mirror of https://github.com/rust-lang/rust
1ae521e9d5
This example triggers an assertion failure:
```
fn f() -> u32 {
#[cfg_eval] #[cfg(not(FALSE))] 0
}
```
The sequence of events:
- `configure_annotatable` calls `parse_expr_force_collect`, which calls
`collect_tokens`.
- Within that, we end up in `parse_expr_dot_or_call`, which again calls
`collect_tokens`.
- The return value of the `f` call is the expression `0`.
- This inner call collects tokens for `0` (parser range 10..11) and
creates a replacement covering `#[cfg(not(FALSE))] 0` (parser range
0..11).
- We return to the outer `collect_tokens` call. The return value of the
`f` call is *again* the expression `0`, again with the range 10..11,
but the replacement from earlier covers the range 0..11. The code
mistakenly assumes that any attributes from an inner `collect_tokens`
call fit entirely within the body of the result of an outer
`collect_tokens` call. So it adjusts the replacement parser range
0..11 to a node range by subtracting 10, resulting in -10..1. This is
an invalid range and triggers an assertion failure.
It's tricky to follow, but basically things get complicated when an AST
node is returned from an inner `collect_tokens` call and then returned
again from an outer `collect_token` node without being wrapped in any
kind of additional layer.
This commit changes `collect_tokens` to return early in some extra cases,
avoiding the construction of lazy tokens. In the example above, the
outer `collect_tokens` returns earlier because the `0` token already has
tokens and `self.capture_state.capturing` is `Capturing::No`. This early
return avoids the creation of the invalid range and the assertion
failure.
Fixes #129166. Note: these invalid ranges have been happening for a long
time. #128725 looks like it's at fault only because it introduced the
assertion that catches the invalid ranges.
|
||
|---|---|---|
| .. | ||
| auxiliary | ||
| cfg-arg-invalid-1.rs | ||
| cfg-arg-invalid-1.stderr | ||
| cfg-arg-invalid-2.rs | ||
| cfg-arg-invalid-2.stderr | ||
| cfg-arg-invalid-3.rs | ||
| cfg-arg-invalid-3.stderr | ||
| cfg-arg-invalid-4.rs | ||
| cfg-arg-invalid-4.stderr | ||
| cfg-arg-invalid-5.rs | ||
| cfg-arg-invalid-5.stderr | ||
| cfg-arg-invalid-6.rs | ||
| cfg-arg-invalid-6.stderr | ||
| cfg-arg-invalid-7.rs | ||
| cfg-arg-invalid-7.stderr | ||
| cfg-arg-invalid-8.rs | ||
| cfg-arg-invalid-8.stderr | ||
| cfg-arg-invalid-9.rs | ||
| cfg-arg-invalid-9.stderr | ||
| cfg-attr-cfg-2.rs | ||
| cfg-attr-cfg-2.stderr | ||
| cfg-attr-crate-2.rs | ||
| cfg-attr-crate-2.stderr | ||
| cfg-attr-empty-is-unused.rs | ||
| cfg-attr-empty-is-unused.stderr | ||
| cfg-attr-invalid-predicate.rs | ||
| cfg-attr-invalid-predicate.stderr | ||
| cfg-attr-multi-false.rs | ||
| cfg-attr-multi-invalid-1.rs | ||
| cfg-attr-multi-invalid-1.stderr | ||
| cfg-attr-multi-invalid-2.rs | ||
| cfg-attr-multi-invalid-2.stderr | ||
| cfg-attr-multi-true.rs | ||
| cfg-attr-multi-true.stderr | ||
| cfg-attr-parse.rs | ||
| cfg-attr-parse.stderr | ||
| cfg-attr-syntax-validation.rs | ||
| cfg-attr-syntax-validation.stderr | ||
| cfg-attr-unknown-attribute-macro-expansion.rs | ||
| cfg-attr-unknown-attribute-macro-expansion.stderr | ||
| cfg-empty-codemap.rs | ||
| cfg-empty-codemap.stderr | ||
| cfg-generic-params.rs | ||
| cfg-generic-params.stderr | ||
| cfg-in-crate-1.rs | ||
| cfg-in-crate-1.stderr | ||
| cfg-non-opt-expr.rs | ||
| cfg-non-opt-expr.stderr | ||
| cfg_accessible-bugs.rs | ||
| cfg_accessible-bugs.stderr | ||
| cfg_accessible-input-validation.rs | ||
| cfg_accessible-input-validation.stderr | ||
| cfg_accessible-not_sure.edition2015.stderr | ||
| cfg_accessible-not_sure.edition2021.stderr | ||
| cfg_accessible-not_sure.rs | ||
| cfg_accessible-private.rs | ||
| cfg_accessible-stuck.rs | ||
| cfg_accessible-stuck.stderr | ||
| cfg_accessible-unstable.rs | ||
| cfg_accessible-unstable.stderr | ||
| cfg_accessible.rs | ||
| cfg_accessible.stderr | ||
| cfg_attr_path.rs | ||
| inner-cfg-non-inline-mod.rs | ||
| invalid-node-range-issue-129166.rs | ||
| invalid-node-range-issue-129166.stderr | ||
| issue-34028.rs | ||
| module_with_cfg.rs | ||
| test-cfg.rs | ||
| test-cfg.stderr | ||