Auto merge of #64658 - Centril:rollup-9s3raz6, r=Centril

Rollup of 9 pull requests

Successful merges:

 - #64010 (Stabilize `param_attrs` in Rust 1.39.0)
 - #64136 (Document From trait for LhsExpr in parser)
 - #64342 (factor out pluralisation remains after #64280)
 - #64347 (Add long error explanation for E0312)
 - #64621 (Add Compatibility Notes to RELEASES.md for 1.38.0)
 - #64632 (remove the extra comma after the match arm)
 - #64640 (No home directory on vxWorks)
 - #64641 (Exempt extern "Rust" from improper_ctypes)
 - #64642 (Fix the span used to suggest avoiding for-loop moves)

Failed merges:

r? @ghost

Author: bors

RELEASES.md

@@ -68,6 +68,13 @@ Misc
 - [`rustc` will now warn about some incorrect uses of
   `mem::{uninitialized, zeroed}` that are known to cause undefined behaviour.][63346]
 
+Compatibility Notes
+-------------------
+- Unfortunately the [`x86_64-unknown-uefi` platform can not be built][62785]
+  with rustc 1.39.0.
+- The [`armv7-unknown-linux-gnueabihf` platform is also known to have
+  issues][62896] for certain crates such as libc.
+
 [60260]: https://github.com/rust-lang/rust/pull/60260/
 [61457]: https://github.com/rust-lang/rust/pull/61457/
 [61491]: https://github.com/rust-lang/rust/pull/61491/
@@ -79,7 +86,9 @@ Misc
 [62735]: https://github.com/rust-lang/rust/pull/62735/
 [62766]: https://github.com/rust-lang/rust/pull/62766/
 [62784]: https://github.com/rust-lang/rust/pull/62784/
+[62785]: https://github.com/rust-lang/rust/issues/62785/
 [62814]: https://github.com/rust-lang/rust/pull/62814/
+[62896]: https://github.com/rust-lang/rust/issues/62896/
 [63000]: https://github.com/rust-lang/rust/pull/63000/
 [63056]: https://github.com/rust-lang/rust/pull/63056/
 [63107]: https://github.com/rust-lang/rust/pull/63107/

src/doc/unstable-book/src/language-features/param-attrs.md

@@ -240,7 +240,7 @@ pub(crate) unsafe fn box_free<T: ?Sized>(ptr: Unique<T>) {
 #[stable(feature = "global_alloc", since = "1.28.0")]
 #[rustc_allocator_nounwind]
 pub fn handle_alloc_error(layout: Layout) -> ! {
-    #[allow(improper_ctypes)]
+    #[cfg_attr(bootstrap, allow(improper_ctypes))]
     extern "Rust" {
         #[lang = "oom"]
         fn oom_impl(layout: Layout) -> !;

src/liballoc/alloc.rs

@@ -71,7 +71,7 @@ pub fn panic_fmt(fmt: fmt::Arguments<'_>, file_line_col: &(&'static str, u32, u3
     }
 
     // NOTE This function never crosses the FFI boundary; it's a Rust-to-Rust call
-    #[allow(improper_ctypes)] // PanicInfo contains a trait object which is not FFI safe
+    #[cfg_attr(boostrap_stdarch_ignore_this, allow(improper_ctypes))]
     extern "Rust" {
         #[lang = "panic_impl"]
         fn panic_impl(pi: &PanicInfo<'_>) -> !;

src/libcore/panicking.rs

@@ -1347,6 +1347,39 @@ struct Foo<T: 'static> {
 ```
 "##,
 
+E0312: r##"
+Reference's lifetime of borrowed content doesn't match the expected lifetime.
+
+Erroneous code example:
+
+```compile_fail,E0312
+pub fn opt_str<'a>(maybestr: &'a Option<String>) -> &'static str {
+    if maybestr.is_none() {
+        "(none)"
+    } else {
+        let s: &'a str = maybestr.as_ref().unwrap();
+        s  // Invalid lifetime!
+    }
+}
+```
+
+To fix this error, either lessen the expected lifetime or find a way to not have
+to use this reference outside of its current scope (by running the code directly
+in the same block for example?):
+
+```
+// In this case, we can fix the issue by switching from "static" lifetime to 'a
+pub fn opt_str<'a>(maybestr: &'a Option<String>) -> &'a str {
+    if maybestr.is_none() {
+        "(none)"
+    } else {
+        let s: &'a str = maybestr.as_ref().unwrap();
+        s  // Ok!
+    }
+}
+```
+"##,
+
 E0317: r##"
 This error occurs when an `if` expression without an `else` block is used in a
 context where a type other than `()` is expected, for example a `let`
@@ -2202,7 +2235,6 @@ static X: u32 = 42;
 //  E0304, // expected signed integer constant
 //  E0305, // expected constant
     E0311, // thing may not live long enough
-    E0312, // lifetime of reference outlives lifetime of borrowed content
     E0313, // lifetime of borrowed pointer outlives lifetime of captured
            // variable
     E0314, // closure outlives stack frame

src/librustc/error_codes.rs

@@ -7,7 +7,7 @@
 use crate::lint::{LintPass, LateLintPass, LintArray};
 use crate::middle::stability;
 use crate::session::Session;
-use errors::{Applicability, DiagnosticBuilder};
+use errors::{Applicability, DiagnosticBuilder, pluralise};
 use syntax::ast;
 use syntax::source_map::Span;
 use syntax::symbol::Symbol;
@@ -524,7 +524,7 @@ pub(crate) fn add_elided_lifetime_in_path_suggestion(
     };
     db.span_suggestion(
         replace_span,
-        &format!("indicate the anonymous lifetime{}", if n >= 2 { "s" } else { "" }),
+        &format!("indicate the anonymous lifetime{}", pluralise!(n)),
         suggestion,
         Applicability::MachineApplicable
     );

src/librustc/lint/builtin.rs

@@ -17,7 +17,7 @@ use crate::ty::{self, DefIdTree, GenericParamDefKind, TyCtxt};
 use crate::rustc::lint;
 use crate::session::Session;
 use crate::util::nodemap::{DefIdMap, FxHashMap, FxHashSet, HirIdMap, HirIdSet};
-use errors::{Applicability, DiagnosticBuilder};
+use errors::{Applicability, DiagnosticBuilder, pluralise};
 use rustc_macros::HashStable;
 use std::borrow::Cow;
 use std::cell::Cell;
@@ -3047,7 +3047,7 @@ pub fn report_missing_lifetime_specifiers(
         span,
         E0106,
         "missing lifetime specifier{}",
-        if count > 1 { "s" } else { "" }
+        pluralise!(count)
     )
 }
 

src/librustc/middle/resolve_lifetime.rs

@@ -33,7 +33,7 @@ use crate::ty::subst::Subst;
 use crate::ty::SubtypePredicate;
 use crate::util::nodemap::{FxHashMap, FxHashSet};
 
-use errors::{Applicability, DiagnosticBuilder};
+use errors::{Applicability, DiagnosticBuilder, pluralise};
 use std::fmt;
 use syntax::ast;
 use syntax::symbol::{sym, kw};
@@ -1214,7 +1214,7 @@ impl<'a, 'tcx> InferCtxt<'a, 'tcx> {
                 _ => format!("{} {}argument{}",
                              arg_length,
                              if distinct && arg_length > 1 { "distinct " } else { "" },
-                             if arg_length == 1 { "" } else { "s" }),
+                             pluralise!(arg_length))
             }
         };
 

src/librustc/traits/error_reporting.rs

@@ -196,7 +196,7 @@ impl<'tcx> ty::TyS<'tcx> {
                 let n = tcx.lift_to_global(&n).unwrap();
                 match n.try_eval_usize(tcx, ty::ParamEnv::empty()) {
                     Some(n) => {
-                        format!("array of {} element{}", n, if n != 1 { "s" } else { "" }).into()
+                        format!("array of {} element{}", n, pluralise!(n)).into()
                     }
                     None => "array".into(),
                 }

src/librustc/ty/error.rs

@@ -975,7 +975,9 @@ impl<'a, 'tcx> LateLintPass<'a, 'tcx> for ImproperCTypes {
     fn check_foreign_item(&mut self, cx: &LateContext<'_, '_>, it: &hir::ForeignItem) {
         let mut vis = ImproperCTypesVisitor { cx };
         let abi = cx.tcx.hir().get_foreign_abi(it.hir_id);
-        if abi != Abi::RustIntrinsic && abi != Abi::PlatformIntrinsic {
+        if let Abi::Rust | Abi::RustCall | Abi::RustIntrinsic | Abi::PlatformIntrinsic = abi {
+            // Don't worry about types in internal ABIs.
+        } else {
             match it.node {
                 hir::ForeignItemKind::Fn(ref decl, _, _) => {
                     vis.check_foreign_fn(it.hir_id, decl);

src/librustc_lint/types.rs

@@ -9,7 +9,7 @@ use lint::{LintPass, EarlyLintPass, LateLintPass};
 
 use syntax::ast;
 use syntax::attr;
-use syntax::errors::Applicability;
+use syntax::errors::{Applicability, pluralise};
 use syntax::feature_gate::{AttributeType, BuiltinAttribute, BUILTIN_ATTRIBUTE_MAP};
 use syntax::print::pprust;
 use syntax::symbol::{kw, sym};
@@ -48,7 +48,7 @@ impl<'a, 'tcx> LateLintPass<'a, 'tcx> for UnusedResults {
         }
 
         let ty = cx.tables.expr_ty(&expr);
-        let type_permits_lack_of_use = check_must_use_ty(cx, ty, &expr, s.span, "", "", false);
+        let type_permits_lack_of_use = check_must_use_ty(cx, ty, &expr, s.span, "", "", 1);
 
         let mut fn_warned = false;
         let mut op_warned = false;
@@ -135,21 +135,21 @@ impl<'a, 'tcx> LateLintPass<'a, 'tcx> for UnusedResults {
             span: Span,
             descr_pre: &str,
             descr_post: &str,
-            plural: bool,
+            plural_len: usize,
         ) -> bool {
             if ty.is_unit() || cx.tcx.is_ty_uninhabited_from(
                 cx.tcx.hir().get_module_parent(expr.hir_id), ty)
             {
                 return true;
             }
 
-            let plural_suffix = if plural { "s" } else { "" };
+            let plural_suffix = pluralise!(plural_len);
 
             match ty.sty {
                 ty::Adt(..) if ty.is_box() => {
                     let boxed_ty = ty.boxed_ty();
                     let descr_pre = &format!("{}boxed ", descr_pre);
-                    check_must_use_ty(cx, boxed_ty, expr, span, descr_pre, descr_post, plural)
+                    check_must_use_ty(cx, boxed_ty, expr, span, descr_pre, descr_post, plural_len)
                 }
                 ty::Adt(def, _) => {
                     check_must_use_def(cx, def.did, span, descr_pre, descr_post)
@@ -202,7 +202,15 @@ impl<'a, 'tcx> LateLintPass<'a, 'tcx> for UnusedResults {
                     for (i, ty) in tys.iter().map(|k| k.expect_ty()).enumerate() {
                         let descr_post = &format!(" in tuple element {}", i);
                         let span = *spans.get(i).unwrap_or(&span);
-                        if check_must_use_ty(cx, ty, expr, span, descr_pre, descr_post, plural) {
+                        if check_must_use_ty(
+                            cx,
+                            ty,
+                            expr,
+                            span,
+                            descr_pre,
+                            descr_post,
+                            plural_len
+                        ) {
                             has_emitted = true;
                         }
                     }
@@ -216,7 +224,7 @@ impl<'a, 'tcx> LateLintPass<'a, 'tcx> for UnusedResults {
                             descr_pre,
                             plural_suffix,
                         );
-                        check_must_use_ty(cx, ty, expr, span, descr_pre, descr_post, true)
+                        check_must_use_ty(cx, ty, expr, span, descr_pre, descr_post, n as usize + 1)
                     }
                     // Otherwise, we don't lint, to avoid false positives.
                     _ => false,

src/librustc_lint/unused.rs

@@ -180,7 +180,8 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
                     );
                 }
                 if Some(DesugaringKind::ForLoop) == move_span.desugaring_kind() {
-                    if let Ok(snippet) = self.infcx.tcx.sess.source_map().span_to_snippet(span) {
+                    let sess = self.infcx.tcx.sess;
+                    if let Ok(snippet) = sess.source_map().span_to_snippet(move_span) {
                         err.span_suggestion(
                             move_span,
                             "consider borrowing to avoid moving into the for loop",

src/librustc_mir/borrow_check/conflict_errors.rs

@@ -26,6 +26,8 @@
 use crate::Resolver;
 use crate::resolve_imports::ImportDirectiveSubclass;
 
+use errors::pluralise;
+
 use rustc::util::nodemap::NodeMap;
 use rustc::{lint, ty};
 use rustc_data_structures::fx::FxHashSet;
@@ -295,7 +297,7 @@ impl Resolver<'_> {
                 }).collect::<Vec<String>>();
             span_snippets.sort();
             let msg = format!("unused import{}{}",
-                            if len > 1 { "s" } else { "" },
+                            pluralise!(len),
                             if !span_snippets.is_empty() {
                                 format!(": {}", span_snippets.join(", "))
                             } else {

src/librustc_resolve/check_unused.rs

@@ -424,7 +424,7 @@ impl<'a> LateResolutionVisitor<'a, '_> {
                 } else {
                     err.note("did you mean to use one of the enum's variants?");
                 }
-            },
+            }
             (Res::Def(DefKind::Struct, def_id), _) if ns == ValueNS => {
                 if let Some((ctor_def, ctor_vis))
                         = self.r.struct_constructors.get(&def_id).cloned() {

src/librustc_resolve/late/diagnostics.rs

@@ -11,7 +11,7 @@ use crate::{Resolver, ResolutionError, Segment, ModuleKind};
 use crate::{names_to_string, module_to_string};
 use crate::diagnostics::Suggestion;
 
-use errors::Applicability;
+use errors::{Applicability, pluralise};
 
 use rustc_data_structures::ptr_key::PtrKey;
 use rustc::ty;
@@ -728,7 +728,7 @@ impl<'a, 'b> ImportResolver<'a, 'b> {
 
             let msg = format!(
                 "unresolved import{} {}",
-                if paths.len() > 1 { "s" } else { "" },
+                pluralise!(paths.len()),
                 paths.join(", "),
             );
 

src/librustc_resolve/resolve_imports.rs

@@ -1346,7 +1346,7 @@ impl<'o, 'tcx> dyn AstConv<'tcx> + 'o {
                 span,
                 E0191,
                 "the value of the associated type{} {} must be specified",
-                if associated_types.len() == 1 { "" } else { "s" },
+                pluralise!(associated_types.len()),
                 names,
             );
             let (suggest, potential_assoc_types_spans) =

src/librustc_typeck/astconv.rs

@@ -17,7 +17,7 @@ use crate::util::common::ErrorReported;
 use crate::util::nodemap::FxHashMap;
 use crate::astconv::AstConv as _;
 
-use errors::{Applicability, DiagnosticBuilder};
+use errors::{Applicability, DiagnosticBuilder, pluralise};
 use syntax::ast;
 use syntax::symbol::{Symbol, kw, sym};
 use syntax::source_map::Span;
@@ -1178,7 +1178,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
 
             struct_span_err!(tcx.sess, span, E0063,
                              "missing field{} {}{} in initializer of `{}`",
-                             if remaining_fields.len() == 1 { "" } else { "s" },
+                             pluralise!(remaining_fields.len()),
                              remaining_fields_names,
                              truncated_fields_error,
                              adt_ty)

src/librustc_typeck/check/expr.rs

@@ -5,7 +5,7 @@ use crate::check::FnCtxt;
 use crate::middle::lang_items::FnOnceTraitLangItem;
 use crate::namespace::Namespace;
 use crate::util::nodemap::FxHashSet;
-use errors::{Applicability, DiagnosticBuilder};
+use errors::{Applicability, DiagnosticBuilder, pluralise};
 use rustc::hir::{self, ExprKind, Node, QPath};
 use rustc::hir::def::{Res, DefKind};
 use rustc::hir::def_id::{CRATE_DEF_INDEX, LOCAL_CRATE, DefId};
@@ -560,7 +560,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                     let help = format!("{an}other candidate{s} {were} found in the following \
                                         trait{s}, perhaps add a `use` for {one_of_them}:",
                                     an = if candidates.len() == 1 {"an" } else { "" },
-                                    s = if candidates.len() == 1 { "" } else { "s" },
+                                    s = pluralise!(candidates.len()),
                                     were = if candidates.len() == 1 { "was" } else { "were" },
                                     one_of_them = if candidates.len() == 1 {
                                         "it"

src/librustc_typeck/check/method/suggest.rs

@@ -88,7 +88,7 @@ pub mod intrinsic;
 mod op;
 
 use crate::astconv::{AstConv, PathSeg};
-use errors::{Applicability, DiagnosticBuilder, DiagnosticId};
+use errors::{Applicability, DiagnosticBuilder, DiagnosticId, pluralise};
 use rustc::hir::{self, ExprKind, GenericArg, ItemKind, Node, PatKind, QPath};
 use rustc::hir::def::{CtorOf, Res, DefKind};
 use rustc::hir::def_id::{CrateNum, DefId, LOCAL_CRATE};
@@ -4935,5 +4935,5 @@ fn fatally_break_rust(sess: &Session) {
 }
 
 fn potentially_plural_count(count: usize, word: &str) -> String {
-    format!("{} {}{}", count, word, if count == 1 { "" } else { "s" })
+    format!("{} {}{}", count, word, pluralise!(count))
 }