diff --git a/port/linux/.vscode/launch.json b/port/linux/.vscode/launch.json
index 3a92acf72..dbd045741 100644
--- a/port/linux/.vscode/launch.json
+++ b/port/linux/.vscode/launch.json
@@ -21,7 +21,7 @@
                 // "--gtest_filter=parser.tuple_single"
                 // "--gtest_filter=parser.*"
                 // "--gtest_filter=parser.page_add"
-                "--gtest_filter=builtin.fn_default1"
+                "--gtest_filter=builtin.fn_default_tuple"
             ],
             "stopAtEntry": false,
             "cwd": "${workspaceFolder}",
diff --git a/src/PikaVM.c b/src/PikaVM.c
index 53f40d3e9..2592b0a3d 100644
--- a/src/PikaVM.c
+++ b/src/PikaVM.c
@@ -1216,35 +1216,35 @@ static void _type_list_parse(FunctionArgsInfo* f) {
         f->n_positional = 0;
         return;
     }
-    int8_t res = strCountSign(f->type_list, ',') + 1;
-    int8_t x = strCountSign(f->type_list, '*');
-    int8_t y = strCountSign(f->type_list, '=');
+    int8_t iArgc = strCountSign(f->type_list, ',') + 1;
+    int8_t iStar = strCountSign(f->type_list, '*');
+    int8_t iAssign = strCountSign(f->type_list, '=');
     /* default */
-    if (y > 0) {
-        res -= y;
+    if (iAssign > 0) {
+        iArgc -= iAssign;
         f->is_default = PIKA_TRUE;
-        f->n_default = y;
+        f->n_default = iAssign;
     }
     /* vars */
-    if (x == 1) {
+    if (iStar == 1) {
         f->is_vars = PIKA_TRUE;
-        f->n_positional = res - 1;
+        f->n_positional = iArgc - 1;
         return;
     }
     /* kw */
-    if (x == 2) {
+    if (iStar == 2) {
         f->is_keys = PIKA_TRUE;
-        f->n_positional = res - 1;
+        f->n_positional = iArgc - 1;
         return;
     }
     /* vars and kw */
-    if (x == 3) {
+    if (iStar == 3) {
         f->is_vars = PIKA_TRUE;
         f->is_keys = PIKA_TRUE;
-        f->n_positional = res - 2;
+        f->n_positional = iArgc - 2;
         return;
     }
-    f->n_positional = res;
+    f->n_positional = iArgc;
     return;
 }
 
diff --git a/src/dataString.c b/src/dataString.c
index e62d016e4..d63b34bc5 100644
--- a/src/dataString.c
+++ b/src/dataString.c
@@ -90,17 +90,45 @@ char* strAppendWithSize(char* strOut, char* pData, int32_t Size) {
 
     return strOut;
 }
+const char bracketStart[] = {'(', '[', '{', '\'', '\"'};
+const char bracketEnd[] = {')', ']', '}', '\'', '\"'};
+#define BRACKET_TYPE_NUM (sizeof(bracketStart) / sizeof(char))
+
+int32_t _strCountSign(char* strIn, char sign, PIKA_BOOL bracketDepth0) {
+    int32_t iCount = 0;
+    int32_t iTotalDepth = 0;
+    PIKA_BOOL bEscaped = PIKA_FALSE;
+    for (size_t i = 0; strIn[i] != '\0'; i++) {
+        if (!bracketDepth0) {
+            if (strIn[i] == sign) {
+                iCount++;
+            }
+            continue;
+        }
+        char cCurrentChar = strIn[i];
+        if (cCurrentChar == '\\') {
+            bEscaped = !bEscaped;
+            continue;
+        }
+        if (!bEscaped) {
+            for (int j = 0; j < BRACKET_TYPE_NUM; j++) {
+                if (cCurrentChar == bracketStart[j]) {
+                    iTotalDepth++;
+                } else if (cCurrentChar == bracketEnd[j]) {
+                    iTotalDepth--;
+                }
+            }
+        }
+        if (cCurrentChar == sign && iTotalDepth == 0) {
+            iCount++;
+        }
+        bEscaped = PIKA_FALSE;
+    }
+    return iCount;
+}
 
 int32_t strCountSign(char* strIn, char sign) {
-    pika_assert(NULL != strIn);
-    int count = 0;
-    while (*strIn) {
-        if (*strIn == sign) {
-            count++;
-        }
-        strIn++;
-    }
-    return count;
+    return _strCountSign(strIn, sign, 0);
 }
 
 char* strReplaceChar(char* strIn, char src, char dst) {
diff --git a/src/dataString.h b/src/dataString.h
index 16903af7e..a685b1e26 100644
--- a/src/dataString.h
+++ b/src/dataString.h
@@ -72,6 +72,7 @@ int strPathGetFileName(char* input, char* output);
 int strGetIndent(char* string);
 int strIsBlank(char* string);
 int strOnly(char* string, char ch);
+int _strCountSign(char* strIn, char sign, PIKA_BOOL bracketDepth0);
 
 #endif
 #ifdef __cplusplus
diff --git a/test/builtin-test.cpp b/test/builtin-test.cpp
index d4078e34d..3ee546de9 100644
--- a/test/builtin-test.cpp
+++ b/test/builtin-test.cpp
@@ -196,6 +196,10 @@ TEST_RUN_SINGLE_FILE_PASS(builtin,
                           fn_default1,
                           "test/python/builtin/fn_default1.py")
 
+TEST_RUN_SINGLE_FILE(builtin,
+                     fn_default_tuple,
+                     "test/python/builtin/fn_default_tuple.py")
+
 #endif
 
 TEST_END
\ No newline at end of file
diff --git a/test/python/builtin/fn_default_tuple.py b/test/python/builtin/fn_default_tuple.py
new file mode 100644
index 000000000..eb67dbab2
--- /dev/null
+++ b/test/python/builtin/fn_default_tuple.py
@@ -0,0 +1,6 @@
+
+def test_default_tuple(t=(1, 2)):
+    print(t)
+
+
+test_default_tuple()