Support static type in intersection

Probably should not use the arena directly anymore
Also variance tests need to be done

Author: Girgias

Zend/tests/type_declarations/intersection_types/invalid_types/invalid_static_type.phpt

@@ -0,0 +1,13 @@
+--TEST--
+Duplicate static type
+--FILE--
+<?php
+
+class A {
+    public function test(): static&A&static {
+    }
+}
+
+?>
+--EXPECTF--
+Fatal error: Duplicate type static is redundant in %s on line %d

Zend/tests/type_declarations/intersection_types/redundant_types/duplicate_static_type.phpt

@@ -0,0 +1,41 @@
+--TEST--
+Using self/parent/static part of an intersection
+--FILE--
+<?php
+
+interface X {}
+interface Y {}
+interface Z {}
+
+abstract class A {
+    abstract public function test(): static&X;
+}
+class B extends A implements X {
+     public function test(): static&X {
+         return new self();
+     }
+}
+
+class C extends B {
+    public function test(): static&X {
+        return new $this;
+    }
+}
+class CError extends B {}
+
+$c = new C();
+$ce = new CError();
+
+// Self tests
+var_dump($c->test());
+try {
+    var_dump($ce->test());
+} catch (\TypeError $e) {
+    echo $e->getMessage(), PHP_EOL;
+}
+
+?>
+--EXPECT--
+object(C)#3 (0) {
+}
+B::test(): Return value must be of type X&CError, B returned

Zend/tests/type_declarations/intersection_types/static_in_intersection.phpt

@@ -1247,7 +1247,7 @@ zend_string *zend_type_to_string_resolved(zend_type type, zend_class_entry *scop
 				name = called_scope->name;
 			}
 		}
-		str = add_type_string(str, name, /* is_intersection */ false);
+		str = add_type_string(str, name, ZEND_TYPE_IS_INTERSECTION(type));
 	}
 	if (type_mask & MAY_BE_CALLABLE) {
 		str = add_type_string(str, ZSTR_KNOWN(ZEND_STR_CALLABLE), /* is_intersection */ false);
@@ -6306,8 +6306,9 @@ static zend_type zend_compile_typename(
 	} else if (ast->kind == ZEND_AST_TYPE_INTERSECTION) {
 		zend_ast_list *list = zend_ast_get_list(ast);
 		zend_type_list *type_list;
+		unsigned int has_static = 0;
 
-		// TODO Is this still true if self/parent are accepted?
+		// TODO static means that one slot may be unused
 		/* Allocate the type list directly on the arena as it must be a type
 		 * list of the same number of elements as the AST list has children */
 		type_list = zend_arena_alloc(&CG(arena), ZEND_TYPE_LIST_SIZE(list->children));
@@ -6320,13 +6321,27 @@ static zend_type zend_compile_typename(
 			zend_type single_type = zend_compile_single_typename(type_ast);
 
 			/* An intersection of standard types cannot exist so invalidate it */
-			if (ZEND_TYPE_IS_ONLY_MASK(single_type)) {
+			/* Treat "static" as a class type. */
+			if (ZEND_TYPE_IS_ONLY_MASK(single_type) && !(ZEND_TYPE_FULL_MASK(single_type) & MAY_BE_STATIC)) {
 				zend_string *standard_type_str = zend_type_to_string(single_type);
 				zend_error_noreturn(E_COMPILE_ERROR,
 					"Type %s cannot be part of an intersection type", ZSTR_VAL(standard_type_str));
 				zend_string_release_ex(standard_type_str, false);
 			}
 
+			/* If the type is static */
+			if (UNEXPECTED(!ZEND_TYPE_IS_COMPLEX(single_type))) {
+				/* Check that static doesn't overlap */
+				uint32_t type_mask_overlap = ZEND_TYPE_PURE_MASK(type) & MAY_BE_STATIC;
+				if (type_mask_overlap) {
+					zend_error_noreturn(E_COMPILE_ERROR, "Duplicate type static is redundant");
+				}
+				ZEND_TYPE_FULL_MASK(type) |= MAY_BE_STATIC;
+				ZEND_TYPE_FULL_MASK(single_type) &= ~_ZEND_TYPE_MAY_BE_MASK;
+				has_static = 1;
+				continue;
+			}
+
 			/* Add type to the type list */
 			type_list->types[type_list->num_types++] = single_type;
 
@@ -6341,7 +6356,7 @@ static zend_type zend_compile_typename(
 			}
 		}
 
-		ZEND_ASSERT(list->children == type_list->num_types);
+		ZEND_ASSERT((list->children - has_static) == type_list->num_types);
 
 		ZEND_TYPE_SET_LIST(type, type_list);
 		ZEND_TYPE_FULL_MASK(type) |= _ZEND_TYPE_ARENA_BIT;

Zend/zend_compile.c

@@ -856,6 +856,7 @@ static bool zend_check_and_resolve_property_class_type(
 		zend_type *list_type;
 
 		if (ZEND_TYPE_IS_INTERSECTION(info->type)) {
+			/* Property class can't have static as a type so need to check it here */
 			ZEND_TYPE_LIST_FOREACH(ZEND_TYPE_LIST(info->type), list_type) {
 				if (ZEND_TYPE_HAS_NAME(*list_type)) {
 					zend_string *name = ZEND_TYPE_NAME(*list_type);
@@ -1030,6 +1031,10 @@ static zend_always_inline bool zend_check_type_slow(
 		if (UNEXPECTED(ZEND_TYPE_HAS_LIST(*type))) {
 			zend_type *list_type;
 			if (ZEND_TYPE_IS_INTERSECTION(*type)) {
+				/* Check if intersection has static inside it */
+				if ((ZEND_TYPE_FULL_MASK(*type) & MAY_BE_STATIC) && !zend_value_instanceof_static(arg)) {
+					return false;
+				}
 				ZEND_TYPE_LIST_FOREACH(ZEND_TYPE_LIST(*type), list_type) {
 					if (HAVE_CACHE_SLOT && *cache_slot) {
 						ce = *cache_slot;