From dda30f690206870ed6f8fc14216e92cdc1f2687a Mon Sep 17 00:00:00 2001 From: Vadim Petrochenkov Date: Wed, 26 Jul 2017 18:59:07 +0300 Subject: Better diagnostics and recovery for `mut ref` in patterns --- src/libsyntax/parse/parser.rs | 14 ++++++++++++-- 1 file changed, 12 insertions(+), 2 deletions(-) (limited to 'src/libsyntax/parse') diff --git a/src/libsyntax/parse/parser.rs b/src/libsyntax/parse/parser.rs index d6a57c2874f..a48d2dcf1c1 100644 --- a/src/libsyntax/parse/parser.rs +++ b/src/libsyntax/parse/parser.rs @@ -3523,8 +3523,18 @@ impl<'a> Parser<'a> { } // At this point, token != _, &, &&, (, [ _ => if self.eat_keyword(keywords::Mut) { - // Parse mut ident @ pat - pat = self.parse_pat_ident(BindingMode::ByValue(Mutability::Mutable))?; + // Parse mut ident @ pat / mut ref ident @ pat + let mutref_span = self.prev_span.to(self.span); + let binding_mode = if self.eat_keyword(keywords::Ref) { + self.diagnostic() + .struct_span_err(mutref_span, "the order of `mut` and `ref` is incorrect") + .span_suggestion(mutref_span, "try switching the order", "ref mut".into()) + .emit(); + BindingMode::ByRef(Mutability::Mutable) + } else { + BindingMode::ByValue(Mutability::Mutable) + }; + pat = self.parse_pat_ident(binding_mode)?; } else if self.eat_keyword(keywords::Ref) { // Parse ref ident @ pat / ref mut ident @ pat let mutbl = self.parse_mutability(); -- cgit 1.4.1-3-g733a5