Auto merge of rust-lang#92996 - matthiaskrgr:rollup-50wpzva, r=matthiaskrgr

Rollup of 10 pull requests

Successful merges:

 - rust-lang#92795 (Link sidebar "location" heading to top of page)
 - rust-lang#92799 (Remove some unnecessary uses of `FieldDef::ident`)
 - rust-lang#92808 (Fix `try wrapping expression in variant` suggestion with struct field shorthand)
 - rust-lang#92819 (rustdoc: remove hand-rolled isatty)
 - rust-lang#92876 (Fix suggesting turbofish with lifetime arguments)
 - rust-lang#92921 (Rename Printer constructor from mk_printer() to Printer::new())
 - rust-lang#92937 (rustdoc: Add missing dot separator)
 - rust-lang#92953 (Copy an example to PartialOrd as well)
 - rust-lang#92977 (Docs: recommend VecDeque instead of Vec::remove(0))
 - rust-lang#92981 (fix const_ptr_offset_from tracking issue)

Failed merges:

r? `@ghost`
`@rustbot` modify labels: rollup

Author: bors

Diff for: Cargo.lock

@@ -4443,6 +4443,7 @@ version = "0.0.0"
 dependencies = [
  "arrayvec",
  "askama",
+ "atty",
  "expect-test",
  "itertools 0.9.0",
  "minifier",

Diff for: compiler/rustc_ast_pretty/src/pp.rs

@@ -222,29 +222,6 @@ struct PrintStackElem {
 
 const SIZE_INFINITY: isize = 0xffff;
 
-pub fn mk_printer() -> Printer {
-    let linewidth = 78;
-    // Yes 55, it makes the ring buffers big enough to never fall behind.
-    let n: usize = 55 * linewidth;
-    debug!("mk_printer {}", linewidth);
-    Printer {
-        out: String::new(),
-        buf_max_len: n,
-        margin: linewidth as isize,
-        space: linewidth as isize,
-        left: 0,
-        right: 0,
-        // Initialize a single entry; advance_right() will extend it on demand
-        // up to `buf_max_len` elements.
-        buf: vec![BufEntry::default()],
-        left_total: 0,
-        right_total: 0,
-        scan_stack: VecDeque::new(),
-        print_stack: Vec::new(),
-        pending_indentation: 0,
-    }
-}
-
 pub struct Printer {
     out: String,
     buf_max_len: usize,
@@ -288,6 +265,29 @@ impl Default for BufEntry {
 }
 
 impl Printer {
+    pub fn new() -> Self {
+        let linewidth = 78;
+        // Yes 55, it makes the ring buffers big enough to never fall behind.
+        let n: usize = 55 * linewidth;
+        debug!("Printer::new {}", linewidth);
+        Printer {
+            out: String::new(),
+            buf_max_len: n,
+            margin: linewidth as isize,
+            space: linewidth as isize,
+            left: 0,
+            right: 0,
+            // Initialize a single entry; advance_right() will extend it on demand
+            // up to `buf_max_len` elements.
+            buf: vec![BufEntry::default()],
+            left_total: 0,
+            right_total: 0,
+            scan_stack: VecDeque::new(),
+            print_stack: Vec::new(),
+            pending_indentation: 0,
+        }
+    }
+
     pub fn last_token(&self) -> Token {
         self.buf[self.right].token.clone()
     }

Diff for: compiler/rustc_ast_pretty/src/pprust/state.rs

@@ -103,7 +103,7 @@ pub fn print_crate<'a>(
     edition: Edition,
 ) -> String {
     let mut s =
-        State { s: pp::mk_printer(), comments: Some(Comments::new(sm, filename, input)), ann };
+        State { s: pp::Printer::new(), comments: Some(Comments::new(sm, filename, input)), ann };
 
     if is_expanded && !krate.attrs.iter().any(|attr| attr.has_name(sym::no_core)) {
         // We need to print `#![no_std]` (and its feature gate) so that
@@ -910,7 +910,7 @@ impl<'a> PrintState<'a> for State<'a> {
 
 impl<'a> State<'a> {
     pub fn new() -> State<'a> {
-        State { s: pp::mk_printer(), comments: None, ann: &NoAnn }
+        State { s: pp::Printer::new(), comments: None, ann: &NoAnn }
     }
 
     crate fn commasep_cmnt<T, F, G>(&mut self, b: Breaks, elts: &[T], mut op: F, mut get_span: G)

Diff for: compiler/rustc_hir_pretty/src/lib.rs

@@ -170,7 +170,7 @@ impl<'a> State<'a> {
         ann: &'a dyn PpAnn,
     ) -> State<'a> {
         State {
-            s: pp::mk_printer(),
+            s: pp::Printer::new(),
             comments: Some(Comments::new(sm, filename, input)),
             attrs,
             ann,
@@ -186,7 +186,7 @@ pub fn to_string<F>(ann: &dyn PpAnn, f: F) -> String
 where
     F: FnOnce(&mut State<'_>),
 {
-    let mut printer = State { s: pp::mk_printer(), comments: None, attrs: &|_| &[], ann };
+    let mut printer = State { s: pp::Printer::new(), comments: None, attrs: &|_| &[], ann };
     f(&mut printer);
     printer.s.eof()
 }

Diff for: compiler/rustc_parse/src/parser/diagnostics.rs

@@ -27,7 +27,7 @@ use std::mem::take;
 use tracing::{debug, trace};
 
 const TURBOFISH_SUGGESTION_STR: &str =
-    "use `::<...>` instead of `<...>` to specify type or const arguments";
+    "use `::<...>` instead of `<...>` to specify lifetime, type, or const arguments";
 
 /// Creates a placeholder argument.
 pub(super) fn dummy_arg(ident: Ident) -> Param {
@@ -731,21 +731,28 @@ impl<'a> Parser<'a> {
                     match x {
                         Ok((_, _, false)) => {
                             if self.eat(&token::Gt) {
-                                match self.parse_expr() {
-                                    Ok(_) => {
-                                        e.span_suggestion_verbose(
-                                            binop.span.shrink_to_lo(),
-                                            TURBOFISH_SUGGESTION_STR,
-                                            "::".to_string(),
-                                            Applicability::MaybeIncorrect,
-                                        );
-                                        e.emit();
-                                        *expr =
-                                            self.mk_expr_err(expr.span.to(self.prev_token.span));
-                                        return Ok(());
-                                    }
-                                    Err(mut err) => {
-                                        err.cancel();
+                                let turbo_err = e.span_suggestion_verbose(
+                                    binop.span.shrink_to_lo(),
+                                    TURBOFISH_SUGGESTION_STR,
+                                    "::".to_string(),
+                                    Applicability::MaybeIncorrect,
+                                );
+                                if self.check(&TokenKind::Semi) {
+                                    turbo_err.emit();
+                                    *expr = self.mk_expr_err(expr.span);
+                                    return Ok(());
+                                } else {
+                                    match self.parse_expr() {
+                                        Ok(_) => {
+                                            turbo_err.emit();
+                                            *expr = self
+                                                .mk_expr_err(expr.span.to(self.prev_token.span));
+                                            return Ok(());
+                                        }
+                                        Err(mut err) => {
+                                            turbo_err.cancel();
+                                            err.cancel();
+                                        }
                                     }
                                 }
                             }

Diff for: compiler/rustc_parse/src/parser/expr.rs

@@ -1443,7 +1443,7 @@ impl<'a> Parser<'a> {
         &mut self,
         label: Label,
         attrs: AttrVec,
-        consume_colon: bool,
+        mut consume_colon: bool,
     ) -> PResult<'a, P<Expr>> {
         let lo = label.ident.span;
         let label = Some(label);
@@ -1456,6 +1456,12 @@ impl<'a> Parser<'a> {
             self.parse_loop_expr(label, lo, attrs)
         } else if self.check(&token::OpenDelim(token::Brace)) || self.token.is_whole_block() {
             self.parse_block_expr(label, lo, BlockCheckMode::Default, attrs)
+        } else if !ate_colon && (self.check(&TokenKind::Comma) || self.check(&TokenKind::Gt)) {
+            // We're probably inside of a `Path<'a>` that needs a turbofish, so suppress the
+            // "must be followed by a colon" error.
+            self.diagnostic().delay_span_bug(lo, "this label wasn't parsed correctly");
+            consume_colon = false;
+            Ok(self.mk_expr_err(lo))
         } else {
             let msg = "expected `while`, `for`, `loop` or `{` after a label";
             self.struct_span_err(self.token.span, msg).span_label(self.token.span, msg).emit();