diff --git a/extra/errors.awk b/extra/errors.awk
index 1ddffca7..3dc1faaf 100644
--- a/extra/errors.awk
+++ b/extra/errors.awk
@@ -34,6 +34,8 @@ BEGIN { matched = 0
         err_pat["'for' step is zero"] = 0
         err_pat["attempt to assign to const variable"] = 0
         err_pat["got a non-closable value"] = 0
+        err_pat["unfinished string near"] = 0
+        err_pat["syntax error near"] = 0
       }
 
 # String that function report_error() prints with every error message.
diff --git a/tests/capi/luaL_loadbuffer_proto/lua_grammar.proto b/tests/capi/luaL_loadbuffer_proto/lua_grammar.proto
index 6a4fbfad..c45d247f 100644
--- a/tests/capi/luaL_loadbuffer_proto/lua_grammar.proto
+++ b/tests/capi/luaL_loadbuffer_proto/lua_grammar.proto
@@ -383,6 +383,16 @@ message BinaryOperator {
         uint32 notEqual = 13;
         uint32 and = 14;
         uint32 or = 15;
+
+        /* Arithmetic operators (5.3+). */
+        uint32 idiv = 16;
+
+        /* Bitwise operators (5.3+). */
+        uint32 band = 17;
+        uint32 bor = 18;
+        uint32 bxor = 19;
+        uint32 shl = 20;
+        uint32 shr = 21;
     }
 }
 
@@ -392,6 +402,9 @@ message UnaryOperator {
         uint32 negate = 1;
         uint32 not = 2;
         uint32 length = 3;
+
+        /* Bitwise operators (5.3+). */
+        uint32 bnot = 4;
     }
 }
 
diff --git a/tests/capi/luaL_loadbuffer_proto/preamble.lua b/tests/capi/luaL_loadbuffer_proto/preamble.lua
index 92b6b8bd..e41afe5d 100644
--- a/tests/capi/luaL_loadbuffer_proto/preamble.lua
+++ b/tests/capi/luaL_loadbuffer_proto/preamble.lua
@@ -8,6 +8,8 @@ local not_nan_and_nil = function(val)
     return (val ~= val or val == nil) and DEFAULT_NUMBER or val
 end
 
+_G.always_number = always_number
+
 local __add = function(v1, v2)
     return always_number(v1) + always_number(v2)
 end
@@ -70,11 +72,40 @@ end
 local __unm = function(v)
     return - always_number(v)
 end
+local __idiv = load([[
+    local v1, v2 = ...
+    return always_number(v1) // always_number(v2)
+]])
+local __band = load([[
+    local v1, v2 = ...
+    return always_number(v1) & always_number(v2)
+]])
+local __bor = load([[
+    local v1, v2 = ...
+    return always_number(v1) | always_number(v2)
+]])
+local __bxor = load([[
+    local v1, v2 = ...
+    return always_number(v1) ~ always_number(v2)
+]])
+local __bnot = load([[
+    local v = ...
+    return ~always_number(v)
+]])
+local __shl = load([[
+    local v1, v2 = ...
+    return always_number(v1) << always_number(v2)
+]])
+local __shr = load([[
+    local v1, v2 = ...
+    return always_number(v1) >> always_number(v2)
+]])
 
 debug.setmetatable('string', {
     __add = __add,
     __call = __call,
     __div = __div,
+    __idiv = __idiv,
     __index = __index,
     __mod = __mod,
     __mul = __mul,
@@ -82,12 +113,19 @@ debug.setmetatable('string', {
     __pow = __pow,
     __sub = __sub,
     __unm = __unm,
+    __band = __band,
+    __bor = __bor,
+    __bxor = __bxor,
+    __bnot = __bnot,
+    __shl = __shl,
+    __shr = __shr,
 })
 debug.setmetatable(0, {
     __add = __add,
     __call = __call,
     __concat = __concat,
     __div = __div,
+    __idiv = __idiv,
     __index = __index,
     __len = __len,
     __newindex = __newindex,
@@ -97,6 +135,7 @@ debug.setmetatable(nil, {
     __call = __call,
     __concat = __concat,
     __div = __div,
+    __idiv = __idiv,
     __index = __index,
     __le = __le,
     __len = __len,
@@ -112,6 +151,7 @@ debug.setmetatable(function() end, {
     __add = __add,
     __concat = __concat,
     __div = __div,
+    __idiv = __idiv,
     __index = __index,
     __le = __le,
     __len = __len,
@@ -128,6 +168,7 @@ debug.setmetatable(true, {
     __call = __call,
     __concat = __concat,
     __div = __div,
+    __idiv = __idiv,
     __index = __index,
     __le = __le,
     __len = __len,
@@ -144,6 +185,7 @@ local table_mt = {
     __call = __call,
     __concat = __concat,
     __div = __div,
+    __idiv = __idiv,
     __le = __le,
     __len = __len,
     __lt = __lt,
diff --git a/tests/capi/luaL_loadbuffer_proto/serializer.cc b/tests/capi/luaL_loadbuffer_proto/serializer.cc
index 312b128f..ea951afd 100644
--- a/tests/capi/luaL_loadbuffer_proto/serializer.cc
+++ b/tests/capi/luaL_loadbuffer_proto/serializer.cc
@@ -1157,6 +1157,10 @@ PROTO_TOSTRING(BinaryOperator, op)
 		return "*";
 	case BinopType::kDiv:
 		return "/";
+#if LUA_VERSION_NUM >= 503
+	case BinopType::kIDiv:
+		return "//";
+#endif
 	case BinopType::kExp:
 		return "^";
 	case BinopType::kMod:
@@ -1181,6 +1185,19 @@ PROTO_TOSTRING(BinaryOperator, op)
 		return "and";
 	case BinopType::kOr:
 		return "or";
+
+#if LUA_VERSION_NUM >= 503
+	case BinopType::kBAnd:
+		return "&";
+	case BinopType::kBOr:
+		return "|";
+	case BinopType::kBXor:
+		return "~";
+	case BinopType::kBShl:
+		return "<<";
+	case BinopType::kBShr:
+		return ">>";
+#endif
 	default:
 		/* Works in most cases. */
 		return "==";
@@ -1197,6 +1214,10 @@ PROTO_TOSTRING(UnaryOperator, op)
 		return "not ";
 	case UnaryopType::kLength:
 		return "#";
+#if LUA_VERSION_NUM >= 503
+	case UnaryopType::kBNot:
+		return "~";
+#endif
 	default:
 		/* Works in most cases. */
 		return "not ";