From 6b9c72567363edcff5f4e703646b7246fdf5c671 Mon Sep 17 00:00:00 2001
From: Aleksey Kladov <aleksey.kladov@gmail.com>
Date: Wed, 15 Jul 2020 17:18:19 +0200
Subject: [PATCH] Cap macro expansion depth for IDE features

closes #4453
---
 crates/ra_hir/src/source_analyzer.rs |  2 +-
 crates/ra_hir_expand/src/lib.rs      | 19 +++++++++++++++++++
 2 files changed, 20 insertions(+), 1 deletion(-)

diff --git a/crates/ra_hir/src/source_analyzer.rs b/crates/ra_hir/src/source_analyzer.rs
index d76345525fc..ecb54f6536f 100644
--- a/crates/ra_hir/src/source_analyzer.rs
+++ b/crates/ra_hir/src/source_analyzer.rs
@@ -352,7 +352,7 @@ impl SourceAnalyzer {
         let macro_call_id = macro_call.as_call_id(db.upcast(), krate, |path| {
             self.resolver.resolve_path_as_macro(db.upcast(), &path)
         })?;
-        Some(macro_call_id.as_file())
+        Some(macro_call_id.as_file()).filter(|it| it.expansion_level(db.upcast()) < 64)
     }
 
     pub(crate) fn resolve_variant(
diff --git a/crates/ra_hir_expand/src/lib.rs b/crates/ra_hir_expand/src/lib.rs
index 5eac2605b9c..1cf6c1ba93e 100644
--- a/crates/ra_hir_expand/src/lib.rs
+++ b/crates/ra_hir_expand/src/lib.rs
@@ -88,6 +88,25 @@ impl HirFileId {
         }
     }
 
+    pub fn expansion_level(self, db: &dyn db::AstDatabase) -> u32 {
+        let mut level = 0;
+        let mut curr = self;
+        while let HirFileIdRepr::MacroFile(macro_file) = curr.0 {
+            level += 1;
+            curr = match macro_file.macro_call_id {
+                MacroCallId::LazyMacro(id) => {
+                    let loc = db.lookup_intern_macro(id);
+                    loc.kind.file_id()
+                }
+                MacroCallId::EagerMacro(id) => {
+                    let loc = db.lookup_intern_eager_expansion(id);
+                    loc.file_id
+                }
+            };
+        }
+        level
+    }
+
     /// If this is a macro call, returns the syntax node of the call.
     pub fn call_node(self, db: &dyn db::AstDatabase) -> Option<InFile<SyntaxNode>> {
         match self.0 {