Closes #4133

ChangeLog-8.5.md

@@ -7,6 +7,7 @@ All notable changes of the PHPUnit 8.5 release series are documented in this fil
 ### Fixed
 
 * [#4017](https://github.com/sebastianbergmann/phpunit/issues/4017): Do not suggest refactoring to something that is also deprecated
+* [#4133](https://github.com/sebastianbergmann/phpunit/issues/4133): `expectExceptionMessageRegExp()` has been removed in PHPUnit 9 without a deprecation warning being given in PHPUnit 8
 * [#4139](https://github.com/sebastianbergmann/phpunit/issues/4139): Cannot double interfaces that declare a constructor with PHP 8
 * [#4144](https://github.com/sebastianbergmann/phpunit/issues/4144): Empty objects are converted to empty arrays in JSON comparison failure diff
 

src/Framework/TestCase.php

@@ -269,6 +269,11 @@ abstract class TestCase extends Assert implements SelfDescribing, Test
      */
     private $doubledTypes = [];
 
+    /**
+     * @var bool
+     */
+    private $deprecatedExpectExceptionMessageRegExpUsed = false;
+
     /**
      * Returns a matcher that matches when the method is executed
      * zero or more times.
@@ -506,6 +511,8 @@ public function expectExceptionMessageMatches(string $regularExpression): void
      */
     public function expectExceptionMessageRegExp(string $regularExpression): void
     {
+        $this->deprecatedExpectExceptionMessageRegExpUsed = true;
+
         $this->expectExceptionMessageMatches($regularExpression);
     }
 
@@ -1447,6 +1454,10 @@ protected function runTest()
                 );
             }
 
+            if ($this->deprecatedExpectExceptionMessageRegExpUsed) {
+                $this->addWarning('expectExceptionMessageRegExp() is deprecated in PHPUnit 8 and will be removed in PHPUnit 9.');
+            }
+
             return;
         }