Merge #2318

2318: Fix panic when use `Expand Macro` on `assert_eq` r=matklad a=edwin0cheng

The cause of this [bug](https://github.com/rust-analyzer/rust-analyzer/pull/2291#issuecomment-555651542) is, when calling `SourceAnalyzer::expand` when an `ast::MacroCall` which is outside of `SourceAnalyzer::node`. 

Note that if we use a node in `SourceAnalyzer::new` with a `MacroFile` file id, the resolver inside `SourceAnalyzer` still will not work properly. Another PR will need to fix it.

Co-authored-by: Edwin Cheng <[email protected]>

3 files changed, 16 insertions, 9 deletions

diff --git a/crates/ra_hir/src/source_binder.rs b/crates/ra_hir/src/source_binder.rs
index 5d9e22ee2..caa8d0082 100644
--- a/crates/ra_hir/src/source_binder.rs
+++ b/crates/ra_hir/src/source_binder.rs
@@ -405,9 +405,16 @@ impl SourceAnalyzer {
         implements_trait(&canonical_ty, db, &self.resolver, krate, std_future_trait)
     }
 
-    pub fn expand(&self, db: &impl HirDatabase, macro_call: &ast::MacroCall) -> Option<Expansion> {
-        let def = self.resolve_macro_call(db, macro_call)?.id;
-        let ast_id = AstId::new(self.file_id, db.ast_id_map(self.file_id).ast_id(macro_call));
+    pub fn expand(
+        &self,
+        db: &impl HirDatabase,
+        macro_call: Source<&ast::MacroCall>,
+    ) -> Option<Expansion> {
+        let def = self.resolve_macro_call(db, macro_call.value)?.id;
+        let ast_id = AstId::new(
+            macro_call.file_id,
+            db.ast_id_map(macro_call.file_id).ast_id(macro_call.value),
+        );
         let macro_call_loc = MacroCallLoc { def, ast_id };
         Some(Expansion { macro_call_id: db.intern_macro(macro_call_loc) })
     }
diff --git a/crates/ra_ide_api/src/expand.rs b/crates/ra_ide_api/src/expand.rs
index 0ad125a9e..2f1abf509 100644
--- a/crates/ra_ide_api/src/expand.rs
+++ b/crates/ra_ide_api/src/expand.rs
@@ -55,7 +55,7 @@ pub(crate) fn descend_into_macros(
         }
         let source_analyzer =
             hir::SourceAnalyzer::new(db, token.with_value(token.value.parent()).as_ref(), None);
-        let exp = source_analyzer.expand(db, &macro_call)?;
+        let exp = source_analyzer.expand(db, token.with_value(&macro_call))?;
         exp.map_token_down(db, token.as_ref())
     })
     .last()
diff --git a/crates/ra_ide_api/src/expand_macro.rs b/crates/ra_ide_api/src/expand_macro.rs
index 2d478ec09..7f39262dc 100644
--- a/crates/ra_ide_api/src/expand_macro.rs
+++ b/crates/ra_ide_api/src/expand_macro.rs
@@ -23,7 +23,7 @@ pub(crate) fn expand_macro(db: &RootDatabase, position: FilePosition) -> Option<
     let mac = name_ref.syntax().ancestors().find_map(ast::MacroCall::cast)?;
 
     let source = hir::Source::new(position.file_id.into(), mac.syntax());
-    let expanded = expand_macro_recur(db, source, &mac)?;
+    let expanded = expand_macro_recur(db, source, source.with_value(&mac))?;
 
     // FIXME:
     // macro expansion may lose all white space information
@@ -35,10 +35,10 @@ pub(crate) fn expand_macro(db: &RootDatabase, position: FilePosition) -> Option<
 fn expand_macro_recur(
     db: &RootDatabase,
     source: hir::Source<&SyntaxNode>,
-    macro_call: &ast::MacroCall,
+    macro_call: hir::Source<&ast::MacroCall>,
 ) -> Option<SyntaxNode> {
     let analyzer = hir::SourceAnalyzer::new(db, source, None);
-    let expansion = analyzer.expand(db, &macro_call)?;
+    let expansion = analyzer.expand(db, macro_call)?;
     let macro_file_id = expansion.file_id();
     let expanded: SyntaxNode = db.parse_or_expand(macro_file_id)?;
 
@@ -46,8 +46,8 @@ fn expand_macro_recur(
     let mut replaces = FxHashMap::default();
 
     for child in children.into_iter() {
-        let source = hir::Source::new(macro_file_id, source.value);
-        let new_node = expand_macro_recur(db, source, &child)?;
+        let node = hir::Source::new(macro_file_id, &child);
+        let new_node = expand_macro_recur(db, source, node)?;
 
         replaces.insert(child.syntax().clone().into(), new_node.into());
     }