Merge #7137

7137: Revert "Proper handling $crate and local_inner_macros" r=jonas-schievink a=jonas-schievink

Reverts rust-analyzer/rust-analyzer#7133

It caused a fairly significant performance regression.

bors r+

Co-authored-by: Jonas Schievink <[email protected]>

2 files changed, 32 insertions, 130 deletions

diff --git a/crates/hir_expand/src/hygiene.rs b/crates/hir_expand/src/hygiene.rs
index 6042e15b2..7ab0a5e52 100644
--- a/crates/hir_expand/src/hygiene.rs
+++ b/crates/hir_expand/src/hygiene.rs
@@ -2,94 +2,30 @@
 //!
 //! Specifically, `ast` + `Hygiene` allows you to create a `Name`. Note that, at
 //! this moment, this is horribly incomplete and handles only `$crate`.
-use std::sync::Arc;
-
-use arena::{Arena, Idx};
 use base_db::CrateId;
 use either::Either;
-use mbe::Origin;
-use syntax::{ast, AstNode};
+use syntax::ast;
 
 use crate::{
     db::AstDatabase,
     name::{AsName, Name},
-    ExpansionInfo, HirFileId, HirFileIdRepr, MacroCallId, MacroDefKind,
+    HirFileId, HirFileIdRepr, MacroCallId, MacroDefKind,
 };
 
 #[derive(Clone, Debug)]
 pub struct Hygiene {
-    frames: Option<Arc<HygieneFrames>>,
-}
-
-impl Hygiene {
-    pub fn new(db: &dyn AstDatabase, file_id: HirFileId) -> Hygiene {
-        Hygiene { frames: Some(Arc::new(HygieneFrames::new(db, file_id.clone()))) }
-    }
-
-    pub fn new_unhygienic() -> Hygiene {
-        Hygiene { frames: None }
-    }
-
-    // FIXME: this should just return name
-    pub fn name_ref_to_name(&self, name_ref: ast::NameRef) -> Either<Name, CrateId> {
-        if let Some(frames) = &self.frames {
-            if name_ref.text() == "$crate" {
-                if let Some(krate) = frames.root_crate(&name_ref) {
-                    return Either::Right(krate);
-                }
-            }
-        }
-
-        Either::Left(name_ref.as_name())
-    }
-
-    pub fn local_inner_macros(&self, path: ast::Path) -> Option<CrateId> {
-        let frames = self.frames.as_ref()?;
-
-        let mut token = path.syntax().first_token()?;
-        let mut current = frames.first();
-
-        while let Some((frame, data)) =
-            current.and_then(|it| Some((it, it.expansion.as_ref()?.map_token_up(&token)?)))
-        {
-            let (mapped, origin) = data;
-            if origin == Origin::Def {
-                return if frame.local_inner { frame.krate } else { None };
-            }
-            current = Some(&frames.0[frame.call_site?]);
-            token = mapped.value;
-        }
-        None
-    }
-}
-
-#[derive(Default, Debug)]
-struct HygieneFrames(Arena<HygieneFrame>);
-
-#[derive(Clone, Debug)]
-struct HygieneFrame {
-    expansion: Option<ExpansionInfo>,
+    // This is what `$crate` expands to
+    def_crate: Option<CrateId>,
 
     // Indicate this is a local inner macro
     local_inner: bool,
-    krate: Option<CrateId>,
-
-    call_site: Option<Idx<HygieneFrame>>,
-    def_site: Option<Idx<HygieneFrame>>,
 }
 
-impl HygieneFrames {
-    fn new(db: &dyn AstDatabase, file_id: HirFileId) -> Self {
-        let mut frames = HygieneFrames::default();
-        frames.add(db, file_id);
-        frames
-    }
-
-    fn add(&mut self, db: &dyn AstDatabase, file_id: HirFileId) -> Option<Idx<HygieneFrame>> {
-        let (krate, local_inner) = match file_id.0 {
+impl Hygiene {
+    pub fn new(db: &dyn AstDatabase, file_id: HirFileId) -> Hygiene {
+        let (def_crate, local_inner) = match file_id.0 {
             HirFileIdRepr::FileId(_) => (None, false),
             HirFileIdRepr::MacroFile(macro_file) => match macro_file.macro_call_id {
-                MacroCallId::EagerMacro(_id) => (None, false),
                 MacroCallId::LazyMacro(id) => {
                     let loc = db.lookup_intern_macro(id);
                     match loc.def.kind {
@@ -100,68 +36,31 @@ impl HygieneFrames {
                         MacroDefKind::ProcMacro(_) => (None, false),
                     }
                 }
+                MacroCallId::EagerMacro(_id) => (None, false),
             },
         };
-
-        let expansion = file_id.expansion_info(db);
-        let expansion = match expansion {
-            None => {
-                return Some(self.0.alloc(HygieneFrame {
-                    expansion: None,
-                    local_inner,
-                    krate,
-                    call_site: None,
-                    def_site: None,
-                }));
-            }
-            Some(it) => it,
-        };
-
-        let def_site = expansion.def.clone();
-        let call_site = expansion.arg.file_id;
-        let idx = self.0.alloc(HygieneFrame {
-            expansion: Some(expansion),
-            local_inner,
-            krate,
-            call_site: None,
-            def_site: None,
-        });
-
-        self.0[idx].call_site = self.add(db, call_site);
-        self.0[idx].def_site = def_site.and_then(|it| self.add(db, it.file_id));
-
-        Some(idx)
+        Hygiene { def_crate, local_inner }
     }
 
-    fn first(&self) -> Option<&HygieneFrame> {
-        self.0.iter().next().map(|it| it.1)
+    pub fn new_unhygienic() -> Hygiene {
+        Hygiene { def_crate: None, local_inner: false }
     }
 
-    fn root_crate(&self, name_ref: &ast::NameRef) -> Option<CrateId> {
-        let mut token = name_ref.syntax().first_token()?;
-        let first = self.first()?;
-        let mut result = first.krate;
-        let mut current = Some(first);
-
-        while let Some((frame, (mapped, origin))) =
-            current.and_then(|it| Some((it, it.expansion.as_ref()?.map_token_up(&token)?)))
-        {
-            result = frame.krate;
-
-            let site = match origin {
-                Origin::Def => frame.def_site,
-                Origin::Call => frame.call_site,
-            };
-
-            let site = match site {
-                None => break,
-                Some(it) => it,
-            };
-
-            current = Some(&self.0[site]);
-            token = mapped.value;
+    // FIXME: this should just return name
+    pub fn name_ref_to_name(&self, name_ref: ast::NameRef) -> Either<Name, CrateId> {
+        if let Some(def_crate) = self.def_crate {
+            if name_ref.text() == "$crate" {
+                return Either::Right(def_crate);
+            }
         }
+        Either::Left(name_ref.as_name())
+    }
 
-        result
+    pub fn local_inner_macros(&self) -> Option<CrateId> {
+        if self.local_inner {
+            self.def_crate
+        } else {
+            None
+        }
     }
 }
diff --git a/crates/hir_expand/src/lib.rs b/crates/hir_expand/src/lib.rs
index 5b6734a5f..3fa1b1d77 100644
--- a/crates/hir_expand/src/lib.rs
+++ b/crates/hir_expand/src/lib.rs
@@ -340,8 +340,11 @@ impl ExpansionInfo {
         Some(self.expanded.with_value(token))
     }
 
-    pub fn map_token_up(&self, token: &SyntaxToken) -> Option<(InFile<SyntaxToken>, Origin)> {
-        let token_id = self.exp_map.token_by_range(token.text_range())?;
+    pub fn map_token_up(
+        &self,
+        token: InFile<&SyntaxToken>,
+    ) -> Option<(InFile<SyntaxToken>, Origin)> {
+        let token_id = self.exp_map.token_by_range(token.value.text_range())?;
 
         let (token_id, origin) = self.macro_def.0.map_id_up(token_id);
         let (token_map, tt) = match origin {
@@ -356,7 +359,7 @@ impl ExpansionInfo {
             ),
         };
 
-        let range = token_map.range_by_token(token_id)?.by_kind(token.kind())?;
+        let range = token_map.range_by_token(token_id)?.by_kind(token.value.kind())?;
         let token = algo::find_covering_element(&tt.value, range + tt.value.text_range().start())
             .into_token()?;
         Some((tt.with_value(token), origin))
@@ -492,7 +495,7 @@ fn ascend_call_token(
     expansion: &ExpansionInfo,
     token: InFile<SyntaxToken>,
 ) -> Option<InFile<SyntaxToken>> {
-    let (mapped, origin) = expansion.map_token_up(&token.value)?;
+    let (mapped, origin) = expansion.map_token_up(token.as_ref())?;
     if origin != Origin::Call {
         return None;
     }