Rollup of 9 pull requests

compiler/rustc_ast/src/token.rs

@@ -473,6 +473,7 @@ impl Token {
                 kw::Extern,
                 kw::Impl,
                 kw::Unsafe,
+                kw::Const,
                 kw::Static,
                 kw::Union,
                 kw::Macro,

compiler/rustc_ast/src/util/literal.rs

@@ -163,12 +163,7 @@ impl LitKind {
             }
             LitKind::Str(symbol, ast::StrStyle::Raw(n)) => (token::StrRaw(n), symbol, None),
             LitKind::ByteStr(ref bytes) => {
-                let string = bytes
-                    .iter()
-                    .cloned()
-                    .flat_map(ascii::escape_default)
-                    .map(Into::<char>::into)
-                    .collect::<String>();
+                let string = bytes.escape_ascii().to_string();
                 (token::ByteStr, Symbol::intern(&string), None)
             }
             LitKind::Byte(byte) => {

compiler/rustc_codegen_llvm/src/attributes.rs

@@ -35,6 +35,10 @@ pub fn apply_to_callsite(callsite: &Value, idx: AttributePlace, attrs: &[&Attrib
 /// Get LLVM attribute for the provided inline heuristic.
 #[inline]
 fn inline_attr<'ll>(cx: &CodegenCx<'ll, '_>, inline: InlineAttr) -> Option<&'ll Attribute> {
+    if !cx.tcx.sess.opts.unstable_opts.inline_llvm {
+        // disable LLVM inlining
+        return Some(AttributeKind::NoInline.create_attr(cx.llcx));
+    }
     match inline {
         InlineAttr::Hint => Some(AttributeKind::InlineHint.create_attr(cx.llcx)),
         InlineAttr::Always => Some(AttributeKind::AlwaysInline.create_attr(cx.llcx)),

compiler/rustc_codegen_ssa/src/back/link.rs

@@ -44,7 +44,7 @@ use std::io::{BufWriter, Write};
 use std::ops::Deref;
 use std::path::{Path, PathBuf};
 use std::process::{ExitStatus, Output, Stdio};
-use std::{ascii, char, env, fmt, fs, io, mem, str};
+use std::{env, fmt, fs, io, mem, str};
 
 pub fn ensure_removed(diag_handler: &Handler, path: &Path) {
     if let Err(e) = fs::remove_file(path) {
@@ -552,14 +552,6 @@ fn link_staticlib<'a>(
     Ok(())
 }
 
-fn escape_stdout_stderr_string(s: &[u8]) -> String {
-    str::from_utf8(s).map(|s| s.to_owned()).unwrap_or_else(|_| {
-        let mut x = "Non-UTF-8 output: ".to_string();
-        x.extend(s.iter().flat_map(|&b| ascii::escape_default(b)).map(char::from));
-        x
-    })
-}
-
 /// Use `thorin` (rust implementation of a dwarf packaging utility) to link DWARF objects into a
 /// DWARF package.
 fn link_dwarf_object<'a>(
@@ -866,7 +858,7 @@ fn link_natively<'a>(
             if !prog.status.success() {
                 let mut output = prog.stderr.clone();
                 output.extend_from_slice(&prog.stdout);
-                let escaped_output = escape_stdout_stderr_string(&output);
+                let escaped_output = escape_string(&output);
                 let mut err = sess.struct_err(&format!(
                     "linking with `{}` failed: {}",
                     linker_path.display(),
@@ -934,8 +926,8 @@ fn link_natively<'a>(
 
                 sess.abort_if_errors();
             }
-            info!("linker stderr:\n{}", escape_stdout_stderr_string(&prog.stderr));
-            info!("linker stdout:\n{}", escape_stdout_stderr_string(&prog.stdout));
+            info!("linker stderr:\n{}", escape_string(&prog.stderr));
+            info!("linker stdout:\n{}", escape_string(&prog.stdout));
         }
         Err(e) => {
             let linker_not_found = e.kind() == io::ErrorKind::NotFound;
@@ -1065,11 +1057,10 @@ fn strip_symbols_in_osx<'a>(sess: &'a Session, out_filename: &Path, option: Opti
 }
 
 fn escape_string(s: &[u8]) -> String {
-    str::from_utf8(s).map(|s| s.to_owned()).unwrap_or_else(|_| {
-        let mut x = "Non-UTF-8 output: ".to_string();
-        x.extend(s.iter().flat_map(|&b| ascii::escape_default(b)).map(char::from));
-        x
-    })
+    match str::from_utf8(s) {
+        Ok(s) => s.to_owned(),
+        Err(_) => format!("Non-UTF-8 output: {}", s.escape_ascii()),
+    }
 }
 
 fn add_sanitizer_libraries(sess: &Session, crate_type: CrateType, linker: &mut dyn Linker) {

compiler/rustc_middle/src/mir/mod.rs

@@ -2633,15 +2633,7 @@ fn pretty_print_const<'tcx>(
 }
 
 fn pretty_print_byte_str(fmt: &mut Formatter<'_>, byte_str: &[u8]) -> fmt::Result {
-    fmt.write_str("b\"")?;
-    for &c in byte_str {
-        for e in std::ascii::escape_default(c) {
-            fmt.write_char(e as char)?;
-        }
-    }
-    fmt.write_str("\"")?;
-
-    Ok(())
+    write!(fmt, "b\"{}\"", byte_str.escape_ascii())
 }
 
 fn comma_sep<'tcx>(fmt: &mut Formatter<'_>, elems: Vec<ConstantKind<'tcx>>) -> fmt::Result {

compiler/rustc_middle/src/traits/mod.rs

@@ -915,6 +915,12 @@ impl ObjectSafetyViolation {
             ObjectSafetyViolation::Method(name, MethodViolationCode::ReferencesSelfOutput, _) => {
                 format!("method `{}` references the `Self` type in its return type", name).into()
             }
+            ObjectSafetyViolation::Method(
+                name,
+                MethodViolationCode::ReferencesImplTraitInTrait,
+                _,
+            ) => format!("method `{}` references an `impl Trait` type in its return type", name)
+                .into(),
             ObjectSafetyViolation::Method(
                 name,
                 MethodViolationCode::WhereClauseReferencesSelf,
@@ -1021,6 +1027,9 @@ pub enum MethodViolationCode {
     /// e.g., `fn foo(&self) -> Self`
     ReferencesSelfOutput,
 
+    /// e.g., `fn foo(&self) -> impl Sized`
+    ReferencesImplTraitInTrait,
+
     /// e.g., `fn foo(&self) where Self: Clone`
     WhereClauseReferencesSelf,
 

compiler/rustc_middle/src/ty/print/pretty.rs

@@ -1405,14 +1405,7 @@ pub trait PrettyPrinter<'tcx>:
     }
 
     fn pretty_print_byte_str(mut self, byte_str: &'tcx [u8]) -> Result<Self::Const, Self::Error> {
-        define_scoped_cx!(self);
-        p!("b\"");
-        for &c in byte_str {
-            for e in std::ascii::escape_default(c) {
-                self.write_char(e as char)?;
-            }
-        }
-        p!("\"");
+        write!(self, "b\"{}\"", byte_str.escape_ascii())?;
         Ok(self)
     }
 

compiler/rustc_session/src/options.rs

@@ -1345,6 +1345,8 @@ options! {
         "hash spans relative to their parent item for incr. comp. (default: no)"),
     incremental_verify_ich: bool = (false, parse_bool, [UNTRACKED],
         "verify incr. comp. hashes of green query instances (default: no)"),
+    inline_llvm: bool = (true, parse_bool, [TRACKED],
+        "enable LLVM inlining (default: yes)"),
     inline_mir: Option<bool> = (None, parse_opt_bool, [TRACKED],
         "enable MIR inlining (default: no)"),
     inline_mir_threshold: Option<usize> = (None, parse_opt_number, [TRACKED],

compiler/rustc_trait_selection/src/traits/object_safety.rs

@@ -13,6 +13,7 @@ use super::elaborate_predicates;
 use crate::infer::TyCtxtInferExt;
 use crate::traits::query::evaluate_obligation::InferCtxtExt;
 use crate::traits::{self, Obligation, ObligationCause};
+use hir::def::DefKind;
 use rustc_errors::{FatalError, MultiSpan};
 use rustc_hir as hir;
 use rustc_hir::def_id::DefId;
@@ -431,6 +432,9 @@ fn virtual_call_violation_for_method<'tcx>(
     if contains_illegal_self_type_reference(tcx, trait_def_id, sig.output()) {
         return Some(MethodViolationCode::ReferencesSelfOutput);
     }
+    if contains_illegal_impl_trait_in_trait(tcx, sig.output()) {
+        return Some(MethodViolationCode::ReferencesImplTraitInTrait);
+    }
 
     // We can't monomorphize things like `fn foo<A>(...)`.
     let own_counts = tcx.generics_of(method.def_id).own_counts();
@@ -793,6 +797,12 @@ fn contains_illegal_self_type_reference<'tcx, T: TypeVisitable<'tcx>>(
                         ControlFlow::CONTINUE
                     }
                 }
+                ty::Projection(ref data)
+                    if self.tcx.def_kind(data.item_def_id) == DefKind::ImplTraitPlaceholder =>
+                {
+                    // We'll deny these later in their own pass
+                    ControlFlow::CONTINUE
+                }
                 ty::Projection(ref data) => {
                     // This is a projected type `<Foo as SomeTrait>::X`.
 
@@ -861,6 +871,22 @@ fn contains_illegal_self_type_reference<'tcx, T: TypeVisitable<'tcx>>(
         .is_break()
 }
 
+pub fn contains_illegal_impl_trait_in_trait<'tcx>(
+    tcx: TyCtxt<'tcx>,
+    ty: ty::Binder<'tcx, Ty<'tcx>>,
+) -> bool {
+    // FIXME(RPITIT): Perhaps we should use a visitor here?
+    ty.skip_binder().walk().any(|arg| {
+        if let ty::GenericArgKind::Type(ty) = arg.unpack()
+            && let ty::Projection(proj) = ty.kind()
+        {
+            tcx.def_kind(proj.item_def_id) == DefKind::ImplTraitPlaceholder
+        } else {
+            false
+        }
+    })
+}
+
 pub fn provide(providers: &mut ty::query::Providers) {
     *providers = ty::query::Providers { object_safety_violations, ..*providers };
 }

compiler/rustc_typeck/src/check/wfcheck.rs

@@ -1,4 +1,5 @@
 use crate::constrained_generic_params::{identify_constrained_generic_params, Parameter};
+use hir::def::DefKind;
 use rustc_ast as ast;
 use rustc_data_structures::fx::{FxHashMap, FxHashSet};
 use rustc_errors::{pluralize, struct_span_err, Applicability, DiagnosticBuilder, ErrorGuaranteed};
@@ -1530,6 +1531,49 @@ fn check_fn_or_method<'tcx>(
     );
 
     check_where_clauses(wfcx, span, def_id);
+
+    check_return_position_impl_trait_in_trait_bounds(
+        tcx,
+        wfcx,
+        def_id,
+        sig.output(),
+        hir_decl.output.span(),
+    );
+}
+
+/// Basically `check_associated_type_bounds`, but separated for now and should be
+/// deduplicated when RPITITs get lowered into real associated items.
+fn check_return_position_impl_trait_in_trait_bounds<'tcx>(
+    tcx: TyCtxt<'tcx>,
+    wfcx: &WfCheckingCtxt<'_, 'tcx>,
+    fn_def_id: LocalDefId,
+    fn_output: Ty<'tcx>,
+    span: Span,
+) {
+    if let Some(assoc_item) = tcx.opt_associated_item(fn_def_id.to_def_id())
+        && assoc_item.container == ty::AssocItemContainer::TraitContainer
+    {
+        for arg in fn_output.walk() {
+            if let ty::GenericArgKind::Type(ty) = arg.unpack()
+                && let ty::Projection(proj) = ty.kind()
+                && tcx.def_kind(proj.item_def_id) == DefKind::ImplTraitPlaceholder
+                && tcx.impl_trait_in_trait_parent(proj.item_def_id) == fn_def_id.to_def_id()
+            {
+                let bounds = wfcx.tcx().explicit_item_bounds(proj.item_def_id);
+                let wf_obligations = bounds.iter().flat_map(|&(bound, bound_span)| {
+                    let normalized_bound = wfcx.normalize(span, None, bound);
+                    traits::wf::predicate_obligations(
+                        wfcx.infcx,
+                        wfcx.param_env,
+                        wfcx.body_id,
+                        normalized_bound,
+                        bound_span,
+                    )
+                });
+                wfcx.register_obligations(wf_obligations);
+            }
+        }
+    }
 }
 
 const HELP_FOR_SELF_TYPE: &str = "consider changing to `self`, `&self`, `&mut self`, `self: Box<Self>`, \

library/core/src/ffi/c_double.md

@@ -1,6 +1,6 @@
 Equivalent to C's `double` type.
 
-This type will almost always be [`f64`], which is guaranteed to be an [IEEE-754 double-precision float] in Rust. That said, the standard technically only guarantees that it be a floating-point number with at least the precision of a [`float`], and it may be `f32` or something entirely different from the IEEE-754 standard.
+This type will almost always be [`f64`], which is guaranteed to be an [IEEE 754 double-precision float] in Rust. That said, the standard technically only guarantees that it be a floating-point number with at least the precision of a [`float`], and it may be `f32` or something entirely different from the IEEE-754 standard.
 
-[IEEE-754 double-precision float]: https://en.wikipedia.org/wiki/IEEE_754
+[IEEE 754 double-precision float]: https://en.wikipedia.org/wiki/IEEE_754
 [`float`]: c_float

library/core/src/ffi/c_float.md

@@ -1,5 +1,5 @@
 Equivalent to C's `float` type.
 
-This type will almost always be [`f32`], which is guaranteed to be an [IEEE-754 single-precision float] in Rust. That said, the standard technically only guarantees that it be a floating-point number, and it may have less precision than `f32` or not follow the IEEE-754 standard at all.
+This type will almost always be [`f32`], which is guaranteed to be an [IEEE 754 single-precision float] in Rust. That said, the standard technically only guarantees that it be a floating-point number, and it may have less precision than `f32` or not follow the IEEE-754 standard at all.
 
-[IEEE-754 single-precision float]: https://en.wikipedia.org/wiki/IEEE_754
+[IEEE 754 single-precision float]: https://en.wikipedia.org/wiki/IEEE_754

library/core/src/ffi/c_str.rs

@@ -1,7 +1,6 @@
-use crate::ascii;
 use crate::cmp::Ordering;
 use crate::ffi::c_char;
-use crate::fmt::{self, Write};
+use crate::fmt;
 use crate::intrinsics;
 use crate::ops;
 use crate::slice;
@@ -161,11 +160,7 @@ impl fmt::Display for FromBytesUntilNulError {
 #[stable(feature = "cstr_debug", since = "1.3.0")]
 impl fmt::Debug for CStr {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
-        write!(f, "\"")?;
-        for byte in self.to_bytes().iter().flat_map(|&b| ascii::escape_default(b)) {
-            f.write_char(byte as char)?;
-        }
-        write!(f, "\"")
+        write!(f, "\"{}\"", self.to_bytes().escape_ascii())
     }
 }
 

library/core/src/num/dec2flt/decimal.rs

@@ -32,7 +32,7 @@ impl Default for Decimal {
 impl Decimal {
     /// The maximum number of digits required to unambiguously round a float.
     ///
-    /// For a double-precision IEEE-754 float, this required 767 digits,
+    /// For a double-precision IEEE 754 float, this required 767 digits,
     /// so we store the max digits + 1.
     ///
     /// We can exactly represent a float in radix `b` from radix 2 if

library/core/src/num/f32.rs

@@ -394,7 +394,7 @@ impl f32 {
 
     /// Not a Number (NaN).
     ///
-    /// Note that IEEE-754 doesn't define just a single NaN value;
+    /// Note that IEEE 754 doesn't define just a single NaN value;
     /// a plethora of bit patterns are considered to be NaN.
     /// Furthermore, the standard makes a difference
     /// between a "signaling" and a "quiet" NaN,
@@ -632,7 +632,7 @@ impl f32 {
     }
 
     /// Returns `true` if `self` has a positive sign, including `+0.0`, NaNs with
-    /// positive sign bit and positive infinity. Note that IEEE-754 doesn't assign any
+    /// positive sign bit and positive infinity. Note that IEEE 754 doesn't assign any
     /// meaning to the sign bit in case of a NaN, and as Rust doesn't guarantee that
     /// the bit pattern of NaNs are conserved over arithmetic operations, the result of
     /// `is_sign_positive` on a NaN might produce an unexpected result in some cases.
@@ -654,7 +654,7 @@ impl f32 {
     }
 
     /// Returns `true` if `self` has a negative sign, including `-0.0`, NaNs with
-    /// negative sign bit and negative infinity. Note that IEEE-754 doesn't assign any
+    /// negative sign bit and negative infinity. Note that IEEE 754 doesn't assign any
     /// meaning to the sign bit in case of a NaN, and as Rust doesn't guarantee that
     /// the bit pattern of NaNs are conserved over arithmetic operations, the result of
     /// `is_sign_negative` on a NaN might produce an unexpected result in some cases.
@@ -833,7 +833,7 @@ impl f32 {
     /// Returns the maximum of the two numbers, ignoring NaN.
     ///
     /// If one of the arguments is NaN, then the other argument is returned.
-    /// This follows the IEEE-754 2008 semantics for maxNum, except for handling of signaling NaNs;
+    /// This follows the IEEE 754-2008 semantics for maxNum, except for handling of signaling NaNs;
     /// this function handles all NaNs the same way and avoids maxNum's problems with associativity.
     /// This also matches the behavior of libm’s fmax.
     ///
@@ -853,7 +853,7 @@ impl f32 {
     /// Returns the minimum of the two numbers, ignoring NaN.
     ///
     /// If one of the arguments is NaN, then the other argument is returned.
-    /// This follows the IEEE-754 2008 semantics for minNum, except for handling of signaling NaNs;
+    /// This follows the IEEE 754-2008 semantics for minNum, except for handling of signaling NaNs;
     /// this function handles all NaNs the same way and avoids minNum's problems with associativity.
     /// This also matches the behavior of libm’s fmin.
     ///
@@ -1051,9 +1051,9 @@ impl f32 {
     /// It turns out this is incredibly portable, for two reasons:
     ///
     /// * Floats and Ints have the same endianness on all supported platforms.
-    /// * IEEE-754 very precisely specifies the bit layout of floats.
+    /// * IEEE 754 very precisely specifies the bit layout of floats.
     ///
-    /// However there is one caveat: prior to the 2008 version of IEEE-754, how
+    /// However there is one caveat: prior to the 2008 version of IEEE 754, how
     /// to interpret the NaN signaling bit wasn't actually specified. Most platforms
     /// (notably x86 and ARM) picked the interpretation that was ultimately
     /// standardized in 2008, but some didn't (notably MIPS). As a result, all