bendns' repos / rust-analyzer
Unnamed repository; edit this file 'description' to name the repository.
Diffstat (limited to 'crates/hir-expand/src/fixup.rs')
-rw-r--r--crates/hir-expand/src/fixup.rs34
1 files changed, 21 insertions, 13 deletions
diff --git a/crates/hir-expand/src/fixup.rs b/crates/hir-expand/src/fixup.rs
index 90012dd1f7..7404b1a52e 100644
--- a/crates/hir-expand/src/fixup.rs
+++ b/crates/hir-expand/src/fixup.rs
@@ -388,6 +388,7 @@ pub(crate) fn reverse_fixups(tt: &mut TopSubtree, undo_info: &SyntaxFixupUndoInf
reverse_fixups_(tt, undo_info);
}
+#[derive(Debug)]
enum TransformTtAction<'a> {
Keep,
ReplaceWith(tt::TokenTreesView<'a>),
@@ -399,27 +400,40 @@ impl TransformTtAction<'_> {
}
}
+/// This function takes a token tree, and calls `callback` with each token tree in it.
+/// Then it does what the callback says: keeps the tt or replaces it with a (possibly empty)
+/// tts view.
fn transform_tt<'a, 'b>(
tt: &'a mut Vec<tt::TokenTree>,
mut callback: impl FnMut(&mut tt::TokenTree) -> TransformTtAction<'b>,
) {
+ // We need to keep a stack of the currently open subtrees, because we need to update
+ // them if we change the number of items in them.
let mut subtrees_stack = Vec::new();
let mut i = 0;
while i < tt.len() {
- while let Some(&subtree_idx) = subtrees_stack.last() {
+ 'pop_finished_subtrees: while let Some(&subtree_idx) = subtrees_stack.last() {
let tt::TokenTree::Subtree(subtree) = &tt[subtree_idx] else {
unreachable!("non-subtree on subtrees stack");
};
- if subtree_idx + 1 + subtree.usize_len() == i {
+ if i >= subtree_idx + 1 + subtree.usize_len() {
subtrees_stack.pop();
} else {
- break;
+ break 'pop_finished_subtrees;
}
}
let action = callback(&mut tt[i]);
match action {
- TransformTtAction::Keep => {}
+ TransformTtAction::Keep => {
+ // This cannot be shared with the replaced case, because then we may push the same subtree
+ // twice, and will update it twice which will lead to errors.
+ if let tt::TokenTree::Subtree(_) = &tt[i] {
+ subtrees_stack.push(i);
+ }
+
+ i += 1;
+ }
TransformTtAction::ReplaceWith(replacement) => {
let old_len = 1 + match &tt[i] {
tt::TokenTree::Leaf(_) => 0,
@@ -427,23 +441,17 @@ fn transform_tt<'a, 'b>(
};
let len_diff = replacement.len() as i64 - old_len as i64;
tt.splice(i..i + old_len, replacement.flat_tokens().iter().cloned());
- i = i.checked_add_signed(len_diff as isize).unwrap();
+ // `+1` for the loop.
+ i = i.checked_add_signed(len_diff as isize + 1).unwrap();
for &subtree_idx in &subtrees_stack {
let tt::TokenTree::Subtree(subtree) = &mut tt[subtree_idx] else {
unreachable!("non-subtree on subtrees stack");
};
- subtree.len = (subtree.len as i64 + len_diff).try_into().unwrap();
+ subtree.len = (i64::from(subtree.len) + len_diff).try_into().unwrap();
}
}
}
-
- // `tt[i]` might have been removed.
- if let Some(tt::TokenTree::Subtree(_)) = tt.get(i) {
- subtrees_stack.push(i);
- }
-
- i += 1;
}
}