diff --git a/CODING_STANDARDS.md b/CODING_STANDARDS.md
index 47b76717c839..3a53d0e258ca 100644
--- a/CODING_STANDARDS.md
+++ b/CODING_STANDARDS.md
@@ -79,6 +79,16 @@ rewritten to comply with these rules.
     return value for functions that perform some operation that may
     succeed or fail.
 
+1. When throwing a `ValueError` or emitting a warning, use consistent
+    phrasing for error messages. Common patterns are:
+
+    * Type errors: `must be of type int` (use the type name, not e.g. `must be an integer`)
+    * Range/boundary: `must be between X and Y` / `must be greater than [or equal to] X` / `must be less than X` / `must be finite`
+    * String constraints: `must not contain any null bytes` / `must not be empty` / `must be a single character`
+    * Valid value: `must be a valid X` (e.g. `must be a valid encoding`, `must be a valid calendar ID`)
+    * Enum-like: `must be one of X, Y, or Z`
+    * Structural: `must have X` / `must have key X` / `must have N elements`
+
 ## User functions/methods naming conventions
 
 1. Function names for user-level functions should be enclosed with in the
diff --git a/sapi/cli/php_cli.c b/sapi/cli/php_cli.c
index b5109ab6f998..9a05f8e68547 100644
--- a/sapi/cli/php_cli.c
+++ b/sapi/cli/php_cli.c
@@ -1054,13 +1054,25 @@ static int do_cli(int argc, char **argv) /* {{{ */
 				}
 
 				ZVAL_STRING(&arg, reflection_what);
-				object_init_ex(&ref, pce);
 
 				memset(&execute_data, 0, sizeof(zend_execute_data));
 				execute_data.func = (zend_function *) &zend_pass_function;
 				EG(current_execute_data) = &execute_data;
-				zend_call_known_instance_method_with_1_params(
-					pce->constructor, Z_OBJ(ref), NULL, &arg);
+				// Avoid deprecation warnings from ReflectionMethod::__construct()
+				// with one argument
+				if (pce == reflection_method_ptr) {
+					zend_function *create_from_method = zend_hash_str_find_ptr(
+						&(pce->function_table),
+						"createfrommethodname",
+						strlen( "createFromMethodName" )
+					);
+					zend_call_known_function(
+						create_from_method, NULL, pce, &ref, 1, &arg, NULL);
+				} else {
+					object_init_ex(&ref, pce);
+					zend_call_known_instance_method_with_1_params(
+						pce->constructor, Z_OBJ(ref), NULL, &arg);
+				}
 
 				if (EG(exception)) {
 					zval rv;
diff --git a/sapi/cli/tests/004.phpt b/sapi/cli/tests/004.phpt
index c88b85480bdb..b6e0e74fa6ff 100644
--- a/sapi/cli/tests/004.phpt
+++ b/sapi/cli/tests/004.phpt
@@ -12,6 +12,9 @@ $php = getenv('TEST_PHP_EXECUTABLE_ESCAPED');
 var_dump(shell_exec("$php -n --rf unknown"));
 var_dump(shell_exec("$php -n --rf echo"));
 var_dump(shell_exec("$php -n --rf phpinfo"));
+// Regression tests for https://github.com/php/php-src/issues/21754
+var_dump(shell_exec("$php -n --rf ReflectionMethod::__construct"));
+var_dump(shell_exec("$php -n --rf ReflectionMethod::missing"));
 
 echo "Done\n";
 ?>
@@ -28,5 +31,16 @@ string(155) "Function [ <internal:standard> function phpinfo ] {
   - Return [ true ]
 }
 
+"
+string(213) "Method [ <internal:Reflection, ctor> public method __construct ] {
+
+  - Parameters [2] {
+    Parameter #0 [ <required> object|string $objectOrMethod ]
+    Parameter #1 [ <optional> ?string $method = null ]
+  }
+}
+
+"
+string(61) "Exception: Method ReflectionMethod::missing() does not exist
 "
 Done