Remove bareword fallback for constants

Access to undefined constants will now always result in an Error
exception being thrown.

This required quite a few test changes, because there were many
buggy tests that unintentionally used bareword fallback in combination
with error suppression.

Author: nikic

UPGRADING

@@ -29,6 +29,9 @@ PHP 8.0 UPGRADE NOTES
     longer available. The error_get_last() function may be used instead.
   . Removed the ability to define case-insensitive constants. The third
     argument to define() may no longer be true.
+  . Access to undefined constants now always results in an Error exception.
+    Previously, unqualified constant accesses resulted in a warning and were
+    interpreted as strings.
   . Removed ability to specify an autoloader using an __autoload() function.
     spl_autoload_register() should be used instead.
   . Removed create_function(). Anonymous functions may be used instead.

Zend/tests/bug37811.phpt

@@ -23,6 +23,7 @@ string(3) "Foo"
 
 Warning: Constants may only evaluate to scalar values, arrays or resources in %sbug37811.php on line %d
 
-Warning: Use of undefined constant Baz - assumed 'Baz' (this will throw an Error in a future version of PHP) in %sbug37811.php on line %d
-string(3) "Baz"
-===DONE===
+Fatal error: Uncaught Error: Undefined constant 'Baz' in %s:%d
+Stack trace:
+#0 {main}
+  thrown in %s on line %d

Zend/tests/bug43344_1.phpt

@@ -3,6 +3,8 @@ Bug #43344.1 (Wrong error message for undefined namespace constant)
 --FILE--
 <?php
 namespace Foo;
+use Error;
+
 function f1($a=bar) {
 	return $a;
 }
@@ -13,20 +15,31 @@ function f3($a=array(bar=>0)) {
 	reset($a);
 	return key($a);
 }
-echo bar."\n";
-echo f1()."\n";
-echo f2()."\n";
-echo f3()."\n";
-?>
---EXPECTF--
-Warning: Use of undefined constant bar - assumed 'bar' (this will throw an Error in a future version of PHP) in %sbug43344_1.php on line 13
-bar
 
-Warning: Use of undefined constant bar - assumed 'bar' (this will throw an Error in a future version of PHP) in %sbug43344_1.php on line 3
-bar
-
-Warning: Use of undefined constant bar - assumed 'bar' (this will throw an Error in a future version of PHP) in %sbug43344_1.php on line 6
-bar
+try {
+    echo bar."\n";
+} catch (Error $e) {
+    echo $e->getMessage(), "\n";
+}
+try {
+    echo f1()."\n";
+} catch (Error $e) {
+    echo $e->getMessage(), "\n";
+}
+try {
+    echo f2()."\n";
+} catch (Error $e) {
+    echo $e->getMessage(), "\n";
+}
+try {
+    echo f3()."\n";
+} catch (Error $e) {
+    echo $e->getMessage(), "\n";
+}
 
-Warning: Use of undefined constant bar - assumed 'bar' (this will throw an Error in a future version of PHP) in %sbug43344_1.php on line 9
-bar
+?>
+--EXPECT--
+Undefined constant 'Foo\bar'
+Undefined constant 'Foo\bar'
+Undefined constant 'Foo\bar'
+Undefined constant 'Foo\bar'

Zend/tests/bug47572.phpt

@@ -14,4 +14,7 @@ $foo = new Foo();
 
 ?>
 --EXPECTF--
-Warning: Use of undefined constant FOO - assumed 'FOO' (this will throw an Error in a future version of PHP) in %s on line %d
+Fatal error: Uncaught Error: Undefined constant 'FOO' in %s:%d
+Stack trace:
+#0 {main}
+  thrown in %s on line %d

Zend/tests/bug69755.phpt

@@ -5,4 +5,7 @@ Bug #69755: segfault in ZEND_CONCAT_SPEC_TMPVAR_CONST_HANDLER
 c . 10;
 ?>
 --EXPECTF--
-Warning: Use of undefined constant c - assumed 'c' (this will throw an Error in a future version of PHP) in %sbug69755.php on line 2
+Fatal error: Uncaught Error: Undefined constant 'c' in %s:%d
+Stack trace:
+#0 {main}
+  thrown in %s on line %d

Zend/tests/bug69788.phpt

@@ -5,4 +5,7 @@ Bug #69788: Malformed script causes Uncaught Error in php-cgi, valgrind SIGILL
 --EXPECTF--
 Notice: Array to string conversion in %s on line %d
 
-Warning: Use of undefined constant t - assumed 't' (this will throw an Error in a future version of PHP) in %s on line %d
+Fatal error: Uncaught Error: Undefined constant 't' in %s:%d
+Stack trace:
+#0 {main}
+  thrown in %s on line %d

Zend/tests/bug72944.phpt

@@ -2,11 +2,10 @@
 Bug #72944 (Null pointer deref in zval_delref_p).
 --FILE--
 <?php
+define('e', 'e');
 "a"== e & $A = $A? 0 : 0 ?:0;
 echo "OK\n";
 ?>
 --EXPECTF--
-Warning: Use of undefined constant e - assumed 'e' (this will throw an Error in a future version of PHP) in %sbug72944.php on line 2
-
-Notice: Undefined variable: A in %sbug72944.php on line 2
+Notice: Undefined variable: A in %sbug72944.php on line 3
 OK

Zend/tests/bug73163.phpt

@@ -4,15 +4,17 @@ Defining constants with non-scalar values
 <?php
 
 define('foo', new stdClass);
-var_dump(foo);
+try {
+    var_dump(foo);
+} catch (Error $e) {
+    echo $e->getMessage(), "\n";
+}
 
 define('foo', fopen(__FILE__, 'r'));
 var_dump(foo);
 
 ?>
 --EXPECTF--
 Warning: Constants may only evaluate to scalar values, arrays or resources in %s on line %d
-
-Warning: Use of undefined constant foo - assumed 'foo' (this will throw an Error in a future version of PHP) in %s on line %d
-string(%d) "foo"
-resource(%d) of type (stream)
+Undefined constant 'foo'
+resource(5) of type (stream)

Zend/tests/constants_002.phpt

@@ -2,11 +2,10 @@
 Persistent case insensitive and user defined constants
 --FILE--
 <?php
-var_dump(ZEND_THREAD_safe);
+var_dump(defined('ZEND_THREAD_safe'));
 define("ZEND_THREAD_safe", 123);
 var_dump(ZEND_THREAD_safe);
 ?>
---EXPECTF--
-Warning: Use of undefined constant ZEND_THREAD_safe - assumed 'ZEND_THREAD_safe' (this will throw an Error in a future version of PHP) in %s on line %d
-string(16) "ZEND_THREAD_safe"
+--EXPECT--
+bool(false)
 int(123)