T> {
         }
     }
 
+    /// Returns the contained [`Some`] value, consuming the `self` value,
+    /// without checking that the value is not [`None`].
+    ///
+    /// # Safety
+    ///
+    /// Calling this method on [`None`] is *[undefined behavior]*.
+    ///
+    /// [undefined behavior]: https://doc.rust-lang.org/reference/behavior-considered-undefined.html
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// #![feature(option_result_unwrap_unchecked)]
+    /// let x = Some("air");
+    /// assert_eq!(unsafe { x.unwrap_unchecked() }, "air");
+    /// ```
+    ///
+    /// ```no_run
+    /// #![feature(option_result_unwrap_unchecked)]
+    /// let x: Option<&str> = None;
+    /// assert_eq!(unsafe { x.unwrap_unchecked() }, "air"); // Undefined behavior!
+    /// ```
+    #[inline]
+    #[track_caller]
+    #[unstable(feature = "option_result_unwrap_unchecked", reason = "newly added", issue = "81383")]
+    pub unsafe fn unwrap_unchecked(self) -> T {
+        debug_assert!(self.is_some());
+        match self {
+            Some(val) => val,
+            // SAFETY: the safety contract must be upheld by the caller.
+            None => unsafe { hint::unreachable_unchecked() },
+        }
+    }
+
     /////////////////////////////////////////////////////////////////////////
     // Transforming contained values
     /////////////////////////////////////////////////////////////////////////

library/core/src/result.rs

@@ -229,7 +229,7 @@
 
 use crate::iter::{self, FromIterator, FusedIterator, TrustedLen};
 use crate::ops::{self, Deref, DerefMut};
-use crate::{convert, fmt};
+use crate::{convert, fmt, hint};
 
 /// `Result` is a type that represents either success ([`Ok`]) or failure ([`Err`]).
 ///
@@ -821,6 +821,74 @@ impl<T, E> Result<T, E> {
             Err(e) => op(e),
         }
     }
+
+    /// Returns the contained [`Ok`] value, consuming the `self` value,
+    /// without checking that the value is not an [`Err`].
+    ///
+    /// # Safety
+    ///
+    /// Calling this method on an [`Err`] is *[undefined behavior]*.
+    ///
+    /// [undefined behavior]: https://doc.rust-lang.org/reference/behavior-considered-undefined.html
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// #![feature(option_result_unwrap_unchecked)]
+    /// let x: Result<u32, &str> = Ok(2);
+    /// assert_eq!(unsafe { x.unwrap_unchecked() }, 2);
+    /// ```
+    ///
+    /// ```no_run
+    /// #![feature(option_result_unwrap_unchecked)]
+    /// let x: Result<u32, &str> = Err("emergency failure");
+    /// unsafe { x.unwrap_unchecked(); } // Undefined behavior!
+    /// ```
+    #[inline]
+    #[track_caller]
+    #[unstable(feature = "option_result_unwrap_unchecked", reason = "newly added", issue = "81383")]
+    pub unsafe fn unwrap_unchecked(self) -> T {
+        debug_assert!(self.is_ok());
+        match self {
+            Ok(t) => t,
+            // SAFETY: the safety contract must be upheld by the caller.
+            Err(_) => unsafe { hint::unreachable_unchecked() },
+        }
+    }
+
+    /// Returns the contained [`Err`] value, consuming the `self` value,
+    /// without checking that the value is not an [`Ok`].
+    ///
+    /// # Safety
+    ///
+    /// Calling this method on an [`Ok`] is *[undefined behavior]*.
+    ///
+    /// [undefined behavior]: https://doc.rust-lang.org/reference/behavior-considered-undefined.html
+    ///
+    /// # Examples
+    ///
+    /// ```no_run
+    /// #![feature(option_result_unwrap_unchecked)]
+    /// let x: Result<u32, &str> = Ok(2);
+    /// unsafe { x.unwrap_err_unchecked() }; // Undefined behavior!
+    /// ```
+    ///
+    /// ```
+    /// #![feature(option_result_unwrap_unchecked)]
+    /// let x: Result<u32, &str> = Err("emergency failure");
+    /// assert_eq!(unsafe { x.unwrap_err_unchecked() }, "emergency failure");
+    /// ```
+    #[inline]
+    #[track_caller]
+    #[unstable(feature = "option_result_unwrap_unchecked", reason = "newly added", issue = "81383")]
+    pub unsafe fn unwrap_err_unchecked(self) -> E {
+        debug_assert!(self.is_err());
+        match self {
+            // SAFETY: the safety contract must be upheld by the caller.
+            Ok(_) => unsafe { hint::unreachable_unchecked() },
+            Err(e) => e,
+        }
+    }
 }
 
 impl<T: Copy, E> Result<&T, E> {