diff --git a/src/Psalm/Internal/Visitor/ReflectorVisitor.php b/src/Psalm/Internal/Visitor/ReflectorVisitor.php
index f02ede30099..caedede15f9 100644
--- a/src/Psalm/Internal/Visitor/ReflectorVisitor.php
+++ b/src/Psalm/Internal/Visitor/ReflectorVisitor.php
@@ -1209,6 +1209,20 @@ private function extendTemplatedType(
         PhpParser\Node\Stmt\ClassLike $node,
         string $extended_class_name
     ) {
+        if (trim($extended_class_name) === '') {
+            if (IssueBuffer::accepts(
+                new InvalidDocblock(
+                    'Extended class cannot be empty in docblock for ' . implode('.', $this->fq_classlike_names),
+                    new CodeLocation($this->file_scanner, $node, null, true)
+                )
+            )) {
+            }
+
+            $storage->has_docblock_issues = true;
+
+            return;
+        }
+
         try {
             $extended_union_type = Type::parseTokens(
                 Type::fixUpLocalType(
@@ -1296,6 +1310,20 @@ private function implementTemplatedType(
         PhpParser\Node\Stmt\ClassLike $node,
         string $implemented_class_name
     ) {
+        if (trim($implemented_class_name) === '') {
+            if (IssueBuffer::accepts(
+                new InvalidDocblock(
+                    'Extended class cannot be empty in docblock for ' . implode('.', $this->fq_classlike_names),
+                    new CodeLocation($this->file_scanner, $node, null, true)
+                )
+            )) {
+            }
+
+            $storage->has_docblock_issues = true;
+
+            return;
+        }
+
         try {
             $implemented_union_type = Type::parseTokens(
                 Type::fixUpLocalType(
@@ -1381,6 +1409,20 @@ private function useTemplatedType(
         PhpParser\Node\Stmt\TraitUse $node,
         string $used_class_name
     ) {
+        if (trim($used_class_name) === '') {
+            if (IssueBuffer::accepts(
+                new InvalidDocblock(
+                    'Extended class cannot be empty in docblock for ' . implode('.', $this->fq_classlike_names),
+                    new CodeLocation($this->file_scanner, $node, null, true)
+                )
+            )) {
+            }
+
+            $storage->has_docblock_issues = true;
+
+            return;
+        }
+
         try {
             $used_union_type = Type::parseTokens(
                 Type::fixUpLocalType(
diff --git a/tests/Template/ClassTemplateExtendsTest.php b/tests/Template/ClassTemplateExtendsTest.php
index f8546a26a22..e3e01108626 100644
--- a/tests/Template/ClassTemplateExtendsTest.php
+++ b/tests/Template/ClassTemplateExtendsTest.php
@@ -3081,6 +3081,14 @@ public static function getString($t, object $o = null) : string {
                     }',
                 'error_message' => 'ArgumentTypeCoercion',
             ],
+            'invalidExtendsAnnotation' => [
+                '<?php
+                    /**
+                    * @template-extends
+                    */
+                    class Foo extends DateTimeImmutable {}',
+                'error_message' => 'InvalidDocblock'
+            ],
         ];
     }
 }