ecbe3fd550
Pretty-print let-else with added parenthesization when needed
Rustc used to produce invalid syntax for the following code, which is problematic because it means we cannot apply rustfmt to the output of `-Zunpretty=expanded`.
```rust
macro_rules! expr {
($e:expr) => { $e };
}
fn main() {
let _ = expr!(loop {}) else { return; };
}
```
```console
$ rustc repro.rs -Zunpretty=expanded | rustfmt
error: `loop...else` loops are not supported
--> <stdin>:9:29
|
9 | fn main() { let _ = loop {} else { return; }; }
| ---- ^^^^^^^^^^^^^^^^
| |
| `else` is attached to this loop
|
= note: consider moving this `else` clause to a separate `if` statement and use a `bool` variable to control if it should run
```
|
||
|---|---|---|
| .. | ||
| assembly | ||
| auxiliary | ||
| codegen | ||
| codegen-units | ||
| coverage | ||
| coverage-run-rustdoc | ||
| crashes | ||
| debuginfo | ||
| incremental | ||
| mir-opt | ||
| pretty | ||
| run-make | ||
| run-make-fulldeps | ||
| run-pass-valgrind | ||
| rustdoc | ||
| rustdoc-gui | ||
| rustdoc-js | ||
| rustdoc-js-std | ||
| rustdoc-json | ||
| rustdoc-ui | ||
| ui | ||
| ui-fulldeps | ||
| COMPILER_TESTS.md | ||