feat: Implement a rust-analyzer span backed proc-macro server mode

.github/workflows/ci.yaml

@@ -38,7 +38,6 @@ jobs:
               - 'crates/proc-macro-api/**'
               - 'crates/proc-macro-srv/**'
               - 'crates/proc-macro-srv-cli/**'
-              - 'crates/proc-macro-test/**'
 
   rust:
     needs: changes

Cargo.toml

@@ -1,6 +1,6 @@
 [workspace]
 members = ["xtask/", "lib/*", "crates/*"]
-exclude = ["crates/proc-macro-test/imp"]
+exclude = ["crates/proc-macro-srv/proc-macro-test/"]
 resolver = "2"
 
 [workspace.package]
@@ -81,7 +81,6 @@ vfs = { path = "./crates/vfs", version = "0.0.0" }
 rustc-dependencies = { path = "./crates/rustc-dependencies", version = "0.0.0" }
 
 # local crates that aren't published to crates.io. These should not have versions.
-proc-macro-test = { path = "./crates/proc-macro-test" }
 sourcegen = { path = "./crates/sourcegen" }
 test-fixture = { path = "./crates/test-fixture" }
 test-utils = { path = "./crates/test-utils" }

crates/hir-expand/src/builtin_fn_macro.rs

@@ -108,6 +108,7 @@ register_builtin! {
     (format_args, FormatArgs) => format_args_expand,
     (const_format_args, ConstFormatArgs) => format_args_expand,
     (format_args_nl, FormatArgsNl) => format_args_nl_expand,
+    (quote, Quote) => quote_expand,
 
     EAGER:
     (compile_error, CompileError) => compile_error_expand,
@@ -770,3 +771,15 @@ fn option_env_expand(
 
     ExpandResult::ok(expanded)
 }
+
+fn quote_expand(
+    _db: &dyn ExpandDatabase,
+    _arg_id: MacroCallId,
+    _tt: &tt::Subtree,
+    span: Span,
+) -> ExpandResult<tt::Subtree> {
+    ExpandResult::new(
+        tt::Subtree::empty(tt::DelimSpan { open: span, close: span }),
+        ExpandError::other("quote! is not implemented"),
+    )
+}

crates/hir-expand/src/fixup.rs

@@ -1,10 +1,9 @@
 //! 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 la_arena::RawIdx;
 use rustc_hash::{FxHashMap, FxHashSet};
 use smallvec::SmallVec;
-use span::{ErasedFileAstId, FileId, Span, SpanAnchor, SpanData};
+use span::{ErasedFileAstId, Span, SpanAnchor, SpanData, FIXUP_ERASED_FILE_AST_ID_MARKER};
 use stdx::never;
 use syntax::{
     ast::{self, AstNode, HasLoopBody},
@@ -39,13 +38,11 @@ impl SyntaxFixupUndoInfo {
     pub(crate) const NONE: Self = SyntaxFixupUndoInfo { original: None };
 }
 
-// censoring -> just don't convert the node
-// replacement -> censor + append
-// append -> insert a fake node, here we need to assemble some dummy span that we can figure out how
-// to remove later
-const FIXUP_DUMMY_FILE: FileId = FileId::from_raw(FileId::MAX_FILE_ID);
-const FIXUP_DUMMY_AST_ID: ErasedFileAstId = ErasedFileAstId::from_raw(RawIdx::from_u32(!0));
+// 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(
@@ -58,13 +55,13 @@ pub(crate) fn fixup_syntax(
     let mut preorder = node.preorder();
     let mut original = Vec::new();
     let dummy_range = FIXUP_DUMMY_RANGE;
-    // we use a file id of `FileId(!0)` to signal a fake node, and the text range's start offset as
-    // the index into the replacement vec but only if the end points to !0
-    let dummy_anchor = SpanAnchor { file_id: FIXUP_DUMMY_FILE, ast_id: FIXUP_DUMMY_AST_ID };
-    let fake_span = |range| SpanData {
-        range: dummy_range,
-        anchor: dummy_anchor,
-        ctx: span_map.span_for_range(range).ctx,
+    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 };
@@ -76,12 +73,13 @@ pub(crate) fn fixup_syntax(
             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: dummy_anchor,
-                    ctx: span_map.span_for_range(node_range).ctx,
+                    anchor: SpanAnchor { ast_id: FIXUP_DUMMY_AST_ID, ..span.anchor },
+                    ctx: span.ctx,
                 },
             });
             append.insert(node.clone().into(), vec![replacement]);
@@ -304,8 +302,8 @@ pub(crate) fn reverse_fixups(tt: &mut Subtree, undo_info: &SyntaxFixupUndoInfo)
     let undo_info = &**undo_info;
     #[allow(deprecated)]
     if never!(
-        tt.delimiter.close.anchor.file_id == FIXUP_DUMMY_FILE
-            || tt.delimiter.open.anchor.file_id == FIXUP_DUMMY_FILE
+        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;
@@ -321,16 +319,16 @@ fn reverse_fixups_(tt: &mut Subtree, undo_info: &[Subtree]) {
         .filter(|tt| match tt {
             tt::TokenTree::Leaf(leaf) => {
                 let span = leaf.span();
-                let is_real_leaf = span.anchor.file_id != FIXUP_DUMMY_FILE;
+                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.file_id == FIXUP_DUMMY_FILE
-                    || tt.delimiter.open.anchor.file_id == FIXUP_DUMMY_FILE
+                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
@@ -341,7 +339,7 @@ fn reverse_fixups_(tt: &mut Subtree, undo_info: &[Subtree]) {
                 SmallVec::from_const([tt.into()])
             }
             tt::TokenTree::Leaf(leaf) => {
-                if leaf.span().anchor.file_id == FIXUP_DUMMY_FILE {
+                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 {

crates/hir-expand/src/name.rs

@@ -388,6 +388,7 @@ pub mod known {
         log_syntax,
         module_path,
         option_env,
+        quote,
         std_panic,
         stringify,
         trace_macros,

crates/hir/src/source_analyzer.rs

@@ -1162,9 +1162,40 @@ fn resolve_hir_path_qualifier(
     resolver: &Resolver,
     path: &Path,
 ) -> Option<PathResolution> {
-    resolver
-        .resolve_path_in_type_ns_fully(db.upcast(), &path)
-        .map(|ty| match ty {
+    (|| {
+        let (ty, unresolved) = match path.type_anchor() {
+            Some(type_ref) => {
+                let (_, res) =
+                    TyLoweringContext::new_maybe_unowned(db, resolver, resolver.type_owner())
+                        .lower_ty_ext(type_ref);
+                res.map(|ty_ns| (ty_ns, path.segments().first()))
+            }
+            None => {
+                let (ty, remaining_idx, _) = resolver.resolve_path_in_type_ns(db.upcast(), path)?;
+                match remaining_idx {
+                    Some(remaining_idx) => {
+                        if remaining_idx + 1 == path.segments().len() {
+                            Some((ty, path.segments().last()))
+                        } else {
+                            None
+                        }
+                    }
+                    None => Some((ty, None)),
+                }
+            }
+        }?;
+
+        // If we are in a TypeNs for a Trait, and we have an unresolved name, try to resolve it as a type
+        // within the trait's associated types.
+        if let (Some(unresolved), &TypeNs::TraitId(trait_id)) = (&unresolved, &ty) {
+            if let Some(type_alias_id) =
+                db.trait_data(trait_id).associated_type_by_name(unresolved.name)
+            {
+                return Some(PathResolution::Def(ModuleDefId::from(type_alias_id).into()));
+            }
+        }
+
+        let res = match ty {
             TypeNs::SelfType(it) => PathResolution::SelfType(it.into()),
             TypeNs::GenericParam(id) => PathResolution::TypeParam(id.into()),
             TypeNs::AdtSelfType(it) | TypeNs::AdtId(it) => {
@@ -1175,11 +1206,28 @@ fn resolve_hir_path_qualifier(
             TypeNs::BuiltinType(it) => PathResolution::Def(BuiltinType::from(it).into()),
             TypeNs::TraitId(it) => PathResolution::Def(Trait::from(it).into()),
             TypeNs::TraitAliasId(it) => PathResolution::Def(TraitAlias::from(it).into()),
-        })
-        .or_else(|| {
-            resolver
-                .resolve_module_path_in_items(db.upcast(), path.mod_path()?)
-                .take_types()
-                .map(|it| PathResolution::Def(it.into()))
-        })
+        };
+        match unresolved {
+            Some(unresolved) => resolver
+                .generic_def()
+                .and_then(|def| {
+                    hir_ty::associated_type_shorthand_candidates(
+                        db,
+                        def,
+                        res.in_type_ns()?,
+                        |name, id| (name == unresolved.name).then_some(id),
+                    )
+                })
+                .map(TypeAlias::from)
+                .map(Into::into)
+                .map(PathResolution::Def),
+            None => Some(res),
+        }
+    })()
+    .or_else(|| {
+        resolver
+            .resolve_module_path_in_items(db.upcast(), path.mod_path()?)
+            .take_types()
+            .map(|it| PathResolution::Def(it.into()))
+    })
 }

crates/proc-macro-api/src/lib.rs

@@ -20,7 +20,10 @@ use triomphe::Arc;
 use serde::{Deserialize, Serialize};
 
 use crate::{
-    msg::{ExpandMacro, ExpnGlobals, FlatTree, PanicMessage, HAS_GLOBAL_SPANS},
+    msg::{
+        deserialize_span_data_index_map, flat::serialize_span_data_index_map, ExpandMacro,
+        ExpnGlobals, FlatTree, PanicMessage, HAS_GLOBAL_SPANS, RUST_ANALYZER_SPAN_SUPPORT,
+    },
     process::ProcMacroProcessSrv,
 };
 
@@ -166,6 +169,11 @@ impl ProcMacro {
                 call_site,
                 mixed_site,
             },
+            span_data_table: if version >= RUST_ANALYZER_SPAN_SUPPORT {
+                serialize_span_data_index_map(&span_data_table)
+            } else {
+                Vec::new()
+            },
         };
 
         let response = self
@@ -178,9 +186,14 @@ impl ProcMacro {
             msg::Response::ExpandMacro(it) => {
                 Ok(it.map(|tree| FlatTree::to_subtree_resolved(tree, version, &span_data_table)))
             }
-            msg::Response::ListMacros(..) | msg::Response::ApiVersionCheck(..) => {
-                Err(ServerError { message: "unexpected response".to_string(), io: None })
-            }
+            msg::Response::ExpandMacroExtended(it) => Ok(it.map(|resp| {
+                FlatTree::to_subtree_resolved(
+                    resp.tree,
+                    version,
+                    &deserialize_span_data_index_map(&resp.span_data_table),
+                )
+            })),
+            _ => Err(ServerError { message: "unexpected response".to_string(), io: None }),
         }
     }
 }