diff --git a/src/frontends/lean/decl_attributes.cpp b/src/frontends/lean/decl_attributes.cpp
index 65b15b49bf..b70a333dd7 100644
--- a/src/frontends/lean/decl_attributes.cpp
+++ b/src/frontends/lean/decl_attributes.cpp
@@ -16,8 +16,10 @@ Author: Leonardo de Moura
 
 namespace lean {
 void decl_attributes::parse(parser & p) {
-    while (p.curr_is_token(get_lbracket_tk())) {
-        p.next();
+    if (!p.curr_is_token(get_lbracket_tk()))
+        return;
+    p.next();
+    while (true) {
         auto pos = p.pos();
         auto name = p.check_id_next("invalid attribute declaration, identifier expected");
         if (name == "priority") {
@@ -50,7 +52,15 @@ void decl_attributes::parse(parser & p) {
             if (name == "parsing_only")
                 m_parsing_only = true;
         }
-        p.check_token_next(get_rbracket_tk(), "invalid attribute declaration, ']' expected");
+        if (p.curr_is_token(get_comma_tk())) {
+            p.next();
+        } else {
+            p.check_token_next(get_rbracket_tk(), "invalid attribute declaration, ']' expected");
+            if (p.curr_is_token(get_lbracket_tk()))
+                p.next();
+            else
+                break;
+        }
     }
 }
 
diff --git a/src/frontends/lean/parser.h b/src/frontends/lean/parser.h
index 9bbd72d64c..ab6638bd50 100644
--- a/src/frontends/lean/parser.h
+++ b/src/frontends/lean/parser.h
@@ -312,7 +312,7 @@ public:
     /** \brief Return true iff the current token is an identifier */
     bool curr_is_identifier() const { return curr() == scanner::token_kind::Identifier; }
     /** \brief Return true iff the current token is a numeral */
-    bool curr_is_numeral() const { return curr() == scanner::token_kind::Numeral; }
+    virtual bool curr_is_numeral() const final override { return curr() == scanner::token_kind::Numeral; }
     bool curr_is_decimal() const { return curr() == scanner::token_kind::Decimal; }
     /** \brief Return true iff the current token is a string */
     bool curr_is_string() const { return curr() == scanner::token_kind::String; }
diff --git a/src/library/abstract_parser.h b/src/library/abstract_parser.h
index 95a6ee3278..7e50ba48cf 100644
--- a/src/library/abstract_parser.h
+++ b/src/library/abstract_parser.h
@@ -25,6 +25,8 @@ public:
 
     /** \brief Return true iff the current token is a keyword (or command keyword) named \c tk */
     virtual bool curr_is_token(name const & tk) const = 0;
+    /** \brief Return true iff the current token is a numeral */
+    virtual bool curr_is_numeral() const = 0;
     /** \brief Read the next token if the current one is not End-of-file. */
     virtual void next() = 0;
 
diff --git a/src/library/attribute_manager.cpp b/src/library/attribute_manager.cpp
index 7a0379a808..5e56a271ef 100644
--- a/src/library/attribute_manager.cpp
+++ b/src/library/attribute_manager.cpp
@@ -145,7 +145,7 @@ environment basic_attribute::set(environment const & env, io_state const & ios,
 
 void indices_attribute_data::parse(abstract_parser & p) {
     buffer<unsigned> vs;
-    while (!p.curr_is_token("]")) {
+    while (p.curr_is_numeral()) {
         auto pos = p.pos();
         unsigned v = p.parse_small_nat();
         if (v == 0)