diff --git a/.github/actions/freebsd/action.yml b/.github/actions/freebsd/action.yml
index d375a51a6d173..98163d28a82e9 100644
--- a/.github/actions/freebsd/action.yml
+++ b/.github/actions/freebsd/action.yml
@@ -1,4 +1,8 @@
 name: FreeBSD
+inputs:
+  configurationParameters:
+    default: ''
+    required: false
 runs:
   using: composite
   steps:
@@ -80,7 +84,9 @@ runs:
             --with-sodium \
             --enable-werror \
             --with-config-file-path=/etc \
-            --with-config-file-scan-dir=/etc/php.d
+            --with-config-file-scan-dir=/etc/php.d \
+            ${{ inputs.configurationParameters }}
+
           gmake -j2
           mkdir /etc/php.d
           gmake install > /dev/null
diff --git a/.github/workflows/nightly.yml b/.github/workflows/nightly.yml
index 1b1532af7f799..1167b9c5d2934 100644
--- a/.github/workflows/nightly.yml
+++ b/.github/workflows/nightly.yml
@@ -23,6 +23,9 @@ on:
       run_macos_arm64:
         required: true
         type: boolean
+      run_freebsd_zts:
+        required: true
+        type: boolean
       ubuntu_version:
         required: true
         type: string
@@ -1052,7 +1055,13 @@ jobs:
       - name: Test
         run: .github/scripts/windows/test.bat
   FREEBSD:
-    name: FREEBSD
+    strategy:
+      fail-fast: false
+      matrix:
+        zts: [true, false]
+        exclude:
+          - zts: ${{ !inputs.run_freebsd_zts && true || '*never*' }}
+    name: "FREEBSD_${{ matrix.zts && 'ZTS' || 'NTS' }}"
     runs-on: ubuntu-latest
     steps:
       - name: git checkout
@@ -1061,3 +1070,6 @@ jobs:
           ref: ${{ inputs.branch }}
       - name: FreeBSD
         uses: ./.github/actions/freebsd
+        with:
+          configurationParameters: >-
+            --${{ matrix.zts && 'enable' || 'disable' }}-zts
diff --git a/.github/workflows/root.yml b/.github/workflows/root.yml
index 78e0d47aa1d15..30abc1da852bb 100644
--- a/.github/workflows/root.yml
+++ b/.github/workflows/root.yml
@@ -55,6 +55,7 @@ jobs:
       run_alpine: ${{ (matrix.branch.version[0] == 8 && matrix.branch.version[1] >= 4) || matrix.branch.version[0] >= 9 }}
       run_linux_ppc64: ${{ (matrix.branch.version[0] == 8 && matrix.branch.version[1] >= 4) || matrix.branch.version[0] >= 9 }}
       run_macos_arm64: ${{ (matrix.branch.version[0] == 8 && matrix.branch.version[1] >= 4) || matrix.branch.version[0] >= 9 }}
+      run_freebsd_zts: ${{ (matrix.branch.version[0] == 8 && matrix.branch.version[1] >= 3) || matrix.branch.version[0] >= 9 }}
       ubuntu_version: ${{
         (((matrix.branch.version[0] == 8 && matrix.branch.version[1] >= 5) || matrix.branch.version[0] >= 9) && '24.04')
         || '22.04' }}
diff --git a/UPGRADING.INTERNALS b/UPGRADING.INTERNALS
index 3b248614c376d..6b5959fe030fb 100644
--- a/UPGRADING.INTERNALS
+++ b/UPGRADING.INTERNALS
@@ -45,6 +45,8 @@ PHP 8.5 INTERNALS UPGRADE NOTES
     properties.
   . ZEND_IS_XDIGIT() macro was removed because it was unused and its name
     did not match its actual behavior.
+  . zend_register_constant() now returns a pointer to the added constant
+    on success and NULL on failure instead of SUCCESS/FAILURE.
 
 ========================
 2. Build system changes
diff --git a/Zend/tests/attributes/constants/oss_fuzz_428053935.phpt b/Zend/tests/attributes/constants/oss_fuzz_428053935.phpt
new file mode 100644
index 0000000000000..97747fd6194fd
--- /dev/null
+++ b/Zend/tests/attributes/constants/oss_fuzz_428053935.phpt
@@ -0,0 +1,19 @@
+--TEST--
+OSS-Fuzz #428053935
+--FILE--
+<?php
+namespace Foo; // Capital letter is important for the ns lookup
+#[Attr]
+const MyConst = '';
+
+$rc = new \ReflectionConstant('Foo\\MyConst');
+var_dump($rc->getAttributes());
+?>
+--EXPECTF--
+array(1) {
+  [0]=>
+  object(ReflectionAttribute)#%d (1) {
+    ["name"]=>
+    string(8) "Foo\Attr"
+  }
+}
diff --git a/Zend/tests/clone/ast.phpt b/Zend/tests/clone/ast.phpt
index 89a1a0a481000..e482854a94482 100644
--- a/Zend/tests/clone/ast.phpt
+++ b/Zend/tests/clone/ast.phpt
@@ -18,6 +18,60 @@ try {
 	echo $e->getMessage(), PHP_EOL;
 }
 
+try {
+	assert(false && $y = clone($x, ));
+} catch (Error $e) {
+	echo $e->getMessage(), PHP_EOL;
+}
+
+try {
+	assert(false && $y = clone($x, [ "foo" => $foo, "bar" => $bar ]));
+} catch (Error $e) {
+	echo $e->getMessage(), PHP_EOL;
+}
+
+try {
+	assert(false && $y = clone($x, $array));
+} catch (Error $e) {
+	echo $e->getMessage(), PHP_EOL;
+}
+
+try {
+	assert(false && $y = clone($x, $array, $extraParameter, $trailingComma, ));
+} catch (Error $e) {
+	echo $e->getMessage(), PHP_EOL;
+}
+
+try {
+	assert(false && $y = clone(object: $x, withProperties: [ "foo" => $foo, "bar" => $bar ]));
+} catch (Error $e) {
+	echo $e->getMessage(), PHP_EOL;
+}
+
+try {
+	assert(false && $y = clone($x, withProperties: [ "foo" => $foo, "bar" => $bar ]));
+} catch (Error $e) {
+	echo $e->getMessage(), PHP_EOL;
+}
+
+try {
+	assert(false && $y = clone(object: $x));
+} catch (Error $e) {
+	echo $e->getMessage(), PHP_EOL;
+}
+
+try {
+	assert(false && $y = clone(object: $x, [ "foo" => $foo, "bar" => $bar ]));
+} catch (Error $e) {
+	echo $e->getMessage(), PHP_EOL;
+}
+
+try {
+	assert(false && $y = clone(...["object" => $x, "withProperties" => [ "foo" => $foo, "bar" => $bar ]]));
+} catch (Error $e) {
+	echo $e->getMessage(), PHP_EOL;
+}
+
 try {
 	assert(false && $y = clone(...));
 } catch (Error $e) {
@@ -28,4 +82,13 @@ try {
 --EXPECT--
 assert(false && ($y = \clone($x)))
 assert(false && ($y = \clone($x)))
+assert(false && ($y = \clone($x)))
+assert(false && ($y = \clone($x, ['foo' => $foo, 'bar' => $bar])))
+assert(false && ($y = \clone($x, $array)))
+assert(false && ($y = \clone($x, $array, $extraParameter, $trailingComma)))
+assert(false && ($y = \clone(object: $x, withProperties: ['foo' => $foo, 'bar' => $bar])))
+assert(false && ($y = \clone($x, withProperties: ['foo' => $foo, 'bar' => $bar])))
+assert(false && ($y = \clone(object: $x)))
+assert(false && ($y = \clone(object: $x, ['foo' => $foo, 'bar' => $bar])))
+assert(false && ($y = \clone(...['object' => $x, 'withProperties' => ['foo' => $foo, 'bar' => $bar]])))
 assert(false && ($y = \clone(...)))
diff --git a/Zend/zend_builtin_functions.c b/Zend/zend_builtin_functions.c
index 48e5c70897294..fc3b0f57d85e7 100644
--- a/Zend/zend_builtin_functions.c
+++ b/Zend/zend_builtin_functions.c
@@ -592,7 +592,7 @@ ZEND_FUNCTION(define)
 	/* non persistent */
 	ZEND_CONSTANT_SET_FLAGS(&c, 0, PHP_USER_CONSTANT);
 	c.name = zend_string_copy(name);
-	if (zend_register_constant(&c) == SUCCESS) {
+	if (zend_register_constant(&c) != NULL) {
 		RETURN_TRUE;
 	} else {
 		RETURN_FALSE;
diff --git a/Zend/zend_constants.c b/Zend/zend_constants.c
index ffad8315ae40d..db37b9cf76824 100644
--- a/Zend/zend_constants.c
+++ b/Zend/zend_constants.c
@@ -505,11 +505,11 @@ static void* zend_hash_add_constant(HashTable *ht, zend_string *key, zend_consta
 	return ret;
 }
 
-ZEND_API zend_result zend_register_constant(zend_constant *c)
+ZEND_API zend_constant *zend_register_constant(zend_constant *c)
 {
 	zend_string *lowercase_name = NULL;
 	zend_string *name;
-	zend_result ret = SUCCESS;
+	zend_constant *ret = NULL;
 	bool persistent = (ZEND_CONSTANT_FLAGS(c) & CONST_PERSISTENT) != 0;
 
 #if 0
@@ -539,7 +539,7 @@ ZEND_API zend_result zend_register_constant(zend_constant *c)
 	/* Check if the user is trying to define any special constant */
 	if (zend_string_equals_literal(name, "__COMPILER_HALT_OFFSET__")
 		|| (!persistent && zend_get_special_const(ZSTR_VAL(name), ZSTR_LEN(name)))
-		|| zend_hash_add_constant(EG(zend_constants), name, c) == NULL
+		|| (ret = zend_hash_add_constant(EG(zend_constants), name, c)) == NULL
 	) {
 		zend_error(E_WARNING, "Constant %s already defined", ZSTR_VAL(name));
 		zend_string_release(c->name);
@@ -550,7 +550,6 @@ ZEND_API zend_result zend_register_constant(zend_constant *c)
 		if (!persistent) {
 			zval_ptr_dtor_nogc(&c->value);
 		}
-		ret = FAILURE;
 	}
 	if (lowercase_name) {
 		zend_string_release(lowercase_name);
diff --git a/Zend/zend_constants.h b/Zend/zend_constants.h
index 3912215d80775..69ea1d9021a83 100644
--- a/Zend/zend_constants.h
+++ b/Zend/zend_constants.h
@@ -97,7 +97,7 @@ ZEND_API void zend_register_long_constant(const char *name, size_t name_len, zen
 ZEND_API void zend_register_double_constant(const char *name, size_t name_len, double dval, int flags, int module_number);
 ZEND_API void zend_register_string_constant(const char *name, size_t name_len, const char *strval, int flags, int module_number);
 ZEND_API void zend_register_stringl_constant(const char *name, size_t name_len, const char *strval, size_t strlen, int flags, int module_number);
-ZEND_API zend_result zend_register_constant(zend_constant *c);
+ZEND_API zend_constant *zend_register_constant(zend_constant *c);
 void zend_constant_add_attributes(zend_constant *c, HashTable *attributes);
 #ifdef ZTS
 void zend_copy_constants(HashTable *target, HashTable *source);
diff --git a/Zend/zend_language_parser.y b/Zend/zend_language_parser.y
index 016c6e5c9d098..805f378cb983c 100644
--- a/Zend/zend_language_parser.y
+++ b/Zend/zend_language_parser.y
@@ -259,7 +259,7 @@ static YYSIZE_T zend_yytnamerr(char*, const char*);
 %type <ast> unprefixed_use_declarations const_decl inner_statement
 %type <ast> expr optional_expr while_statement for_statement foreach_variable
 %type <ast> foreach_statement declare_statement finally_statement unset_variable variable
-%type <ast> extends_from parameter optional_type_without_static argument global_var
+%type <ast> extends_from parameter optional_type_without_static argument argument_no_expr global_var
 %type <ast> static_var class_statement trait_adaptation trait_precedence trait_alias
 %type <ast> absolute_trait_method_reference trait_method_reference property echo_expr
 %type <ast> new_dereferenceable new_non_dereferenceable anonymous_class class_name class_name_reference simple_variable
@@ -287,7 +287,7 @@ static YYSIZE_T zend_yytnamerr(char*, const char*);
 %type <ast> enum_declaration_statement enum_backing_type enum_case enum_case_expr
 %type <ast> function_name non_empty_member_modifiers
 %type <ast> property_hook property_hook_list optional_property_hook_list hooked_property property_hook_body
-%type <ast> optional_parameter_list
+%type <ast> optional_parameter_list clone_argument_list non_empty_clone_argument_list
 
 %type <num> returns_ref function fn is_reference is_variadic property_modifiers property_hook_modifiers
 %type <num> method_modifiers class_const_modifiers member_modifier optional_cpp_modifiers
@@ -914,13 +914,42 @@ non_empty_argument_list:
 			{ $$ = zend_ast_list_add($1, $3); }
 ;
 
-argument:
-		expr				{ $$ = $1; }
-	|	identifier ':' expr
+/* `clone_argument_list` is necessary to resolve a parser ambiguity (shift-reduce conflict)
+ * of `clone($expr)`, which could either be parsed as a function call with `$expr` as the first
+ * argument or as a use of the `clone` language construct with an expression with useless
+ * parenthesis. Both would be valid and result in the same AST / the same semantics.
+ * `clone_argument_list` is defined in a way that an `expr` in the first position needs to
+ * be followed by a `,` which is not valid syntax for a parenthesized `expr`, ensuring
+ * that calling `clone()` with a single unnamed parameter is handled by the language construct
+ * syntax.
+ */
+clone_argument_list:
+		'(' ')'	{ $$ = zend_ast_create_list(0, ZEND_AST_ARG_LIST); }
+	|	'(' non_empty_clone_argument_list possible_comma ')' { $$ = $2; }
+	|	'(' expr ',' ')' { $$ = zend_ast_create_list(1, ZEND_AST_ARG_LIST, $2); }
+	|	'(' T_ELLIPSIS ')' { $$ = zend_ast_create_fcc(); }
+;
+
+non_empty_clone_argument_list:
+		expr ',' argument
+			{ $$ = zend_ast_create_list(2, ZEND_AST_ARG_LIST, $1, $3); }
+	|	argument_no_expr
+			{ $$ = zend_ast_create_list(1, ZEND_AST_ARG_LIST, $1); }
+	|	non_empty_clone_argument_list ',' argument
+			{ $$ = zend_ast_list_add($1, $3); }
+;
+
+argument_no_expr:
+		identifier ':' expr
 			{ $$ = zend_ast_create(ZEND_AST_NAMED_ARG, $1, $3); }
 	|	T_ELLIPSIS expr	{ $$ = zend_ast_create(ZEND_AST_UNPACK, $2); }
 ;
 
+argument:
+		expr { $$ = $1; }
+	|	argument_no_expr { $$ = $1; }
+;
+
 global_var_list:
 		global_var_list ',' global_var { $$ = zend_ast_list_add($1, $3); }
 	|	global_var { $$ = zend_ast_create_list(1, ZEND_AST_STMT_LIST, $1); }
@@ -1228,10 +1257,10 @@ expr:
 			{ $$ = zend_ast_create(ZEND_AST_ASSIGN, $1, $3); }
 	|	variable '=' ampersand variable
 			{ $$ = zend_ast_create(ZEND_AST_ASSIGN_REF, $1, $4); }
-	|	T_CLONE '(' T_ELLIPSIS ')' {
+	|	T_CLONE clone_argument_list {
 			zend_ast *name = zend_ast_create_zval_from_str(ZSTR_KNOWN(ZEND_STR_CLONE));
 			name->attr = ZEND_NAME_FQ;
-			$$ = zend_ast_create(ZEND_AST_CALL, name, zend_ast_create_fcc());
+			$$ = zend_ast_create(ZEND_AST_CALL, name, $2);
 		}
 	|	T_CLONE expr {
 			zend_ast *name = zend_ast_create_zval_from_str(ZSTR_KNOWN(ZEND_STR_CLONE));
diff --git a/Zend/zend_vm_def.h b/Zend/zend_vm_def.h
index be7bc8b37b7dd..51aaf635b3b30 100644
--- a/Zend/zend_vm_def.h
+++ b/Zend/zend_vm_def.h
@@ -8261,7 +8261,7 @@ ZEND_VM_HANDLER(143, ZEND_DECLARE_CONST, CONST, CONST)
 	ZEND_CONSTANT_SET_FLAGS(&c, 0, PHP_USER_CONSTANT);
 	c.name = zend_string_copy(Z_STR_P(name));
 
-	if (zend_register_constant(&c) == FAILURE) {
+	if (zend_register_constant(&c) == NULL) {
 	}
 
 	FREE_OP1();
@@ -8274,7 +8274,7 @@ ZEND_VM_HANDLER(210, ZEND_DECLARE_ATTRIBUTED_CONST, CONST, CONST)
 	USE_OPLINE
 	zval *name;
 	zval *val;
-	zend_constant c;
+	zend_constant c, *registered;
 
 	SAVE_OPLINE();
 	name  = GET_OP1_ZVAL_PTR(BP_VAR_R);
@@ -8293,7 +8293,8 @@ ZEND_VM_HANDLER(210, ZEND_DECLARE_ATTRIBUTED_CONST, CONST, CONST)
 	ZEND_CONSTANT_SET_FLAGS(&c, 0, PHP_USER_CONSTANT);
 	c.name = zend_string_copy(Z_STR_P(name));
 
-	if (zend_register_constant(&c) == FAILURE) {
+	registered = zend_register_constant(&c);
+	if (registered == NULL) {
 		FREE_OP1();
 		FREE_OP2();
 		/* two opcodes used, second one is the data with attributes */
@@ -8301,9 +8302,7 @@ ZEND_VM_HANDLER(210, ZEND_DECLARE_ATTRIBUTED_CONST, CONST, CONST)
 	}
 
 	HashTable *attributes = Z_PTR_P(GET_OP_DATA_ZVAL_PTR(BP_VAR_R));
-	zend_constant *registered = zend_get_constant_ptr(c.name);
 	ZEND_ASSERT(attributes != NULL);
-	ZEND_ASSERT(registered != NULL);
 	zend_constant_add_attributes(registered, attributes);
 
 	FREE_OP1();
diff --git a/Zend/zend_vm_execute.h b/Zend/zend_vm_execute.h
index 3a13f4244d361..f29c6b4726145 100644
--- a/Zend/zend_vm_execute.h
+++ b/Zend/zend_vm_execute.h
@@ -8043,7 +8043,7 @@ static ZEND_OPCODE_HANDLER_RET ZEND_FASTCALL ZEND_DECLARE_CONST_SPEC_CONST_CONST
 	ZEND_CONSTANT_SET_FLAGS(&c, 0, PHP_USER_CONSTANT);
 	c.name = zend_string_copy(Z_STR_P(name));
 
-	if (zend_register_constant(&c) == FAILURE) {
+	if (zend_register_constant(&c) == NULL) {
 	}
 
 
@@ -8055,7 +8055,7 @@ static ZEND_OPCODE_HANDLER_RET ZEND_FASTCALL ZEND_DECLARE_ATTRIBUTED_CONST_SPEC_
 	USE_OPLINE
 	zval *name;
 	zval *val;
-	zend_constant c;
+	zend_constant c, *registered;
 
 	SAVE_OPLINE();
 	name  = RT_CONSTANT(opline, opline->op1);
@@ -8074,7 +8074,8 @@ static ZEND_OPCODE_HANDLER_RET ZEND_FASTCALL ZEND_DECLARE_ATTRIBUTED_CONST_SPEC_
 	ZEND_CONSTANT_SET_FLAGS(&c, 0, PHP_USER_CONSTANT);
 	c.name = zend_string_copy(Z_STR_P(name));
 
-	if (zend_register_constant(&c) == FAILURE) {
+	registered = zend_register_constant(&c);
+	if (registered == NULL) {
 
 
 		/* two opcodes used, second one is the data with attributes */
@@ -8082,9 +8083,7 @@ static ZEND_OPCODE_HANDLER_RET ZEND_FASTCALL ZEND_DECLARE_ATTRIBUTED_CONST_SPEC_
 	}
 
 	HashTable *attributes = Z_PTR_P(get_op_data_zval_ptr_r((opline+1)->op1_type, (opline+1)->op1));
-	zend_constant *registered = zend_get_constant_ptr(c.name);
 	ZEND_ASSERT(attributes != NULL);
-	ZEND_ASSERT(registered != NULL);
 	zend_constant_add_attributes(registered, attributes);