4 files changed, 51 insertions, 33 deletions

diff --git a/crates/ra_hir/src/source_binder.rs b/crates/ra_hir/src/source_binder.rs
index 3af477818..2c422af8b 100644
--- a/crates/ra_hir/src/source_binder.rs
+++ b/crates/ra_hir/src/source_binder.rs
@@ -17,7 +17,7 @@ use hir_def::{
     nameres::ModuleSource,
     path::path,
     resolver::{self, resolver_for_scope, HasResolver, Resolver, TypeNs, ValueNs},
-    AssocItemId, DefWithBodyId, Expander,
+    AssocItemId, DefWithBodyId,
 };
 use hir_expand::{
     hygiene::Hygiene, name::AsName, AstId, HirFileId, InFile, MacroCallId, MacroCallKind,
@@ -215,10 +215,27 @@ impl SourceAnalyzer {
         self.body_source_map.as_ref()?.node_pat(src)
     }
 
+    fn expand_expr(
+        &self,
+        db: &impl HirDatabase,
+        expr: InFile<&ast::Expr>,
+    ) -> Option<InFile<ast::Expr>> {
+        let macro_call = ast::MacroCall::cast(expr.value.syntax().clone())?;
+        let macro_file =
+            self.body_source_map.as_ref()?.node_macro_file(expr.with_value(&macro_call))?;
+        let expanded = db.parse_or_expand(macro_file)?;
+        let kind = expanded.kind();
+        let expr = InFile::new(macro_file, ast::Expr::cast(expanded)?);
+
+        if ast::MacroCall::can_cast(kind) {
+            self.expand_expr(db, expr.as_ref())
+        } else {
+            Some(expr)
+        }
+    }
+
     pub fn type_of(&self, db: &impl HirDatabase, expr: &ast::Expr) -> Option<Type> {
-        let expr_id = if let Some(macro_call) = ast::MacroCall::cast(expr.syntax().clone()) {
-            let mut expander = Expander::new(db, self.file_id, self.body_owner?.module(db).id);
-            let expr = expand_macro_call_to_expr(db, &mut expander, macro_call)?;
+        let expr_id = if let Some(expr) = self.expand_expr(db, InFile::new(self.file_id, expr)) {
             self.body_source_map.as_ref()?.node_expr(expr.as_ref())?
         } else {
             self.expr_id(expr)?
@@ -508,21 +525,6 @@ fn scope_for_offset(
         })
 }
 
-fn expand_macro_call_to_expr(
-    db: &impl HirDatabase,
-    expander: &mut Expander,
-    macro_call: ast::MacroCall,
-) -> Option<InFile<ast::Expr>> {
-    let (mark, expr): (_, ast::Expr) = expander.enter_expand(db, macro_call)?;
-    let expr = if let Some(child) = ast::MacroCall::cast(expr.syntax().clone()) {
-        expand_macro_call_to_expr(db, expander, child)
-    } else {
-        Some(expander.to_source(expr))
-    };
-    expander.exit(db, mark);
-    expr
-}
-
 // XXX: during completion, cursor might be outside of any particular
 // expression. Try to figure out the correct scope...
 fn adjust(
diff --git a/crates/ra_hir_def/src/body.rs b/crates/ra_hir_def/src/body.rs
index 8ab92b23a..142c52d35 100644
--- a/crates/ra_hir_def/src/body.rs
+++ b/crates/ra_hir_def/src/body.rs
@@ -26,7 +26,7 @@ use crate::{
     DefWithBodyId, HasModule, Lookup, ModuleId,
 };
 
-pub struct Expander {
+pub(crate) struct Expander {
     crate_def_map: Arc<CrateDefMap>,
     current_file_id: HirFileId,
     hygiene: Hygiene,
@@ -35,14 +35,18 @@ pub struct Expander {
 }
 
 impl Expander {
-    pub fn new(db: &impl DefDatabase, current_file_id: HirFileId, module: ModuleId) -> Expander {
+    pub(crate) fn new(
+        db: &impl DefDatabase,
+        current_file_id: HirFileId,
+        module: ModuleId,
+    ) -> Expander {
         let crate_def_map = db.crate_def_map(module.krate);
         let hygiene = Hygiene::new(db, current_file_id);
         let ast_id_map = db.ast_id_map(current_file_id);
         Expander { crate_def_map, current_file_id, hygiene, ast_id_map, module }
     }
 
-    pub fn enter_expand<T: ast::AstNode, DB: DefDatabase>(
+    pub(crate) fn enter_expand<T: ast::AstNode, DB: DefDatabase>(
         &mut self,
         db: &DB,
         macro_call: ast::MacroCall,
@@ -80,14 +84,14 @@ impl Expander {
         None
     }
 
-    pub fn exit(&mut self, db: &impl DefDatabase, mut mark: Mark) {
+    pub(crate) fn exit(&mut self, db: &impl DefDatabase, mut mark: Mark) {
         self.hygiene = Hygiene::new(db, mark.file_id);
         self.current_file_id = mark.file_id;
         self.ast_id_map = mem::take(&mut mark.ast_id_map);
         mark.bomb.defuse();
     }
 
-    pub fn to_source<T>(&self, value: T) -> InFile<T> {
+    pub(crate) fn to_source<T>(&self, value: T) -> InFile<T> {
         InFile { file_id: self.current_file_id, value }
     }
 
@@ -112,7 +116,7 @@ impl Expander {
     }
 }
 
-pub struct Mark {
+pub(crate) struct Mark {
     file_id: HirFileId,
     ast_id_map: Arc<AstIdMap>,
     bomb: DropBomb,
@@ -159,6 +163,7 @@ pub struct BodySourceMap {
     pat_map: FxHashMap<PatSource, PatId>,
     pat_map_back: ArenaMap<PatId, PatSource>,
     field_map: FxHashMap<(ExprId, usize), AstPtr<ast::RecordField>>,
+    expansions: FxHashMap<InFile<AstPtr<ast::MacroCall>>, HirFileId>,
 }
 
 impl Body {
@@ -233,6 +238,11 @@ impl BodySourceMap {
         self.expr_map.get(&src).cloned()
     }
 
+    pub fn node_macro_file(&self, node: InFile<&ast::MacroCall>) -> Option<HirFileId> {
+        let src = node.map(|it| AstPtr::new(it));
+        self.expansions.get(&src).cloned()
+    }
+
     pub fn field_init_shorthand_expr(&self, node: InFile<&ast::RecordField>) -> Option<ExprId> {
         let src = node.map(|it| Either::Right(AstPtr::new(it)));
         self.expr_map.get(&src).cloned()
diff --git a/crates/ra_hir_def/src/body/lower.rs b/crates/ra_hir_def/src/body/lower.rs
index 5323af097..57c77304c 100644
--- a/crates/ra_hir_def/src/body/lower.rs
+++ b/crates/ra_hir_def/src/body/lower.rs
@@ -446,14 +446,20 @@ where
                 }
             }
             // FIXME expand to statements in statement position
-            ast::Expr::MacroCall(e) => match self.expander.enter_expand(self.db, e) {
-                Some((mark, expansion)) => {
-                    let id = self.collect_expr(expansion);
-                    self.expander.exit(self.db, mark);
-                    id
+            ast::Expr::MacroCall(e) => {
+                let macro_call = self.expander.to_source(AstPtr::new(&e));
+                match self.expander.enter_expand(self.db, e.clone()) {
+                    Some((mark, expansion)) => {
+                        self.source_map
+                            .expansions
+                            .insert(macro_call, self.expander.current_file_id);
+                        let id = self.collect_expr(expansion);
+                        self.expander.exit(self.db, mark);
+                        id
+                    }
+                    None => self.alloc_expr(Expr::Missing, syntax_ptr),
                 }
-                None => self.alloc_expr(Expr::Missing, syntax_ptr),
-            },
+            }
 
             // FIXME implement HIR for these:
             ast::Expr::Label(_e) => self.alloc_expr(Expr::Missing, syntax_ptr),
diff --git a/crates/ra_hir_def/src/lib.rs b/crates/ra_hir_def/src/lib.rs
index f58ce9a95..f6c7f38d1 100644
--- a/crates/ra_hir_def/src/lib.rs
+++ b/crates/ra_hir_def/src/lib.rs
@@ -48,7 +48,7 @@ use ra_arena::{impl_arena_id, RawId};
 use ra_db::{impl_intern_key, salsa, CrateId};
 use ra_syntax::{ast, AstNode};
 
-pub use crate::body::Expander;
+use crate::body::Expander;
 use crate::builtin_type::BuiltinType;
 
 #[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]