From d8a18dfd9e9e67da0ef19c5f44e847534790e58f Mon Sep 17 00:00:00 2001
From: Devon Govett <devongovett@gmail.com>
Date: Wed, 14 Apr 2021 01:42:07 -0700
Subject: [PATCH] fix(es/transforms/compat): Fix block scoping of class
 declarations (#1569)

---
 .../transforms/base/src/resolver/mod.rs       |  3 ++
 .../transforms/base/src/resolver/tests.rs     | 28 +++++++++++++++++++
 2 files changed, 31 insertions(+)

diff --git a/ecmascript/transforms/base/src/resolver/mod.rs b/ecmascript/transforms/base/src/resolver/mod.rs
index 0dcfda3f21cc..d30489cd1aad 100644
--- a/ecmascript/transforms/base/src/resolver/mod.rs
+++ b/ecmascript/transforms/base/src/resolver/mod.rs
@@ -1245,6 +1245,9 @@ impl VisitMut for Hoister<'_, '_> {
     }
 
     fn visit_mut_class_decl(&mut self, node: &mut ClassDecl) {
+        if self.in_block {
+            return;
+        }
         self.resolver.in_type = false;
         self.resolver
             .visit_mut_binding_ident(&mut node.ident, Some(VarDeclKind::Let));
diff --git a/ecmascript/transforms/base/src/resolver/tests.rs b/ecmascript/transforms/base/src/resolver/tests.rs
index 27af359e84db..05bc14bf467d 100644
--- a/ecmascript/transforms/base/src/resolver/tests.rs
+++ b/ecmascript/transforms/base/src/resolver/tests.rs
@@ -2646,3 +2646,31 @@ to!(
     })();
     "#
 );
+
+to!(
+    block_scope_class,
+    r#"
+    const g = 20;
+
+    function baz() {
+        {
+            class g {}
+            console.log(g);
+        }
+
+        return g;
+    }
+    "#,
+    r#"
+    const g = 20;
+
+    function baz() {
+        {
+            class g1 {}
+            console.log(g1);
+        }
+
+        return g;
+    }
+    "#
+);