Auto merge of #57209 - estebank:suggest-raw-ident, r=petrochenkov

Suggest using raw identifiers in 2018 edition when using keywords

1 files changed, 12 insertions, 0 deletions

diff --git a/src/libsyntax/parse/parser.rs b/src/libsyntax/parse/parser.rs
index 52da8a072c7..7c471fdebb3 100644
--- a/src/libsyntax/parse/parser.rs
+++ b/src/libsyntax/parse/parser.rs
@@ -798,6 +798,18 @@ impl<'a> Parser<'a> {
         let mut err = self.struct_span_err(self.span,
                                            &format!("expected identifier, found {}",
                                                     self.this_token_descr()));
+        if let token::Ident(ident, false) = &self.token {
+            if ident.is_reserved() && !ident.is_path_segment_keyword() &&
+                ident.name != keywords::Underscore.name()
+            {
+                err.span_suggestion_with_applicability(
+                    self.span,
+                    "you can escape reserved keywords to use them as identifiers",
+                    format!("r#{}", ident),
+                    Applicability::MaybeIncorrect,
+                );
+            }
+        }
         if let Some(token_descr) = self.token_descr() {
             err.span_label(self.span, format!("expected identifier, found {}", token_descr));
         } else {