4 files changed, 22 insertions, 62 deletions

diff --git a/crates/ra_analysis/src/db.rs b/crates/ra_analysis/src/db.rs
index b072a5eba..712f72484 100644
--- a/crates/ra_analysis/src/db.rs
+++ b/crates/ra_analysis/src/db.rs
@@ -98,5 +98,8 @@ salsa::database_storage! {
             fn struct_data() for hir::db::StructDataQuery;
             fn enum_data() for hir::db::EnumDataQuery;
         }
+        impl hir::MacroDatabase {
+            fn expand_macro() for hir::ExpandMacroQuery;
+        }
     }
 }
diff --git a/crates/ra_analysis/src/extend_selection.rs b/crates/ra_analysis/src/extend_selection.rs
index 805e9059e..62133ef29 100644
--- a/crates/ra_analysis/src/extend_selection.rs
+++ b/crates/ra_analysis/src/extend_selection.rs
@@ -23,10 +23,10 @@ fn extend_selection_in_macro(
     frange: FileRange,
 ) -> Option<TextRange> {
     let macro_call = find_macro_call(source_file.syntax(), frange.range)?;
-    let exp = crate::macros::expand(db, frange.file_id, macro_call)?;
-    let dst_range = exp.map_range_forward(frange.range)?;
-    let dst_range = ra_editor::extend_selection(exp.source_file().syntax(), dst_range)?;
-    let src_range = exp.map_range_back(dst_range)?;
+    let (off, exp) = crate::macros::expand(db, frange.file_id, macro_call)?;
+    let dst_range = exp.map_range_forward(frange.range - off)?;
+    let dst_range = ra_editor::extend_selection(exp.syntax().borrowed(), dst_range)?;
+    let src_range = exp.map_range_back(dst_range)? + off;
     Some(src_range)
 }
 
diff --git a/crates/ra_analysis/src/macros.rs b/crates/ra_analysis/src/macros.rs
index b9feb7fad..21ec36cd6 100644
--- a/crates/ra_analysis/src/macros.rs
+++ b/crates/ra_analysis/src/macros.rs
@@ -1,15 +1,18 @@
 /// Begining of macro expansion.
 ///
 /// This code should be moved out of ra_analysis into hir (?) ideally.
-use ra_syntax::{ast, AstNode, SourceFileNode, TextRange};
+use std::sync::Arc;
+
+use ra_syntax::{ast, AstNode, TextUnit};
+use hir::MacroDatabase;
 
 use crate::{db::RootDatabase, FileId};
 
 pub(crate) fn expand(
-    _db: &RootDatabase,
+    db: &RootDatabase,
     _file_id: FileId,
     macro_call: ast::MacroCall,
-) -> Option<MacroExpansion> {
+) -> Option<(TextUnit, Arc<hir::MacroExpansion>)> {
     let path = macro_call.path()?;
     if path.qualifier().is_some() {
         return None;
@@ -18,58 +21,12 @@ pub(crate) fn expand(
     if name_ref.text() != "ctry" {
         return None;
     }
+    let arg = macro_call.token_tree()?.syntax();
 
-    let arg = macro_call.token_tree()?;
-    let text = format!(
-        r"
-        fn dummy() {{
-            match {} {{
-                None => return Ok(None),
-                Some(it) => it,
-            }}
-        }}",
-        arg.syntax().text()
-    );
-    let file = SourceFileNode::parse(&text);
-    let match_expr = file.syntax().descendants().find_map(ast::MatchExpr::cast)?;
-    let match_arg = match_expr.expr()?;
-    let ranges_map = vec![(arg.syntax().range(), match_arg.syntax().range())];
-    let res = MacroExpansion {
-        source_file: file,
-        ranges_map,
+    let def = hir::MacroDef::CTry;
+    let input = hir::MacroInput {
+        text: arg.text().to_string(),
     };
-    Some(res)
-}
-
-pub(crate) struct MacroExpansion {
-    pub(crate) source_file: SourceFileNode,
-    pub(crate) ranges_map: Vec<(TextRange, TextRange)>,
-}
-
-impl MacroExpansion {
-    pub(crate) fn source_file(&self) -> &SourceFileNode {
-        &self.source_file
-    }
-    pub(crate) fn map_range_back(&self, tgt_range: TextRange) -> Option<TextRange> {
-        for (s_range, t_range) in self.ranges_map.iter() {
-            if tgt_range.is_subrange(&t_range) {
-                let tgt_at_zero_range = tgt_range - tgt_range.start();
-                let tgt_range_offset = tgt_range.start() - t_range.start();
-                let src_range = tgt_at_zero_range + tgt_range_offset + s_range.start();
-                return Some(src_range);
-            }
-        }
-        None
-    }
-    pub(crate) fn map_range_forward(&self, src_range: TextRange) -> Option<TextRange> {
-        for (s_range, t_range) in self.ranges_map.iter() {
-            if src_range.is_subrange(&s_range) {
-                let src_at_zero_range = src_range - src_range.start();
-                let src_range_offset = src_range.start() - s_range.start();
-                let src_range = src_at_zero_range + src_range_offset + t_range.start();
-                return Some(src_range);
-            }
-        }
-        None
-    }
+    let exp = db.expand_macro(def, input)?;
+    Some((arg.range().start(), exp))
 }
diff --git a/crates/ra_analysis/src/syntax_highlighting.rs b/crates/ra_analysis/src/syntax_highlighting.rs
index 7e9139a74..35a4630e9 100644
--- a/crates/ra_analysis/src/syntax_highlighting.rs
+++ b/crates/ra_analysis/src/syntax_highlighting.rs
@@ -15,13 +15,13 @@ pub(crate) fn highlight(db: &RootDatabase, file_id: FileId) -> Cancelable<Vec<Hi
         .descendants()
         .filter_map(ast::MacroCall::cast)
     {
-        if let Some(exp) = crate::macros::expand(db, file_id, macro_call) {
-            let mapped_ranges = ra_editor::highlight(exp.source_file().syntax())
+        if let Some((off, exp)) = crate::macros::expand(db, file_id, macro_call) {
+            let mapped_ranges = ra_editor::highlight(exp.syntax().borrowed())
                 .into_iter()
                 .filter_map(|r| {
                     let mapped_range = exp.map_range_back(r.range)?;
                     let res = HighlightedRange {
-                        range: mapped_range,
+                        range: mapped_range + off,
                         tag: r.tag,
                     };
                     Some(res)