Make shift an implementation detail of mbe

2 files changed, 16 insertions, 9 deletions

diff --git a/crates/ra_hir_expand/src/db.rs b/crates/ra_hir_expand/src/db.rs
index 5eadee9c2..9de7c1ea8 100644
--- a/crates/ra_hir_expand/src/db.rs
+++ b/crates/ra_hir_expand/src/db.rs
@@ -32,10 +32,17 @@ impl TokenExpander {
         }
     }
 
-    pub fn shift(&self) -> u32 {
+    pub fn map_id_down(&self, id: tt::TokenId) -> tt::TokenId {
         match self {
-            TokenExpander::MacroRules(it) => it.shift(),
-            TokenExpander::Builtin(_) => 0,
+            TokenExpander::MacroRules(it) => it.map_id_down(id),
+            TokenExpander::Builtin(..) => id,
+        }
+    }
+
+    pub fn map_id_up(&self, id: tt::TokenId) -> (tt::TokenId, mbe::Origin) {
+        match self {
+            TokenExpander::MacroRules(it) => it.map_id_up(id),
+            TokenExpander::Builtin(..) => (id, mbe::Origin::Def),
         }
     }
 }
diff --git a/crates/ra_hir_expand/src/lib.rs b/crates/ra_hir_expand/src/lib.rs
index 1774cb58b..5927a03ba 100644
--- a/crates/ra_hir_expand/src/lib.rs
+++ b/crates/ra_hir_expand/src/lib.rs
@@ -161,7 +161,7 @@ impl ExpansionInfo {
     pub fn translate_offset(&self, offset: TextUnit) -> Option<TextUnit> {
         let offset = offset.checked_sub(self.arg_start.1)?;
         let token_id = self.macro_arg.1.token_by_offset(offset)?;
-        let token_id = tt::TokenId(token_id.0 + self.macro_def.0.shift());
+        let token_id = self.macro_def.0.map_id_down(token_id);
 
         let (r, _) = self.exp_map.ranges.iter().find(|(_, tid)| *tid == token_id)?;
         Some(r.start())
@@ -170,11 +170,11 @@ impl ExpansionInfo {
     pub fn find_range(&self, from: TextRange) -> Option<(HirFileId, TextRange)> {
         let token_id = look_in_rev_map(&self.exp_map, from)?;
 
-        let shift = self.macro_def.0.shift();
-        let (token_map, (file_id, start_offset), token_id) = if token_id.0 >= shift {
-            (&self.macro_arg.1, self.arg_start, tt::TokenId(token_id.0 - shift).into())
-        } else {
-            (&self.macro_def.1, self.def_start, token_id)
+        let (token_id, origin) = self.macro_def.0.map_id_up(token_id);
+
+        let (token_map, (file_id, start_offset)) = match origin {
+            mbe::Origin::Call => (&self.macro_arg.1, self.arg_start),
+            mbe::Origin::Def => (&self.macro_def.1, self.def_start),
         };
 
         let range = token_map.relative_range_of(token_id)?;