rust/crates/hir-expand/src/fixup.rs

745 lines
21 KiB
Rust

//! To make attribute macros work reliably when typing, we need to take care to
//! fix up syntax errors in the code we're passing to them.
use rustc_hash::{FxHashMap, FxHashSet};
use smallvec::SmallVec;
use span::{ErasedFileAstId, Span, SpanAnchor, SpanData, FIXUP_ERASED_FILE_AST_ID_MARKER};
use stdx::never;
use syntax::{
ast::{self, AstNode, HasLoopBody},
match_ast, SyntaxElement, SyntaxKind, SyntaxNode, TextRange, TextSize,
};
use triomphe::Arc;
use tt::Spacing;
use crate::{
span_map::SpanMapRef,
tt::{Ident, Leaf, Punct, Subtree},
};
/// The result of calculating fixes for a syntax node -- a bunch of changes
/// (appending to and replacing nodes), the information that is needed to
/// reverse those changes afterwards, and a token map.
#[derive(Debug, Default)]
pub(crate) struct SyntaxFixups {
pub(crate) append: FxHashMap<SyntaxElement, Vec<Leaf>>,
pub(crate) remove: FxHashSet<SyntaxNode>,
pub(crate) undo_info: SyntaxFixupUndoInfo,
}
/// This is the information needed to reverse the fixups.
#[derive(Clone, Debug, Default, PartialEq, Eq)]
pub struct SyntaxFixupUndoInfo {
// FIXME: ThinArc<[Subtree]>
original: Option<Arc<Box<[Subtree]>>>,
}
impl SyntaxFixupUndoInfo {
pub(crate) const NONE: Self = SyntaxFixupUndoInfo { original: None };
}
// We mark spans with `FIXUP_DUMMY_AST_ID` to indicate that they are fake.
const FIXUP_DUMMY_AST_ID: ErasedFileAstId = FIXUP_ERASED_FILE_AST_ID_MARKER;
const FIXUP_DUMMY_RANGE: TextRange = TextRange::empty(TextSize::new(0));
// If the fake span has this range end, that means that the range start is an index into the
// `original` list in `SyntaxFixupUndoInfo`.
const FIXUP_DUMMY_RANGE_END: TextSize = TextSize::new(!0);
pub(crate) fn fixup_syntax(
span_map: SpanMapRef<'_>,
node: &SyntaxNode,
call_site: Span,
) -> SyntaxFixups {
let mut append = FxHashMap::<SyntaxElement, _>::default();
let mut remove = FxHashSet::<SyntaxNode>::default();
let mut preorder = node.preorder();
let mut original = Vec::new();
let dummy_range = FIXUP_DUMMY_RANGE;
let fake_span = |range| {
let span = span_map.span_for_range(range);
SpanData {
range: dummy_range,
anchor: SpanAnchor { ast_id: FIXUP_DUMMY_AST_ID, ..span.anchor },
ctx: span.ctx,
}
};
while let Some(event) = preorder.next() {
let syntax::WalkEvent::Enter(node) = event else { continue };
let node_range = node.text_range();
if can_handle_error(&node) && has_error_to_handle(&node) {
remove.insert(node.clone());
// the node contains an error node, we have to completely replace it by something valid
let original_tree = mbe::syntax_node_to_token_tree(&node, span_map, call_site);
let idx = original.len() as u32;
original.push(original_tree);
let span = span_map.span_for_range(node_range);
let replacement = Leaf::Ident(Ident {
text: "__ra_fixup".into(),
span: SpanData {
range: TextRange::new(TextSize::new(idx), FIXUP_DUMMY_RANGE_END),
anchor: SpanAnchor { ast_id: FIXUP_DUMMY_AST_ID, ..span.anchor },
ctx: span.ctx,
},
});
append.insert(node.clone().into(), vec![replacement]);
preorder.skip_subtree();
continue;
}
// In some other situations, we can fix things by just appending some tokens.
match_ast! {
match node {
ast::FieldExpr(it) => {
if it.name_ref().is_none() {
// incomplete field access: some_expr.|
append.insert(node.clone().into(), vec![
Leaf::Ident(Ident {
text: "__ra_fixup".into(),
span: fake_span(node_range),
}),
]);
}
},
ast::ExprStmt(it) => {
if it.semicolon_token().is_none() {
append.insert(node.clone().into(), vec![
Leaf::Punct(Punct {
char: ';',
spacing: Spacing::Alone,
span: fake_span(node_range),
}),
]);
}
},
ast::LetStmt(it) => {
if it.semicolon_token().is_none() {
append.insert(node.clone().into(), vec![
Leaf::Punct(Punct {
char: ';',
spacing: Spacing::Alone,
span: fake_span(node_range)
}),
]);
}
},
ast::IfExpr(it) => {
if it.condition().is_none() {
// insert placeholder token after the if token
let if_token = match it.if_token() {
Some(t) => t,
None => continue,
};
append.insert(if_token.into(), vec![
Leaf::Ident(Ident {
text: "__ra_fixup".into(),
span: fake_span(node_range)
}),
]);
}
if it.then_branch().is_none() {
append.insert(node.clone().into(), vec![
// FIXME: THis should be a subtree no?
Leaf::Punct(Punct {
char: '{',
spacing: Spacing::Alone,
span: fake_span(node_range)
}),
Leaf::Punct(Punct {
char: '}',
spacing: Spacing::Alone,
span: fake_span(node_range)
}),
]);
}
},
ast::WhileExpr(it) => {
if it.condition().is_none() {
// insert placeholder token after the while token
let while_token = match it.while_token() {
Some(t) => t,
None => continue,
};
append.insert(while_token.into(), vec![
Leaf::Ident(Ident {
text: "__ra_fixup".into(),
span: fake_span(node_range)
}),
]);
}
if it.loop_body().is_none() {
append.insert(node.clone().into(), vec![
// FIXME: THis should be a subtree no?
Leaf::Punct(Punct {
char: '{',
spacing: Spacing::Alone,
span: fake_span(node_range)
}),
Leaf::Punct(Punct {
char: '}',
spacing: Spacing::Alone,
span: fake_span(node_range)
}),
]);
}
},
ast::LoopExpr(it) => {
if it.loop_body().is_none() {
append.insert(node.clone().into(), vec![
// FIXME: THis should be a subtree no?
Leaf::Punct(Punct {
char: '{',
spacing: Spacing::Alone,
span: fake_span(node_range)
}),
Leaf::Punct(Punct {
char: '}',
spacing: Spacing::Alone,
span: fake_span(node_range)
}),
]);
}
},
// FIXME: foo::
ast::MatchExpr(it) => {
if it.expr().is_none() {
let match_token = match it.match_token() {
Some(t) => t,
None => continue
};
append.insert(match_token.into(), vec![
Leaf::Ident(Ident {
text: "__ra_fixup".into(),
span: fake_span(node_range)
}),
]);
}
if it.match_arm_list().is_none() {
// No match arms
append.insert(node.clone().into(), vec![
// FIXME: THis should be a subtree no?
Leaf::Punct(Punct {
char: '{',
spacing: Spacing::Alone,
span: fake_span(node_range)
}),
Leaf::Punct(Punct {
char: '}',
spacing: Spacing::Alone,
span: fake_span(node_range)
}),
]);
}
},
ast::ForExpr(it) => {
let for_token = match it.for_token() {
Some(token) => token,
None => continue
};
let [pat, in_token, iter] = [
"_",
"in",
"__ra_fixup"
].map(|text|
Leaf::Ident(Ident {
text: text.into(),
span: fake_span(node_range)
}),
);
if it.pat().is_none() && it.in_token().is_none() && it.iterable().is_none() {
append.insert(for_token.into(), vec![pat, in_token, iter]);
// does something funky -- see test case for_no_pat
} else if it.pat().is_none() {
append.insert(for_token.into(), vec![pat]);
}
if it.loop_body().is_none() {
append.insert(node.clone().into(), vec![
// FIXME: THis should be a subtree no?
Leaf::Punct(Punct {
char: '{',
spacing: Spacing::Alone,
span: fake_span(node_range)
}),
Leaf::Punct(Punct {
char: '}',
spacing: Spacing::Alone,
span: fake_span(node_range)
}),
]);
}
},
_ => (),
}
}
}
let needs_fixups = !append.is_empty() || !original.is_empty();
SyntaxFixups {
append,
remove,
undo_info: SyntaxFixupUndoInfo {
original: needs_fixups.then(|| Arc::new(original.into_boxed_slice())),
},
}
}
fn has_error(node: &SyntaxNode) -> bool {
node.children().any(|c| c.kind() == SyntaxKind::ERROR)
}
fn can_handle_error(node: &SyntaxNode) -> bool {
ast::Expr::can_cast(node.kind())
}
fn has_error_to_handle(node: &SyntaxNode) -> bool {
has_error(node) || node.children().any(|c| !can_handle_error(&c) && has_error_to_handle(&c))
}
pub(crate) fn reverse_fixups(tt: &mut Subtree, undo_info: &SyntaxFixupUndoInfo) {
let Some(undo_info) = undo_info.original.as_deref() else { return };
let undo_info = &**undo_info;
#[allow(deprecated)]
if never!(
tt.delimiter.close.anchor.ast_id == FIXUP_DUMMY_AST_ID
|| tt.delimiter.open.anchor.ast_id == FIXUP_DUMMY_AST_ID
) {
tt.delimiter.close = SpanData::DUMMY;
tt.delimiter.open = SpanData::DUMMY;
}
reverse_fixups_(tt, undo_info);
}
fn reverse_fixups_(tt: &mut Subtree, undo_info: &[Subtree]) {
let tts = std::mem::take(&mut tt.token_trees).into_vec();
tt.token_trees = tts
.into_iter()
// delete all fake nodes
.filter(|tt| match tt {
tt::TokenTree::Leaf(leaf) => {
let span = leaf.span();
let is_real_leaf = span.anchor.ast_id != FIXUP_DUMMY_AST_ID;
let is_replaced_node = span.range.end() == FIXUP_DUMMY_RANGE_END;
is_real_leaf || is_replaced_node
}
tt::TokenTree::Subtree(_) => true,
})
.flat_map(|tt| match tt {
tt::TokenTree::Subtree(mut tt) => {
if tt.delimiter.close.anchor.ast_id == FIXUP_DUMMY_AST_ID
|| tt.delimiter.open.anchor.ast_id == FIXUP_DUMMY_AST_ID
{
// Even though fixup never creates subtrees with fixup spans, the old proc-macro server
// might copy them if the proc-macro asks for it, so we need to filter those out
// here as well.
return SmallVec::new_const();
}
reverse_fixups_(&mut tt, undo_info);
SmallVec::from_const([tt.into()])
}
tt::TokenTree::Leaf(leaf) => {
if leaf.span().anchor.ast_id == FIXUP_DUMMY_AST_ID {
// we have a fake node here, we need to replace it again with the original
let original = undo_info[u32::from(leaf.span().range.start()) as usize].clone();
if original.delimiter.kind == tt::DelimiterKind::Invisible {
SmallVec::from(original.token_trees.into_vec())
} else {
SmallVec::from_const([original.into()])
}
} else {
// just a normal leaf
SmallVec::from_const([leaf.into()])
}
}
})
.collect();
}
#[cfg(test)]
mod tests {
use base_db::FileId;
use expect_test::{expect, Expect};
use syntax::TextRange;
use triomphe::Arc;
use crate::{
fixup::reverse_fixups,
span_map::{RealSpanMap, SpanMap},
tt,
};
// The following three functions are only meant to check partial structural equivalence of
// `TokenTree`s, see the last assertion in `check()`.
fn check_leaf_eq(a: &tt::Leaf, b: &tt::Leaf) -> bool {
match (a, b) {
(tt::Leaf::Literal(a), tt::Leaf::Literal(b)) => a.text == b.text,
(tt::Leaf::Punct(a), tt::Leaf::Punct(b)) => a.char == b.char,
(tt::Leaf::Ident(a), tt::Leaf::Ident(b)) => a.text == b.text,
_ => false,
}
}
fn check_subtree_eq(a: &tt::Subtree, b: &tt::Subtree) -> bool {
a.delimiter.kind == b.delimiter.kind
&& a.token_trees.len() == b.token_trees.len()
&& a.token_trees.iter().zip(b.token_trees.iter()).all(|(a, b)| check_tt_eq(a, b))
}
fn check_tt_eq(a: &tt::TokenTree, b: &tt::TokenTree) -> bool {
match (a, b) {
(tt::TokenTree::Leaf(a), tt::TokenTree::Leaf(b)) => check_leaf_eq(a, b),
(tt::TokenTree::Subtree(a), tt::TokenTree::Subtree(b)) => check_subtree_eq(a, b),
_ => false,
}
}
#[track_caller]
fn check(ra_fixture: &str, mut expect: Expect) {
let parsed = syntax::SourceFile::parse(ra_fixture);
let span_map = SpanMap::RealSpanMap(Arc::new(RealSpanMap::absolute(FileId::from_raw(0))));
let fixups = super::fixup_syntax(
span_map.as_ref(),
&parsed.syntax_node(),
span_map.span_for_range(TextRange::empty(0.into())),
);
let mut tt = mbe::syntax_node_to_token_tree_modified(
&parsed.syntax_node(),
span_map.as_ref(),
fixups.append,
fixups.remove,
span_map.span_for_range(TextRange::empty(0.into())),
);
let actual = format!("{tt}\n");
expect.indent(false);
expect.assert_eq(&actual);
// the fixed-up tree should be syntactically valid
let (parse, _) = mbe::token_tree_to_syntax_node(&tt, ::mbe::TopEntryPoint::MacroItems);
assert!(
parse.errors().is_empty(),
"parse has syntax errors. parse tree:\n{:#?}",
parse.syntax_node()
);
reverse_fixups(&mut tt, &fixups.undo_info);
// the fixed-up + reversed version should be equivalent to the original input
// modulo token IDs and `Punct`s' spacing.
let original_as_tt = mbe::syntax_node_to_token_tree(
&parsed.syntax_node(),
span_map.as_ref(),
span_map.span_for_range(TextRange::empty(0.into())),
);
assert!(
check_subtree_eq(&tt, &original_as_tt),
"different token tree:\n{tt:?}\n\n{original_as_tt:?}"
);
}
#[test]
fn just_for_token() {
check(
r#"
fn foo() {
for
}
"#,
expect![[r#"
fn foo () {for _ in __ra_fixup { }}
"#]],
)
}
#[test]
fn for_no_iter_pattern() {
check(
r#"
fn foo() {
for {}
}
"#,
expect![[r#"
fn foo () {for _ in __ra_fixup {}}
"#]],
)
}
#[test]
fn for_no_body() {
check(
r#"
fn foo() {
for bar in qux
}
"#,
expect![[r#"
fn foo () {for bar in qux { }}
"#]],
)
}
// FIXME: https://github.com/rust-lang/rust-analyzer/pull/12937#discussion_r937633695
#[test]
fn for_no_pat() {
check(
r#"
fn foo() {
for in qux {
}
}
"#,
expect![[r#"
fn foo () {__ra_fixup}
"#]],
)
}
#[test]
fn match_no_expr_no_arms() {
check(
r#"
fn foo() {
match
}
"#,
expect![[r#"
fn foo () {match __ra_fixup { }}
"#]],
)
}
#[test]
fn match_expr_no_arms() {
check(
r#"
fn foo() {
match it {
}
}
"#,
expect![[r#"
fn foo () {match it {}}
"#]],
)
}
#[test]
fn match_no_expr() {
check(
r#"
fn foo() {
match {
_ => {}
}
}
"#,
expect![[r#"
fn foo () {match __ra_fixup { }}
"#]],
)
}
#[test]
fn incomplete_field_expr_1() {
check(
r#"
fn foo() {
a.
}
"#,
expect![[r#"
fn foo () {a . __ra_fixup}
"#]],
)
}
#[test]
fn incomplete_field_expr_2() {
check(
r#"
fn foo() {
a.;
}
"#,
expect![[r#"
fn foo () {a . __ra_fixup ;}
"#]],
)
}
#[test]
fn incomplete_field_expr_3() {
check(
r#"
fn foo() {
a.;
bar();
}
"#,
expect![[r#"
fn foo () {a . __ra_fixup ; bar () ;}
"#]],
)
}
#[test]
fn incomplete_let() {
check(
r#"
fn foo() {
let it = a
}
"#,
expect![[r#"
fn foo () {let it = a ;}
"#]],
)
}
#[test]
fn incomplete_field_expr_in_let() {
check(
r#"
fn foo() {
let it = a.
}
"#,
expect![[r#"
fn foo () {let it = a . __ra_fixup ;}
"#]],
)
}
#[test]
fn field_expr_before_call() {
// another case that easily happens while typing
check(
r#"
fn foo() {
a.b
bar();
}
"#,
expect![[r#"
fn foo () {a . b ; bar () ;}
"#]],
)
}
#[test]
fn extraneous_comma() {
check(
r#"
fn foo() {
bar(,);
}
"#,
expect![[r#"
fn foo () {__ra_fixup ;}
"#]],
)
}
#[test]
fn fixup_if_1() {
check(
r#"
fn foo() {
if a
}
"#,
expect![[r#"
fn foo () {if a { }}
"#]],
)
}
#[test]
fn fixup_if_2() {
check(
r#"
fn foo() {
if
}
"#,
expect![[r#"
fn foo () {if __ra_fixup { }}
"#]],
)
}
#[test]
fn fixup_if_3() {
check(
r#"
fn foo() {
if {}
}
"#,
expect![[r#"
fn foo () {if __ra_fixup {} { }}
"#]],
)
}
#[test]
fn fixup_while_1() {
check(
r#"
fn foo() {
while
}
"#,
expect![[r#"
fn foo () {while __ra_fixup { }}
"#]],
)
}
#[test]
fn fixup_while_2() {
check(
r#"
fn foo() {
while foo
}
"#,
expect![[r#"
fn foo () {while foo { }}
"#]],
)
}
#[test]
fn fixup_while_3() {
check(
r#"
fn foo() {
while {}
}
"#,
expect![[r#"
fn foo () {while __ra_fixup {}}
"#]],
)
}
#[test]
fn fixup_loop() {
check(
r#"
fn foo() {
loop
}
"#,
expect![[r#"
fn foo () {loop { }}
"#]],
)
}
}