diff --git a/pandas/_libs/hashtable_func_helper.pxi.in b/pandas/_libs/hashtable_func_helper.pxi.in
index e5e64f8dc7b5f..be57d2cd5f844 100644
--- a/pandas/_libs/hashtable_func_helper.pxi.in
+++ b/pandas/_libs/hashtable_func_helper.pxi.in
@@ -17,7 +17,7 @@ dtypes = [('Complex128', 'complex128', 'complex128',
           ('UInt32', 'uint32', 'uint32', 'uint32_t', ''),
           ('UInt16', 'uint16', 'uint16', 'uint16_t', ''),
           ('UInt8', 'uint8', 'uint8', 'uint8_t', ''),
-          ('Object', 'object', 'pymap', 'object', ''),
+          ('Object', 'object', 'pymap', 'object', '<PyObject*>'),
           ('Int64', 'int64', 'int64', 'int64_t', ''),
           ('Int32', 'int32', 'int32', 'int32_t', ''),
           ('Int16', 'int16', 'int16', 'int16_t', ''),
@@ -61,11 +61,11 @@ cdef value_count_{{dtype}}(const {{dtype}}_t[:] values, bint dropna):
     for i in range(n):
         val = values[i]
         if not dropna or not checknull(val):
-            k = kh_get_{{ttype}}(table, <PyObject*>val)
+            k = kh_get_{{ttype}}(table, {{to_c_type}}val)
             if k != table.n_buckets:
                 table.vals[k] += 1
             else:
-                k = kh_put_{{ttype}}(table, <PyObject*>val, &ret)
+                k = kh_put_{{ttype}}(table, {{to_c_type}}val, &ret)
                 table.vals[k] = 1
                 result_keys.append(val)
     {{else}}
@@ -110,6 +110,8 @@ cdef duplicated_{{dtype}}(const {{dtype}}_t[:] values, object keep='first'):
         int ret = 0
         {{if dtype != 'object'}}
         {{c_type}} value
+        {{else}}
+        PyObject* value
         {{endif}}
         Py_ssize_t i, n = len(values)
         khiter_t k
@@ -123,44 +125,33 @@ cdef duplicated_{{dtype}}(const {{dtype}}_t[:] values, object keep='first'):
 
     if keep == 'last':
         {{if dtype == 'object'}}
-        for i in range(n - 1, -1, -1):
-            # equivalent: range(n)[::-1], which cython doesn't like in nogil
-            kh_put_{{ttype}}(table, <PyObject*>values[i], &ret)
-            out[i] = ret == 0
+        if True:
         {{else}}
         with nogil:
+        {{endif}}
             for i in range(n - 1, -1, -1):
                 # equivalent: range(n)[::-1], which cython doesn't like in nogil
                 value = {{to_c_type}}(values[i])
                 kh_put_{{ttype}}(table, value, &ret)
                 out[i] = ret == 0
-        {{endif}}
+
     elif keep == 'first':
         {{if dtype == 'object'}}
-        for i in range(n):
-            kh_put_{{ttype}}(table, <PyObject*>values[i], &ret)
-            out[i] = ret == 0
+        if True:
         {{else}}
         with nogil:
+        {{endif}}
             for i in range(n):
                 value = {{to_c_type}}(values[i])
                 kh_put_{{ttype}}(table, value, &ret)
                 out[i] = ret == 0
-        {{endif}}
+
     else:
         {{if dtype == 'object'}}
-        for i in range(n):
-            value = values[i]
-            k = kh_get_{{ttype}}(table, <PyObject*>value)
-            if k != table.n_buckets:
-                out[table.vals[k]] = 1
-                out[i] = 1
-            else:
-                k = kh_put_{{ttype}}(table, <PyObject*>value, &ret)
-                table.vals[k] = i
-                out[i] = 0
+        if True:
         {{else}}
         with nogil:
+        {{endif}}
             for i in range(n):
                 value = {{to_c_type}}(values[i])
                 k = kh_get_{{ttype}}(table, value)
@@ -171,7 +162,7 @@ cdef duplicated_{{dtype}}(const {{dtype}}_t[:] values, object keep='first'):
                     k = kh_put_{{ttype}}(table, value, &ret)
                     table.vals[k] = i
                     out[i] = 0
-        {{endif}}
+
     kh_destroy_{{ttype}}(table)
     return out
 
@@ -206,7 +197,13 @@ cdef ismember_{{dtype}}(const {{dtype}}_t[:] arr, const {{dtype}}_t[:] values):
         khiter_t k
         int ret = 0
         ndarray[uint8_t] result
+
+        {{if dtype == "object"}}
+        PyObject* val
+        {{else}}
         {{c_type}} val
+        {{endif}}
+
         kh_{{ttype}}_t *table = kh_init_{{ttype}}()
 
     # construct the table
@@ -214,31 +211,27 @@ cdef ismember_{{dtype}}(const {{dtype}}_t[:] arr, const {{dtype}}_t[:] values):
     kh_resize_{{ttype}}(table, n)
 
     {{if dtype == 'object'}}
-    for i in range(n):
-        kh_put_{{ttype}}(table, <PyObject*>values[i], &ret)
+    if True:
     {{else}}
     with nogil:
+    {{endif}}
         for i in range(n):
             val = {{to_c_type}}(values[i])
             kh_put_{{ttype}}(table, val, &ret)
-    {{endif}}
 
     # test membership
     n = len(arr)
     result = np.empty(n, dtype=np.uint8)
 
     {{if dtype == 'object'}}
-    for i in range(n):
-        val = arr[i]
-        k = kh_get_{{ttype}}(table, <PyObject*>val)
-        result[i] = (k != table.n_buckets)
+    if True:
     {{else}}
     with nogil:
+    {{endif}}
         for i in range(n):
             val = {{to_c_type}}(arr[i])
             k = kh_get_{{ttype}}(table, val)
             result[i] = (k != table.n_buckets)
-    {{endif}}
 
     kh_destroy_{{ttype}}(table)
     return result.view(np.bool_)