Rollup of 8 pull requests

.gitignore

@@ -42,6 +42,7 @@ no_llvm_build
 /llvm/
 /mingw-build/
 build/
+!/compiler/rustc_mir_build/src/build/
 /build-rust-analyzer/
 /dist/
 /unicode-downloads

compiler/rustc_codegen_cranelift/src/base.rs

@@ -346,17 +346,10 @@ fn codegen_fn_body(fx: &mut FunctionCx<'_, '_, '_>, start_block: Block) {
                 crate::abi::codegen_return(fx);
             }
             TerminatorKind::Assert { cond, expected, msg, target, cleanup: _ } => {
-                if !fx.tcx.sess.overflow_checks() {
-                    let overflow_not_to_check = match msg {
-                        AssertKind::OverflowNeg(..) => true,
-                        AssertKind::Overflow(op, ..) => op.is_checkable(),
-                        _ => false,
-                    };
-                    if overflow_not_to_check {
-                        let target = fx.get_block(*target);
-                        fx.bcx.ins().jump(target, &[]);
-                        continue;
-                    }
+                if !fx.tcx.sess.overflow_checks() && msg.is_optional_overflow_check() {
+                    let target = fx.get_block(*target);
+                    fx.bcx.ins().jump(target, &[]);
+                    continue;
                 }
                 let cond = codegen_operand(fx, cond).load_scalar(fx);
 

compiler/rustc_codegen_ssa/src/glue.rs

@@ -46,7 +46,7 @@ pub fn size_and_align_of_dst<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>>(
                 // NOTE: ideally, we want the effects of both `unchecked_smul` and `unchecked_umul`
                 // (resulting in `mul nsw nuw` in LLVM IR), since we know that the multiplication
                 // cannot signed wrap, and that both operands are non-negative. But at the time of writing,
-                // `BuilderMethods` can't do this, and it doesn't seem to enable any further optimizations.
+                // the `LLVM-C` binding can't do this, and it doesn't seem to enable any further optimizations.
                 bx.unchecked_smul(info.unwrap(), bx.const_usize(unit.size.bytes())),
                 bx.const_usize(unit.align.abi.bytes()),
             )

compiler/rustc_codegen_ssa/src/mir/block.rs

@@ -563,15 +563,8 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
         // with #[rustc_inherit_overflow_checks] and inlined from
         // another crate (mostly core::num generic/#[inline] fns),
         // while the current crate doesn't use overflow checks.
-        if !bx.cx().check_overflow() {
-            let overflow_not_to_check = match msg {
-                AssertKind::OverflowNeg(..) => true,
-                AssertKind::Overflow(op, ..) => op.is_checkable(),
-                _ => false,
-            };
-            if overflow_not_to_check {
-                const_cond = Some(expected);
-            }
+        if !bx.cx().check_overflow() && msg.is_optional_overflow_check() {
+            const_cond = Some(expected);
         }
 
         // Don't codegen the panic block if success if known.

compiler/rustc_const_eval/src/interpret/machine.rs

@@ -155,7 +155,7 @@ pub trait Machine<'mir, 'tcx>: Sized {
 
     /// Whether Assert(OverflowNeg) and Assert(Overflow) MIR terminators should actually
     /// check for overflow.
-    fn ignore_checkable_overflow_assertions(_ecx: &InterpCx<'mir, 'tcx, Self>) -> bool;
+    fn ignore_optional_overflow_checks(_ecx: &InterpCx<'mir, 'tcx, Self>) -> bool;
 
     /// Entry point for obtaining the MIR of anything that should get evaluated.
     /// So not just functions and shims, but also const/static initializers, anonymous
@@ -474,7 +474,7 @@ pub macro compile_time_machine(<$mir: lifetime, $tcx: lifetime>) {
     }
 
     #[inline(always)]
-    fn ignore_checkable_overflow_assertions(_ecx: &InterpCx<$mir, $tcx, Self>) -> bool {
+    fn ignore_optional_overflow_checks(_ecx: &InterpCx<$mir, $tcx, Self>) -> bool {
         false
     }
 

compiler/rustc_const_eval/src/interpret/terminator.rs

@@ -138,12 +138,8 @@ impl<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
             }
 
             Assert { ref cond, expected, ref msg, target, cleanup } => {
-                let ignored = M::ignore_checkable_overflow_assertions(self)
-                    && match msg {
-                        mir::AssertKind::OverflowNeg(..) => true,
-                        mir::AssertKind::Overflow(op, ..) => op.is_checkable(),
-                        _ => false,
-                    };
+                let ignored =
+                    M::ignore_optional_overflow_checks(self) && msg.is_optional_overflow_check();
                 let cond_val = self.read_scalar(&self.eval_operand(cond, None)?)?.to_bool()?;
                 if ignored || expected == cond_val {
                     self.go_to_block(target);

compiler/rustc_error_codes/src/error_codes.rs

@@ -513,6 +513,7 @@ E0790: include_str!("./error_codes/E0790.md"),
 E0791: include_str!("./error_codes/E0791.md"),
 E0792: include_str!("./error_codes/E0792.md"),
 E0793: include_str!("./error_codes/E0793.md"),
+E0794: include_str!("./error_codes/E0794.md"),
 }
 
 // Undocumented removed error codes. Note that many removed error codes are documented.

compiler/rustc_error_codes/src/error_codes/E0794.md

@@ -0,0 +1,64 @@
+A lifetime parameter of a function definition is called *late-bound* if it both:
+
+1. appears in an argument type
+2. does not appear in a generic type constraint
+
+You cannot specify lifetime arguments for late-bound lifetime parameters.
+
+Erroneous code example:
+
+```compile_fail,E0794
+fn foo<'a>(x: &'a str) -> &'a str { x }
+let _ = foo::<'static>;
+```
+
+The type of a concrete instance of a generic function is universally quantified
+over late-bound lifetime parameters. This is because we want the function to
+work for any lifetime substituted for the late-bound lifetime parameter, no
+matter where the function is called. Consequently, it doesn't make sense to
+specify arguments for late-bound lifetime parameters, since they are not
+resolved until the function's call site(s).
+
+To fix the issue, remove the specified lifetime:
+
+```
+fn foo<'a>(x: &'a str) -> &'a str { x }
+let _ = foo;
+```
+
+### Additional information
+
+Lifetime parameters that are not late-bound are called *early-bound*.
+Confusion may arise from the fact that late-bound and early-bound
+lifetime parameters are declared the same way in function definitions.
+When referring to a function pointer type, universal quantification over
+late-bound lifetime parameters can be made explicit:
+
+```
+trait BarTrait<'a> {}
+
+struct Bar<'a> {
+    s: &'a str
+}
+
+impl<'a> BarTrait<'a> for Bar<'a> {}
+
+fn bar<'a, 'b, T>(x: &'a str, _t: T) -> &'a str
+where T: BarTrait<'b>
+{
+    x
+}
+
+let bar_fn: for<'a> fn(&'a str, Bar<'static>) -> &'a str = bar; // OK
+let bar_fn2 = bar::<'static, Bar>; // Not allowed
+let bar_fn3 = bar::<Bar>; // OK
+```
+
+In the definition of `bar`, the lifetime parameter `'a` is late-bound, while
+`'b` is early-bound. This is reflected in the type annotation for `bar_fn`,
+where `'a` is universally quantified and `'b` is substituted by a specific
+lifetime. It is not allowed to explicitly specify early-bound lifetime
+arguments when late-bound lifetime parameters are present (as for `bar_fn2`,
+see issue #42868: https://github.com/rust-lang/rust/issues/42868), although the
+types that are constrained by early-bound parameters can be specified (as for
+`bar_fn3`).

compiler/rustc_hir_analysis/src/astconv/generics.rs

@@ -612,7 +612,7 @@ pub(crate) fn prohibit_explicit_late_bound_lifetimes(
         if position == GenericArgPosition::Value
             && args.num_lifetime_params() != param_counts.lifetimes
         {
-            let mut err = tcx.sess.struct_span_err(span, msg);
+            let mut err = struct_span_err!(tcx.sess, span, E0794, "{}", msg);
             err.span_note(span_late, note);
             err.emit();
         } else {

compiler/rustc_hir_analysis/src/check/compare_impl_item.rs

@@ -1205,6 +1205,17 @@ fn compare_number_of_generics<'tcx>(
         return Ok(());
     }
 
+    // We never need to emit a separate error for RPITITs, since if an RPITIT
+    // has mismatched type or const generic arguments, then the method that it's
+    // inheriting the generics from will also have mismatched arguments, and
+    // we'll report an error for that instead. Delay a bug for safety, though.
+    if tcx.opt_rpitit_info(trait_.def_id).is_some() {
+        return Err(tcx.sess.delay_span_bug(
+            rustc_span::DUMMY_SP,
+            "errors comparing numbers of generics of trait/impl functions were not emitted",
+        ));
+    }
+
     let matchings = [
         ("type", trait_own_counts.types, impl_own_counts.types),
         ("const", trait_own_counts.consts, impl_own_counts.consts),

compiler/rustc_middle/src/mir/mod.rs

@@ -1268,6 +1268,13 @@ impl<'tcx> BasicBlockData<'tcx> {
 }
 
 impl<O> AssertKind<O> {
+    /// Returns true if this an overflow checking assertion controlled by -C overflow-checks.
+    pub fn is_optional_overflow_check(&self) -> bool {
+        use AssertKind::*;
+        use BinOp::*;
+        matches!(self, OverflowNeg(..) | Overflow(Add | Sub | Mul | Shl | Shr, ..))
+    }
+
     /// Getting a description does not require `O` to be printable, and does not
     /// require allocation.
     /// The caller is expected to handle `BoundsCheck` separately.
@@ -1992,16 +1999,6 @@ impl BorrowKind {
     }
 }
 
-impl BinOp {
-    /// The checkable operators are those whose overflow checking behavior is controlled by
-    /// -Coverflow-checks option. The remaining operators have either no overflow conditions (e.g.,
-    /// BitAnd, BitOr, BitXor) or are always checked for overflow (e.g., Div, Rem).
-    pub fn is_checkable(self) -> bool {
-        use self::BinOp::*;
-        matches!(self, Add | Sub | Mul | Shl | Shr)
-    }
-}
-
 impl<'tcx> Debug for Rvalue<'tcx> {
     fn fmt(&self, fmt: &mut Formatter<'_>) -> fmt::Result {
         use self::Rvalue::*;

compiler/rustc_middle/src/mir/syntax.rs

@@ -646,8 +646,7 @@ pub enum TerminatorKind<'tcx> {
     /// When overflow checking is disabled and this is run-time MIR (as opposed to compile-time MIR
     /// that is used for CTFE), the following variants of this terminator behave as `goto target`:
     /// - `OverflowNeg(..)`,
-    /// - `Overflow(op, ..)` if op is a "checkable" operation (add, sub, mul, shl, shr, but NOT
-    /// div or rem).
+    /// - `Overflow(op, ..)` if op is add, sub, mul, shl, shr, but NOT div or rem.
     Assert {
         cond: Operand<'tcx>,
         expected: bool,

compiler/rustc_mir_build/src/build/expr/as_rvalue.rs

@@ -73,19 +73,34 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
             }
             ExprKind::Binary { op, lhs, rhs } => {
                 let lhs = unpack!(
-                    block =
-                        this.as_operand(block, scope, &this.thir[lhs], LocalInfo::Boring, NeedsTemporary::Maybe)
+                    block = this.as_operand(
+                        block,
+                        scope,
+                        &this.thir[lhs],
+                        LocalInfo::Boring,
+                        NeedsTemporary::Maybe
+                    )
                 );
                 let rhs = unpack!(
-                    block =
-                        this.as_operand(block, scope, &this.thir[rhs], LocalInfo::Boring, NeedsTemporary::No)
+                    block = this.as_operand(
+                        block,
+                        scope,
+                        &this.thir[rhs],
+                        LocalInfo::Boring,
+                        NeedsTemporary::No
+                    )
                 );
                 this.build_binary_op(block, op, expr_span, expr.ty, lhs, rhs)
             }
             ExprKind::Unary { op, arg } => {
                 let arg = unpack!(
-                    block =
-                        this.as_operand(block, scope, &this.thir[arg], LocalInfo::Boring, NeedsTemporary::No)
+                    block = this.as_operand(
+                        block,
+                        scope,
+                        &this.thir[arg],
+                        LocalInfo::Boring,
+                        NeedsTemporary::No
+                    )
                 );
                 // Check for -MIN on signed integers
                 if this.check_overflow && op == UnOp::Neg && expr.ty.is_signed() {
@@ -272,8 +287,13 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
             }
             ExprKind::Pointer { cast, source } => {
                 let source = unpack!(
-                    block =
-                        this.as_operand(block, scope, &this.thir[source], LocalInfo::Boring, NeedsTemporary::No)
+                    block = this.as_operand(
+                        block,
+                        scope,
+                        &this.thir[source],
+                        LocalInfo::Boring,
+                        NeedsTemporary::No
+                    )
                 );
                 block.and(Rvalue::Cast(CastKind::Pointer(cast), source, expr.ty))
             }
@@ -502,8 +522,10 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
                     Category::of(&expr.kind),
                     Some(Category::Rvalue(RvalueFunc::AsRvalue) | Category::Constant)
                 ));
-                let operand =
-                    unpack!(block = this.as_operand(block, scope, expr, LocalInfo::Boring, NeedsTemporary::No));
+                let operand = unpack!(
+                    block =
+                        this.as_operand(block, scope, expr, LocalInfo::Boring, NeedsTemporary::No)
+                );
                 block.and(Rvalue::Use(operand))
             }
         }
@@ -662,8 +684,9 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
             // Repeating a const does nothing
         } else {
             // For a non-const, we may need to generate an appropriate `Drop`
-            let value_operand =
-                unpack!(block = this.as_operand(block, scope, value, LocalInfo::Boring, NeedsTemporary::No));
+            let value_operand = unpack!(
+                block = this.as_operand(block, scope, value, LocalInfo::Boring, NeedsTemporary::No)
+            );
             if let Operand::Move(to_drop) = value_operand {
                 let success = this.cfg.start_new_block();
                 this.cfg.terminate(

compiler/rustc_mir_build/src/build/matches/mod.rs

@@ -2252,7 +2252,9 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
                 user_ty: None,
                 source_info,
                 internal: false,
-                local_info: ClearCrossCrate::Set(Box::new(LocalInfo::User(BindingForm::RefForGuard))),
+                local_info: ClearCrossCrate::Set(Box::new(LocalInfo::User(
+                    BindingForm::RefForGuard,
+                ))),
             });
             self.var_debug_info.push(VarDebugInfo {
                 name,

compiler/rustc_mir_build/src/build/mod.rs

@@ -876,21 +876,18 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
                 } => {
                     self.local_decls[local].mutability = mutability;
                     self.local_decls[local].source_info.scope = self.source_scope;
-                    **self.local_decls[local].local_info.as_mut().assert_crate_local() = if let Some(kind) = param.self_kind {
-                        LocalInfo::User(
-                            BindingForm::ImplicitSelf(kind),
-                        )
-                    } else {
-                        let binding_mode = ty::BindingMode::BindByValue(mutability);
-                        LocalInfo::User(BindingForm::Var(
-                            VarBindingForm {
+                    **self.local_decls[local].local_info.as_mut().assert_crate_local() =
+                        if let Some(kind) = param.self_kind {
+                            LocalInfo::User(BindingForm::ImplicitSelf(kind))
+                        } else {
+                            let binding_mode = ty::BindingMode::BindByValue(mutability);
+                            LocalInfo::User(BindingForm::Var(VarBindingForm {
                                 binding_mode,
                                 opt_ty_info: param.ty_span,
                                 opt_match_place: Some((None, span)),
                                 pat_span: span,
-                            },
-                        ))
-                    };
+                            }))
+                        };
                     self.var_indices.insert(var, LocalsForNode::One(local));
                 }
                 _ => {

library/core/src/hash/mod.rs

@@ -834,7 +834,7 @@ mod impls {
 
                 #[inline]
                 fn hash_slice<H: ~const Hasher>(data: &[$ty], state: &mut H) {
-                    let newlen = data.len() * mem::size_of::<$ty>();
+                    let newlen = mem::size_of_val(data);
                     let ptr = data.as_ptr() as *const u8;
                     // SAFETY: `ptr` is valid and aligned, as this macro is only used
                     // for numeric primitives which have no padding. The new slice only

library/std/src/os/android/net.rs

@@ -1,8 +1,8 @@
 //! Android-specific networking functionality.
 
-#![unstable(feature = "tcp_quickack", issue = "96256")]
+#![stable(feature = "unix_socket_abstract", since = "CURRENT_RUSTC_VERSION")]
 
-#[unstable(feature = "unix_socket_abstract", issue = "85410")]
+#[stable(feature = "unix_socket_abstract", since = "CURRENT_RUSTC_VERSION")]
 pub use crate::os::net::linux_ext::addr::SocketAddrExt;
 
 #[unstable(feature = "tcp_quickack", issue = "96256")]

library/std/src/os/linux/net.rs

@@ -1,8 +1,8 @@
 //! Linux-specific networking functionality.
 
-#![unstable(feature = "tcp_quickack", issue = "96256")]
+#![stable(feature = "unix_socket_abstract", since = "CURRENT_RUSTC_VERSION")]
 
-#[unstable(feature = "unix_socket_abstract", issue = "85410")]
+#[stable(feature = "unix_socket_abstract", since = "CURRENT_RUSTC_VERSION")]
 pub use crate::os::net::linux_ext::addr::SocketAddrExt;
 
 #[unstable(feature = "tcp_quickack", issue = "96256")]