Detect and provide suggestion for &raw EXPR
#139392
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| @@ -829,6 +829,18 @@ impl<'a> Parser<'a> { | |||
| if let Some(lt) = lifetime { | |||
| self.error_remove_borrow_lifetime(span, lt.ident.span.until(expr.span)); | |||
| } | |||
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| // Add expected tokens if we parsed `&raw` as an expression. | |||
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🤔 do we know anything about the parser grammar such that we could eagerly recover here (if self.may_recover(), of course), at least in some cases?
I don't think we ever expect an identifier token to follow another expr in valid rust, so if we see &raw IDENT, we could actually do recovery here rather than just failing later on in parsing.
| // guides recovery in case we write `&raw expr`. | ||
| if borrow_kind == ast::BorrowKind::Ref | ||
| && mutbl == ast::Mutability::Not | ||
| && matches!(&expr.kind, ExprKind::Path(None, p) if p.is_ident(kw::Raw)) |
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(minor) is_ident or this matches! needs to account for raw identifiers, so we can exclude r#raw (raw raw) here
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This is a parsed ident, not an ident token, so we don't have a way to distinguish r#raw here, since ident is just a span and a symbol.
When emitting an error in the parser, and we detect that the previous token was
rawand we could have consumedconst/mut, suggest that this may have been a mistyped raw ref expr. To do this, we addconst/mutto the expected token set when parsing&rawas an expression (which does not affect the "good path" of parsing, for the record).This is kind of a rudimentary error improvement, since it doesn't actually attempt to recover anything, leading to some other knock-on errors b/c we still treat
&rawas the expression that was parsed... but at least we add the suggestion! I don't think the parser grammar means we can faithfully recover&raw EXPRearly, i.e. duringparse_expr_borrow.Fixes #133231