Consider these expples
{ 92 }
async { 92 }
'a: { 92 }
#[a] { 92 }
Previously the tree for them were
BLOCK_EXPR
{ ... }
EFFECT_EXPR
async
BLOCK_EXPR
{ ... }
EFFECT_EXPR
'a:
BLOCK_EXPR
{ ... }
BLOCK_EXPR
#[a]
{ ... }
As you see, it gets progressively worse :) The last two items are
especially odd. The last one even violates the balanced curleys
invariant we have (#10357) The new approach is to say that the stuff in
`{}` is stmt_list, and the block is stmt_list + optional modifiers
BLOCK_EXPR
STMT_LIST
{ ... }
BLOCK_EXPR
async
STMT_LIST
{ ... }
BLOCK_EXPR
'a:
STMT_LIST
{ ... }
BLOCK_EXPR
#[a]
STMT_LIST
{ ... }
Originally we tried to maintain the invariant that `{}` always match.
That is, that in the parse tree the pair of corresponding `{}` is always
first and last tokens of some nodes.
We had the code to validate that, but apparently it's been broken for
**years** since we introduced tokens/nodes split. Fixing it now makes
some tests fail.
It's unclear if we want to keep this invariant: there's a strong
motivation for breaking it in the following case:
```
use std::{ // unclosed paren
fn main() {
}
} // don't actually want to pair up this with the one from `use`
```
So let's fix the code, but disable it for the time being
The code here is intentionally dense and does exactly what is written.
Explaining semantic difference between Rust 2015 and 2018 doesn't help
with understanding syntax. Better to just add more targeted tests.
Group related stuff together, use only on path for parsing extern blocks
(they actually have modifiers).
Perhaps we should get rid of items_without_modifiers altogether? Better
to handle these kinds on diagnostics in validation layer...
9944: internal: introduce in-place indenting API r=matklad a=iDawer
Introduce `edit_in_place::Indent` that uses mutable tree API and intended to replace `edit::AstNodeEdit`.
Closes#9903
Co-authored-by: Dawer <7803845+iDawer@users.noreply.github.com>
