Rollup merge of #64342 - glorv:master, r=varkor

factor out pluralisation remains after #64280

there are two case that doesn't not match the original macro pattern at [here](https://github.com/rust-lang/rust/blob/master/src/librustc_lint/unused.rs#L146) and [here](https://github.com/rust-lang/rust/blob/master/src/libsyntax/parse/diagnostics.rs#L539) as the provided param is already a bool or the check condition is not `x != 1`, so I change the macro accept a boolean expr instead of number to fit all the cases.

@Centril  please review

Fixes #64238.

17 files changed, 56 insertions, 45 deletions

diff --git a/src/librustc/lint/builtin.rs b/src/librustc/lint/builtin.rs
index dd290572d7b..5906a6388a8 100644
--- a/src/librustc/lint/builtin.rs
+++ b/src/librustc/lint/builtin.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
     );
diff --git a/src/librustc/middle/resolve_lifetime.rs b/src/librustc/middle/resolve_lifetime.rs
index 8836a632a7c..d833a34385b 100644
--- a/src/librustc/middle/resolve_lifetime.rs
+++ b/src/librustc/middle/resolve_lifetime.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)
     )
 }
 
diff --git a/src/librustc/traits/error_reporting.rs b/src/librustc/traits/error_reporting.rs
index 1d87484ef09..c9018f1c290 100644
--- a/src/librustc/traits/error_reporting.rs
+++ b/src/librustc/traits/error_reporting.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))
             }
         };
 
diff --git a/src/librustc/ty/error.rs b/src/librustc/ty/error.rs
index 62910ec3204..5409cbc4129 100644
--- a/src/librustc/ty/error.rs
+++ b/src/librustc/ty/error.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(),
                 }
diff --git a/src/librustc_lint/unused.rs b/src/librustc_lint/unused.rs
index c3975098351..2d4af2f606a 100644
--- a/src/librustc_lint/unused.rs
+++ b/src/librustc_lint/unused.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;
@@ -135,7 +135,7 @@ 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)
@@ -143,13 +143,13 @@ impl<'a, 'tcx> LateLintPass<'a, 'tcx> for UnusedResults {
                 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,
diff --git a/src/librustc_resolve/check_unused.rs b/src/librustc_resolve/check_unused.rs
index 96d44b4b4c0..0d85be83e12 100644
--- a/src/librustc_resolve/check_unused.rs
+++ b/src/librustc_resolve/check_unused.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 {
diff --git a/src/librustc_resolve/resolve_imports.rs b/src/librustc_resolve/resolve_imports.rs
index e77e8290f1f..360343169bc 100644
--- a/src/librustc_resolve/resolve_imports.rs
+++ b/src/librustc_resolve/resolve_imports.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(", "),
             );
 
diff --git a/src/librustc_typeck/astconv.rs b/src/librustc_typeck/astconv.rs
index 09e6b769003..718d12484f7 100644
--- a/src/librustc_typeck/astconv.rs
+++ b/src/librustc_typeck/astconv.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) =
diff --git a/src/librustc_typeck/check/expr.rs b/src/librustc_typeck/check/expr.rs
index 049f2eb16bb..1ae50b8cb28 100644
--- a/src/librustc_typeck/check/expr.rs
+++ b/src/librustc_typeck/check/expr.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)
diff --git a/src/librustc_typeck/check/method/suggest.rs b/src/librustc_typeck/check/method/suggest.rs
index 3e45b1e98d4..74e4f28255b 100644
--- a/src/librustc_typeck/check/method/suggest.rs
+++ b/src/librustc_typeck/check/method/suggest.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"
diff --git a/src/librustc_typeck/check/mod.rs b/src/librustc_typeck/check/mod.rs
index 0eeeee01c82..7ff8f9c95c8 100644
--- a/src/librustc_typeck/check/mod.rs
+++ b/src/librustc_typeck/check/mod.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))
 }
diff --git a/src/librustc_typeck/check/pat.rs b/src/librustc_typeck/check/pat.rs
index 8502b89de14..d93a4052cd3 100644
--- a/src/librustc_typeck/check/pat.rs
+++ b/src/librustc_typeck/check/pat.rs
@@ -1,6 +1,6 @@
 use crate::check::FnCtxt;
 use crate::util::nodemap::FxHashMap;
-use errors::{Applicability, DiagnosticBuilder};
+use errors::{Applicability, DiagnosticBuilder, pluralise};
 use rustc::hir::{self, PatKind, Pat, HirId};
 use rustc::hir::def::{Res, DefKind, CtorKind};
 use rustc::hir::pat_util::EnumerateAndAdjustIterator;
@@ -684,8 +684,8 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
     }
 
     fn e0023(&self, pat_span: Span, res: Res, subpats: &'tcx [P<Pat>], fields: &[ty::FieldDef]) {
-        let subpats_ending = if subpats.len() == 1 { "" } else { "s" };
-        let fields_ending = if fields.len() == 1 { "" } else { "s" };
+        let subpats_ending = pluralise!(subpats.len());
+        let fields_ending = pluralise!(fields.len());
         let res_span = self.tcx.def_span(res.def_id());
         struct_span_err!(
             self.tcx.sess,
@@ -1103,10 +1103,10 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
             E0527,
             "pattern requires {} element{} but array has {}",
             min_len,
-            if min_len != 1 { "s" } else { "" },
+            pluralise!(min_len),
             size,
         )
-        .span_label(span, format!("expected {} element{}", size, if size != 1 { "s" } else { "" }))
+        .span_label(span, format!("expected {} element{}", size, pluralise!(size)))
         .emit();
     }
 
@@ -1117,14 +1117,14 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
             E0528,
             "pattern requires at least {} element{} but array has {}",
             min_len,
-            if min_len != 1 { "s" } else { "" },
+            pluralise!(min_len),
             size,
         ).span_label(
             span,
             format!(
                 "pattern cannot match array of {} element{}",
                 size,
-                if size != 1 { "s" } else { "" },
+                pluralise!(size),
             ),
         ).emit();
     }
diff --git a/src/libsyntax/ext/tt/transcribe.rs b/src/libsyntax/ext/tt/transcribe.rs
index 23735727fe8..f9c07e3a2e4 100644
--- a/src/libsyntax/ext/tt/transcribe.rs
+++ b/src/libsyntax/ext/tt/transcribe.rs
@@ -8,6 +8,7 @@ use crate::tokenstream::{DelimSpan, TokenStream, TokenTree, TreeAndJoint};
 
 use smallvec::{smallvec, SmallVec};
 
+use errors::pluralise;
 use rustc_data_structures::fx::FxHashMap;
 use rustc_data_structures::sync::Lrc;
 use syntax_pos::hygiene::{ExpnId, Transparency};
@@ -348,10 +349,10 @@ impl LockstepIterSize {
                         "meta-variable `{}` repeats {} time{}, but `{}` repeats {} time{}",
                         l_id,
                         l_len,
-                        if l_len != 1 { "s" } else { "" },
+                        pluralise!(l_len),
                         r_id,
                         r_len,
-                        if r_len != 1 { "s" } else { "" },
+                        pluralise!(r_len),
                     );
                     LockstepIterSize::Contradiction(msg)
                 }
diff --git a/src/libsyntax/parse/diagnostics.rs b/src/libsyntax/parse/diagnostics.rs
index b74f2492c35..2d7f4f71ca4 100644
--- a/src/libsyntax/parse/diagnostics.rs
+++ b/src/libsyntax/parse/diagnostics.rs
@@ -11,7 +11,7 @@ use crate::ptr::P;
 use crate::symbol::{kw, sym};
 use crate::ThinVec;
 use crate::util::parser::AssocOp;
-use errors::{Applicability, DiagnosticBuilder, DiagnosticId};
+use errors::{Applicability, DiagnosticBuilder, DiagnosticId, pluralise};
 use rustc_data_structures::fx::FxHashSet;
 use syntax_pos::{Span, DUMMY_SP, MultiSpan, SpanSnippetError};
 use log::{debug, trace};
@@ -532,15 +532,15 @@ impl<'a> Parser<'a> {
             self.eat_to_tokens(&[&end]);
             let span = lo.until(self.token.span);
 
-            let plural = number_of_gt > 1 || number_of_shr >= 1;
+            let total_num_of_gt = number_of_gt + number_of_shr * 2;
             self.diagnostic()
                 .struct_span_err(
                     span,
-                    &format!("unmatched angle bracket{}", if plural { "s" } else { "" }),
+                    &format!("unmatched angle bracket{}", pluralise!(total_num_of_gt)),
                 )
                 .span_suggestion(
                     span,
-                    &format!("remove extra angle bracket{}", if plural { "s" } else { "" }),
+                    &format!("remove extra angle bracket{}", pluralise!(total_num_of_gt)),
                     String::new(),
                     Applicability::MachineApplicable,
                 )
diff --git a/src/libsyntax/parse/parser/path.rs b/src/libsyntax/parse/parser/path.rs
index d4b13cc2e01..dcd3c648017 100644
--- a/src/libsyntax/parse/parser/path.rs
+++ b/src/libsyntax/parse/parser/path.rs
@@ -9,7 +9,7 @@ use crate::symbol::kw;
 
 use std::mem;
 use log::debug;
-use errors::{Applicability};
+use errors::{Applicability, pluralise};
 
 /// Specifies how to parse a path.
 #[derive(Copy, Clone, PartialEq)]
@@ -347,20 +347,19 @@ impl<'a> Parser<'a> {
                 let span = lo.with_hi(
                     lo.lo() + BytePos(snapshot.unmatched_angle_bracket_count)
                 );
-                let plural = snapshot.unmatched_angle_bracket_count > 1;
                 self.diagnostic()
                     .struct_span_err(
                         span,
                         &format!(
                             "unmatched angle bracket{}",
-                            if plural { "s" } else { "" }
+                            pluralise!(snapshot.unmatched_angle_bracket_count)
                         ),
                     )
                     .span_suggestion(
                         span,
                         &format!(
                             "remove extra angle bracket{}",
-                            if plural { "s" } else { "" }
+                            pluralise!(snapshot.unmatched_angle_bracket_count)
                         ),
                         String::new(),
                         Applicability::MachineApplicable,
diff --git a/src/libsyntax/parse/parser/ty.rs b/src/libsyntax/parse/parser/ty.rs
index 465e31ac57e..5697edd8e48 100644
--- a/src/libsyntax/parse/parser/ty.rs
+++ b/src/libsyntax/parse/parser/ty.rs
@@ -11,7 +11,7 @@ use crate::symbol::{kw};
 
 use rustc_target::spec::abi::Abi;
 
-use errors::{Applicability};
+use errors::{Applicability, pluralise};
 
 /// Returns `true` if `IDENT t` can start a type -- `IDENT::a::b`, `IDENT<u8, u8>`,
 /// `IDENT<<u8 as Trait>::AssocTy>`.
@@ -397,7 +397,7 @@ impl<'a> Parser<'a> {
         }
 
         if !negative_bounds.is_empty() || was_negative {
-            let plural = negative_bounds.len() > 1;
+            let negative_bounds_len = negative_bounds.len();
             let last_span = negative_bounds.last().map(|sp| *sp);
             let mut err = self.struct_span_err(
                 negative_bounds,
@@ -420,7 +420,7 @@ impl<'a> Parser<'a> {
                 }
                 err.span_suggestion_hidden(
                     bound_list,
-                    &format!("remove the trait bound{}", if plural { "s" } else { "" }),
+                    &format!("remove the trait bound{}", pluralise!(negative_bounds_len)),
                     new_bound_list,
                     Applicability::MachineApplicable,
                 );
diff --git a/src/libsyntax_ext/format.rs b/src/libsyntax_ext/format.rs
index 46c7cbb83de..26455df17b8 100644
--- a/src/libsyntax_ext/format.rs
+++ b/src/libsyntax_ext/format.rs
@@ -5,6 +5,7 @@ use fmt_macros as parse;
 
 use errors::DiagnosticBuilder;
 use errors::Applicability;
+use errors::pluralise;
 
 use syntax::ast;
 use syntax::ext::base::{self, *};
@@ -299,7 +300,7 @@ impl<'a, 'b> Context<'a, 'b> {
                 &format!(
                     "{} positional argument{} in format string, but {}",
                     count,
-                    if count != 1 { "s" } else { "" },
+                    pluralise!(count),
                     self.describe_num_args(),
                 ),
             );