diff --git a/Zend/tests/gh15976/alias-names.phpt b/Zend/tests/gh15976/alias-names.phpt
new file mode 100644
index 00000000000..aa25931eed7
--- /dev/null
+++ b/Zend/tests/gh15976/alias-names.phpt
@@ -0,0 +1,13 @@
+--TEST--
+GH-15976: Bad class alias names
+--FILE--
+<?php
+
+class_alias( 'stdClass', '_' );
+class_alias( 'stdClass', 'bool' );
+
+?>
+--EXPECTF--
+Deprecated: Using "_" as a class name is deprecated since 8.4 in %salias-names.php on line 3
+
+Fatal error: Cannot use 'bool' as class name as it is reserved in %salias-names.php on line 4
diff --git a/Zend/tests/gh15976/class-names.phpt b/Zend/tests/gh15976/class-names.phpt
new file mode 100644
index 00000000000..b9b4c9e6eba
--- /dev/null
+++ b/Zend/tests/gh15976/class-names.phpt
@@ -0,0 +1,13 @@
+--TEST--
+GH-15976: Bad class names
+--FILE--
+<?php
+
+class _ {}
+class bool {}
+
+?>
+--EXPECTF--
+Deprecated: Using "_" as a class name is deprecated since 8.4 in %sclass-names.php on line 3
+
+Fatal error: Cannot use 'bool' as class name as it is reserved in %sclass-names.php on line 4
diff --git a/Zend/tests/gh15976/enum-names.phpt b/Zend/tests/gh15976/enum-names.phpt
new file mode 100644
index 00000000000..3277dd14f8a
--- /dev/null
+++ b/Zend/tests/gh15976/enum-names.phpt
@@ -0,0 +1,13 @@
+--TEST--
+GH-15976: Bad enum names
+--FILE--
+<?php
+
+enum _ {}
+enum bool {}
+
+?>
+--EXPECTF--
+Deprecated: Using "_" as a class name is deprecated since 8.4 in %senum-names.php on line 3
+
+Fatal error: Cannot use 'bool' as class name as it is reserved in %senum-names.php on line 4
diff --git a/Zend/tests/gh15976/interface-names.phpt b/Zend/tests/gh15976/interface-names.phpt
new file mode 100644
index 00000000000..edc1b4e3d33
--- /dev/null
+++ b/Zend/tests/gh15976/interface-names.phpt
@@ -0,0 +1,13 @@
+--TEST--
+GH-15976: Bad interface names
+--FILE--
+<?php
+
+interface _ {}
+interface bool {}
+
+?>
+--EXPECTF--
+Deprecated: Using "_" as a class name is deprecated since 8.4 in %sinterface-names.php on line 3
+
+Fatal error: Cannot use 'bool' as class name as it is reserved in %sinterface-names.php on line 4
diff --git a/Zend/tests/gh15976/trait-names.phpt b/Zend/tests/gh15976/trait-names.phpt
new file mode 100644
index 00000000000..4d68d2f997b
--- /dev/null
+++ b/Zend/tests/gh15976/trait-names.phpt
@@ -0,0 +1,13 @@
+--TEST--
+GH-15976: Bad trait names
+--FILE--
+<?php
+
+trait _ {}
+trait bool {}
+
+?>
+--EXPECTF--
+Deprecated: Using "_" as a class name is deprecated since 8.4 in %strait-names.php on line 3
+
+Fatal error: Cannot use 'bool' as class name as it is reserved in %strait-names.php on line 4