8 files changed, 87 insertions, 19 deletions

diff --git a/crates/ra_hir_def/src/body.rs b/crates/ra_hir_def/src/body.rs
index 27a297e8b..5f9d53ecb 100644
--- a/crates/ra_hir_def/src/body.rs
+++ b/crates/ra_hir_def/src/body.rs
@@ -30,6 +30,7 @@ pub(crate) struct Expander {
     hygiene: Hygiene,
     ast_id_map: Arc<AstIdMap>,
     module: ModuleId,
+    recursive_limit: usize,
 }
 
 impl Expander {
@@ -41,7 +42,7 @@ impl Expander {
         let crate_def_map = db.crate_def_map(module.krate);
         let hygiene = Hygiene::new(db.upcast(), 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 }
+        Expander { crate_def_map, current_file_id, hygiene, ast_id_map, module, recursive_limit: 0 }
     }
 
     pub(crate) fn enter_expand<T: ast::AstNode>(
@@ -50,6 +51,10 @@ impl Expander {
         local_scope: Option<&ItemScope>,
         macro_call: ast::MacroCall,
     ) -> Option<(Mark, T)> {
+        if self.recursive_limit > 1024 {
+            return None;
+        }
+
         let macro_call = InFile::new(self.current_file_id, &macro_call);
 
         if let Some(call_id) = macro_call.as_call_id(db, |path| {
@@ -73,6 +78,7 @@ impl Expander {
                     self.hygiene = Hygiene::new(db.upcast(), file_id);
                     self.current_file_id = file_id;
                     self.ast_id_map = db.ast_id_map(file_id);
+                    self.recursive_limit += 1;
 
                     return Some((mark, expr));
                 }
@@ -88,6 +94,7 @@ impl Expander {
         self.hygiene = Hygiene::new(db.upcast(), mark.file_id);
         self.current_file_id = mark.file_id;
         self.ast_id_map = mem::take(&mut mark.ast_id_map);
+        self.recursive_limit -= 1;
         mark.bomb.defuse();
     }
 
diff --git a/crates/ra_hir_def/src/body/lower.rs b/crates/ra_hir_def/src/body/lower.rs
index e8c58ed32..3cf0c66ea 100644
--- a/crates/ra_hir_def/src/body/lower.rs
+++ b/crates/ra_hir_def/src/body/lower.rs
@@ -453,7 +453,7 @@ impl ExprCollector<'_> {
                 }
             }
             ast::Expr::MacroCall(e) => {
-                if let Some(name) = is_macro_rules(&e) {
+                if let Some(name) = e.is_macro_rules().map(|it| it.as_name()) {
                     let mac = MacroDefId {
                         krate: Some(self.expander.module.krate),
                         ast_id: Some(self.expander.ast_id(&e)),
@@ -697,16 +697,6 @@ impl ExprCollector<'_> {
     }
 }
 
-fn is_macro_rules(m: &ast::MacroCall) -> Option<Name> {
-    let name = m.path()?.segment()?.name_ref()?.as_name();
-
-    if name == name![macro_rules] {
-        Some(m.name()?.as_name())
-    } else {
-        None
-    }
-}
-
 impl From<ast::BinOp> for BinaryOp {
     fn from(ast_op: ast::BinOp) -> Self {
         match ast_op {
diff --git a/crates/ra_hir_expand/src/db.rs b/crates/ra_hir_expand/src/db.rs
index d171d2dfd..5a696542f 100644
--- a/crates/ra_hir_expand/src/db.rs
+++ b/crates/ra_hir_expand/src/db.rs
@@ -6,7 +6,7 @@ use mbe::{ExpandResult, MacroRules};
 use ra_db::{salsa, SourceDatabase};
 use ra_parser::FragmentKind;
 use ra_prof::profile;
-use ra_syntax::{AstNode, Parse, SyntaxKind::*, SyntaxNode};
+use ra_syntax::{algo::diff, AstNode, Parse, SyntaxKind::*, SyntaxNode};
 
 use crate::{
     ast_id_map::AstIdMap, BuiltinDeriveExpander, BuiltinFnLikeExpander, EagerCallLoc, EagerMacroId,
@@ -238,7 +238,7 @@ pub fn parse_macro_with_arg(
     } else {
         db.macro_expand(macro_call_id)
     };
-    if let Some(err) = err {
+    if let Some(err) = &err {
         // Note:
         // The final goal we would like to make all parse_macro success,
         // such that the following log will not call anyway.
@@ -272,7 +272,25 @@ pub fn parse_macro_with_arg(
     let fragment_kind = to_fragment_kind(db, macro_call_id);
 
     let (parse, rev_token_map) = mbe::token_tree_to_syntax_node(&tt, fragment_kind).ok()?;
-    Some((parse, Arc::new(rev_token_map)))
+
+    if err.is_none() {
+        Some((parse, Arc::new(rev_token_map)))
+    } else {
+        // FIXME:
+        // In future, we should propagate the actual error with recovery information
+        // instead of ignore the error here.
+
+        // Safe check for recurisve identity macro
+        let node = parse.syntax_node();
+        let file: HirFileId = macro_file.into();
+        let call_node = file.call_node(db)?;
+
+        if !diff(&node, &call_node.value).is_empty() {
+            Some((parse, Arc::new(rev_token_map)))
+        } else {
+            None
+        }
+    }
 }
 
 /// Given a `MacroCallId`, return what `FragmentKind` it belongs to.
diff --git a/crates/ra_hir_ty/src/tests/regression.rs b/crates/ra_hir_ty/src/tests/regression.rs
index 14c8ed3a9..a02e3ee05 100644
--- a/crates/ra_hir_ty/src/tests/regression.rs
+++ b/crates/ra_hir_ty/src/tests/regression.rs
@@ -453,3 +453,34 @@ pub mod str {
     // should be Option<char>, but currently not because of Chalk ambiguity problem
     assert_eq!("(Option<{unknown}>, Option<{unknown}>)", super::type_at_pos(&db, pos));
 }
+
+#[test]
+fn issue_3642_bad_macro_stackover() {
+    let (db, pos) = TestDB::with_position(
+        r#"
+//- /main.rs
+#[macro_export]
+macro_rules! match_ast {
+    (match $node:ident { $($tt:tt)* }) => { match_ast!(match ($node) { $($tt)* }) };
+
+    (match ($node:expr) {
+        $( ast::$ast:ident($it:ident) => $res:expr, )*
+        _ => $catch_all:expr $(,)?
+    }) => {{
+        $( if let Some($it) = ast::$ast::cast($node.clone()) { $res } else )*
+        { $catch_all }
+    }};
+}
+
+fn main() {
+    let anchor<|> = match_ast! {
+        match parent {
+            as => {},
+            _ => return None
+        }
+    };
+}"#,
+    );
+
+    assert_eq!("()", super::type_at_pos(&db, pos));
+}
diff --git a/crates/ra_ide_db/src/symbol_index.rs b/crates/ra_ide_db/src/symbol_index.rs
index 884359ee3..0f46f93c1 100644
--- a/crates/ra_ide_db/src/symbol_index.rs
+++ b/crates/ra_ide_db/src/symbol_index.rs
@@ -362,6 +362,13 @@ fn to_symbol(node: &SyntaxNode) -> Option<(SmolStr, SyntaxNodePtr, TextRange)> {
             ast::TypeAliasDef(it) => { decl(it) },
             ast::ConstDef(it) => { decl(it) },
             ast::StaticDef(it) => { decl(it) },
+            ast::MacroCall(it) => {
+                if it.is_macro_rules().is_some() {
+                    decl(it)
+                } else {
+                    None
+                }
+            },
             _ => None,
         }
     }
diff --git a/crates/ra_project_model/src/lib.rs b/crates/ra_project_model/src/lib.rs
index b500a74fb..a3ef9acdc 100644
--- a/crates/ra_project_model/src/lib.rs
+++ b/crates/ra_project_model/src/lib.rs
@@ -336,7 +336,7 @@ impl ProjectWorkspace {
                                 extern_source,
                             );
                             if cargo[tgt].kind == TargetKind::Lib {
-                                lib_tgt = Some(crate_id);
+                                lib_tgt = Some((crate_id, cargo[tgt].name.clone()));
                                 pkg_to_lib_crate.insert(pkg, crate_id);
                             }
                             if cargo[tgt].is_proc_macro {
@@ -363,7 +363,7 @@ impl ProjectWorkspace {
 
                     // Set deps to the core, std and to the lib target of the current package
                     for &from in pkg_crates.get(&pkg).into_iter().flatten() {
-                        if let Some(to) = lib_tgt {
+                        if let Some((to, name)) = lib_tgt.clone() {
                             if to != from
                                 && crate_graph
                                     .add_dep(
@@ -371,7 +371,7 @@ impl ProjectWorkspace {
                                         // For root projects with dashes in their name,
                                         // cargo metadata does not do any normalization,
                                         // so we do it ourselves currently
-                                        CrateName::normalize_dashes(&cargo[pkg].name),
+                                        CrateName::normalize_dashes(&name),
                                         to,
                                     )
                                     .is_err()
diff --git a/crates/ra_syntax/src/algo.rs b/crates/ra_syntax/src/algo.rs
index 344cf0fbe..ffdbdc767 100644
--- a/crates/ra_syntax/src/algo.rs
+++ b/crates/ra_syntax/src/algo.rs
@@ -95,6 +95,10 @@ impl TreeDiff {
             builder.replace(from.text_range(), to.to_string())
         }
     }
+
+    pub fn is_empty(&self) -> bool {
+        self.replacements.is_empty()
+    }
 }
 
 /// Finds minimal the diff, which, applied to `from`, will result in `to`.
diff --git a/crates/ra_syntax/src/ast/extensions.rs b/crates/ra_syntax/src/ast/extensions.rs
index c3ae8f90e..392731dac 100644
--- a/crates/ra_syntax/src/ast/extensions.rs
+++ b/crates/ra_syntax/src/ast/extensions.rs
@@ -4,7 +4,7 @@
 use itertools::Itertools;
 
 use crate::{
-    ast::{self, child_opt, children, AstNode, AttrInput, SyntaxNode},
+    ast::{self, child_opt, children, AstNode, AttrInput, NameOwner, SyntaxNode},
     SmolStr, SyntaxElement,
     SyntaxKind::*,
     SyntaxToken, T,
@@ -514,3 +514,14 @@ impl ast::Visibility {
         self.syntax().children_with_tokens().any(|it| it.kind() == T![super])
     }
 }
+
+impl ast::MacroCall {
+    pub fn is_macro_rules(&self) -> Option<ast::Name> {
+        let name_ref = self.path()?.segment()?.name_ref()?;
+        if name_ref.text() == "macro_rules" {
+            self.name()
+        } else {
+            None
+        }
+    }
+}