Conditionally add snippet marker.
Fixes#14161.
Heya, I just added the code with some tests, but not sure if it's *the way* to do it -- I didn't refactor existing methods for the `check` test method, but added another calling layer.
fix: Search raw identifiers without prefix
When we find references/usages of a raw identifier, we should disregard `r#` prefix because there are keywords one can use without the prefix in earlier editions (see #13034; this bug is actually fallout from the PR). `name`, the text we're searching for, has already been stripped of the prefix, but the text of nodes we compare it to hasn't been.
The second commit is strictly refactoring, I can remove it if it's not much of value.
fix: Don't expand macros in the same expansion tree after overflow
This patch fixes 2 bugs:
- In `Expander::enter_expand_id()` (and in code paths it's called), we never check whether we've reached the recursion limit. Although it hasn't been reported as far as I'm aware, this may cause hangs or stack overflows if some malformed attribute macro is used on associated items.
- We keep expansion even when recursion limit is reached. Take the following for example:
```rust
macro_rules! foo { () => {{ foo!(); foo!(); }} }
fn main() { foo!(); }
```
We keep expanding the first `foo!()` in each expansion and would reach the limit at some point, *after which* we would try expanding the second `foo!()` in each expansion until it hits the limit again. This will (by default) lead to ~2^128 expansions.
This is essentially what's happening in #14074. Unlike rustc, we don't just stop expanding macros when we fail as long as it produces some tokens so that we can provide completions and other services in incomplete macro calls.
This patch provides a method that takes care of recursion depths (`Expander::within_limit()`) and stops macro expansions in the whole macro expansion tree once it detects recursion depth overflow. To be honest, I'm not really satisfied with this fix because it can still be used in unintended ways to bypass overflow checks, and I'm still seeking ways such that misuses are caught by the compiler by leveraging types or something.
Fixes#14074
