4 files changed, 43 insertions, 24 deletions

diff --git a/crates/ra_hir_expand/src/db.rs b/crates/ra_hir_expand/src/db.rs
index 8abfbb4ff..b3746924d 100644
--- a/crates/ra_hir_expand/src/db.rs
+++ b/crates/ra_hir_expand/src/db.rs
@@ -18,6 +18,12 @@ pub struct ParseMacroWithInfo {
     pub expansion_info: Arc<ExpansionInfo>,
 }
 
+#[derive(Debug, PartialEq, Eq, Clone)]
+pub struct MacroExpandInfo {
+    pub arg_map: Arc<mbe::TokenMap>,
+    pub def_map: Arc<mbe::TokenMap>,
+}
+
 // FIXME: rename to ExpandDatabase
 #[salsa::query_group(AstDatabaseStorage)]
 pub trait AstDatabase: SourceDatabase {
@@ -35,7 +41,7 @@ pub trait AstDatabase: SourceDatabase {
     fn macro_expand(
         &self,
         macro_call: MacroCallId,
-    ) -> Result<(Arc<tt::Subtree>, (Arc<mbe::TokenMap>, Arc<mbe::TokenMap>)), String>;
+    ) -> Result<(Arc<tt::Subtree>, MacroExpandInfo), String>;
 
     fn macro_expansion_info(&self, macro_file: MacroFile) -> Option<Arc<ExpansionInfo>>;
 }
@@ -77,7 +83,7 @@ pub(crate) fn macro_arg(
 pub(crate) fn macro_expand(
     db: &dyn AstDatabase,
     id: MacroCallId,
-) -> Result<(Arc<tt::Subtree>, (Arc<mbe::TokenMap>, Arc<mbe::TokenMap>)), String> {
+) -> Result<(Arc<tt::Subtree>, MacroExpandInfo), String> {
     let loc = db.lookup_intern_macro(id);
     let macro_arg = db.macro_arg(id).ok_or("Fail to args in to tt::TokenTree")?;
 
@@ -89,7 +95,10 @@ pub(crate) fn macro_expand(
         return Err(format!("Total tokens count exceed limit : count = {}", count));
     }
 
-    Ok((Arc::new(tt), (macro_arg.1.clone(), macro_rules.1.clone())))
+    Ok((
+        Arc::new(tt),
+        MacroExpandInfo { arg_map: macro_arg.1.clone(), def_map: macro_rules.1.clone() },
+    ))
 }
 
 pub(crate) fn parse_or_expand(db: &dyn AstDatabase, file_id: HirFileId) -> Option<SyntaxNode> {
@@ -133,7 +142,7 @@ pub(crate) fn parse_macro_with_info(
     };
 
     res.map(|(parsed, exp_map)| {
-        let (arg_map, def_map) = tt.1;
+        let expand_info = tt.1;
         let loc: MacroCallLoc = db.lookup_intern_macro(macro_call_id);
 
         let def_start =
@@ -141,11 +150,12 @@ pub(crate) fn parse_macro_with_info(
         let arg_start =
             loc.ast_id.to_node(db).token_tree().map(|t| t.syntax().text_range().start());
 
-        let arg_map =
-            arg_start.map(|start| exp_map.ranges(&arg_map, start)).unwrap_or_else(|| Vec::new());
-
-        let def_map =
-            def_start.map(|start| exp_map.ranges(&def_map, start)).unwrap_or_else(|| Vec::new());
+        let arg_map = arg_start
+            .map(|start| exp_map.ranges(&expand_info.arg_map, start))
+            .unwrap_or_else(|| Vec::new());
+        let def_map = def_start
+            .map(|start| exp_map.ranges(&expand_info.def_map, start))
+            .unwrap_or_else(|| Vec::new());
 
         let info = ExpansionInfo { arg_map, def_map };
 
diff --git a/crates/ra_hir_expand/src/lib.rs b/crates/ra_hir_expand/src/lib.rs
index b6e55aa6a..63ba17158 100644
--- a/crates/ra_hir_expand/src/lib.rs
+++ b/crates/ra_hir_expand/src/lib.rs
@@ -132,7 +132,7 @@ impl MacroCallId {
 }
 
 #[derive(Debug, Clone, PartialEq, Eq)]
-/// ExpansionInfo mainly describle how to map text range between src and expaned macro
+/// ExpansionInfo mainly describes how to map text range between src and expanded macro
 pub struct ExpansionInfo {
     pub arg_map: Vec<(TextRange, TextRange)>,
     pub def_map: Vec<(TextRange, TextRange)>,
diff --git a/crates/ra_mbe/src/syntax_bridge.rs b/crates/ra_mbe/src/syntax_bridge.rs
index 8e86742d0..2f21ad6e0 100644
--- a/crates/ra_mbe/src/syntax_bridge.rs
+++ b/crates/ra_mbe/src/syntax_bridge.rs
@@ -26,7 +26,11 @@ static TOKEN_MAP_COUNTER: AtomicU32 = AtomicU32::new(0);
 
 /// Generate an unique token map id for each instance
 fn make_uniq_token_map_id() -> u32 {
-    TOKEN_MAP_COUNTER.fetch_add(1, Ordering::SeqCst)
+    let res = TOKEN_MAP_COUNTER.fetch_add(1, Ordering::SeqCst);
+    if res == std::u32::MAX {
+        panic!("TOKEN_MAP_COUNTER is overflowed");
+    }
+    res
 }
 
 impl std::default::Default for TokenMap {
@@ -35,10 +39,9 @@ impl std::default::Default for TokenMap {
     }
 }
 
-/// Maps Relative range of the expanded syntax node to `tt::TokenId`
+/// Maps relative range of the expanded syntax node to `tt::TokenId`
 #[derive(Debug, PartialEq, Eq, Default)]
 pub struct ExpandedRangeMap {
-    /// Maps `tt::TokenId` to the *relative* source range.
     ranges: Vec<(TextRange, tt::TokenId)>,
 }
 
@@ -85,14 +88,13 @@ fn fragment_to_syntax_node(
     };
     let buffer = TokenBuffer::new(&tokens);
     let mut token_source = SubtreeTokenSource::new(&buffer);
-    let mut range_map = ExpandedRangeMap::default();
-    let mut tree_sink = TtTreeSink::new(buffer.begin(), &mut range_map);
+    let mut tree_sink = TtTreeSink::new(buffer.begin());
     ra_parser::parse_fragment(&mut token_source, &mut tree_sink, fragment_kind);
     if tree_sink.roots.len() != 1 {
         return Err(ExpandError::ConversionError);
     }
     //FIXME: would be cool to report errors
-    let parse = tree_sink.inner.finish();
+    let (parse, range_map) = tree_sink.finish();
     Ok((parse, range_map))
 }
 
@@ -320,7 +322,7 @@ struct TtTreeSink<'a> {
     cursor: Cursor<'a>,
     text_pos: TextUnit,
     inner: SyntaxTreeBuilder,
-    range_map: &'a mut ExpandedRangeMap,
+    range_map: ExpandedRangeMap,
 
     // Number of roots
     // Use for detect ill-form tree which is not single root
@@ -328,16 +330,20 @@ struct TtTreeSink<'a> {
 }
 
 impl<'a> TtTreeSink<'a> {
-    fn new(cursor: Cursor<'a>, range_map: &'a mut ExpandedRangeMap) -> Self {
+    fn new(cursor: Cursor<'a>) -> Self {
         TtTreeSink {
             buf: String::new(),
             cursor,
             text_pos: 0.into(),
             inner: SyntaxTreeBuilder::default(),
             roots: smallvec::SmallVec::new(),
-            range_map,
+            range_map: ExpandedRangeMap::default(),
         }
     }
+
+    fn finish(self) -> (Parse<SyntaxNode>, ExpandedRangeMap) {
+        (self.inner.finish(), self.range_map)
+    }
 }
 
 fn delim_to_str(d: tt::Delimiter, closing: bool) -> SmolStr {
diff --git a/crates/ra_tt/src/lib.rs b/crates/ra_tt/src/lib.rs
index 96410ff22..1449618f3 100644
--- a/crates/ra_tt/src/lib.rs
+++ b/crates/ra_tt/src/lib.rs
@@ -25,23 +25,26 @@ use smol_str::SmolStr;
 /// source token and making sure that identities are preserved during macro
 /// expansion.
 #[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
-pub struct TokenId(u32, u32);
+pub struct TokenId {
+    token_id: u32,
+    map_id: u32,
+}
 
 impl TokenId {
     pub fn new(token_id: u32, map_id: u32) -> TokenId {
-        TokenId(token_id, map_id)
+        TokenId { token_id, map_id }
     }
 
     pub const fn unspecified() -> TokenId {
-        TokenId(!0, !0)
+        TokenId { token_id: !0, map_id: !0 }
     }
 
     pub fn token_id(&self) -> u32 {
-        self.0
+        self.token_id
     }
 
     pub fn map_id(&self) -> u32 {
-        self.1
+        self.map_id
     }
 }