diff --git a/spacy/tests/conftest.py b/spacy/tests/conftest.py
index c021788b9..0bc2604bb 100644
--- a/spacy/tests/conftest.py
+++ b/spacy/tests/conftest.py
@@ -531,7 +531,7 @@ def fully_featured_doc_two_sentences(en_vocab):
         "She",
         "loved",
         "it",
-        "."
+        ".",
     ]
     lemmas = [
         "sarah",
@@ -547,9 +547,24 @@ def fully_featured_doc_two_sentences(en_vocab):
         "she",
         "love",
         "it",
-        "."
+        ".",
+    ]
+    spaces = [
+        False,
+        True,
+        True,
+        True,
+        True,
+        True,
+        True,
+        True,
+        False,
+        True,
+        True,
+        True,
+        False,
+        False,
     ]
-    spaces = [False, True, True, True, True, True, True, True, False, True, True, True, False, False]
     pos = [
         "PROPN",
         "PART",
@@ -564,9 +579,24 @@ def fully_featured_doc_two_sentences(en_vocab):
         "PRON",
         "VERB",
         "PRON",
-        "PUNCT"
+        "PUNCT",
+    ]
+    tags = [
+        "NNP",
+        "POS",
+        "NN",
+        "VBD",
+        "IN",
+        "NNP",
+        "NNP",
+        "IN",
+        "NNP",
+        ".",
+        "PRP",
+        "VBD",
+        "PRP",
+        ".",
     ]
-    tags = ["NNP", "POS", "NN", "VBD", "IN", "NNP", "NNP", "IN", "NNP", ".", "PRP", "VBD", "PRP", "."]
     morphs = [
         "NounType=prop|Number=sing",
         "Poss=yes",
diff --git a/spacy/visualization.py b/spacy/visualization.py
index 0075d9f41..7903d1c4b 100644
--- a/spacy/visualization.py
+++ b/spacy/visualization.py
@@ -1,5 +1,5 @@
 from os import linesep
-from typing import Union
+from typing import Optional, Union, cast
 import wasabi
 from spacy.tokens import Span, Token, Doc
 
@@ -151,7 +151,7 @@ class Visualizer:
         # Check sent is really a sentence
         assert sent.start == sent[0].sent.start
         assert sent.end == sent[0].sent.end
-        heads = [
+        heads: list[Optional[int]] = [
             None
             if token.dep_.lower() == "root" or token.head.i == token.i
             else token.head.i - sent.start
@@ -211,7 +211,7 @@ class Visualizer:
         horizontal_line_lengths = [
             -1 if heads[i] is None else 1
             # length == 1: governed by direct neighbour and has no children itself
-            if len(children_lists[i]) == 0 and abs(heads[i] - i) == 1 else 0
+            if len(children_lists[i]) == 0 and abs(cast(int, heads[i]) - i) == 1 else 0
             for i in range(sent.end - sent.start)
         ]
         while 0 in horizontal_line_lengths:
@@ -223,11 +223,11 @@ class Visualizer:
                 # render relation between this token and its head
                 first_index_in_relation = min(
                     working_token_index,
-                    heads[working_token_index],
+                    cast(int, heads[working_token_index]),
                 )
                 second_index_in_relation = max(
                     working_token_index,
-                    heads[working_token_index],
+                    cast(int, heads[working_token_index]),
                 )
                 # If this token has children, they will already have been rendered.
                 # The line needs to be one character longer than the longest of the
@@ -254,7 +254,8 @@ class Visualizer:
                     horizontal_line_lengths[working_token_index] = max(
                         horizontal_line_lengths[working_token_index],
                         horizontal_line_lengths[inbetween_index]
-                        if inbetween_index in children_lists[heads[working_token_index]]
+                        if inbetween_index
+                        in children_lists[cast(int, heads[working_token_index])]
                         and inbetween_index not in children_lists[working_token_index]
                         else horizontal_line_lengths[inbetween_index] + 1,
                     )
@@ -383,9 +384,9 @@ class Visualizer:
             for column in columns:
                 # get the values without any color codes
                 if column.attribute == "tree_left":
-                    width = len(tree_left[0])
+                    width = len(tree_left[0])  # type: ignore
                 elif column.attribute == "tree_right":
-                    width = len(tree_right[0])
+                    width = len(tree_right[0])  # type: ignore
                 else:
                     if len(sent) > 0:
                         width = max(
@@ -400,9 +401,9 @@ class Visualizer:
                 widths.append(width)
             data = [
                 [
-                    tree_right[token_index]
+                    tree_right[token_index]  # type: ignore
                     if column.attribute == "tree_right"
-                    else tree_left[token_index]
+                    else tree_left[token_index]  # type: ignore
                     if column.attribute == "tree_left"
                     else column.render(token, right_pad_to_length=widths[column_index])
                     for column_index, column in enumerate(columns)