diff options
| -rw-r--r-- | src/librustc_parse/parser/expr.rs | 47 |
1 files changed, 24 insertions, 23 deletions
diff --git a/src/librustc_parse/parser/expr.rs b/src/librustc_parse/parser/expr.rs index cc5e708be48..982b74adfb0 100644 --- a/src/librustc_parse/parser/expr.rs +++ b/src/librustc_parse/parser/expr.rs @@ -482,29 +482,8 @@ impl<'a> Parser<'a> { (lo.to(span), self.mk_unary(UnOp::Deref, e)) } token::BinOp(token::And) | token::AndAnd => self.parse_borrow_expr(lo)?, - token::Ident(..) if self.token.is_keyword(kw::Box) => { - self.bump(); - let e = self.parse_prefix_expr(None); - let (span, e) = self.interpolated_or_expr_span(e)?; - let span = lo.to(span); - self.sess.gated_spans.gate(sym::box_syntax, span); - (span, ExprKind::Box(e)) - } - token::Ident(..) if self.token.is_ident_named(sym::not) => { - // `not` is just an ordinary identifier in Rust-the-language, - // but as `rustc`-the-compiler, we can issue clever diagnostics - // for confused users who really want to say `!` - let token_cannot_continue_expr = |t: &Token| match t.kind { - // These tokens can start an expression after `!`, but - // can't continue an expression after an ident - token::Ident(name, is_raw) => token::ident_can_begin_expr(name, t.span, is_raw), - token::Literal(..) | token::Pound => true, - _ => t.is_whole_expr(), - }; - if !self.look_ahead(1, token_cannot_continue_expr) { - return self.parse_dot_or_call_expr(Some(attrs)); - } - + token::Ident(..) if self.token.is_keyword(kw::Box) => self.parse_box_expr(lo)?, + token::Ident(..) if self.is_mistaken_not_ident_negation() => { self.recover_not_expr(lo)? } _ => return self.parse_dot_or_call_expr(Some(attrs)), @@ -512,6 +491,28 @@ impl<'a> Parser<'a> { return Ok(self.mk_expr(lo.to(hi), ex, attrs)); } + /// Parse `box expr`. + fn parse_box_expr(&mut self, lo: Span) -> PResult<'a, (Span, ExprKind)> { + self.bump(); + let e = self.parse_prefix_expr(None); + let (span, e) = self.interpolated_or_expr_span(e)?; + let span = lo.to(span); + self.sess.gated_spans.gate(sym::box_syntax, span); + Ok((span, ExprKind::Box(e))) + } + + fn is_mistaken_not_ident_negation(&self) -> bool { + let token_cannot_continue_expr = |t: &Token| match t.kind { + // These tokens can start an expression after `!`, but + // can't continue an expression after an ident + token::Ident(name, is_raw) => token::ident_can_begin_expr(name, t.span, is_raw), + token::Literal(..) | token::Pound => true, + _ => t.is_whole_expr(), + }; + self.token.is_ident_named(sym::not) && self.look_ahead(1, token_cannot_continue_expr) + } + + /// Recover on `not expr` in favor of `!expr`. fn recover_not_expr(&mut self, lo: Span) -> PResult<'a, (Span, ExprKind)> { self.bump(); // Emit the error ... |