feat: apply #[cfg] to proc macro inputs

crates/cfg/Cargo.toml

@@ -31,4 +31,4 @@ mbe.workspace = true
 syntax.workspace = true
 
 [lints]
-workspace = true
+workspace = true

crates/cfg/src/cfg_expr.rs

@@ -47,6 +47,7 @@ impl CfgExpr {
     pub fn parse<S>(tt: &tt::Subtree<S>) -> CfgExpr {
         next_cfg_expr(&mut tt.token_trees.iter()).unwrap_or(CfgExpr::Invalid)
     }
+
     /// Fold the cfg by querying all basic `Atom` and `KeyValue` predicates.
     pub fn fold(&self, query: &dyn Fn(&CfgAtom) -> bool) -> Option<bool> {
         match self {
@@ -62,7 +63,6 @@ impl CfgExpr {
         }
     }
 }
-
 fn next_cfg_expr<S>(it: &mut SliceIter<'_, tt::TokenTree<S>>) -> Option<CfgExpr> {
     let name = match it.next() {
         None => return None,

crates/hir-def/src/macro_expansion_tests/builtin_derive_macro.rs

@@ -528,3 +528,121 @@ impl < > $crate::fmt::Debug for Command< > where {
 }"#]],
     );
 }
+#[test]
+fn test_debug_expand_with_cfg() {
+    check(
+        r#"
+            //- minicore: derive, fmt
+            use core::fmt::Debug;
+
+            #[derive(Debug)]
+            struct HideAndShow {
+                #[cfg(never)]
+                always_hide: u32,
+                #[cfg(not(never))]
+                always_show: u32,
+            }
+            #[derive(Debug)]
+            enum HideAndShowEnum {
+                #[cfg(never)]
+                AlwaysHide,
+                #[cfg(not(never))]
+                AlwaysShow{
+                    #[cfg(never)]
+                    always_hide: u32,
+                    #[cfg(not(never))]
+                    always_show: u32,
+                }
+            }
+        "#,
+        expect![[r#"
+use core::fmt::Debug;
+
+#[derive(Debug)]
+struct HideAndShow {
+    #[cfg(never)]
+    always_hide: u32,
+    #[cfg(not(never))]
+    always_show: u32,
+}
+#[derive(Debug)]
+enum HideAndShowEnum {
+    #[cfg(never)]
+    AlwaysHide,
+    #[cfg(not(never))]
+    AlwaysShow{
+        #[cfg(never)]
+        always_hide: u32,
+        #[cfg(not(never))]
+        always_show: u32,
+    }
+}
+
+impl < > $crate::fmt::Debug for HideAndShow< > where {
+    fn fmt(&self , f: &mut $crate::fmt::Formatter) -> $crate::fmt::Result {
+        match self {
+            HideAndShow {
+                always_show: always_show,
+            }
+            =>f.debug_struct("HideAndShow").field("always_show", &always_show).finish()
+        }
+    }
+}
+impl < > $crate::fmt::Debug for HideAndShowEnum< > where {
+    fn fmt(&self , f: &mut $crate::fmt::Formatter) -> $crate::fmt::Result {
+        match self {
+            HideAndShowEnum::AlwaysShow {
+                always_show: always_show,
+            }
+            =>f.debug_struct("AlwaysShow").field("always_show", &always_show).finish(),
+        }
+    }
+}"#]],
+    );
+}
+#[test]
+fn test_default_expand_with_cfg() {
+    check(
+        r#"
+//- minicore: derive, default
+#[derive(Default)]
+struct Foo {
+    field1: i32,
+    #[cfg(never)]
+    field2: (),
+}
+#[derive(Default)]
+enum Bar {
+    Foo,
+    #[cfg_attr(not(never), default)]
+    Bar,
+}
+"#,
+        expect![[r#"
+#[derive(Default)]
+struct Foo {
+    field1: i32,
+    #[cfg(never)]
+    field2: (),
+}
+#[derive(Default)]
+enum Bar {
+    Foo,
+    #[cfg_attr(not(never), default)]
+    Bar,
+}
+
+impl < > $crate::default::Default for Foo< > where {
+    fn default() -> Self {
+        Foo {
+            field1: $crate::default::Default::default(),
+        }
+    }
+}
+impl < > $crate::default::Default for Bar< > where {
+    fn default() -> Self {
+        Bar::Bar
+    }
+}"#]],
+    );
+}

crates/hir-expand/src/cfg_process.rs

@@ -0,0 +1,327 @@
+//! Processes out #[cfg] and #[cfg_attr] attributes from the input for the derive macro
+use std::iter::Peekable;
+
+use cfg::{CfgAtom, CfgExpr};
+use rustc_hash::FxHashSet;
+use syntax::{
+    ast::{self, Attr, HasAttrs, Meta, VariantList},
+    AstNode, NodeOrToken, SyntaxElement, SyntaxNode, T,
+};
+use tracing::{debug, warn};
+use tt::SmolStr;
+
+use crate::{db::ExpandDatabase, MacroCallKind, MacroCallLoc};
+
+fn check_cfg_attr(attr: &Attr, loc: &MacroCallLoc, db: &dyn ExpandDatabase) -> Option<bool> {
+    if !attr.simple_name().as_deref().map(|v| v == "cfg")? {
+        return None;
+    }
+    debug!("Evaluating cfg {}", attr);
+    let cfg = parse_from_attr_meta(attr.meta()?)?;
+    debug!("Checking cfg {:?}", cfg);
+    let enabled = db.crate_graph()[loc.krate].cfg_options.check(&cfg) != Some(false);
+    Some(enabled)
+}
+
+fn check_cfg_attr_attr(attr: &Attr, loc: &MacroCallLoc, db: &dyn ExpandDatabase) -> Option<bool> {
+    if !attr.simple_name().as_deref().map(|v| v == "cfg_attr")? {
+        return None;
+    }
+    debug!("Evaluating cfg_attr {}", attr);
+    let cfg_expr = parse_from_attr_meta(attr.meta()?)?;
+    debug!("Checking cfg_attr {:?}", cfg_expr);
+    let enabled = db.crate_graph()[loc.krate].cfg_options.check(&cfg_expr) != Some(false);
+    Some(enabled)
+}
+
+fn process_has_attrs_with_possible_comma<I: HasAttrs>(
+    items: impl Iterator<Item = I>,
+    loc: &MacroCallLoc,
+    db: &dyn ExpandDatabase,
+    remove: &mut FxHashSet<SyntaxElement>,
+) -> Option<()> {
+    for item in items {
+        let field_attrs = item.attrs();
+        'attrs: for attr in field_attrs {
+            if check_cfg_attr(&attr, loc, db).map(|enabled| !enabled).unwrap_or_default() {
+                debug!("censoring type {:?}", item.syntax());
+                remove.insert(item.syntax().clone().into());
+                // We need to remove the , as well
+                remove_possible_comma(&item, remove);
+                break 'attrs;
+            }
+
+            if let Some(enabled) = check_cfg_attr_attr(&attr, loc, db) {
+                if enabled {
+                    debug!("Removing cfg_attr tokens {:?}", attr);
+                    let meta = attr.meta()?;
+                    let removes_from_cfg_attr = remove_tokens_within_cfg_attr(meta)?;
+                    remove.extend(removes_from_cfg_attr);
+                } else {
+                    debug!("censoring type cfg_attr {:?}", item.syntax());
+                    remove.insert(attr.syntax().clone().into());
+                    continue;
+                }
+            }
+        }
+    }
+    Some(())
+}
+#[derive(Debug, PartialEq, Eq, Clone, Copy)]
+enum CfgExprStage {
+    /// Stripping the CFGExpr part of the attribute
+    StrippigCfgExpr,
+    /// Found the comma after the CFGExpr. Will keep all tokens until the next comma or the end of the attribute
+    FoundComma,
+    /// Everything following the attribute. This could be another attribute or the end of the attribute.
+    // FIXME: cfg_attr with multiple attributes will not be handled correctly. We will only keep the first attribute
+    // Related Issue: https://github.com/rust-lang/rust-analyzer/issues/10110
+    EverythingElse,
+}
+/// This function creates its own set of tokens to remove. To help prevent malformed syntax as input.
+fn remove_tokens_within_cfg_attr(meta: Meta) -> Option<FxHashSet<SyntaxElement>> {
+    let mut remove: FxHashSet<SyntaxElement> = FxHashSet::default();
+    debug!("Enabling attribute {}", meta);
+    let meta_path = meta.path()?;
+    debug!("Removing {:?}", meta_path.syntax());
+    remove.insert(meta_path.syntax().clone().into());
+
+    let meta_tt = meta.token_tree()?;
+    debug!("meta_tt {}", meta_tt);
+    let mut stage = CfgExprStage::StrippigCfgExpr;
+    for tt in meta_tt.token_trees_and_tokens() {
+        debug!("Checking {:?}. Stage: {:?}", tt, stage);
+        match (stage, tt) {
+            (CfgExprStage::StrippigCfgExpr, syntax::NodeOrToken::Node(node)) => {
+                remove.insert(node.syntax().clone().into());
+            }
+            (CfgExprStage::StrippigCfgExpr, syntax::NodeOrToken::Token(token)) => {
+                if token.kind() == T![,] {
+                    stage = CfgExprStage::FoundComma;
+                }
+                remove.insert(token.into());
+            }
+            (CfgExprStage::FoundComma, syntax::NodeOrToken::Token(token))
+                if (token.kind() == T![,] || token.kind() == T![')']) =>
+            {
+                // The end of the attribute or separator for the next attribute
+                stage = CfgExprStage::EverythingElse;
+                remove.insert(token.into());
+            }
+            (CfgExprStage::EverythingElse, syntax::NodeOrToken::Node(node)) => {
+                remove.insert(node.syntax().clone().into());
+            }
+            (CfgExprStage::EverythingElse, syntax::NodeOrToken::Token(token)) => {
+                remove.insert(token.into());
+            }
+            // This is an actual attribute
+            _ => {}
+        }
+    }
+    if stage != CfgExprStage::EverythingElse {
+        warn!("Invalid cfg_attr attribute. {:?}", meta_tt);
+        return None;
+    }
+    Some(remove)
+}
+/// Removes a possible comma after the [AstNode]
+fn remove_possible_comma(item: &impl AstNode, res: &mut FxHashSet<SyntaxElement>) {
+    if let Some(comma) = item.syntax().next_sibling_or_token().filter(|it| it.kind() == T![,]) {
+        res.insert(comma);
+    }
+}
+fn process_enum(
+    variants: VariantList,
+    loc: &MacroCallLoc,
+    db: &dyn ExpandDatabase,
+    remove: &mut FxHashSet<SyntaxElement>,
+) -> Option<()> {
+    'variant: for variant in variants.variants() {
+        for attr in variant.attrs() {
+            if check_cfg_attr(&attr, loc, db).map(|enabled| !enabled).unwrap_or_default() {
+                // Rustc does not strip the attribute if it is enabled. So we will will leave it
+                debug!("censoring type {:?}", variant.syntax());
+                remove.insert(variant.syntax().clone().into());
+                // We need to remove the , as well
+                remove_possible_comma(&variant, remove);
+                continue 'variant;
+            };
+
+            if let Some(enabled) = check_cfg_attr_attr(&attr, loc, db) {
+                if enabled {
+                    debug!("Removing cfg_attr tokens {:?}", attr);
+                    let meta = attr.meta()?;
+                    let removes_from_cfg_attr = remove_tokens_within_cfg_attr(meta)?;
+                    remove.extend(removes_from_cfg_attr);
+                } else {
+                    debug!("censoring type cfg_attr {:?}", variant.syntax());
+                    remove.insert(attr.syntax().clone().into());
+                    continue;
+                }
+            }
+        }
+        if let Some(fields) = variant.field_list() {
+            match fields {
+                ast::FieldList::RecordFieldList(fields) => {
+                    process_has_attrs_with_possible_comma(fields.fields(), loc, db, remove)?;
+                }
+                ast::FieldList::TupleFieldList(fields) => {
+                    process_has_attrs_with_possible_comma(fields.fields(), loc, db, remove)?;
+                }
+            }
+        }
+    }
+    Some(())
+}
+
+pub(crate) fn process_cfg_attrs(
+    node: &SyntaxNode,
+    loc: &MacroCallLoc,
+    db: &dyn ExpandDatabase,
+) -> Option<FxHashSet<SyntaxElement>> {
+    // FIXME: #[cfg_eval] is not implemented. But it is not stable yet
+    if !matches!(loc.kind, MacroCallKind::Derive { .. }) {
+        return None;
+    }
+    let mut remove = FxHashSet::default();
+
+    let item = ast::Item::cast(node.clone())?;
+    for attr in item.attrs() {
+        if let Some(enabled) = check_cfg_attr_attr(&attr, loc, db) {
+            if enabled {
+                debug!("Removing cfg_attr tokens {:?}", attr);
+                let meta = attr.meta()?;
+                let removes_from_cfg_attr = remove_tokens_within_cfg_attr(meta)?;
+                remove.extend(removes_from_cfg_attr);
+            } else {
+                debug!("censoring type cfg_attr {:?}", item.syntax());
+                remove.insert(attr.syntax().clone().into());
+                continue;
+            }
+        }
+    }
+    match item {
+        ast::Item::Struct(it) => match it.field_list()? {
+            ast::FieldList::RecordFieldList(fields) => {
+                process_has_attrs_with_possible_comma(fields.fields(), loc, db, &mut remove)?;
+            }
+            ast::FieldList::TupleFieldList(fields) => {
+                process_has_attrs_with_possible_comma(fields.fields(), loc, db, &mut remove)?;
+            }
+        },
+        ast::Item::Enum(it) => {
+            process_enum(it.variant_list()?, loc, db, &mut remove)?;
+        }
+        ast::Item::Union(it) => {
+            process_has_attrs_with_possible_comma(
+                it.record_field_list()?.fields(),
+                loc,
+                db,
+                &mut remove,
+            )?;
+        }
+        // FIXME: Implement for other items if necessary. As we do not support #[cfg_eval] yet, we do not need to implement it for now
+        _ => {}
+    }
+    Some(remove)
+}
+/// Parses a `cfg` attribute from the meta
+fn parse_from_attr_meta(meta: Meta) -> Option<CfgExpr> {
+    let tt = meta.token_tree()?;
+    let mut iter = tt.token_trees_and_tokens().skip(1).peekable();
+    next_cfg_expr_from_syntax(&mut iter)
+}
+
+fn next_cfg_expr_from_syntax<I>(iter: &mut Peekable<I>) -> Option<CfgExpr>
+where
+    I: Iterator<Item = NodeOrToken<ast::TokenTree, syntax::SyntaxToken>>,
+{
+    let name = match iter.next() {
+        None => return None,
+        Some(NodeOrToken::Token(element)) => match element.kind() {
+            syntax::T![ident] => SmolStr::new(element.text()),
+            _ => return Some(CfgExpr::Invalid),
+        },
+        Some(_) => return Some(CfgExpr::Invalid),
+    };
+    let result = match name.as_str() {
+        "all" | "any" | "not" => {
+            let mut preds = Vec::new();
+            let Some(NodeOrToken::Node(tree)) = iter.next() else {
+                return Some(CfgExpr::Invalid);
+            };
+            let mut tree_iter = tree.token_trees_and_tokens().skip(1).peekable();
+            while tree_iter
+                .peek()
+                .filter(
+                    |element| matches!(element, NodeOrToken::Token(token) if (token.kind() != syntax::T![')'])),
+                )
+                .is_some()
+            {
+                let pred = next_cfg_expr_from_syntax(&mut tree_iter);
+                if let Some(pred) = pred {
+                    preds.push(pred);
+                }
+            }
+            let group = match name.as_str() {
+                "all" => CfgExpr::All(preds),
+                "any" => CfgExpr::Any(preds),
+                "not" => CfgExpr::Not(Box::new(preds.pop().unwrap_or(CfgExpr::Invalid))),
+                _ => unreachable!(),
+            };
+            Some(group)
+        }
+        _ => match iter.peek() {
+            Some(NodeOrToken::Token(element)) if (element.kind() == syntax::T![=]) => {
+                iter.next();
+                match iter.next() {
+                    Some(NodeOrToken::Token(value_token))
+                        if (value_token.kind() == syntax::SyntaxKind::STRING) =>
+                    {
+                        let value = value_token.text();
+                        let value = SmolStr::new(value.trim_matches('"'));
+                        Some(CfgExpr::Atom(CfgAtom::KeyValue { key: name, value }))
+                    }
+                    _ => None,
+                }
+            }
+            _ => Some(CfgExpr::Atom(CfgAtom::Flag(name))),
+        },
+    };
+    if let Some(NodeOrToken::Token(element)) = iter.peek() {
+        if element.kind() == syntax::T![,] {
+            iter.next();
+        }
+    }
+    result
+}
+#[cfg(test)]
+mod tests {
+    use cfg::DnfExpr;
+    use expect_test::{expect, Expect};
+    use syntax::{ast::Attr, AstNode, SourceFile};
+
+    use crate::cfg_process::parse_from_attr_meta;
+
+    fn check_dnf_from_syntax(input: &str, expect: Expect) {
+        let parse = SourceFile::parse(input);
+        let node = match parse.tree().syntax().descendants().find_map(Attr::cast) {
+            Some(it) => it,
+            None => {
+                let node = std::any::type_name::<Attr>();
+                panic!("Failed to make ast node `{node}` from text {input}")
+            }
+        };
+        let node = node.clone_subtree();
+        assert_eq!(node.syntax().text_range().start(), 0.into());
+
+        let cfg = parse_from_attr_meta(node.meta().unwrap()).unwrap();
+        let actual = format!("#![cfg({})]", DnfExpr::new(cfg));
+        expect.assert_eq(&actual);
+    }
+    #[test]
+    fn cfg_from_attr() {
+        check_dnf_from_syntax(r#"#[cfg(test)]"#, expect![[r#"#![cfg(test)]"#]]);
+        check_dnf_from_syntax(r#"#[cfg(not(never))]"#, expect![[r#"#![cfg(not(never))]"#]]);
+    }
+}

crates/hir-expand/src/db.rs

@@ -8,14 +8,15 @@ use rustc_hash::FxHashSet;
 use span::{AstIdMap, SyntaxContextData, SyntaxContextId};
 use syntax::{
     ast::{self, HasAttrs},
-    AstNode, Parse, SyntaxError, SyntaxNode, SyntaxToken, T,
+    AstNode, Parse, SyntaxElement, SyntaxError, SyntaxNode, SyntaxToken, T,
 };
 use triomphe::Arc;
 
 use crate::{
     attrs::collect_attrs,
     builtin_attr_macro::pseudo_derive_attr_expansion,
     builtin_fn_macro::EagerExpander,
+    cfg_process,
     declarative::DeclarativeMacroExpander,
     fixup::{self, reverse_fixups, SyntaxFixupUndoInfo},
     hygiene::{span_with_call_site_ctxt, span_with_def_site_ctxt, span_with_mixed_site_ctxt},
@@ -150,12 +151,16 @@ pub fn expand_speculative(
         ),
         MacroCallKind::Derive { .. } | MacroCallKind::Attr { .. } => {
             let censor = censor_for_macro_input(&loc, speculative_args);
+            let censor_cfg =
+                cfg_process::process_cfg_attrs(speculative_args, &loc, db).unwrap_or_default();
             let mut fixups = fixup::fixup_syntax(span_map, speculative_args, loc.call_site);
             fixups.append.retain(|it, _| match it {
-                syntax::NodeOrToken::Node(it) => !censor.contains(it),
                 syntax::NodeOrToken::Token(_) => true,
+                it => !censor.contains(it) && !censor_cfg.contains(it),
             });
             fixups.remove.extend(censor);
+            fixups.remove.extend(censor_cfg);
+
             (
                 mbe::syntax_node_to_token_tree_modified(
                     speculative_args,
@@ -408,12 +413,16 @@ fn macro_arg(
             ),
             MacroCallKind::Derive { .. } | MacroCallKind::Attr { .. } => {
                 let censor = censor_for_macro_input(&loc, &syntax);
+                let censor_cfg =
+                    cfg_process::process_cfg_attrs(&syntax, &loc, db).unwrap_or_default();
                 let mut fixups = fixup::fixup_syntax(map.as_ref(), &syntax, loc.call_site);
                 fixups.append.retain(|it, _| match it {
-                    syntax::NodeOrToken::Node(it) => !censor.contains(it),
                     syntax::NodeOrToken::Token(_) => true,
+                    it => !censor.contains(it) && !censor_cfg.contains(it),
                 });
                 fixups.remove.extend(censor);
+                fixups.remove.extend(censor_cfg);
+
                 {
                     let mut tt = mbe::syntax_node_to_token_tree_modified(
                         &syntax,
@@ -461,7 +470,7 @@ fn macro_arg(
 /// Certain macro calls expect some nodes in the input to be preprocessed away, namely:
 /// - derives expect all `#[derive(..)]` invocations up to the currently invoked one to be stripped
 /// - attributes expect the invoking attribute to be stripped
-fn censor_for_macro_input(loc: &MacroCallLoc, node: &SyntaxNode) -> FxHashSet<SyntaxNode> {
+fn censor_for_macro_input(loc: &MacroCallLoc, node: &SyntaxNode) -> FxHashSet<SyntaxElement> {
     // FIXME: handle `cfg_attr`
     (|| {
         let censor = match loc.kind {
@@ -477,7 +486,7 @@ fn censor_for_macro_input(loc: &MacroCallLoc, node: &SyntaxNode) -> FxHashSet<Sy
                     // we need to know about all macro calls for the given ast item here
                     // so we require some kind of mapping...
                     .filter(|attr| attr.simple_name().as_deref() == Some("derive"))
-                    .map(|it| it.syntax().clone())
+                    .map(|it| it.syntax().clone().into())
                     .collect()
             }
             MacroCallKind::Attr { .. } if loc.def.is_attribute_derive() => return None,
@@ -486,7 +495,7 @@ fn censor_for_macro_input(loc: &MacroCallLoc, node: &SyntaxNode) -> FxHashSet<Sy
                 collect_attrs(&ast::Item::cast(node.clone())?)
                     .nth(invoc_attr_index.ast_index())
                     .and_then(|x| Either::left(x.1))
-                    .map(|attr| attr.syntax().clone())
+                    .map(|attr| attr.syntax().clone().into())
                     .into_iter()
                     .collect()
             }

crates/hir-expand/src/fixup.rs

@@ -23,7 +23,7 @@ use crate::{
 #[derive(Debug, Default)]
 pub(crate) struct SyntaxFixups {
     pub(crate) append: FxHashMap<SyntaxElement, Vec<Leaf>>,
-    pub(crate) remove: FxHashSet<SyntaxNode>,
+    pub(crate) remove: FxHashSet<SyntaxElement>,
     pub(crate) undo_info: SyntaxFixupUndoInfo,
 }
 
@@ -51,7 +51,7 @@ pub(crate) fn fixup_syntax(
     call_site: Span,
 ) -> SyntaxFixups {
     let mut append = FxHashMap::<SyntaxElement, _>::default();
-    let mut remove = FxHashSet::<SyntaxNode>::default();
+    let mut remove = FxHashSet::<SyntaxElement>::default();
     let mut preorder = node.preorder();
     let mut original = Vec::new();
     let dummy_range = FIXUP_DUMMY_RANGE;
@@ -68,7 +68,7 @@ pub(crate) fn fixup_syntax(
 
         let node_range = node.text_range();
         if can_handle_error(&node) && has_error_to_handle(&node) {
-            remove.insert(node.clone());
+            remove.insert(node.clone().into());
             // 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;

crates/hir-expand/src/lib.rs

@@ -22,8 +22,8 @@ pub mod proc_macro;
 pub mod quote;
 pub mod span_map;
 
+mod cfg_process;
 mod fixup;
-
 use attrs::collect_attrs;
 use triomphe::Arc;
 

crates/mbe/src/syntax_bridge.rs

@@ -92,7 +92,7 @@ pub fn syntax_node_to_token_tree_modified<Ctx, SpanMap>(
     node: &SyntaxNode,
     map: SpanMap,
     append: FxHashMap<SyntaxElement, Vec<tt::Leaf<SpanData<Ctx>>>>,
-    remove: FxHashSet<SyntaxNode>,
+    remove: FxHashSet<SyntaxElement>,
     call_site: SpanData<Ctx>,
 ) -> tt::Subtree<SpanData<Ctx>>
 where
@@ -629,7 +629,7 @@ struct Converter<SpanMap, S> {
     /// Used to make the emitted text ranges in the spans relative to the span anchor.
     map: SpanMap,
     append: FxHashMap<SyntaxElement, Vec<tt::Leaf<S>>>,
-    remove: FxHashSet<SyntaxNode>,
+    remove: FxHashSet<SyntaxElement>,
     call_site: S,
 }
 
@@ -638,7 +638,7 @@ impl<SpanMap, S> Converter<SpanMap, S> {
         node: &SyntaxNode,
         map: SpanMap,
         append: FxHashMap<SyntaxElement, Vec<tt::Leaf<S>>>,
-        remove: FxHashSet<SyntaxNode>,
+        remove: FxHashSet<SyntaxElement>,
         call_site: S,
     ) -> Self {
         let mut this = Converter {
@@ -660,16 +660,25 @@ impl<SpanMap, S> Converter<SpanMap, S> {
     fn next_token(&mut self) -> Option<SyntaxToken> {
         while let Some(ev) = self.preorder.next() {
             match ev {
-                WalkEvent::Enter(SyntaxElement::Token(t)) => return Some(t),
-                WalkEvent::Enter(SyntaxElement::Node(n)) if self.remove.contains(&n) => {
-                    self.preorder.skip_subtree();
-                    if let Some(mut v) = self.append.remove(&n.into()) {
-                        v.reverse();
-                        self.current_leaves.extend(v);
-                        return None;
+                WalkEvent::Enter(token) => {
+                    if self.remove.contains(&token) {
+                        match token {
+                            syntax::NodeOrToken::Token(_) => {
+                                continue;
+                            }
+                            node => {
+                                self.preorder.skip_subtree();
+                                if let Some(mut v) = self.append.remove(&node) {
+                                    v.reverse();
+                                    self.current_leaves.extend(v);
+                                    return None;
+                                }
+                            }
+                        }
+                    } else if let syntax::NodeOrToken::Token(token) = token {
+                        return Some(token);
                     }
                 }
-                WalkEvent::Enter(SyntaxElement::Node(_)) => (),
                 WalkEvent::Leave(ele) => {
                     if let Some(mut v) = self.append.remove(&ele) {
                         v.reverse();