diff --git a/src/Psalm/Internal/Type/TypeTokenizer.php b/src/Psalm/Internal/Type/TypeTokenizer.php
index a772bc7503e..9b4c6fdefda 100644
--- a/src/Psalm/Internal/Type/TypeTokenizer.php
+++ b/src/Psalm/Internal/Type/TypeTokenizer.php
@@ -9,9 +9,11 @@
 use Psalm\Internal\Type\TypeAlias\InlineTypeAlias;
 use Psalm\Type;
 
+use function array_slice;
 use function array_splice;
 use function array_unshift;
 use function count;
+use function implode;
 use function in_array;
 use function is_numeric;
 use function preg_match;
@@ -146,11 +148,9 @@ public static function tokenize(string $string_type, bool $ignore_space = true):
                 $type_tokens[++$rtc] = [' ', $i - 1];
                 $type_tokens[++$rtc] = ['', $i];
             } elseif ($was_space
-                && ($char === 'a' || $char === 'i')
-                && ($chars[$i + 1] ?? null) === 's'
-                && ($chars[$i + 2] ?? null) === ' '
+                && in_array(implode('', array_slice($chars, $i, 3)), ['as ', 'is ', 'of '])
             ) {
-                $type_tokens[++$rtc] = [$char . 's', $i - 1];
+                $type_tokens[++$rtc] = [$char . $chars[$i+1], $i - 1];
                 $type_tokens[++$rtc] = ['', ++$i];
                 $was_char = false;
                 continue;
diff --git a/tests/TypeParseTest.php b/tests/TypeParseTest.php
index 2ebae82ce4b..e092784ee81 100644
--- a/tests/TypeParseTest.php
+++ b/tests/TypeParseTest.php
@@ -935,6 +935,14 @@ public function testClassStringMap(): void
         );
     }
 
+    public function testClassStringMapOf(): void
+    {
+        $this->assertSame(
+            'class-string-map<T of Foo, T>',
+            Type::parseString('class-string-map<T of Foo, T>')->getId(false),
+        );
+    }
+
     public function testVeryLargeType(): void
     {
         $very_large_type = 'array{a: Closure():(array<array-key, mixed>|null), b?: Closure():array<array-key, mixed>, c?: Closure():array<array-key, mixed>, d?: Closure():array<array-key, mixed>, e?: Closure():(array{f: null|string, g: null|string, h: null|string, i: string, j: mixed, k: mixed, l: mixed, m: mixed, n: bool, o?: array{0: string}}|null), p?: Closure():(array{f: null|string, g: null|string, h: null|string, i: string, j: mixed, k: mixed, l: mixed, m: mixed, n: bool, o?: array{0: string}}|null), q: string, r?: Closure():(array<array-key, mixed>|null), s: array<array-key, mixed>}|null';