diff --git a/Zend/zend_builtin_functions.c b/Zend/zend_builtin_functions.c
index eab2a0399011..63517322b470 100644
--- a/Zend/zend_builtin_functions.c
+++ b/Zend/zend_builtin_functions.c
@@ -82,10 +82,10 @@ ZEND_FUNCTION(clone)
 
 	/* clone() also exists as the ZEND_CLONE OPcode and both implementations must be kept in sync. */
 
-	zend_class_entry *scope = zend_get_executed_scope();
+	const zend_class_entry *scope = zend_get_executed_scope();
 
-	zend_class_entry *ce = zobj->ce;
-	zend_function *clone = ce->clone;
+	const zend_class_entry *ce = zobj->ce;
+	const zend_function *clone = ce->clone;
 
 	if (UNEXPECTED(zobj->handlers->clone_obj == NULL)) {
 		zend_throw_error(NULL, "Trying to clone an uncloneable object of class %s", ZSTR_VAL(ce->name));
@@ -237,7 +237,7 @@ ZEND_FUNCTION(gc_status)
 /* {{{ Get the number of arguments that were passed to the function */
 ZEND_FUNCTION(func_num_args)
 {
-	zend_execute_data *ex = EX(prev_execute_data);
+	const zend_execute_data *ex = EX(prev_execute_data);
 
 	ZEND_PARSE_PARAMETERS_NONE();
 
@@ -247,7 +247,7 @@ ZEND_FUNCTION(func_num_args)
 	}
 
 	if (zend_forbid_dynamic_call() == FAILURE) {
-		RETURN_LONG(-1);
+		RETURN_THROWS();
 	}
 
 	RETURN_LONG(ZEND_CALL_NUM_ARGS(ex));
@@ -501,7 +501,7 @@ ZEND_FUNCTION(error_reporting)
 }
 /* }}} */
 
-static bool validate_constant_array_argument(HashTable *ht, int argument_number) /* {{{ */
+static bool validate_constant_array_argument(HashTable *ht, uint32_t argument_number) /* {{{ */
 {
 	bool ret = true;
 	zval *val;
@@ -525,7 +525,7 @@ static bool validate_constant_array_argument(HashTable *ht, int argument_number)
 }
 /* }}} */
 
-static void copy_constant_array(zval *dst, zval *src) /* {{{ */
+static void copy_constant_array(zval *dst, const zval *src) /* {{{ */
 {
 	zend_string *key;
 	zend_ulong idx;
@@ -595,11 +595,7 @@ 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) != NULL) {
-		RETURN_TRUE;
-	} else {
-		RETURN_FALSE;
-	}
+	RETURN_BOOL(zend_register_constant(&c) != NULL);
 }
 /* }}} */
 
@@ -613,11 +609,7 @@ ZEND_FUNCTION(defined)
 		Z_PARAM_STR(name)
 	ZEND_PARSE_PARAMETERS_END();
 
-	if (zend_get_constant_ex(name, zend_get_executed_scope(), ZEND_FETCH_CLASS_SILENT)) {
-		RETURN_TRUE;
-	} else {
-		RETURN_FALSE;
-	}
+	RETURN_BOOL(zend_get_constant_ex(name, zend_get_executed_scope(), ZEND_FETCH_CLASS_SILENT));
 }
 /* }}} */
 
@@ -631,7 +623,7 @@ ZEND_FUNCTION(get_class)
 	}
 
 	if (!obj) {
-		zend_class_entry *scope = zend_get_executed_scope();
+		const zend_class_entry *scope = zend_get_executed_scope();
 
 		if (scope) {
 			zend_error(E_DEPRECATED, "Calling get_class() without arguments is deprecated");
@@ -652,7 +644,7 @@ ZEND_FUNCTION(get_class)
 /* {{{ Retrieves the "Late Static Binding" class name */
 ZEND_FUNCTION(get_called_class)
 {
-	zend_class_entry *called_scope;
+	const zend_class_entry *called_scope;
 
 	ZEND_PARSE_PARAMETERS_NONE();
 
@@ -697,9 +689,7 @@ static void is_a_impl(INTERNAL_FUNCTION_PARAMETERS, bool only_subclass) /* {{{ *
 	zval *obj;
 	zend_string *class_name;
 	zend_class_entry *instance_ce;
-	zend_class_entry *ce;
 	bool allow_string = only_subclass;
-	bool retval;
 
 	ZEND_PARSE_PARAMETERS_START(2, 3)
 		Z_PARAM_ZVAL(obj)
@@ -726,21 +716,19 @@ static void is_a_impl(INTERNAL_FUNCTION_PARAMETERS, bool only_subclass) /* {{{ *
 	}
 
 	if (!only_subclass && EXPECTED(zend_string_equals(instance_ce->name, class_name))) {
-		retval = 1;
-	} else {
-		ce = zend_lookup_class_ex(class_name, NULL, ZEND_FETCH_CLASS_NO_AUTOLOAD);
-		if (!ce) {
-			retval = 0;
-		} else {
-			if (only_subclass && instance_ce == ce) {
-				retval = 0;
-			} else {
-				retval = instanceof_function(instance_ce, ce);
-			}
-		}
+		RETURN_TRUE;
+	}
+
+	const zend_class_entry *ce = zend_lookup_class_ex(class_name, NULL, ZEND_FETCH_CLASS_NO_AUTOLOAD);
+	if (!ce) {
+		RETURN_FALSE;
+	}
+
+	if (only_subclass && instance_ce == ce) {
+		RETURN_FALSE;
 	}
 
-	RETURN_BOOL(retval);
+	RETURN_BOOL(instanceof_function(instance_ce, ce));
 }
 /* }}} */
 
@@ -759,7 +747,7 @@ ZEND_FUNCTION(is_a)
 /* }}} */
 
 /* {{{ add_class_vars */
-static void add_class_vars(zend_class_entry *scope, zend_class_entry *ce, bool statics, zval *return_value)
+static void add_class_vars(const zend_class_entry *scope, zend_class_entry *ce, bool statics, zval *return_value)
 {
 	zend_property_info *prop_info;
 	zval *prop, prop_copy;
@@ -810,7 +798,7 @@ static void add_class_vars(zend_class_entry *scope, zend_class_entry *ce, bool s
 /* {{{ Returns an array of default properties of the class. */
 ZEND_FUNCTION(get_class_vars)
 {
-	zend_class_entry *ce = NULL, *scope;
+	zend_class_entry *ce = NULL;
 
 	if (zend_parse_parameters(ZEND_NUM_ARGS(), "C", &ce) == FAILURE) {
 		RETURN_THROWS();
@@ -823,7 +811,7 @@ ZEND_FUNCTION(get_class_vars)
 		}
 	}
 
-	scope = zend_get_executed_scope();
+	const zend_class_entry *scope = zend_get_executed_scope();
 	add_class_vars(scope, ce, false, return_value);
 	add_class_vars(scope, ce, true, return_value);
 }
@@ -949,7 +937,6 @@ ZEND_FUNCTION(get_class_methods)
 {
 	zval method_name;
 	zend_class_entry *ce = NULL;
-	zend_class_entry *scope;
 	zend_function *mptr;
 
 	ZEND_PARSE_PARAMETERS_START(1, 1)
@@ -957,7 +944,7 @@ ZEND_FUNCTION(get_class_methods)
 	ZEND_PARSE_PARAMETERS_END();
 
 	array_init(return_value);
-	scope = zend_get_executed_scope();
+	const zend_class_entry *scope = zend_get_executed_scope();
 
 	ZEND_HASH_MAP_FOREACH_PTR(&ce->function_table, mptr) {
 		if (zend_check_method_accessible(mptr, scope)) {
@@ -1032,10 +1019,9 @@ ZEND_FUNCTION(method_exists)
 }
 /* }}} */
 
-static void _property_exists(zval *return_value, zval *object, zend_string *property)
+static void _property_exists(zval *return_value, const zval *object, zend_string *property)
 {
 	zend_class_entry *ce;
-	zend_property_info *property_info;
 
 	if (Z_TYPE_P(object) == IS_STRING) {
 		ce = zend_lookup_class(Z_STR_P(object));
@@ -1049,18 +1035,17 @@ static void _property_exists(zval *return_value, zval *object, zend_string *prop
 		RETURN_THROWS();
 	}
 
-	property_info = zend_hash_find_ptr(&ce->properties_info, property);
+	const zend_property_info *property_info = zend_hash_find_ptr(&ce->properties_info, property);
 	if (property_info != NULL
 	 && (!(property_info->flags & ZEND_ACC_PRIVATE)
 	  || property_info->ce == ce)) {
 		RETURN_TRUE;
 	}
 
-	if (Z_TYPE_P(object) == IS_OBJECT &&
-		Z_OBJ_HANDLER_P(object, has_property)(Z_OBJ_P(object), property, ZEND_PROPERTY_EXISTS, NULL)) {
-		RETURN_TRUE;
-	}
-	RETURN_FALSE;
+	RETURN_BOOL(
+		Z_TYPE_P(object) == IS_OBJECT &&
+		Z_OBJ_HANDLER_P(object, has_property)(Z_OBJ_P(object), property, ZEND_PROPERTY_EXISTS, NULL)
+	);
 }
 
 /* {{{ Checks if the object or class has a property */
@@ -1120,11 +1105,7 @@ static inline void _class_exists_impl(zval *return_value, zend_string *name, boo
 		ce = zend_lookup_class(name);
 	}
 
-	if (ce) {
-		RETURN_BOOL(((ce->ce_flags & flags) == flags) && !(ce->ce_flags & skip_flags));
-	} else {
-		RETURN_FALSE;
-	}
+	RETURN_BOOL(ce && ((ce->ce_flags & flags) == flags) && !(ce->ce_flags & skip_flags));
 }
 /* {{{ */
 
@@ -1430,7 +1411,6 @@ static inline void get_declared_class_impl(INTERNAL_FUNCTION_PARAMETERS, int fla
 {
 	zend_string *key;
 	zval *zv;
-	zend_class_entry *ce;
 
 	ZEND_PARSE_PARAMETERS_NONE();
 
@@ -1438,7 +1418,7 @@ static inline void get_declared_class_impl(INTERNAL_FUNCTION_PARAMETERS, int fla
 	zend_hash_real_init_packed(Z_ARRVAL_P(return_value));
 	ZEND_HASH_FILL_PACKED(Z_ARRVAL_P(return_value)) {
 		ZEND_HASH_MAP_FOREACH_STR_KEY_VAL(EG(class_table), key, zv) {
-			ce = Z_PTR_P(zv);
+			const zend_class_entry *ce = Z_PTR_P(zv);
 			if ((ce->ce_flags & (ZEND_ACC_LINKED|ZEND_ACC_INTERFACE|ZEND_ACC_TRAIT)) == flags
 			 && key
 			 && ZSTR_VAL(key)[0] != 0) {
@@ -1556,7 +1536,7 @@ ZEND_FUNCTION(get_resource_type)
 	if (resource_type) {
 		RETURN_STRING(resource_type);
 	} else {
-		RETURN_STRING("Unknown");
+		RETURN_STR(ZSTR_KNOWN(ZEND_STR_UNKNOWN_CAPITALIZED));
 	}
 }
 /* }}} */
@@ -1893,7 +1873,7 @@ ZEND_API void zend_fetch_debug_backtrace(zval *return_value, int skip_last, int
 	zend_execute_data *call, *last_call = NULL;
 	zend_object *object;
 	bool fake_frame = false;
-	int lineno, frameno = 0;
+	int frameno = 0;
 	zend_function *func;
 	zend_string *filename;
 	zend_string *include_filename = NULL;
@@ -1914,12 +1894,12 @@ ZEND_API void zend_fetch_debug_backtrace(zval *return_value, int skip_last, int
 		EG(filename_override) = NULL;
 		EG(lineno_override) = -1;
 
-		zend_string *filename = zend_get_executed_filename_ex();
-		zend_long lineno = zend_get_executed_lineno();
-		if (filename && (!zend_string_equals(filename, filename_override) || lineno != lineno_override)) {
+		zend_string *executed_filename = zend_get_executed_filename_ex();
+		uint32_t lineno = zend_get_executed_lineno();
+		if (executed_filename && (!zend_string_equals(executed_filename, filename_override) || lineno != lineno_override)) {
 			stack_frame = zend_new_array(8);
 			zend_hash_real_init_mixed(stack_frame);
-			ZVAL_STR_COPY(&tmp, filename);
+			ZVAL_STR_COPY(&tmp, executed_filename);
 			_zend_hash_append_ex(stack_frame, ZSTR_KNOWN(ZEND_STR_FILE), &tmp, 1);
 			ZVAL_LONG(&tmp, lineno);
 			_zend_hash_append_ex(stack_frame, ZSTR_KNOWN(ZEND_STR_LINE), &tmp, 1);
@@ -1982,19 +1962,21 @@ ZEND_API void zend_fetch_debug_backtrace(zval *return_value, int skip_last, int
 				zval *arg = zend_get_zval_ptr(op_data, op_data->op1_type, &op_data->op1, call);
 				if (Z_TYPE_P(arg) == IS_UNDEF) goto not_frameless_call;
 			}
-			zend_function *func = ZEND_FLF_FUNC(opline);
+			zend_function *frameless_func = ZEND_FLF_FUNC(opline);
 			/* Assume frameless functions are not recursive with themselves.
 			 * This condition may be true when observers are enabled:
 			 * Observers will put a call frame on top of the frameless opcode. */
-			if (last_call && last_call->func == func) {
+			if (last_call && last_call->func == frameless_func) {
 				goto not_frameless_call;
 			}
 			stack_frame = zend_new_array(8);
 			zend_hash_real_init_mixed(stack_frame);
-			ZVAL_STR_COPY(&tmp, func->common.function_name);
+			ZVAL_STR_COPY(&tmp, frameless_func->common.function_name);
 			_zend_hash_append_ex(stack_frame, ZSTR_KNOWN(ZEND_STR_FUNCTION), &tmp, 1);
 			/* Steal file and line from the previous frame. */
 			if (call->func && ZEND_USER_CODE(call->func->common.type)) {
+				uint32_t lineno;
+
 				filename = call->func->op_array.filename;
 				if (call->opline->opcode == ZEND_HANDLE_EXCEPTION) {
 					if (EG(opline_before_exception)) {
@@ -2046,6 +2028,8 @@ ZEND_API void zend_fetch_debug_backtrace(zval *return_value, int skip_last, int
 		zend_hash_real_init_mixed(stack_frame);
 
 		if (prev && prev->func && ZEND_USER_CODE(prev->func->common.type)) {
+			uint32_t lineno;
+
 			filename = prev->func->op_array.filename;
 			if (prev->opline->opcode == ZEND_HANDLE_EXCEPTION) {
 				if (EG(opline_before_exception)) {
@@ -2230,11 +2214,7 @@ ZEND_FUNCTION(extension_loaded)
 	}
 
 	lcname = zend_string_tolower(extension_name);
-	if (zend_hash_exists(&module_registry, lcname)) {
-		RETVAL_TRUE;
-	} else {
-		RETVAL_FALSE;
-	}
+	RETVAL_BOOL(zend_hash_exists(&module_registry, lcname));
 	zend_string_release_ex(lcname, 0);
 }
 /* }}} */