Auto merge of #50968 - kennytm:rollup, r=kennytm

Rollup of 15 pull requests

Successful merges:

 - #50846 (Add E0665)
 - #50849 (CheckLoopVisitor: also visit closure arguments)
 - #50863 (Make `[T]::len` and `str::len` const fn)
 - #50875 (rustdoc: use "short form" doc(cfg) printing even when combined with other conditionals)
 - #50913 (Fix typo in cell.rs)
 - #50914 (Issue #50636: Improve error diagnostic with missing commas after struct fields.)
 - #50931 (Inline `try_get`.)
 - #50932 (Optimize seen Predicate filtering.)
 - #50945 (Stabilize feature from_ref)
 - #50946 (rustc: Fix procedural macros generating lifetime tokens)
 - #50947 (rustdoc: set tab width in rust source blocks)
 - #50952 (Add the 2018 edition of the book to doc.rust-lang.org)
 - #50958 (Micro-optimization on PR#50697)
 - #50961 (Fix FileCheck finding with MSVC)
 - #50963 (Right-size the `VecDeque` in `coerce_unsized`.)

Failed merges:

2 files changed, 20 insertions, 4 deletions

diff --git a/src/libsyntax/parse/parser.rs b/src/libsyntax/parse/parser.rs
index 729ad491fd5..62d007b4240 100644
--- a/src/libsyntax/parse/parser.rs
+++ b/src/libsyntax/parse/parser.rs
@@ -5807,9 +5807,18 @@ impl<'a> Parser<'a> {
                     return Err(err);
                 }
             }
-            _ => return Err(self.span_fatal_help(self.span,
-                    &format!("expected `,`, or `}}`, found `{}`", self.this_token_to_string()),
-                    "struct fields should be separated by commas")),
+            _ => {
+                let sp = self.sess.codemap().next_point(self.prev_span);
+                let mut err = self.struct_span_err(sp, &format!("expected `,`, or `}}`, found `{}`",
+                                                                self.this_token_to_string()));
+                if self.token.is_ident() {
+                    // This is likely another field; emit the diagnostic and keep going
+                    err.span_suggestion(sp, "try adding a comma", ",".into());
+                    err.emit();
+                } else {
+                    return Err(err)
+                }
+            }
         }
         Ok(a_var)
     }
diff --git a/src/libsyntax/parse/token.rs b/src/libsyntax/parse/token.rs
index 034be6a6864..ed28d5f33b9 100644
--- a/src/libsyntax/parse/token.rs
+++ b/src/libsyntax/parse/token.rs
@@ -22,6 +22,7 @@ use serialize::{Decodable, Decoder, Encodable, Encoder};
 use symbol::keywords;
 use syntax::parse::parse_stream_from_source_str;
 use syntax_pos::{self, Span, FileName};
+use syntax_pos::symbol::{self, Symbol};
 use tokenstream::{TokenStream, TokenTree};
 use tokenstream;
 
@@ -478,7 +479,13 @@ impl Token {
                 _ => return None,
             },
             SingleQuote => match joint {
-                Ident(ident, false) => Lifetime(ident),
+                Ident(ident, false) => {
+                    let name = Symbol::intern(&format!("'{}", ident));
+                    Lifetime(symbol::Ident {
+                        name,
+                        span: ident.span,
+                    })
+                }
                 _ => return None,
             },