Shuffle hir-expand things around

crates/hir-expand/src/ast_id_map.rs

@@ -155,7 +155,14 @@ impl PartialEq for AstIdMap {
 impl Eq for AstIdMap {}
 
 impl AstIdMap {
-    pub(crate) fn from_source(node: &SyntaxNode) -> AstIdMap {
+    pub(crate) fn ast_id_map(
+        db: &dyn ExpandDatabase,
+        file_id: span::HirFileId,
+    ) -> triomphe::Arc<AstIdMap> {
+        triomphe::Arc::new(AstIdMap::from_source(&db.parse_or_expand(file_id)))
+    }
+
+    fn from_source(node: &SyntaxNode) -> AstIdMap {
         assert!(node.parent().is_none());
         let mut res = AstIdMap::default();
 

crates/hir-expand/src/db.rs

@@ -1,16 +1,14 @@
 //! Defines database & queries for macro expansion.
 
-use std::sync::OnceLock;
-
 use base_db::{
     salsa::{self, debug::DebugQueryTable},
-    CrateId, Edition, FileId, SourceDatabase, VersionReq,
+    CrateId, FileId, SourceDatabase,
 };
 use either::Either;
 use limit::Limit;
 use mbe::{syntax_node_to_token_tree, ValueResult};
 use rustc_hash::FxHashSet;
-use span::{Span, SyntaxContextId};
+use span::SyntaxContextId;
 use syntax::{
     ast::{self, HasAttrs},
     AstNode, Parse, SyntaxError, SyntaxNode, SyntaxToken, T,
@@ -19,13 +17,14 @@ use triomphe::Arc;
 
 use crate::{
     ast_id_map::AstIdMap,
-    attrs::{collect_attrs, RawAttrs},
+    attrs::collect_attrs,
     builtin_attr_macro::pseudo_derive_attr_expansion,
     builtin_fn_macro::EagerExpander,
+    declarative::DeclarativeMacroExpander,
     fixup::{self, reverse_fixups, SyntaxFixupUndoInfo},
     hygiene::{
-        apply_mark, span_with_call_site_ctxt, span_with_def_site_ctxt, span_with_mixed_site_ctxt,
+        span_with_call_site_ctxt, span_with_def_site_ctxt, span_with_mixed_site_ctxt,
-        SyntaxContextData, Transparency,
+        SyntaxContextData,
     },
     proc_macro::ProcMacros,
     span_map::{RealSpanMap, SpanMap, SpanMapRef},
@@ -43,82 +42,6 @@ use crate::{
 /// Actual max for `analysis-stats .` at some point: 30672.
 static TOKEN_LIMIT: Limit = Limit::new(1_048_576);
 
-#[derive(Debug, Clone, Eq, PartialEq)]
-/// Old-style `macro_rules` or the new macros 2.0
-pub struct DeclarativeMacroExpander {
-    pub mac: mbe::DeclarativeMacro<span::Span>,
-    pub transparency: Transparency,
-}
-
-// FIXME: Remove this once we drop support for 1.76
-static REQUIREMENT: OnceLock<VersionReq> = OnceLock::new();
-
-impl DeclarativeMacroExpander {
-    pub fn expand(
-        &self,
-        db: &dyn ExpandDatabase,
-        tt: tt::Subtree,
-        call_id: MacroCallId,
-    ) -> ExpandResult<tt::Subtree> {
-        let loc = db.lookup_intern_macro_call(call_id);
-        let toolchain = &db.crate_graph()[loc.def.krate].toolchain;
-        let new_meta_vars = toolchain.as_ref().map_or(false, |version| {
-            REQUIREMENT.get_or_init(|| VersionReq::parse(">=1.76").unwrap()).matches(
-                &base_db::Version {
-                    pre: base_db::Prerelease::EMPTY,
-                    build: base_db::BuildMetadata::EMPTY,
-                    major: version.major,
-                    minor: version.minor,
-                    patch: version.patch,
-                },
-            )
-        });
-        match self.mac.err() {
-            Some(e) => ExpandResult::new(
-                tt::Subtree::empty(tt::DelimSpan { open: loc.call_site, close: loc.call_site }),
-                ExpandError::other(format!("invalid macro definition: {e}")),
-            ),
-            None => self
-                .mac
-                .expand(
-                    &tt,
-                    |s| s.ctx = apply_mark(db, s.ctx, call_id, self.transparency),
-                    new_meta_vars,
-                    loc.call_site,
-                )
-                .map_err(Into::into),
-        }
-    }
-
-    pub fn expand_unhygienic(
-        &self,
-        db: &dyn ExpandDatabase,
-        tt: tt::Subtree,
-        krate: CrateId,
-        call_site: Span,
-    ) -> ExpandResult<tt::Subtree> {
-        let toolchain = &db.crate_graph()[krate].toolchain;
-        let new_meta_vars = toolchain.as_ref().map_or(false, |version| {
-            REQUIREMENT.get_or_init(|| VersionReq::parse(">=1.76").unwrap()).matches(
-                &base_db::Version {
-                    pre: base_db::Prerelease::EMPTY,
-                    build: base_db::BuildMetadata::EMPTY,
-                    major: version.major,
-                    minor: version.minor,
-                    patch: version.patch,
-                },
-            )
-        });
-        match self.mac.err() {
-            Some(e) => ExpandResult::new(
-                tt::Subtree::empty(tt::DelimSpan { open: call_site, close: call_site }),
-                ExpandError::other(format!("invalid macro definition: {e}")),
-            ),
-            None => self.mac.expand(&tt, |_| (), new_meta_vars, call_site).map_err(Into::into),
-        }
-    }
-}
-
 #[derive(Debug, Clone, Eq, PartialEq)]
 pub enum TokenExpander {
     /// Old-style `macro_rules` or the new macros 2.0
@@ -141,6 +64,7 @@ pub trait ExpandDatabase: SourceDatabase {
     #[salsa::input]
     fn proc_macros(&self) -> Arc<ProcMacros>;
 
+    #[salsa::invoke(AstIdMap::ast_id_map)]
     fn ast_id_map(&self, file_id: HirFileId) -> Arc<AstIdMap>;
 
     /// Main public API -- parses a hir file, not caring whether it's a real
@@ -156,8 +80,10 @@ pub trait ExpandDatabase: SourceDatabase {
         macro_file: MacroFileId,
     ) -> ExpandResult<(Parse<SyntaxNode>, Arc<ExpansionSpanMap>)>;
     #[salsa::transparent]
+    #[salsa::invoke(SpanMap::new)]
     fn span_map(&self, file_id: HirFileId) -> SpanMap;
 
+    #[salsa::invoke(crate::span_map::real_span_map)]
     fn real_span_map(&self, file_id: FileId) -> Arc<RealSpanMap>;
 
     /// Macro ids. That's probably the tricksiest bit in rust-analyzer, and the
@@ -173,6 +99,7 @@ pub trait ExpandDatabase: SourceDatabase {
     #[salsa::transparent]
     fn setup_syntax_context_root(&self) -> ();
     #[salsa::transparent]
+    #[salsa::invoke(crate::hygiene::dump_syntax_contexts)]
     fn dump_syntax_contexts(&self) -> String;
 
     /// Lowers syntactic macro call to a token tree representation. That's a firewall
@@ -184,8 +111,10 @@ pub trait ExpandDatabase: SourceDatabase {
     ) -> ValueResult<Option<(Arc<tt::Subtree>, SyntaxFixupUndoInfo)>, Arc<Box<[SyntaxError]>>>;
     /// Fetches the expander for this macro.
     #[salsa::transparent]
+    #[salsa::invoke(TokenExpander::macro_expander)]
     fn macro_expander(&self, id: MacroDefId) -> TokenExpander;
     /// Fetches (and compiles) the expander of this decl macro.
+    #[salsa::invoke(DeclarativeMacroExpander::expander)]
     fn decl_macro_expander(
         &self,
         def_crate: CrateId,
@@ -203,36 +132,6 @@ pub trait ExpandDatabase: SourceDatabase {
     ) -> ExpandResult<Box<[SyntaxError]>>;
 }
 
-#[inline]
-pub fn span_map(db: &dyn ExpandDatabase, file_id: HirFileId) -> SpanMap {
-    match file_id.repr() {
-        HirFileIdRepr::FileId(file_id) => SpanMap::RealSpanMap(db.real_span_map(file_id)),
-        HirFileIdRepr::MacroFile(m) => {
-            SpanMap::ExpansionSpanMap(db.parse_macro_expansion(m).value.1)
-        }
-    }
-}
-
-pub fn real_span_map(db: &dyn ExpandDatabase, file_id: FileId) -> Arc<RealSpanMap> {
-    use syntax::ast::HasModuleItem;
-    let mut pairs = vec![(syntax::TextSize::new(0), span::ROOT_ERASED_FILE_AST_ID)];
-    let ast_id_map = db.ast_id_map(file_id.into());
-    let tree = db.parse(file_id).tree();
-    // FIXME: Descend into modules and other item containing items that are not annotated with attributes
-    // and allocate pairs for those as well. This gives us finer grained span anchors resulting in
-    // better incrementality
-    pairs.extend(
-        tree.items()
-            .map(|item| (item.syntax().text_range().start(), ast_id_map.ast_id(&item).erase())),
-    );
-
-    Arc::new(RealSpanMap::from_file(
-        file_id,
-        pairs.into_boxed_slice(),
-        tree.syntax().text_range().end(),
-    ))
-}
-
 /// This expands the given macro call, but with different arguments. This is
 /// used for completion, where we want to see what 'would happen' if we insert a
 /// token. The `token_to_map` mapped down into the expansion, with the mapped
@@ -357,10 +256,6 @@ pub fn expand_speculative(
     Some((node.syntax_node(), token))
 }
 
-fn ast_id_map(db: &dyn ExpandDatabase, file_id: HirFileId) -> Arc<AstIdMap> {
-    Arc::new(AstIdMap::from_source(&db.parse_or_expand(file_id)))
-}
-
 fn parse_or_expand(db: &dyn ExpandDatabase, file_id: HirFileId) -> SyntaxNode {
     match file_id.repr() {
         HirFileIdRepr::FileId(file_id) => db.parse(file_id).syntax_node(),
@@ -412,7 +307,10 @@ fn parse_macro_expansion_error(
         .map(|it| it.0.errors().to_vec().into_boxed_slice())
 }
 
-fn parse_with_map(db: &dyn ExpandDatabase, file_id: HirFileId) -> (Parse<SyntaxNode>, SpanMap) {
+pub(crate) fn parse_with_map(
+    db: &dyn ExpandDatabase,
+    file_id: HirFileId,
+) -> (Parse<SyntaxNode>, SpanMap) {
     match file_id.repr() {
         HirFileIdRepr::FileId(file_id) => {
             (db.parse(file_id).to_syntax(), SpanMap::RealSpanMap(db.real_span_map(file_id)))
@@ -581,90 +479,7 @@ fn censor_for_macro_input(loc: &MacroCallLoc, node: &SyntaxNode) -> FxHashSet<Sy
     .unwrap_or_default()
 }
 
-fn decl_macro_expander(
+impl TokenExpander {
-    db: &dyn ExpandDatabase,
-    def_crate: CrateId,
-    id: AstId<ast::Macro>,
-) -> Arc<DeclarativeMacroExpander> {
-    let crate_data = &db.crate_graph()[def_crate];
-    let is_2021 = crate_data.edition >= Edition::Edition2021;
-    let (root, map) = parse_with_map(db, id.file_id);
-    let root = root.syntax_node();
-
-    let transparency = |node| {
-        // ... would be nice to have the item tree here
-        let attrs = RawAttrs::new(db, node, map.as_ref()).filter(db, def_crate);
-        match &*attrs
-            .iter()
-            .find(|it| {
-                it.path.as_ident().and_then(|it| it.as_str()) == Some("rustc_macro_transparency")
-            })?
-            .token_tree_value()?
-            .token_trees
-        {
-            [tt::TokenTree::Leaf(tt::Leaf::Ident(i)), ..] => match &*i.text {
-                "transparent" => Some(Transparency::Transparent),
-                "semitransparent" => Some(Transparency::SemiTransparent),
-                "opaque" => Some(Transparency::Opaque),
-                _ => None,
-            },
-            _ => None,
-        }
-    };
-    let toolchain = crate_data.toolchain.as_ref();
-    let new_meta_vars = toolchain.as_ref().map_or(false, |version| {
-        REQUIREMENT.get_or_init(|| VersionReq::parse(">=1.76").unwrap()).matches(
-            &base_db::Version {
-                pre: base_db::Prerelease::EMPTY,
-                build: base_db::BuildMetadata::EMPTY,
-                major: version.major,
-                minor: version.minor,
-                patch: version.patch,
-            },
-        )
-    });
-
-    let (mac, transparency) = match id.to_ptr(db).to_node(&root) {
-        ast::Macro::MacroRules(macro_rules) => (
-            match macro_rules.token_tree() {
-                Some(arg) => {
-                    let tt = mbe::syntax_node_to_token_tree(
-                        arg.syntax(),
-                        map.as_ref(),
-                        map.span_for_range(macro_rules.macro_rules_token().unwrap().text_range()),
-                    );
-
-                    mbe::DeclarativeMacro::parse_macro_rules(&tt, is_2021, new_meta_vars)
-                }
-                None => mbe::DeclarativeMacro::from_err(
-                    mbe::ParseError::Expected("expected a token tree".into()),
-                    is_2021,
-                ),
-            },
-            transparency(&macro_rules).unwrap_or(Transparency::SemiTransparent),
-        ),
-        ast::Macro::MacroDef(macro_def) => (
-            match macro_def.body() {
-                Some(arg) => {
-                    let tt = mbe::syntax_node_to_token_tree(
-                        arg.syntax(),
-                        map.as_ref(),
-                        map.span_for_range(macro_def.macro_token().unwrap().text_range()),
-                    );
-
-                    mbe::DeclarativeMacro::parse_macro2(&tt, is_2021, new_meta_vars)
-                }
-                None => mbe::DeclarativeMacro::from_err(
-                    mbe::ParseError::Expected("expected a token tree".into()),
-                    is_2021,
-                ),
-            },
-            transparency(&macro_def).unwrap_or(Transparency::Opaque),
-        ),
-    };
-    Arc::new(DeclarativeMacroExpander { mac, transparency })
-}
-
     fn macro_expander(db: &dyn ExpandDatabase, id: MacroDefId) -> TokenExpander {
         match id.kind {
             MacroDefKind::Declarative(ast_id) => {
@@ -677,6 +492,7 @@ fn macro_expander(db: &dyn ExpandDatabase, id: MacroDefId) -> TokenExpander {
             MacroDefKind::ProcMacro(expander, ..) => TokenExpander::ProcMacro(expander),
         }
     }
+}
 
 enum CowArc<T> {
     Arc(Arc<T>),
@@ -862,40 +678,3 @@ fn check_tt_count(tt: &tt::Subtree) -> Result<(), ExpandResult<()>> {
 fn setup_syntax_context_root(db: &dyn ExpandDatabase) {
     db.intern_syntax_context(SyntaxContextData::root());
 }
-
-fn dump_syntax_contexts(db: &dyn ExpandDatabase) -> String {
-    let mut s = String::from("Expansions:");
-    let mut entries = InternMacroCallLookupQuery.in_db(db).entries::<Vec<_>>();
-    entries.sort_by_key(|e| e.key);
-    for e in entries {
-        let id = e.key;
-        let expn_data = e.value.as_ref().unwrap();
-        s.push_str(&format!(
-            "\n{:?}: parent: {:?}, call_site_ctxt: {:?}, def_site_ctxt: {:?}, kind: {:?}",
-            id,
-            expn_data.kind.file_id(),
-            expn_data.call_site,
-            SyntaxContextId::ROOT, // FIXME expn_data.def_site,
-            expn_data.kind.descr(),
-        ));
-    }
-
-    s.push_str("\n\nSyntaxContexts:\n");
-    let mut entries = InternSyntaxContextLookupQuery.in_db(db).entries::<Vec<_>>();
-    entries.sort_by_key(|e| e.key);
-    for e in entries {
-        struct SyntaxContextDebug<'a>(
-            &'a dyn ExpandDatabase,
-            SyntaxContextId,
-            &'a SyntaxContextData,
-        );
-
-        impl<'a> std::fmt::Debug for SyntaxContextDebug<'a> {
-            fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
-                self.2.fancy_debug(self.1, self.0, f)
-            }
-        }
-        stdx::format_to!(s, "{:?}\n", SyntaxContextDebug(db, e.key, &e.value.unwrap()));
-    }
-    s
-}

crates/hir-expand/src/declarative.rs

@@ -0,0 +1,176 @@
+use std::sync::OnceLock;
+
+use base_db::{CrateId, Edition, VersionReq};
+use span::{MacroCallId, Span};
+use syntax::{ast, AstNode};
+use triomphe::Arc;
+
+use crate::{
+    attrs::RawAttrs,
+    db::ExpandDatabase,
+    hygiene::{apply_mark, Transparency},
+    tt, AstId, ExpandError, ExpandResult,
+};
+
+/// Old-style `macro_rules` or the new macros 2.0
+#[derive(Debug, Clone, Eq, PartialEq)]
+pub struct DeclarativeMacroExpander {
+    pub mac: mbe::DeclarativeMacro<span::Span>,
+    pub transparency: Transparency,
+}
+
+// FIXME: Remove this once we drop support for 1.76
+static REQUIREMENT: OnceLock<VersionReq> = OnceLock::new();
+
+impl DeclarativeMacroExpander {
+    pub fn expand(
+        &self,
+        db: &dyn ExpandDatabase,
+        tt: tt::Subtree,
+        call_id: MacroCallId,
+    ) -> ExpandResult<tt::Subtree> {
+        let loc = db.lookup_intern_macro_call(call_id);
+        let toolchain = &db.crate_graph()[loc.def.krate].toolchain;
+        let new_meta_vars = toolchain.as_ref().map_or(false, |version| {
+            REQUIREMENT.get_or_init(|| VersionReq::parse(">=1.76").unwrap()).matches(
+                &base_db::Version {
+                    pre: base_db::Prerelease::EMPTY,
+                    build: base_db::BuildMetadata::EMPTY,
+                    major: version.major,
+                    minor: version.minor,
+                    patch: version.patch,
+                },
+            )
+        });
+        match self.mac.err() {
+            Some(e) => ExpandResult::new(
+                tt::Subtree::empty(tt::DelimSpan { open: loc.call_site, close: loc.call_site }),
+                ExpandError::other(format!("invalid macro definition: {e}")),
+            ),
+            None => self
+                .mac
+                .expand(
+                    &tt,
+                    |s| s.ctx = apply_mark(db, s.ctx, call_id, self.transparency),
+                    new_meta_vars,
+                    loc.call_site,
+                )
+                .map_err(Into::into),
+        }
+    }
+
+    pub fn expand_unhygienic(
+        &self,
+        db: &dyn ExpandDatabase,
+        tt: tt::Subtree,
+        krate: CrateId,
+        call_site: Span,
+    ) -> ExpandResult<tt::Subtree> {
+        let toolchain = &db.crate_graph()[krate].toolchain;
+        let new_meta_vars = toolchain.as_ref().map_or(false, |version| {
+            REQUIREMENT.get_or_init(|| VersionReq::parse(">=1.76").unwrap()).matches(
+                &base_db::Version {
+                    pre: base_db::Prerelease::EMPTY,
+                    build: base_db::BuildMetadata::EMPTY,
+                    major: version.major,
+                    minor: version.minor,
+                    patch: version.patch,
+                },
+            )
+        });
+        match self.mac.err() {
+            Some(e) => ExpandResult::new(
+                tt::Subtree::empty(tt::DelimSpan { open: call_site, close: call_site }),
+                ExpandError::other(format!("invalid macro definition: {e}")),
+            ),
+            None => self.mac.expand(&tt, |_| (), new_meta_vars, call_site).map_err(Into::into),
+        }
+    }
+
+    pub(crate) fn expander(
+        db: &dyn ExpandDatabase,
+        def_crate: CrateId,
+        id: AstId<ast::Macro>,
+    ) -> Arc<DeclarativeMacroExpander> {
+        let crate_data = &db.crate_graph()[def_crate];
+        let is_2021 = crate_data.edition >= Edition::Edition2021;
+        let (root, map) = crate::db::parse_with_map(db, id.file_id);
+        let root = root.syntax_node();
+
+        let transparency = |node| {
+            // ... would be nice to have the item tree here
+            let attrs = RawAttrs::new(db, node, map.as_ref()).filter(db, def_crate);
+            match &*attrs
+                .iter()
+                .find(|it| {
+                    it.path.as_ident().and_then(|it| it.as_str())
+                        == Some("rustc_macro_transparency")
+                })?
+                .token_tree_value()?
+                .token_trees
+            {
+                [tt::TokenTree::Leaf(tt::Leaf::Ident(i)), ..] => match &*i.text {
+                    "transparent" => Some(Transparency::Transparent),
+                    "semitransparent" => Some(Transparency::SemiTransparent),
+                    "opaque" => Some(Transparency::Opaque),
+                    _ => None,
+                },
+                _ => None,
+            }
+        };
+        let toolchain = crate_data.toolchain.as_ref();
+        let new_meta_vars = toolchain.as_ref().map_or(false, |version| {
+            REQUIREMENT.get_or_init(|| VersionReq::parse(">=1.76").unwrap()).matches(
+                &base_db::Version {
+                    pre: base_db::Prerelease::EMPTY,
+                    build: base_db::BuildMetadata::EMPTY,
+                    major: version.major,
+                    minor: version.minor,
+                    patch: version.patch,
+                },
+            )
+        });
+
+        let (mac, transparency) = match id.to_ptr(db).to_node(&root) {
+            ast::Macro::MacroRules(macro_rules) => (
+                match macro_rules.token_tree() {
+                    Some(arg) => {
+                        let tt = mbe::syntax_node_to_token_tree(
+                            arg.syntax(),
+                            map.as_ref(),
+                            map.span_for_range(
+                                macro_rules.macro_rules_token().unwrap().text_range(),
+                            ),
+                        );
+
+                        mbe::DeclarativeMacro::parse_macro_rules(&tt, is_2021, new_meta_vars)
+                    }
+                    None => mbe::DeclarativeMacro::from_err(
+                        mbe::ParseError::Expected("expected a token tree".into()),
+                        is_2021,
+                    ),
+                },
+                transparency(&macro_rules).unwrap_or(Transparency::SemiTransparent),
+            ),
+            ast::Macro::MacroDef(macro_def) => (
+                match macro_def.body() {
+                    Some(arg) => {
+                        let tt = mbe::syntax_node_to_token_tree(
+                            arg.syntax(),
+                            map.as_ref(),
+                            map.span_for_range(macro_def.macro_token().unwrap().text_range()),
+                        );
+
+                        mbe::DeclarativeMacro::parse_macro2(&tt, is_2021, new_meta_vars)
+                    }
+                    None => mbe::DeclarativeMacro::from_err(
+                        mbe::ParseError::Expected("expected a token tree".into()),
+                        is_2021,
+                    ),
+                },
+                transparency(&macro_def).unwrap_or(Transparency::Opaque),
+            ),
+        };
+        Arc::new(DeclarativeMacroExpander { mac, transparency })
+    }
+}

crates/hir-expand/src/hygiene.rs

@@ -245,3 +245,43 @@ pub fn marks_rev(
     })
     .map(|ctx| ctx.outer_mark(db))
 }
+
+pub(crate) fn dump_syntax_contexts(db: &dyn ExpandDatabase) -> String {
+    use crate::db::{InternMacroCallLookupQuery, InternSyntaxContextLookupQuery};
+    use base_db::salsa::debug::DebugQueryTable;
+
+    let mut s = String::from("Expansions:");
+    let mut entries = InternMacroCallLookupQuery.in_db(db).entries::<Vec<_>>();
+    entries.sort_by_key(|e| e.key);
+    for e in entries {
+        let id = e.key;
+        let expn_data = e.value.as_ref().unwrap();
+        s.push_str(&format!(
+            "\n{:?}: parent: {:?}, call_site_ctxt: {:?}, def_site_ctxt: {:?}, kind: {:?}",
+            id,
+            expn_data.kind.file_id(),
+            expn_data.call_site,
+            SyntaxContextId::ROOT, // FIXME expn_data.def_site,
+            expn_data.kind.descr(),
+        ));
+    }
+
+    s.push_str("\n\nSyntaxContexts:\n");
+    let mut entries = InternSyntaxContextLookupQuery.in_db(db).entries::<Vec<_>>();
+    entries.sort_by_key(|e| e.key);
+    for e in entries {
+        struct SyntaxContextDebug<'a>(
+            &'a dyn ExpandDatabase,
+            SyntaxContextId,
+            &'a SyntaxContextData,
+        );
+
+        impl<'a> std::fmt::Debug for SyntaxContextDebug<'a> {
+            fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+                self.2.fancy_debug(self.1, self.0, f)
+            }
+        }
+        stdx::format_to!(s, "{:?}\n", SyntaxContextDebug(db, e.key, &e.value.unwrap()));
+    }
+    s
+}

crates/hir-expand/src/lib.rs

@@ -11,16 +11,18 @@ pub mod attrs;
 pub mod builtin_attr_macro;
 pub mod builtin_derive_macro;
 pub mod builtin_fn_macro;
+pub mod change;
 pub mod db;
+pub mod declarative;
 pub mod eager;
 pub mod files;
-pub mod change;
 pub mod hygiene;
 pub mod mod_path;
 pub mod name;
 pub mod proc_macro;
 pub mod quote;
 pub mod span_map;
+
 mod fixup;
 
 use attrs::collect_attrs;
@@ -167,7 +169,8 @@ pub struct MacroCallLoc {
     pub krate: CrateId,
     /// Some if this is a macro call for an eager macro. Note that this is `None`
     /// for the eager input macro file.
-    // FIXME: This seems bad to save in an interned structure
+    // FIXME: This is being interned, subtrees can vary quickly differ just slightly causing
+    // leakage problems here
     eager: Option<Arc<EagerCallInfo>>,
     pub kind: MacroCallKind,
     pub call_site: Span,
@@ -220,7 +223,7 @@ pub enum MacroCallKind {
     },
     Attr {
         ast_id: AstId<ast::Item>,
-        // FIXME: This is being interned, subtrees can very quickly differ just slightly causing
+        // FIXME: This is being interned, subtrees can vary quickly differ just slightly causing
         // leakage problems here
         attr_args: Option<Arc<tt::Subtree>>,
         /// Syntactical index of the invoking `#[attribute]`.

crates/hir-expand/src/mod_path.rs

@@ -40,7 +40,7 @@ pub enum PathKind {
     Crate,
     /// Absolute path (::foo)
     Abs,
-    // FIXME: Remove this
+    // FIXME: Can we remove this somehow?
     /// `$crate` from macro expansion
     DollarCrate(CrateId),
 }
@@ -59,7 +59,8 @@ impl ModPath {
     }
 
     pub fn from_segments(kind: PathKind, segments: impl IntoIterator<Item = Name>) -> ModPath {
-        let segments = segments.into_iter().collect();
+        let mut segments: SmallVec<_> = segments.into_iter().collect();
+        segments.shrink_to_fit();
         ModPath { kind, segments }
     }
 

crates/hir-expand/src/span_map.rs

@@ -1,10 +1,12 @@
 //! Span maps for real files and macro expansions.
-use span::Span;
+use span::{FileId, HirFileId, HirFileIdRepr, Span};
-use syntax::TextRange;
+use syntax::{AstNode, TextRange};
 use triomphe::Arc;
 
 pub use span::RealSpanMap;
 
+use crate::db::ExpandDatabase;
+
 pub type ExpansionSpanMap = span::SpanMap<Span>;
 
 /// Spanmap for a macro file or a real file
@@ -34,7 +36,6 @@ impl mbe::SpanMapper<Span> for SpanMapRef<'_> {
         self.span_for_range(range)
     }
 }
-
 impl SpanMap {
     pub fn span_for_range(&self, range: TextRange) -> Span {
         match self {
@@ -53,6 +54,16 @@ impl SpanMap {
             Self::RealSpanMap(span_map) => SpanMapRef::RealSpanMap(span_map),
         }
     }
+
+    #[inline]
+    pub(crate) fn new(db: &dyn ExpandDatabase, file_id: HirFileId) -> SpanMap {
+        match file_id.repr() {
+            HirFileIdRepr::FileId(file_id) => SpanMap::RealSpanMap(db.real_span_map(file_id)),
+            HirFileIdRepr::MacroFile(m) => {
+                SpanMap::ExpansionSpanMap(db.parse_macro_expansion(m).value.1)
+            }
+        }
+    }
 }
 
 impl SpanMapRef<'_> {
@@ -63,3 +74,23 @@ impl SpanMapRef<'_> {
         }
     }
 }
+
+pub(crate) fn real_span_map(db: &dyn ExpandDatabase, file_id: FileId) -> Arc<RealSpanMap> {
+    use syntax::ast::HasModuleItem;
+    let mut pairs = vec![(syntax::TextSize::new(0), span::ROOT_ERASED_FILE_AST_ID)];
+    let ast_id_map = db.ast_id_map(file_id.into());
+    let tree = db.parse(file_id).tree();
+    // FIXME: Descend into modules and other item containing items that are not annotated with attributes
+    // and allocate pairs for those as well. This gives us finer grained span anchors resulting in
+    // better incrementality
+    pairs.extend(
+        tree.items()
+            .map(|item| (item.syntax().text_range().start(), ast_id_map.ast_id(&item).erase())),
+    );
+
+    Arc::new(RealSpanMap::from_file(
+        file_id,
+        pairs.into_boxed_slice(),
+        tree.syntax().text_range().end(),
+    ))
+}

rustfmt.toml

@@ -1,2 +1,2 @@
-reorder_modules = false
+reorder_modules = true
 use_small_heuristics = "Max"