8 files changed, 40 insertions, 131 deletions

diff --git a/crates/ra_hir/Cargo.toml b/crates/ra_hir/Cargo.toml
index f05ec0b8a..82720da9e 100644
--- a/crates/ra_hir/Cargo.toml
+++ b/crates/ra_hir/Cargo.toml
@@ -19,6 +19,7 @@ ra_cfg = { path = "../ra_cfg" }
 ra_db = { path = "../ra_db" }
 mbe = { path = "../ra_mbe", package = "ra_mbe" }
 tt = { path = "../ra_tt", package = "ra_tt" }
+hir_def = { path = "../ra_hir_def", package = "ra_hir_def" }
 test_utils = { path = "../test_utils" }
 ra_prof = { path = "../ra_prof" }
 
diff --git a/crates/ra_hir/src/db.rs b/crates/ra_hir/src/db.rs
index 489a3b19c..7abbf8dca 100644
--- a/crates/ra_hir/src/db.rs
+++ b/crates/ra_hir/src/db.rs
@@ -59,11 +59,11 @@ pub trait InternDatabase: SourceDatabase {
 /// incremental.
 #[salsa::query_group(AstDatabaseStorage)]
 pub trait AstDatabase: InternDatabase {
-    #[salsa::invoke(crate::source_id::AstIdMap::ast_id_map_query)]
+    #[salsa::invoke(crate::source_id::ast_id_map_query)]
     fn ast_id_map(&self, file_id: HirFileId) -> Arc<AstIdMap>;
 
     #[salsa::transparent]
-    #[salsa::invoke(crate::source_id::AstIdMap::file_item_query)]
+    #[salsa::invoke(crate::source_id::file_item_query)]
     fn ast_id_to_node(&self, file_id: HirFileId, ast_id: ErasedFileAstId) -> SyntaxNode;
 
     #[salsa::transparent]
diff --git a/crates/ra_hir/src/expr/lower.rs b/crates/ra_hir/src/expr/lower.rs
index 50ea429ea..24733b3de 100644
--- a/crates/ra_hir/src/expr/lower.rs
+++ b/crates/ra_hir/src/expr/lower.rs
@@ -16,7 +16,7 @@ use crate::{
     path::GenericArgs,
     ty::primitive::{FloatTy, IntTy, UncertainFloatTy, UncertainIntTy},
     type_ref::TypeRef,
-    DefWithBody, Either, HirFileId, MacroCallLoc, MacroFileKind, Mutability, Path, Resolver,
+    AstId, DefWithBody, Either, HirFileId, MacroCallLoc, MacroFileKind, Mutability, Path, Resolver,
     Source,
 };
 
@@ -458,11 +458,10 @@ where
             ast::Expr::Label(_e) => self.alloc_expr(Expr::Missing, syntax_ptr),
             ast::Expr::RangeExpr(_e) => self.alloc_expr(Expr::Missing, syntax_ptr),
             ast::Expr::MacroCall(e) => {
-                let ast_id = self
-                    .db
-                    .ast_id_map(self.current_file_id)
-                    .ast_id(&e)
-                    .with_file_id(self.current_file_id);
+                let ast_id = AstId::new(
+                    self.current_file_id,
+                    self.db.ast_id_map(self.current_file_id).ast_id(&e),
+                );
 
                 if let Some(path) = e.path().and_then(|path| self.parse_path(path)) {
                     if let Some(def) = self.resolver.resolve_path_as_macro(self.db, &path) {
diff --git a/crates/ra_hir/src/from_source.rs b/crates/ra_hir/src/from_source.rs
index f80d8eb5f..7954c04b2 100644
--- a/crates/ra_hir/src/from_source.rs
+++ b/crates/ra_hir/src/from_source.rs
@@ -11,7 +11,7 @@ use crate::{
     db::{AstDatabase, DefDatabase, HirDatabase},
     ids::{AstItemDef, LocationCtx},
     name::AsName,
-    Const, Crate, Enum, EnumVariant, FieldSource, Function, HasSource, ImplBlock, Module,
+    AstId, Const, Crate, Enum, EnumVariant, FieldSource, Function, HasSource, ImplBlock, Module,
     ModuleSource, Source, Static, Struct, StructField, Trait, TypeAlias, Union, VariantDef,
 };
 
@@ -183,7 +183,7 @@ impl Module {
             ModuleSource::Module(ref module) => {
                 assert!(!module.has_semi());
                 let ast_id_map = db.ast_id_map(src.file_id);
-                let item_id = ast_id_map.ast_id(module).with_file_id(src.file_id);
+                let item_id = AstId::new(src.file_id, ast_id_map.ast_id(module));
                 Some(item_id)
             }
             ModuleSource::SourceFile(_) => None,
diff --git a/crates/ra_hir/src/ids.rs b/crates/ra_hir/src/ids.rs
index 518ea32e9..f141206c6 100644
--- a/crates/ra_hir/src/ids.rs
+++ b/crates/ra_hir/src/ids.rs
@@ -264,7 +264,7 @@ pub(crate) trait AstItemDef<N: AstNode>: salsa::InternKey + Clone {
         Self::from_ast_id(ctx, item_id)
     }
     fn from_ast_id(ctx: LocationCtx<&impl InternDatabase>, ast_id: FileAstId<N>) -> Self {
-        let loc = ItemLoc { module: ctx.module, ast_id: ast_id.with_file_id(ctx.file_id) };
+        let loc = ItemLoc { module: ctx.module, ast_id: AstId::new(ctx.file_id, ast_id) };
         Self::intern(ctx.db, loc)
     }
     fn source(self, db: &impl AstDatabase) -> Source<N> {
diff --git a/crates/ra_hir/src/impl_block.rs b/crates/ra_hir/src/impl_block.rs
index 33ef87563..9c739f3f1 100644
--- a/crates/ra_hir/src/impl_block.rs
+++ b/crates/ra_hir/src/impl_block.rs
@@ -20,7 +20,7 @@ use crate::{
     resolve::Resolver,
     ty::Ty,
     type_ref::TypeRef,
-    AssocItem, Const, Function, HasSource, HirFileId, MacroFileKind, Path, Source, TraitRef,
+    AssocItem, AstId, Const, Function, HasSource, HirFileId, MacroFileKind, Path, Source, TraitRef,
     TypeAlias,
 };
 
@@ -256,7 +256,7 @@ impl ModuleImplBlocks {
                     }
 
                     //FIXME: we should really cut down on the boilerplate required to process a macro
-                    let ast_id = db.ast_id_map(file_id).ast_id(&macro_call).with_file_id(file_id);
+                    let ast_id = AstId::new(file_id, db.ast_id_map(file_id).ast_id(&macro_call));
                     if let Some(path) = macro_call
                         .path()
                         .and_then(|path| Path::from_src(Source { ast: path, file_id }, db))
diff --git a/crates/ra_hir/src/nameres/collector.rs b/crates/ra_hir/src/nameres/collector.rs
index b5fe16bfa..4f363df36 100644
--- a/crates/ra_hir/src/nameres/collector.rs
+++ b/crates/ra_hir/src/nameres/collector.rs
@@ -567,7 +567,7 @@ where
             // inline module, just recurse
             raw::ModuleData::Definition { name, items, ast_id } => {
                 let module_id =
-                    self.push_child_module(name.clone(), ast_id.with_file_id(self.file_id), None);
+                    self.push_child_module(name.clone(), AstId::new(self.file_id, *ast_id), None);
 
                 ModCollector {
                     def_collector: &mut *self.def_collector,
@@ -583,7 +583,7 @@ where
             }
             // out of line module, resolve, parse and recurse
             raw::ModuleData::Declaration { name, ast_id } => {
-                let ast_id = ast_id.with_file_id(self.file_id);
+                let ast_id = AstId::new(self.file_id, *ast_id);
                 match self.mod_dir.resolve_declaration(
                     self.def_collector.db,
                     self.file_id,
@@ -671,21 +671,18 @@ where
     }
 
     fn collect_macro(&mut self, mac: &raw::MacroData) {
+        let ast_id = AstId::new(self.file_id, mac.ast_id);
+
         // Case 1: macro rules, define a macro in crate-global mutable scope
         if is_macro_rules(&mac.path) {
             if let Some(name) = &mac.name {
-                let macro_id = MacroDefId {
-                    ast_id: mac.ast_id.with_file_id(self.file_id),
-                    krate: self.def_collector.def_map.krate,
-                };
+                let macro_id = MacroDefId { ast_id, krate: self.def_collector.def_map.krate };
                 let macro_ = MacroDef { id: macro_id };
                 self.def_collector.define_macro(self.module_id, name.clone(), macro_, mac.export);
             }
             return;
         }
 
-        let ast_id = mac.ast_id.with_file_id(self.file_id);
-
         // Case 2: try to resolve in legacy scope and expand macro_rules, triggering
         // recursive item collection.
         if let Some(macro_def) = mac.path.as_ident().and_then(|name| {
diff --git a/crates/ra_hir/src/source_id.rs b/crates/ra_hir/src/source_id.rs
index a4dd99598..260b79661 100644
--- a/crates/ra_hir/src/source_id.rs
+++ b/crates/ra_hir/src/source_id.rs
@@ -2,18 +2,18 @@
 
 use std::{
     hash::{Hash, Hasher},
-    marker::PhantomData,
     sync::Arc,
 };
 
-use ra_arena::{impl_arena_id, Arena, RawId};
-use ra_syntax::{ast, AstNode, SyntaxNode, SyntaxNodePtr};
+pub use hir_def::ast_id_map::{AstIdMap, ErasedFileAstId, FileAstId};
+use ra_syntax::{AstNode, SyntaxNode};
 
 use crate::{db::AstDatabase, HirFileId};
 
 /// `AstId` points to an AST node in any file.
 ///
 /// It is stable across reparses, and can be used as salsa key/value.
+// FIXME: isn't this just a `Source<FileAstId<N>>` ?
 #[derive(Debug)]
 pub(crate) struct AstId<N: AstNode> {
     file_id: HirFileId,
@@ -40,122 +40,34 @@ impl<N: AstNode> Hash for AstId<N> {
 }
 
 impl<N: AstNode> AstId<N> {
+    pub fn new(file_id: HirFileId, file_ast_id: FileAstId<N>) -> AstId<N> {
+        AstId { file_id, file_ast_id }
+    }
+
     pub(crate) fn file_id(&self) -> HirFileId {
         self.file_id
     }
 
     pub(crate) fn to_node(&self, db: &impl AstDatabase) -> N {
-        let syntax_node = db.ast_id_to_node(self.file_id, self.file_ast_id.raw);
+        let syntax_node = db.ast_id_to_node(self.file_id, self.file_ast_id.into());
         N::cast(syntax_node).unwrap()
     }
 }
 
-/// `AstId` points to an AST node in a specific file.
-#[derive(Debug)]
-pub(crate) struct FileAstId<N: AstNode> {
-    raw: ErasedFileAstId,
-    _ty: PhantomData<fn() -> N>,
-}
-
-impl<N: AstNode> Clone for FileAstId<N> {
-    fn clone(&self) -> FileAstId<N> {
-        *self
-    }
-}
-impl<N: AstNode> Copy for FileAstId<N> {}
-
-impl<N: AstNode> PartialEq for FileAstId<N> {
-    fn eq(&self, other: &Self) -> bool {
-        self.raw == other.raw
-    }
-}
-impl<N: AstNode> Eq for FileAstId<N> {}
-impl<N: AstNode> Hash for FileAstId<N> {
-    fn hash<H: Hasher>(&self, hasher: &mut H) {
-        self.raw.hash(hasher);
-    }
-}
-
-impl<N: AstNode> FileAstId<N> {
-    pub(crate) fn with_file_id(self, file_id: HirFileId) -> AstId<N> {
-        AstId { file_id, file_ast_id: self }
-    }
-}
-
-#[derive(Debug, Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash)]
-pub struct ErasedFileAstId(RawId);
-impl_arena_id!(ErasedFileAstId);
-
-/// Maps items' `SyntaxNode`s to `ErasedFileAstId`s and back.
-#[derive(Debug, PartialEq, Eq, Default)]
-pub struct AstIdMap {
-    arena: Arena<ErasedFileAstId, SyntaxNodePtr>,
+pub(crate) fn ast_id_map_query(db: &impl AstDatabase, file_id: HirFileId) -> Arc<AstIdMap> {
+    let map = if let Some(node) = db.parse_or_expand(file_id) {
+        AstIdMap::from_source(&node)
+    } else {
+        AstIdMap::default()
+    };
+    Arc::new(map)
 }
 
-impl AstIdMap {
-    pub(crate) fn ast_id_map_query(db: &impl AstDatabase, file_id: HirFileId) -> Arc<AstIdMap> {
-        let map = if let Some(node) = db.parse_or_expand(file_id) {
-            AstIdMap::from_source(&node)
-        } else {
-            AstIdMap::default()
-        };
-        Arc::new(map)
-    }
-
-    pub(crate) fn file_item_query(
-        db: &impl AstDatabase,
-        file_id: HirFileId,
-        ast_id: ErasedFileAstId,
-    ) -> SyntaxNode {
-        let node = db.parse_or_expand(file_id).unwrap();
-        db.ast_id_map(file_id).arena[ast_id].to_node(&node)
-    }
-
-    pub(crate) fn ast_id<N: AstNode>(&self, item: &N) -> FileAstId<N> {
-        let ptr = SyntaxNodePtr::new(item.syntax());
-        let raw = match self.arena.iter().find(|(_id, i)| **i == ptr) {
-            Some((it, _)) => it,
-            None => panic!(
-                "Can't find {:?} in AstIdMap:\n{:?}",
-                item.syntax(),
-                self.arena.iter().map(|(_id, i)| i).collect::<Vec<_>>(),
-            ),
-        };
-
-        FileAstId { raw, _ty: PhantomData }
-    }
-
-    fn from_source(node: &SyntaxNode) -> AstIdMap {
-        assert!(node.parent().is_none());
-        let mut res = AstIdMap { arena: Arena::default() };
-        // By walking the tree in bread-first order we make sure that parents
-        // get lower ids then children. That is, adding a new child does not
-        // change parent's id. This means that, say, adding a new function to a
-        // trait does not change ids of top-level items, which helps caching.
-        bfs(node, |it| {
-            if let Some(module_item) = ast::ModuleItem::cast(it.clone()) {
-                res.alloc(module_item.syntax());
-            } else if let Some(macro_call) = ast::MacroCall::cast(it) {
-                res.alloc(macro_call.syntax());
-            }
-        });
-        res
-    }
-
-    fn alloc(&mut self, item: &SyntaxNode) -> ErasedFileAstId {
-        self.arena.alloc(SyntaxNodePtr::new(item))
-    }
-}
-
-/// Walks the subtree in bfs order, calling `f` for each node.
-fn bfs(node: &SyntaxNode, mut f: impl FnMut(SyntaxNode)) {
-    let mut curr_layer = vec![node.clone()];
-    let mut next_layer = vec![];
-    while !curr_layer.is_empty() {
-        curr_layer.drain(..).for_each(|node| {
-            next_layer.extend(node.children());
-            f(node);
-        });
-        std::mem::swap(&mut curr_layer, &mut next_layer);
-    }
+pub(crate) fn file_item_query(
+    db: &impl AstDatabase,
+    file_id: HirFileId,
+    ast_id: ErasedFileAstId,
+) -> SyntaxNode {
+    let node = db.parse_or_expand(file_id).unwrap();
+    db.ast_id_map(file_id)[ast_id].to_node(&node)
 }