Detect and provide suggestion for &raw EXPR
#139392
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r? @davidtwco rustbot has assigned @davidtwco. Use |
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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.
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Hmm 🤔 why is this being checked on the parsed expr and not as a lookahead after parsing the borrow modifiers? I guess kinda related to the recovery comment above, but would trivially allow checking for non-raw ident
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Well we do want to avoid putting the expectation down for something like &raw.field
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r? oli-obk |
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…iaskrgr Rollup of 8 pull requests Successful merges: - rust-lang#139127 (Fix up partial res of segment in primitive resolution hack) - rust-lang#139392 (Detect and provide suggestion for `&raw EXPR`) - rust-lang#139767 (Visit place in `BackwardIncompatibleDropHint` statement) - rust-lang#139777 (Remove `define_debug_via_print` for `ExistentialProjection`, use regular structural debug impl) - rust-lang#139796 (ptr docs: add missing backtics around 'usize') - rust-lang#139801 (Add myself to mailmap) - rust-lang#139804 (use `realpath` in `bootstrap.py` when creating build-dir) - rust-lang#139807 (Improve wording of post-merge report) r? `@ghost` `@rustbot` modify labels: rollup
Rollup merge of rust-lang#139392 - compiler-errors:raw-expr, r=oli-obk Detect and provide suggestion for `&raw EXPR` When emitting an error in the parser, and we detect that the previous token was `raw` and we *could* have consumed `const`/`mut`, suggest that this may have been a mistyped raw ref expr. To do this, we add `const`/`mut` to the expected token set when parsing `&raw` as 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 `&raw` as 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 EXPR` early, i.e. during `parse_expr_borrow`. Fixes rust-lang#133231
…iaskrgr Rollup of 8 pull requests Successful merges: - rust-lang#139127 (Fix up partial res of segment in primitive resolution hack) - rust-lang#139392 (Detect and provide suggestion for `&raw EXPR`) - rust-lang#139767 (Visit place in `BackwardIncompatibleDropHint` statement) - rust-lang#139777 (Remove `define_debug_via_print` for `ExistentialProjection`, use regular structural debug impl) - rust-lang#139796 (ptr docs: add missing backtics around 'usize') - rust-lang#139801 (Add myself to mailmap) - rust-lang#139804 (use `realpath` in `bootstrap.py` when creating build-dir) - rust-lang#139807 (Improve wording of post-merge report) r? `@ghost` `@rustbot` modify labels: rollup
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