diff --git a/composer.json b/composer.json
index c66f40706..b27459b20 100644
--- a/composer.json
+++ b/composer.json
@@ -47,7 +47,7 @@
         "ext-json": "*",
         "ext-libxml": "*",
         "composer/xdebug-handler": "^2.0",
-        "infection/abstract-testframework-adapter": "^0.3.1",
+        "infection/abstract-testframework-adapter": "^0.5.0",
         "infection/extension-installer": "^0.1.0",
         "infection/include-interceptor": "^0.2.4",
         "justinrainbow/json-schema": "^5.2.10",
diff --git a/composer.lock b/composer.lock
index 89b035c5a..5fce70f41 100644
--- a/composer.lock
+++ b/composer.lock
@@ -4,7 +4,7 @@
         "Read more about it at https://getcomposer.org/doc/01-basic-usage.md#installing-dependencies",
         "This file is @generated automatically"
     ],
-    "content-hash": "e386c963bbc78549523114db79bcb94c",
+    "content-hash": "d9cfb23acce60abd6aa6cc78193cd142",
     "packages": [
         {
             "name": "composer/xdebug-handler",
@@ -72,25 +72,25 @@
         },
         {
             "name": "infection/abstract-testframework-adapter",
-            "version": "0.3.1",
+            "version": "0.5.0",
             "source": {
                 "type": "git",
                 "url": "https://github.com/infection/abstract-testframework-adapter.git",
-                "reference": "c52539339f28d6b67625ff24496289b3e6d66025"
+                "reference": "18925e20d15d1a5995bb85c9dc09e8751e1e069b"
             },
             "dist": {
                 "type": "zip",
-                "url": "https://api.github.com/repos/infection/abstract-testframework-adapter/zipball/c52539339f28d6b67625ff24496289b3e6d66025",
-                "reference": "c52539339f28d6b67625ff24496289b3e6d66025",
+                "url": "https://api.github.com/repos/infection/abstract-testframework-adapter/zipball/18925e20d15d1a5995bb85c9dc09e8751e1e069b",
+                "reference": "18925e20d15d1a5995bb85c9dc09e8751e1e069b",
                 "shasum": ""
             },
             "require": {
-                "php": "^7.3 || ^8.0"
+                "php": "^7.4 || ^8.0"
             },
             "require-dev": {
                 "ergebnis/composer-normalize": "^2.8",
-                "friendsofphp/php-cs-fixer": "^2.16",
-                "phpunit/phpunit": "^9.0"
+                "friendsofphp/php-cs-fixer": "^2.17",
+                "phpunit/phpunit": "^9.5"
             },
             "type": "library",
             "autoload": {
@@ -111,9 +111,19 @@
             "description": "Abstract Test Framework Adapter for Infection",
             "support": {
                 "issues": "https://github.com/infection/abstract-testframework-adapter/issues",
-                "source": "https://github.com/infection/abstract-testframework-adapter/tree/0.3"
+                "source": "https://github.com/infection/abstract-testframework-adapter/tree/0.5.0"
             },
-            "time": "2020-08-30T13:50:12+00:00"
+            "funding": [
+                {
+                    "url": "https://github.com/infection",
+                    "type": "github"
+                },
+                {
+                    "url": "https://opencollective.com/infection",
+                    "type": "open_collective"
+                }
+            ],
+            "time": "2021-08-17T18:49:12+00:00"
         },
         {
             "name": "infection/extension-installer",
diff --git a/resources/schema.json b/resources/schema.json
index a274eebe3..a17f81b67 100644
--- a/resources/schema.json
+++ b/resources/schema.json
@@ -339,6 +339,7 @@
                 "SpreadOneItem": { "$ref": "#/definitions/default-mutator-config" },
                 "SpreadAssignment": { "$ref": "#/definitions/default-mutator-config" },
                 "SpreadRemoval": { "$ref": "#/definitions/default-mutator-config" },
+                "SyntaxError": { "$ref": "#/definitions/default-mutator-config" },
                 "Foreach_": { "$ref": "#/definitions/default-mutator-config" },
                 "For_": { "$ref": "#/definitions/default-mutator-config" },
                 "DoWhile": { "$ref": "#/definitions/default-mutator-config" },
diff --git a/src/Console/OutputFormatter/DotFormatter.php b/src/Console/OutputFormatter/DotFormatter.php
index 87920f9a1..204964c35 100644
--- a/src/Console/OutputFormatter/DotFormatter.php
+++ b/src/Console/OutputFormatter/DotFormatter.php
@@ -66,6 +66,7 @@ public function start(int $mutationCount): void
             . '<escaped>M</escaped>: escaped, '
             . '<uncovered>U</uncovered>: uncovered, '
             . '<with-error>E</with-error>: fatal error, '
+            . '<with-syntax-error>X</with-syntax-error>: syntax error, '
             . '<timeout>T</timeout>: timed out, '
             . '<skipped>S</skipped>: skipped',
             '',
@@ -100,6 +101,10 @@ public function advance(MutantExecutionResult $executionResult, int $mutationCou
             case DetectionStatus::ERROR:
                 $this->output->write('<with-error>E</with-error>');
 
+                break;
+            case DetectionStatus::SYNTAX_ERROR:
+                $this->output->write('<with-syntax-error>X</with-syntax-error>');
+
                 break;
         }
 
diff --git a/src/Console/OutputFormatterStyleConfigurator.php b/src/Console/OutputFormatterStyleConfigurator.php
index 55e62eb63..66e3bccbc 100644
--- a/src/Console/OutputFormatterStyleConfigurator.php
+++ b/src/Console/OutputFormatterStyleConfigurator.php
@@ -59,6 +59,7 @@ public static function configure(OutputInterface $output): void
     private static function configureMutantStyle(OutputFormatterInterface $formatter): void
     {
         $formatter->setStyle('with-error', new OutputFormatterStyle('green'));
+        $formatter->setStyle('with-syntax-error', new OutputFormatterStyle('red', null, ['bold']));
         $formatter->setStyle(
             'uncovered',
             new OutputFormatterStyle('blue', null, ['bold'])
diff --git a/src/Event/Subscriber/MutationTestingConsoleLoggerSubscriber.php b/src/Event/Subscriber/MutationTestingConsoleLoggerSubscriber.php
index 7fb1eb3dc..f18146864 100644
--- a/src/Event/Subscriber/MutationTestingConsoleLoggerSubscriber.php
+++ b/src/Event/Subscriber/MutationTestingConsoleLoggerSubscriber.php
@@ -150,6 +150,7 @@ private function showMetrics(): void
         $this->output->writeln('<options=bold>' . $this->getPadded($this->metricsCalculator->getNotTestedCount()) . '</options=bold> mutants were not covered by tests');
         $this->output->writeln('<options=bold>' . $this->getPadded($this->metricsCalculator->getEscapedCount()) . '</options=bold> covered mutants were not detected');
         $this->output->writeln('<options=bold>' . $this->getPadded($this->metricsCalculator->getErrorCount()) . '</options=bold> errors were encountered');
+        $this->output->writeln('<options=bold>' . $this->getPadded($this->metricsCalculator->getSyntaxErrorCount()) . '</options=bold> syntax errors were encountered');
         $this->output->writeln('<options=bold>' . $this->getPadded($this->metricsCalculator->getTimedOutCount()) . '</options=bold> time outs were encountered');
         $this->output->writeln('<options=bold>' . $this->getPadded($this->metricsCalculator->getSkippedCount()) . '</options=bold> mutants required more time than configured');
 
diff --git a/src/Logger/DebugFileLogger.php b/src/Logger/DebugFileLogger.php
index ea7f7b3bb..9e6bbc3b0 100644
--- a/src/Logger/DebugFileLogger.php
+++ b/src/Logger/DebugFileLogger.php
@@ -84,6 +84,11 @@ public function getLogLines(): array
             'Errors',
             $separateSections
         );
+        $logs[] = $this->getResultsLine(
+            $this->resultsCollector->getSyntaxErrorExecutionResults(),
+            'Syntax Errors',
+            $separateSections
+        );
         $logs[] = $this->getResultsLine(
             $this->resultsCollector->getEscapedExecutionResults(),
             'Escaped',
diff --git a/src/Logger/FederatedLogger.php b/src/Logger/FederatedLogger.php
index 3d90363e1..fe369abb4 100644
--- a/src/Logger/FederatedLogger.php
+++ b/src/Logger/FederatedLogger.php
@@ -43,7 +43,7 @@ final class FederatedLogger implements MutationTestingResultsLogger
     /**
      * @var MutationTestingResultsLogger[]
      */
-    private $loggers;
+    private array $loggers;
 
     public function __construct(MutationTestingResultsLogger ...$loggers)
     {
diff --git a/src/Logger/JsonLogger.php b/src/Logger/JsonLogger.php
index 8f9849efd..de363cbd1 100644
--- a/src/Logger/JsonLogger.php
+++ b/src/Logger/JsonLogger.php
@@ -74,6 +74,7 @@ public function getLogLines(): array
                 'notCoveredCount' => $this->metricsCalculator->getNotTestedCount(),
                 'escapedCount' => $this->metricsCalculator->getEscapedCount(),
                 'errorCount' => $this->metricsCalculator->getErrorCount(),
+                'syntaxErrorCount' => $this->metricsCalculator->getSyntaxErrorCount(),
                 'skippedCount' => $this->metricsCalculator->getSkippedCount(),
                 'timeOutCount' => $this->metricsCalculator->getTimedOutCount(),
                 'msi' => $this->metricsCalculator->getMutationScoreIndicator(),
@@ -84,6 +85,7 @@ public function getLogLines(): array
             'timeouted' => $this->getResultsLine($this->resultsCollector->getTimedOutExecutionResults()),
             'killed' => $this->getResultsLine($this->resultsCollector->getKilledExecutionResults()),
             'errored' => $this->getResultsLine($this->resultsCollector->getErrorExecutionResults()),
+            'syntaxErrors' => $this->getResultsLine($this->resultsCollector->getSyntaxErrorExecutionResults()),
             'uncovered' => $this->onlyCoveredMode ? [] : $this->getResultsLine($this->resultsCollector->getNotCoveredExecutionResults()),
         ];
 
diff --git a/src/Logger/PerMutatorLogger.php b/src/Logger/PerMutatorLogger.php
index d9cf6c9ee..a6f2bda17 100644
--- a/src/Logger/PerMutatorLogger.php
+++ b/src/Logger/PerMutatorLogger.php
@@ -73,7 +73,7 @@ public function getLogLines(): array
         $calculatorPerMutator = $this->createMetricsPerMutators();
 
         $table = [
-            ['Mutator', 'Mutations', 'Killed', 'Escaped', 'Errors', 'Timed Out', 'Skipped', 'MSI (%s)', 'Covered MSI (%s)'],
+            ['Mutator', 'Mutations', 'Killed', 'Escaped', 'Errors', 'Syntax Errors', 'Timed Out', 'Skipped', 'MSI (%s)', 'Covered MSI (%s)'],
         ];
 
         foreach ($calculatorPerMutator as $mutatorName => $calculator) {
@@ -85,6 +85,7 @@ public function getLogLines(): array
                 (string) $calculator->getKilledCount(),
                 (string) $calculator->getEscapedCount(),
                 (string) $calculator->getErrorCount(),
+                (string) $calculator->getSyntaxErrorCount(),
                 (string) $calculator->getTimedOutCount(),
                 (string) $calculator->getSkippedCount(),
                 self::formatScore($calculator->getMutationScoreIndicator()),
diff --git a/src/Logger/SummaryFileLogger.php b/src/Logger/SummaryFileLogger.php
index 0e3480c14..e9044b756 100644
--- a/src/Logger/SummaryFileLogger.php
+++ b/src/Logger/SummaryFileLogger.php
@@ -59,6 +59,7 @@ public function getLogLines(): array
             '',
             'Killed: ' . $this->metricsCalculator->getKilledCount(),
             'Errored: ' . $this->metricsCalculator->getErrorCount(),
+            'Syntax Errors: ' . $this->metricsCalculator->getSyntaxErrorCount(),
             'Escaped: ' . $this->metricsCalculator->getEscapedCount(),
             'Timed Out: ' . $this->metricsCalculator->getTimedOutCount(),
             'Skipped: ' . $this->metricsCalculator->getSkippedCount(),
diff --git a/src/Logger/TextFileLogger.php b/src/Logger/TextFileLogger.php
index 1de18b03e..2c1630311 100644
--- a/src/Logger/TextFileLogger.php
+++ b/src/Logger/TextFileLogger.php
@@ -102,6 +102,12 @@ public function getLogLines(): array
                 'Errors',
                 $separateSections
             );
+
+            $logs[] = $this->getResultsLine(
+                $this->resultsCollector->getSyntaxErrorExecutionResults(),
+                'Syntax Errors',
+                $separateSections
+            );
         }
 
         if (!$this->onlyCoveredMode) {
diff --git a/src/Metrics/MetricsCalculator.php b/src/Metrics/MetricsCalculator.php
index 859c5faf9..527c99092 100644
--- a/src/Metrics/MetricsCalculator.php
+++ b/src/Metrics/MetricsCalculator.php
@@ -103,6 +103,11 @@ public function getErrorCount(): int
         return $this->countByStatus[DetectionStatus::ERROR];
     }
 
+    public function getSyntaxErrorCount(): int
+    {
+        return $this->countByStatus[DetectionStatus::SYNTAX_ERROR];
+    }
+
     public function getSkippedCount(): int
     {
         return $this->countByStatus[DetectionStatus::SKIPPED];
diff --git a/src/Metrics/ResultsCollector.php b/src/Metrics/ResultsCollector.php
index e27da417f..7078c560c 100644
--- a/src/Metrics/ResultsCollector.php
+++ b/src/Metrics/ResultsCollector.php
@@ -105,6 +105,14 @@ public function getErrorExecutionResults(): array
         return $this->getResultListForStatus(DetectionStatus::ERROR)->getSortedExecutionResults();
     }
 
+    /**
+     * @return MutantExecutionResult[]
+     */
+    public function getSyntaxErrorExecutionResults(): array
+    {
+        return $this->getResultListForStatus(DetectionStatus::SYNTAX_ERROR)->getSortedExecutionResults();
+    }
+
     /**
      * @return MutantExecutionResult[]
      */
diff --git a/src/Metrics/TargetDetectionStatusesProvider.php b/src/Metrics/TargetDetectionStatusesProvider.php
index be141bc8d..6915bc2b9 100644
--- a/src/Metrics/TargetDetectionStatusesProvider.php
+++ b/src/Metrics/TargetDetectionStatusesProvider.php
@@ -123,6 +123,8 @@ private function findRequired(): Generator
 
             yield DetectionStatus::ERROR;
 
+            yield DetectionStatus::SYNTAX_ERROR;
+
             yield DetectionStatus::TIMED_OUT;
 
             if (!$this->onlyCoveredMode) {
@@ -138,6 +140,8 @@ private function findRequired(): Generator
 
             yield DetectionStatus::SKIPPED;
 
+            yield DetectionStatus::SYNTAX_ERROR;
+
             if ($this->logVerbosity === LogVerbosity::DEBUG) {
                 yield DetectionStatus::KILLED;
 
diff --git a/src/Mutant/DetectionStatus.php b/src/Mutant/DetectionStatus.php
index 9b8fa1263..b3fcc4879 100644
--- a/src/Mutant/DetectionStatus.php
+++ b/src/Mutant/DetectionStatus.php
@@ -49,6 +49,7 @@ final class DetectionStatus
     public const ERROR = 'error';
     public const TIMED_OUT = 'timed out';
     public const SKIPPED = 'skipped';
+    public const SYNTAX_ERROR = 'syntax error';
     public const NOT_COVERED = 'not covered';
 
     public const ALL = [
@@ -57,6 +58,7 @@ final class DetectionStatus
         self::ERROR,
         self::TIMED_OUT,
         self::SKIPPED,
+        self::SYNTAX_ERROR,
         self::NOT_COVERED,
     ];
 }
diff --git a/src/Mutant/MutantExecutionResultFactory.php b/src/Mutant/MutantExecutionResultFactory.php
index cd487c511..c17731dd5 100644
--- a/src/Mutant/MutantExecutionResultFactory.php
+++ b/src/Mutant/MutantExecutionResultFactory.php
@@ -35,6 +35,7 @@
 
 namespace Infection\Mutant;
 
+use Infection\AbstractTestFramework\SyntaxErrorAware;
 use Infection\AbstractTestFramework\TestFrameworkAdapter;
 use Infection\Process\MutantProcess;
 use function Safe\sprintf;
@@ -103,10 +104,16 @@ private function retrieveDetectionStatus(MutantProcess $mutantProcess): string
             return DetectionStatus::ERROR;
         }
 
-        if ($this->testFrameworkAdapter->testsPass($this->retrieveProcessOutput($process))) {
+        $output = $this->retrieveProcessOutput($process);
+
+        if ($this->testFrameworkAdapter->testsPass($output)) {
             return DetectionStatus::ESCAPED;
         }
 
+        if ($this->testFrameworkAdapter instanceof SyntaxErrorAware && $this->testFrameworkAdapter->isSyntaxError($output)) {
+            return DetectionStatus::SYNTAX_ERROR;
+        }
+
         return DetectionStatus::KILLED;
     }
 }
diff --git a/src/Mutator/ProfileList.php b/src/Mutator/ProfileList.php
index cb224528c..17bdf5407 100644
--- a/src/Mutator/ProfileList.php
+++ b/src/Mutator/ProfileList.php
@@ -464,6 +464,9 @@ final class ProfileList
         // Extensions
         'BCMath' => Mutator\Extensions\BCMath::class,
         'MBString' => Mutator\Extensions\MBString::class,
+
+        // Internal only usage
+        'SyntaxError' => Mutator\SyntaxError::class,
     ];
 
     /** @var array<int, string>|null */
diff --git a/src/Mutator/SyntaxError.php b/src/Mutator/SyntaxError.php
new file mode 100644
index 000000000..1094b0150
--- /dev/null
+++ b/src/Mutator/SyntaxError.php
@@ -0,0 +1,81 @@
+<?php
+/**
+ * This code is licensed under the BSD 3-Clause License.
+ *
+ * Copyright (c) 2017, Maks Rafalko
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * * Redistributions of source code must retain the above copyright notice, this
+ *   list of conditions and the following disclaimer.
+ *
+ * * Redistributions in binary form must reproduce the above copyright notice,
+ *   this list of conditions and the following disclaimer in the documentation
+ *   and/or other materials provided with the distribution.
+ *
+ * * Neither the name of the copyright holder nor the names of its
+ *   contributors may be used to endorse or promote products derived from
+ *   this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+ * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+ * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+ * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+declare(strict_types=1);
+
+namespace Infection\Mutator;
+
+use PhpParser\Node;
+
+/**
+ * @internal
+ *
+ * @implements Mutator<Node\Expr\Variable>
+ */
+final class SyntaxError implements Mutator
+{
+    use GetMutatorName;
+
+    public static function getDefinition(): ?Definition
+    {
+        return new Definition(
+            'Replaces a `$this` with `false` to produce a syntax error. Internal usage only.',
+            MutatorCategory::ORTHOGONAL_REPLACEMENT,
+            null,
+            <<<'DIFF'
+class X {
+    function foo()
+    {
+-        $this->method();
++        $->method();
+    }
+}
+DIFF
+        );
+    }
+
+    /**
+     * @psalm-mutation-free
+     *
+     * @return iterable<Node\Expr\ConstFetch>
+     */
+    public function mutate(Node $node): iterable
+    {
+        yield new Node\Expr\ConstFetch(new Node\Name('$'));
+    }
+
+    public function canMutate(Node $node): bool
+    {
+        return $node instanceof Node\Expr\Variable && $node->name === 'this';
+    }
+}
diff --git a/src/TestFramework/PhpUnit/Adapter/PestAdapter.php b/src/TestFramework/PhpUnit/Adapter/PestAdapter.php
index 3fb1dc642..fb829034e 100644
--- a/src/TestFramework/PhpUnit/Adapter/PestAdapter.php
+++ b/src/TestFramework/PhpUnit/Adapter/PestAdapter.php
@@ -36,6 +36,7 @@
 namespace Infection\TestFramework\PhpUnit\Adapter;
 
 use Infection\AbstractTestFramework\MemoryUsageAware;
+use Infection\AbstractTestFramework\SyntaxErrorAware;
 use Infection\AbstractTestFramework\TestFrameworkAdapter;
 use Infection\TestFramework\ProvidesInitialRunOnlyOptions;
 use function Safe\preg_match;
@@ -44,7 +45,7 @@
 /**
  * @internal
  */
-final class PestAdapter implements MemoryUsageAware, ProvidesInitialRunOnlyOptions, TestFrameworkAdapter
+final class PestAdapter implements MemoryUsageAware, ProvidesInitialRunOnlyOptions, SyntaxErrorAware, TestFrameworkAdapter
 {
     private const NAME = 'Pest';
 
@@ -76,6 +77,11 @@ public function testsPass(string $output): bool
         return $isOk || $isOkRisked;
     }
 
+    public function isSyntaxError(string $output): bool
+    {
+        return preg_match('/ParseError\s*syntax error/i', $output) === 1;
+    }
+
     public function hasJUnitReport(): bool
     {
         return $this->phpUnitAdapter->hasJUnitReport();
diff --git a/src/TestFramework/PhpUnit/Adapter/PhpUnitAdapter.php b/src/TestFramework/PhpUnit/Adapter/PhpUnitAdapter.php
index 5258633b1..3b3b3e0c6 100644
--- a/src/TestFramework/PhpUnit/Adapter/PhpUnitAdapter.php
+++ b/src/TestFramework/PhpUnit/Adapter/PhpUnitAdapter.php
@@ -37,6 +37,7 @@
 
 use function escapeshellarg;
 use Infection\AbstractTestFramework\MemoryUsageAware;
+use Infection\AbstractTestFramework\SyntaxErrorAware;
 use Infection\Config\ValueProvider\PCOVDirectoryProvider;
 use Infection\TestFramework\AbstractTestFrameworkAdapter;
 use Infection\TestFramework\CommandLineArgumentsAndOptionsBuilder;
@@ -54,7 +55,7 @@
  * @internal
  * @final
  */
-class PhpUnitAdapter extends AbstractTestFrameworkAdapter implements MemoryUsageAware, ProvidesInitialRunOnlyOptions
+class PhpUnitAdapter extends AbstractTestFrameworkAdapter implements MemoryUsageAware, ProvidesInitialRunOnlyOptions, SyntaxErrorAware
 {
     public const COVERAGE_DIR = 'coverage-xml';
 
@@ -142,6 +143,11 @@ public function testsPass(string $output): bool
         return $isOk || $isOkWithInfo || $isWarning | $isNoTestsExecuted;
     }
 
+    public function isSyntaxError(string $output): bool
+    {
+        return preg_match('/ParseError: syntax error/i', $output) === 1;
+    }
+
     public function getMemoryUsed(string $output): float
     {
         if (preg_match('/Memory: (\d+(?:\.\d+))\s*MB/', $output, $match)) {
diff --git a/tests/e2e/Config_Bootstrap/expected-output.txt b/tests/e2e/Config_Bootstrap/expected-output.txt
index 7bcb80de3..a31fc060f 100644
--- a/tests/e2e/Config_Bootstrap/expected-output.txt
+++ b/tests/e2e/Config_Bootstrap/expected-output.txt
@@ -2,6 +2,7 @@ Total: 1
 
 Killed: 1
 Errored: 0
+Syntax Errors: 0
 Escaped: 0
 Timed Out: 0
 Skipped: 0
diff --git a/tests/e2e/Custom_tmp_dir/expected-output.txt b/tests/e2e/Custom_tmp_dir/expected-output.txt
index 7bcb80de3..a31fc060f 100644
--- a/tests/e2e/Custom_tmp_dir/expected-output.txt
+++ b/tests/e2e/Custom_tmp_dir/expected-output.txt
@@ -2,6 +2,7 @@ Total: 1
 
 Killed: 1
 Errored: 0
+Syntax Errors: 0
 Escaped: 0
 Timed Out: 0
 Skipped: 0
diff --git a/tests/e2e/Empty_Path/expected-output.txt b/tests/e2e/Empty_Path/expected-output.txt
index 7bcb80de3..a31fc060f 100644
--- a/tests/e2e/Empty_Path/expected-output.txt
+++ b/tests/e2e/Empty_Path/expected-output.txt
@@ -2,6 +2,7 @@ Total: 1
 
 Killed: 1
 Errored: 0
+Syntax Errors: 0
 Escaped: 0
 Timed Out: 0
 Skipped: 0
diff --git a/tests/e2e/Example_Test/expected-output.txt b/tests/e2e/Example_Test/expected-output.txt
index 7bcb80de3..a31fc060f 100644
--- a/tests/e2e/Example_Test/expected-output.txt
+++ b/tests/e2e/Example_Test/expected-output.txt
@@ -2,6 +2,7 @@ Total: 1
 
 Killed: 1
 Errored: 0
+Syntax Errors: 0
 Escaped: 0
 Timed Out: 0
 Skipped: 0
diff --git a/tests/e2e/Example_Test/infection.json b/tests/e2e/Example_Test/infection.json
index 7029746fb..a5d873d67 100644
--- a/tests/e2e/Example_Test/infection.json
+++ b/tests/e2e/Example_Test/infection.json
@@ -1,4 +1,5 @@
 {
+    "$schema": "../../../resources/schema.json",
     "timeout": 25,
     "source": {
         "directories": [
diff --git a/tests/e2e/Exclude_Mutations_By_Regex/expected-output.txt b/tests/e2e/Exclude_Mutations_By_Regex/expected-output.txt
index aa6c03830..95e73f9ca 100644
--- a/tests/e2e/Exclude_Mutations_By_Regex/expected-output.txt
+++ b/tests/e2e/Exclude_Mutations_By_Regex/expected-output.txt
@@ -2,6 +2,7 @@ Total: 0
 
 Killed: 0
 Errored: 0
+Syntax Errors: 0
 Escaped: 0
 Timed Out: 0
 Skipped: 0
diff --git a/tests/e2e/Exclude_by_file_name/expected-output.txt b/tests/e2e/Exclude_by_file_name/expected-output.txt
index 7bcb80de3..a31fc060f 100644
--- a/tests/e2e/Exclude_by_file_name/expected-output.txt
+++ b/tests/e2e/Exclude_by_file_name/expected-output.txt
@@ -2,6 +2,7 @@ Total: 1
 
 Killed: 1
 Errored: 0
+Syntax Errors: 0
 Escaped: 0
 Timed Out: 0
 Skipped: 0
diff --git a/tests/e2e/Exec_Path/expected-output.txt b/tests/e2e/Exec_Path/expected-output.txt
index afaccc04a..c654acc50 100644
--- a/tests/e2e/Exec_Path/expected-output.txt
+++ b/tests/e2e/Exec_Path/expected-output.txt
@@ -2,6 +2,7 @@ Total: 6
 
 Killed: 5
 Errored: 0
+Syntax Errors: 0
 Escaped: 0
 Timed Out: 0
 Skipped: 0
diff --git a/tests/e2e/Ignore_All_Mutations/expected-output.txt b/tests/e2e/Ignore_All_Mutations/expected-output.txt
index 76a558afd..b53522bf8 100644
--- a/tests/e2e/Ignore_All_Mutations/expected-output.txt
+++ b/tests/e2e/Ignore_All_Mutations/expected-output.txt
@@ -2,6 +2,7 @@ Total: 2
 
 Killed: 2
 Errored: 0
+Syntax Errors: 0
 Escaped: 0
 Timed Out: 0
 Skipped: 0
diff --git a/tests/e2e/Ignore_MSI_Zero_Mutations/expected-output.txt b/tests/e2e/Ignore_MSI_Zero_Mutations/expected-output.txt
index aa6c03830..95e73f9ca 100644
--- a/tests/e2e/Ignore_MSI_Zero_Mutations/expected-output.txt
+++ b/tests/e2e/Ignore_MSI_Zero_Mutations/expected-output.txt
@@ -2,6 +2,7 @@ Total: 0
 
 Killed: 0
 Errored: 0
+Syntax Errors: 0
 Escaped: 0
 Timed Out: 0
 Skipped: 0
diff --git a/tests/e2e/Memory_Limit/expected-output.txt b/tests/e2e/Memory_Limit/expected-output.txt
index 5aec86877..003c4078e 100644
--- a/tests/e2e/Memory_Limit/expected-output.txt
+++ b/tests/e2e/Memory_Limit/expected-output.txt
@@ -2,6 +2,7 @@ Total: 1
 
 Killed: 0
 Errored: 1
+Syntax Errors: 0
 Escaped: 0
 Timed Out: 0
 Skipped: 0
diff --git a/tests/e2e/Multiline_Statement/expected-output.txt b/tests/e2e/Multiline_Statement/expected-output.txt
index af47cacd2..b975cd448 100644
--- a/tests/e2e/Multiline_Statement/expected-output.txt
+++ b/tests/e2e/Multiline_Statement/expected-output.txt
@@ -49,6 +49,9 @@ Line 22
 Errors mutants:
 ===============
 
+Syntax Errors mutants:
+======================
+
 Escaped mutants:
 ================
 
diff --git a/tests/e2e/Output_Stream/expected-output.txt b/tests/e2e/Output_Stream/expected-output.txt
index 4cc565248..e887c84cd 100644
--- a/tests/e2e/Output_Stream/expected-output.txt
+++ b/tests/e2e/Output_Stream/expected-output.txt
@@ -13,6 +13,9 @@ Line 9
 Errors mutants:
 ===============
 
+Syntax Errors mutants:
+======================
+
 Escaped mutants:
 ================
 
diff --git a/tests/e2e/PCOV_Directory/expected-output.txt b/tests/e2e/PCOV_Directory/expected-output.txt
index 7bcb80de3..a31fc060f 100644
--- a/tests/e2e/PCOV_Directory/expected-output.txt
+++ b/tests/e2e/PCOV_Directory/expected-output.txt
@@ -2,6 +2,7 @@ Total: 1
 
 Killed: 1
 Errored: 0
+Syntax Errors: 0
 Escaped: 0
 Timed Out: 0
 Skipped: 0
diff --git a/tests/e2e/PCOV_PHPUnit8/expected-output.txt b/tests/e2e/PCOV_PHPUnit8/expected-output.txt
index 7bcb80de3..a31fc060f 100644
--- a/tests/e2e/PCOV_PHPUnit8/expected-output.txt
+++ b/tests/e2e/PCOV_PHPUnit8/expected-output.txt
@@ -2,6 +2,7 @@ Total: 1
 
 Killed: 1
 Errored: 0
+Syntax Errors: 0
 Escaped: 0
 Timed Out: 0
 Skipped: 0
diff --git a/tests/e2e/PHPUnit93/expected-output.txt b/tests/e2e/PHPUnit93/expected-output.txt
index 7bcb80de3..a31fc060f 100644
--- a/tests/e2e/PHPUnit93/expected-output.txt
+++ b/tests/e2e/PHPUnit93/expected-output.txt
@@ -2,6 +2,7 @@ Total: 1
 
 Killed: 1
 Errored: 0
+Syntax Errors: 0
 Escaped: 0
 Timed Out: 0
 Skipped: 0
diff --git a/tests/e2e/PHPUnit_Custom_Config_Dir/expected-output.txt b/tests/e2e/PHPUnit_Custom_Config_Dir/expected-output.txt
index 7bcb80de3..a31fc060f 100644
--- a/tests/e2e/PHPUnit_Custom_Config_Dir/expected-output.txt
+++ b/tests/e2e/PHPUnit_Custom_Config_Dir/expected-output.txt
@@ -2,6 +2,7 @@ Total: 1
 
 Killed: 1
 Errored: 0
+Syntax Errors: 0
 Escaped: 0
 Timed Out: 0
 Skipped: 0
diff --git a/tests/e2e/PHPUnit_Hidden_Dependency/expected-output.txt b/tests/e2e/PHPUnit_Hidden_Dependency/expected-output.txt
index 7bcb80de3..a31fc060f 100644
--- a/tests/e2e/PHPUnit_Hidden_Dependency/expected-output.txt
+++ b/tests/e2e/PHPUnit_Hidden_Dependency/expected-output.txt
@@ -2,6 +2,7 @@ Total: 1
 
 Killed: 1
 Errored: 0
+Syntax Errors: 0
 Escaped: 0
 Timed Out: 0
 Skipped: 0
diff --git a/tests/e2e/PHPUnit_XSD_Validation/expected-output.txt b/tests/e2e/PHPUnit_XSD_Validation/expected-output.txt
index 7bcb80de3..a31fc060f 100644
--- a/tests/e2e/PHPUnit_XSD_Validation/expected-output.txt
+++ b/tests/e2e/PHPUnit_XSD_Validation/expected-output.txt
@@ -2,6 +2,7 @@ Total: 1
 
 Killed: 1
 Errored: 0
+Syntax Errors: 0
 Escaped: 0
 Timed Out: 0
 Skipped: 0
diff --git a/tests/e2e/PSR_0_Autoloader/expected-output.txt b/tests/e2e/PSR_0_Autoloader/expected-output.txt
index 7bcb80de3..a31fc060f 100644
--- a/tests/e2e/PSR_0_Autoloader/expected-output.txt
+++ b/tests/e2e/PSR_0_Autoloader/expected-output.txt
@@ -2,6 +2,7 @@ Total: 1
 
 Killed: 1
 Errored: 0
+Syntax Errors: 0
 Escaped: 0
 Timed Out: 0
 Skipped: 0
diff --git a/tests/e2e/PestTestFramework/expected-output.txt b/tests/e2e/PestTestFramework/expected-output.txt
index 0a408ead3..00e5e6f54 100644
--- a/tests/e2e/PestTestFramework/expected-output.txt
+++ b/tests/e2e/PestTestFramework/expected-output.txt
@@ -2,6 +2,7 @@ Total: 11
 
 Killed: 9
 Errored: 0
+Syntax Errors: 0
 Escaped: 2
 Timed Out: 0
 Skipped: 0
diff --git a/tests/e2e/PhpUnit_Depends_Order/expected-output.txt b/tests/e2e/PhpUnit_Depends_Order/expected-output.txt
index aa6c03830..95e73f9ca 100644
--- a/tests/e2e/PhpUnit_Depends_Order/expected-output.txt
+++ b/tests/e2e/PhpUnit_Depends_Order/expected-output.txt
@@ -2,6 +2,7 @@ Total: 0
 
 Killed: 0
 Errored: 0
+Syntax Errors: 0
 Escaped: 0
 Timed Out: 0
 Skipped: 0
diff --git a/tests/e2e/Phpunit_Bat_Wrapper/expected-output.txt b/tests/e2e/Phpunit_Bat_Wrapper/expected-output.txt
index 7bcb80de3..a31fc060f 100644
--- a/tests/e2e/Phpunit_Bat_Wrapper/expected-output.txt
+++ b/tests/e2e/Phpunit_Bat_Wrapper/expected-output.txt
@@ -2,6 +2,7 @@ Total: 1
 
 Killed: 1
 Errored: 0
+Syntax Errors: 0
 Escaped: 0
 Timed Out: 0
 Skipped: 0
diff --git a/tests/e2e/Profiles_Ignore_Combination/expected-output.txt b/tests/e2e/Profiles_Ignore_Combination/expected-output.txt
index 01d3ef456..c0e51b061 100644
--- a/tests/e2e/Profiles_Ignore_Combination/expected-output.txt
+++ b/tests/e2e/Profiles_Ignore_Combination/expected-output.txt
@@ -2,6 +2,7 @@ Total: 4
 
 Killed: 0
 Errored: 0
+Syntax Errors: 0
 Escaped: 0
 Timed Out: 0
 Skipped: 0
diff --git a/tests/e2e/Provide_Existing_Coverage/expected-output_phpunit.txt b/tests/e2e/Provide_Existing_Coverage/expected-output_phpunit.txt
index e0322f347..e2f0f5d54 100644
--- a/tests/e2e/Provide_Existing_Coverage/expected-output_phpunit.txt
+++ b/tests/e2e/Provide_Existing_Coverage/expected-output_phpunit.txt
@@ -28,6 +28,9 @@ Line 15
 Errors mutants:
 ===============
 
+Syntax Errors mutants:
+======================
+
 Escaped mutants:
 ================
 
diff --git a/tests/e2e/Save_PHPUnit_Bootstrap_File/expected-output.txt b/tests/e2e/Save_PHPUnit_Bootstrap_File/expected-output.txt
index 7bcb80de3..a31fc060f 100644
--- a/tests/e2e/Save_PHPUnit_Bootstrap_File/expected-output.txt
+++ b/tests/e2e/Save_PHPUnit_Bootstrap_File/expected-output.txt
@@ -2,6 +2,7 @@ Total: 1
 
 Killed: 1
 Errored: 0
+Syntax Errors: 0
 Escaped: 0
 Timed Out: 0
 Skipped: 0
diff --git a/tests/e2e/Skip_Initial_Tests/expected-output_phpunit.txt b/tests/e2e/Skip_Initial_Tests/expected-output_phpunit.txt
index c73cd3f1f..9323b3835 100644
--- a/tests/e2e/Skip_Initial_Tests/expected-output_phpunit.txt
+++ b/tests/e2e/Skip_Initial_Tests/expected-output_phpunit.txt
@@ -28,6 +28,9 @@ Line 15
 Errors mutants:
 ===============
 
+Syntax Errors mutants:
+======================
+
 Escaped mutants:
 ================
 
diff --git a/tests/e2e/Source_Directories_Config/expected-output.txt b/tests/e2e/Source_Directories_Config/expected-output.txt
index 7bcb80de3..a31fc060f 100644
--- a/tests/e2e/Source_Directories_Config/expected-output.txt
+++ b/tests/e2e/Source_Directories_Config/expected-output.txt
@@ -2,6 +2,7 @@ Total: 1
 
 Killed: 1
 Errored: 0
+Syntax Errors: 0
 Escaped: 0
 Timed Out: 0
 Skipped: 0
diff --git a/tests/e2e/SymfonyBridge/expected-output.txt b/tests/e2e/SymfonyBridge/expected-output.txt
index 7bcb80de3..a31fc060f 100644
--- a/tests/e2e/SymfonyBridge/expected-output.txt
+++ b/tests/e2e/SymfonyBridge/expected-output.txt
@@ -2,6 +2,7 @@ Total: 1
 
 Killed: 1
 Errored: 0
+Syntax Errors: 0
 Escaped: 0
 Timed Out: 0
 Skipped: 0
diff --git a/tests/e2e/SymfonyFlex/expected-output.txt b/tests/e2e/SymfonyFlex/expected-output.txt
index 7bcb80de3..a31fc060f 100644
--- a/tests/e2e/SymfonyFlex/expected-output.txt
+++ b/tests/e2e/SymfonyFlex/expected-output.txt
@@ -2,6 +2,7 @@ Total: 1
 
 Killed: 1
 Errored: 0
+Syntax Errors: 0
 Escaped: 0
 Timed Out: 0
 Skipped: 0
diff --git a/tests/e2e/Syntax_Error_PHPUnit/README.md b/tests/e2e/Syntax_Error_PHPUnit/README.md
new file mode 100644
index 000000000..e5f27ff79
--- /dev/null
+++ b/tests/e2e/Syntax_Error_PHPUnit/README.md
@@ -0,0 +1,7 @@
+# Title
+
+* This test ensures that the results produced by Mutators that generate invalid syntax (with "syntax error") are treated separately
+
+## Summary
+
+Related to https://github.com/infection/infection/issues/262
diff --git a/tests/e2e/Syntax_Error_PHPUnit/composer.json b/tests/e2e/Syntax_Error_PHPUnit/composer.json
new file mode 100644
index 000000000..8f49b60f7
--- /dev/null
+++ b/tests/e2e/Syntax_Error_PHPUnit/composer.json
@@ -0,0 +1,15 @@
+{
+    "require-dev": {
+        "phpunit/phpunit": "^9.5.8"
+    },
+    "autoload": {
+        "psr-4": {
+            "Syntax_Error_PHPUnit\\": "src/"
+        }
+    },
+    "autoload-dev": {
+        "psr-4": {
+            "Syntax_Error_PHPUnit\\Test\\": "tests/"
+        }
+    }
+}
diff --git a/tests/e2e/Syntax_Error_PHPUnit/expected-output.txt b/tests/e2e/Syntax_Error_PHPUnit/expected-output.txt
new file mode 100644
index 000000000..b3a0bb786
--- /dev/null
+++ b/tests/e2e/Syntax_Error_PHPUnit/expected-output.txt
@@ -0,0 +1,9 @@
+Total: 1
+
+Killed: 0
+Errored: 0
+Syntax Errors: 1
+Escaped: 0
+Timed Out: 0
+Skipped: 0
+Not Covered: 0
diff --git a/tests/e2e/Syntax_Error_PHPUnit/infection.json b/tests/e2e/Syntax_Error_PHPUnit/infection.json
new file mode 100644
index 000000000..3164ffe15
--- /dev/null
+++ b/tests/e2e/Syntax_Error_PHPUnit/infection.json
@@ -0,0 +1,17 @@
+{
+    "$schema": "../../../resources/schema.json",
+    "timeout": 25,
+    "source": {
+        "directories": [
+            "src"
+        ]
+    },
+    "logs": {
+        "summary": "infection.log"
+    },
+    "tmpDir": ".",
+    "mutators": {
+        "@default": false,
+        "SyntaxError": true
+    }
+}
diff --git a/tests/e2e/Syntax_Error_PHPUnit/phpunit.xml b/tests/e2e/Syntax_Error_PHPUnit/phpunit.xml
new file mode 100644
index 000000000..df138fe3f
--- /dev/null
+++ b/tests/e2e/Syntax_Error_PHPUnit/phpunit.xml
@@ -0,0 +1,18 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<phpunit xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+         xsi:noNamespaceSchemaLocation="./vendor/phpunit/phpunit/schema/9.2.xsd"
+         bootstrap="./vendor/autoload.php"
+         colors="true"
+>
+    <testsuites>
+        <testsuite name="Test Suite">
+            <directory>./tests/</directory>
+        </testsuite>
+    </testsuites>
+
+    <filter>
+        <whitelist>
+            <directory>./src/</directory>
+        </whitelist>
+    </filter>
+</phpunit>
diff --git a/tests/e2e/Syntax_Error_PHPUnit/src/SourceClass.php b/tests/e2e/Syntax_Error_PHPUnit/src/SourceClass.php
new file mode 100644
index 000000000..f92913337
--- /dev/null
+++ b/tests/e2e/Syntax_Error_PHPUnit/src/SourceClass.php
@@ -0,0 +1,16 @@
+<?php
+
+namespace Syntax_Error_PHPUnit;
+
+class SourceClass
+{
+    public function foo(): string
+    {
+        return 'hello';
+    }
+
+    public function bar(): string
+    {
+        return $this->foo();
+    }
+}
diff --git a/tests/e2e/Syntax_Error_PHPUnit/tests/SourceClassTest.php b/tests/e2e/Syntax_Error_PHPUnit/tests/SourceClassTest.php
new file mode 100644
index 000000000..ba2ac274d
--- /dev/null
+++ b/tests/e2e/Syntax_Error_PHPUnit/tests/SourceClassTest.php
@@ -0,0 +1,15 @@
+<?php
+
+namespace Syntax_Error_PHPUnit\Test;
+
+use Syntax_Error_PHPUnit\SourceClass;
+use PHPUnit\Framework\TestCase;
+
+class SourceClassTest extends TestCase
+{
+    public function test_hello()
+    {
+        $sourceClass = new SourceClass();
+        $this->assertSame('hello', $sourceClass->bar());
+    }
+}
diff --git a/tests/e2e/Syntax_Error_Pest/README.md b/tests/e2e/Syntax_Error_Pest/README.md
new file mode 100644
index 000000000..e5f27ff79
--- /dev/null
+++ b/tests/e2e/Syntax_Error_Pest/README.md
@@ -0,0 +1,7 @@
+# Title
+
+* This test ensures that the results produced by Mutators that generate invalid syntax (with "syntax error") are treated separately
+
+## Summary
+
+Related to https://github.com/infection/infection/issues/262
diff --git a/tests/e2e/Syntax_Error_Pest/composer.json b/tests/e2e/Syntax_Error_Pest/composer.json
new file mode 100644
index 000000000..a41b55ed7
--- /dev/null
+++ b/tests/e2e/Syntax_Error_Pest/composer.json
@@ -0,0 +1,15 @@
+{
+    "require-dev": {
+        "pestphp/pest": "^1.2.0"
+    },
+    "autoload": {
+        "psr-4": {
+            "Syntax_Error_Pest\\": "src/"
+        }
+    },
+    "autoload-dev": {
+        "psr-4": {
+            "Syntax_Error_Pest\\Test\\": "tests/"
+        }
+    }
+}
diff --git a/tests/e2e/Syntax_Error_Pest/expected-output.txt b/tests/e2e/Syntax_Error_Pest/expected-output.txt
new file mode 100644
index 000000000..b3a0bb786
--- /dev/null
+++ b/tests/e2e/Syntax_Error_Pest/expected-output.txt
@@ -0,0 +1,9 @@
+Total: 1
+
+Killed: 0
+Errored: 0
+Syntax Errors: 1
+Escaped: 0
+Timed Out: 0
+Skipped: 0
+Not Covered: 0
diff --git a/tests/e2e/Syntax_Error_Pest/infection.json b/tests/e2e/Syntax_Error_Pest/infection.json
new file mode 100644
index 000000000..3164ffe15
--- /dev/null
+++ b/tests/e2e/Syntax_Error_Pest/infection.json
@@ -0,0 +1,17 @@
+{
+    "$schema": "../../../resources/schema.json",
+    "timeout": 25,
+    "source": {
+        "directories": [
+            "src"
+        ]
+    },
+    "logs": {
+        "summary": "infection.log"
+    },
+    "tmpDir": ".",
+    "mutators": {
+        "@default": false,
+        "SyntaxError": true
+    }
+}
diff --git a/tests/e2e/Syntax_Error_Pest/phpunit.xml b/tests/e2e/Syntax_Error_Pest/phpunit.xml
new file mode 100644
index 000000000..df138fe3f
--- /dev/null
+++ b/tests/e2e/Syntax_Error_Pest/phpunit.xml
@@ -0,0 +1,18 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<phpunit xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+         xsi:noNamespaceSchemaLocation="./vendor/phpunit/phpunit/schema/9.2.xsd"
+         bootstrap="./vendor/autoload.php"
+         colors="true"
+>
+    <testsuites>
+        <testsuite name="Test Suite">
+            <directory>./tests/</directory>
+        </testsuite>
+    </testsuites>
+
+    <filter>
+        <whitelist>
+            <directory>./src/</directory>
+        </whitelist>
+    </filter>
+</phpunit>
diff --git a/tests/e2e/Syntax_Error_Pest/run_tests.bash b/tests/e2e/Syntax_Error_Pest/run_tests.bash
new file mode 100755
index 000000000..949873a44
--- /dev/null
+++ b/tests/e2e/Syntax_Error_Pest/run_tests.bash
@@ -0,0 +1,14 @@
+#!/usr/bin/env bash
+
+readonly INFECTION="../../../bin/infection --test-framework=pest"
+
+set -e pipefail
+
+if [ "$DRIVER" = "phpdbg" ]
+then
+    phpdbg -qrr $INFECTION
+else
+    php $INFECTION
+fi
+
+diff -w expected-output.txt infection.log
diff --git a/tests/e2e/Syntax_Error_Pest/src/ForPest.php b/tests/e2e/Syntax_Error_Pest/src/ForPest.php
new file mode 100644
index 000000000..6692b610f
--- /dev/null
+++ b/tests/e2e/Syntax_Error_Pest/src/ForPest.php
@@ -0,0 +1,16 @@
+<?php
+
+namespace Syntax_Error_Pest;
+
+class ForPest
+{
+    public function foo(): string
+    {
+        return 'hello';
+    }
+
+    public function hello(): string
+    {
+        return $this->foo();
+    }
+}
diff --git a/tests/e2e/Syntax_Error_Pest/tests/ForPestTest.php b/tests/e2e/Syntax_Error_Pest/tests/ForPestTest.php
new file mode 100644
index 000000000..e12e6c83f
--- /dev/null
+++ b/tests/e2e/Syntax_Error_Pest/tests/ForPestTest.php
@@ -0,0 +1,11 @@
+<?php
+
+use Syntax_Error_Pest\Test;
+
+use Syntax_Error_Pest\ForPest;
+
+test('Syntax Error for Pest', function () {
+    $sourceClass = new ForPest();
+
+    expect($sourceClass->hello())->toBe('hello');
+});
diff --git a/tests/e2e/Test_Framework_Options_Config/expected-output.txt b/tests/e2e/Test_Framework_Options_Config/expected-output.txt
index 7bcb80de3..a31fc060f 100644
--- a/tests/e2e/Test_Framework_Options_Config/expected-output.txt
+++ b/tests/e2e/Test_Framework_Options_Config/expected-output.txt
@@ -2,6 +2,7 @@ Total: 1
 
 Killed: 1
 Errored: 0
+Syntax Errors: 0
 Escaped: 0
 Timed Out: 0
 Skipped: 0
diff --git a/tests/e2e/Test_PHP_Options_Config/expected-output.txt b/tests/e2e/Test_PHP_Options_Config/expected-output.txt
index 7bcb80de3..a31fc060f 100644
--- a/tests/e2e/Test_PHP_Options_Config/expected-output.txt
+++ b/tests/e2e/Test_PHP_Options_Config/expected-output.txt
@@ -2,6 +2,7 @@ Total: 1
 
 Killed: 1
 Errored: 0
+Syntax Errors: 0
 Escaped: 0
 Timed Out: 0
 Skipped: 0
diff --git a/tests/e2e/TimeoutSkipped/expected-output.txt b/tests/e2e/TimeoutSkipped/expected-output.txt
index 4c78b02b4..129bf771f 100644
--- a/tests/e2e/TimeoutSkipped/expected-output.txt
+++ b/tests/e2e/TimeoutSkipped/expected-output.txt
@@ -2,6 +2,7 @@ Total: 5
 
 Killed: 2
 Errored: 0
+Syntax Errors: 0
 Escaped: 2
 Timed Out: 1
 Skipped: 0
diff --git a/tests/e2e/Variables_Order_EGPCS/expected-output.txt b/tests/e2e/Variables_Order_EGPCS/expected-output.txt
index 7bcb80de3..a31fc060f 100644
--- a/tests/e2e/Variables_Order_EGPCS/expected-output.txt
+++ b/tests/e2e/Variables_Order_EGPCS/expected-output.txt
@@ -2,6 +2,7 @@ Total: 1
 
 Killed: 1
 Errored: 0
+Syntax Errors: 0
 Escaped: 0
 Timed Out: 0
 Skipped: 0
diff --git a/tests/e2e/YieldValue/expected-output.txt b/tests/e2e/YieldValue/expected-output.txt
index 3c92154a1..1ce4f94ab 100644
--- a/tests/e2e/YieldValue/expected-output.txt
+++ b/tests/e2e/YieldValue/expected-output.txt
@@ -1,6 +1,6 @@
 # Effects per Mutator
 
-| Mutator    | Mutations | Killed | Escaped | Errors | Timed Out | Skipped | MSI (%s) | Covered MSI (%s) |
-| ---------- | --------- | ------ | ------- | ------ | --------- | ------- | -------- | ---------------- |
-| YieldValue |         2 |      1 |       0 |      0 |         0 |       0 |    50.00 |           100.00 |
-| Yield_     |         2 |      1 |       0 |      0 |         0 |       0 |    50.00 |           100.00 |
+| Mutator    | Mutations | Killed | Escaped | Errors | Syntax Errors | Timed Out | Skipped | MSI (%s) | Covered MSI (%s) |
+| ---------- | --------- | ------ | ------- | ------ | ------------- | --------- | ------- | -------- | ---------------- |
+| YieldValue |         2 |      1 |       0 |      0 |             0 |         0 |       0 |    50.00 |           100.00 |
+| Yield_     |         2 |      1 |       0 |      0 |             0 |         0 |       0 |    50.00 |           100.00 |
diff --git a/tests/phpunit/Console/OutputFormatter/DotFormatterTest.php b/tests/phpunit/Console/OutputFormatter/DotFormatterTest.php
index 60f440f6f..fd6768c6f 100644
--- a/tests/phpunit/Console/OutputFormatter/DotFormatterTest.php
+++ b/tests/phpunit/Console/OutputFormatter/DotFormatterTest.php
@@ -58,6 +58,7 @@ public function test_start_logs_initial_starting_text(): void
             . '<escaped>M</escaped>: escaped, '
             . '<uncovered>U</uncovered>: uncovered, '
             . '<with-error>E</with-error>: fatal error, '
+            . '<with-syntax-error>X</with-syntax-error>: syntax error, '
             . '<timeout>T</timeout>: timed out, '
             . '<skipped>S</skipped>: skipped',
             '',
@@ -184,7 +185,7 @@ public function test_it_prints_total_number_of_mutations(): void
         $this->assertSame(str_replace("\n", PHP_EOL,
             <<<'TXT'
 
-.: killed, M: escaped, U: uncovered, E: fatal error, T: timed out, S: skipped
+.: killed, M: escaped, U: uncovered, E: fatal error, X: syntax error, T: timed out, S: skipped
 
 ..................................................   ( 50 / 127)
 ..................................................   (100 / 127)
@@ -213,7 +214,7 @@ public function test_it_prints_current_number_of_pending_mutations(): void
         $this->assertSame(str_replace("\n", PHP_EOL,
             <<<'TXT'
 
-.: killed, M: escaped, U: uncovered, E: fatal error, T: timed out, S: skipped
+.: killed, M: escaped, U: uncovered, E: fatal error, X: syntax error, T: timed out, S: skipped
 
 ..................................................   (   50)
 ..................................................   (  100)
@@ -252,6 +253,7 @@ private function getStartOutputFormatter()
             . '<escaped>M</escaped>: escaped, '
             . '<uncovered>U</uncovered>: uncovered, '
             . '<with-error>E</with-error>: fatal error, '
+            . '<with-syntax-error>X</with-syntax-error>: syntax error, '
             . '<timeout>T</timeout>: timed out, '
             . '<skipped>S</skipped>: skipped',
             '',
diff --git a/tests/phpunit/Console/OutputFormatterStyleConfiguratorTest.php b/tests/phpunit/Console/OutputFormatterStyleConfiguratorTest.php
index ad0d7ad90..6c1214269 100644
--- a/tests/phpunit/Console/OutputFormatterStyleConfiguratorTest.php
+++ b/tests/phpunit/Console/OutputFormatterStyleConfiguratorTest.php
@@ -46,7 +46,7 @@ public function test_it_adds_styles(): void
     {
         $formatter = $this->createMock(OutputFormatterInterface::class);
         $formatter
-            ->expects($this->exactly(12))
+            ->expects($this->exactly(13))
             ->method('setStyle')
         ;
 
diff --git a/tests/phpunit/Fixtures/TestFramework/DummyTestFrameworkAdapter.php b/tests/phpunit/Fixtures/TestFramework/DummyTestFrameworkAdapter.php
index 7f2d982a7..c18dcf6bf 100644
--- a/tests/phpunit/Fixtures/TestFramework/DummyTestFrameworkAdapter.php
+++ b/tests/phpunit/Fixtures/TestFramework/DummyTestFrameworkAdapter.php
@@ -5,6 +5,7 @@
 namespace Infection\Tests\Fixtures\TestFramework;
 
 use Infection\AbstractTestFramework\TestFrameworkAdapter;
+use Infection\AbstractTestFramework\UnsupportedTestFrameworkVersion;
 
 final class DummyTestFrameworkAdapter implements TestFrameworkAdapter
 {
diff --git a/tests/phpunit/Logger/CreateMetricsCalculator.php b/tests/phpunit/Logger/CreateMetricsCalculator.php
index 7d3dc21fa..70eabdda4 100644
--- a/tests/phpunit/Logger/CreateMetricsCalculator.php
+++ b/tests/phpunit/Logger/CreateMetricsCalculator.php
@@ -93,6 +93,18 @@ private function feedCollector(Collector $collector): void
                 DetectionStatus::ERROR,
                 'error#1'
             ),
+            $this->createMutantExecutionResult(
+                0,
+                For_::class,
+                DetectionStatus::SYNTAX_ERROR,
+                'syntaxError#0'
+            ),
+            $this->createMutantExecutionResult(
+                1,
+                PregQuote::class,
+                DetectionStatus::SYNTAX_ERROR,
+                'syntaxError#1'
+            ),
             $this->createMutantExecutionResult(
                 0,
                 For_::class,
diff --git a/tests/phpunit/Logger/DebugFileLoggerTest.php b/tests/phpunit/Logger/DebugFileLoggerTest.php
index cbf9f63ef..bbe286361 100644
--- a/tests/phpunit/Logger/DebugFileLoggerTest.php
+++ b/tests/phpunit/Logger/DebugFileLoggerTest.php
@@ -74,6 +74,9 @@ public function metricsProvider(): iterable
 Errors mutants:
 ===============
 
+Syntax Errors mutants:
+======================
+
 Escaped mutants:
 ================
 
@@ -94,7 +97,7 @@ public function metricsProvider(): iterable
             $this->createCompleteResultsCollector(),
             false,
             <<<'TXT'
-Total: 12
+Total: 14
 
 Killed mutants:
 ===============
@@ -116,6 +119,16 @@ public function metricsProvider(): iterable
 Line 10
 
 
+Syntax Errors mutants:
+======================
+
+Mutator: PregQuote
+Line 9
+
+Mutator: For_
+Line 10
+
+
 Escaped mutants:
 ================
 
@@ -163,7 +176,7 @@ public function metricsProvider(): iterable
             $this->createCompleteResultsCollector(),
             true,
             <<<'TXT'
-Total: 12
+Total: 14
 
 Killed mutants:
 ===============
@@ -185,6 +198,16 @@ public function metricsProvider(): iterable
 Line 10
 
 
+Syntax Errors mutants:
+======================
+
+Mutator: PregQuote
+Line 9
+
+Mutator: For_
+Line 10
+
+
 Escaped mutants:
 ================
 
diff --git a/tests/phpunit/Logger/JsonLoggerTest.php b/tests/phpunit/Logger/JsonLoggerTest.php
index a4d1f933e..f3fc9c0db 100644
--- a/tests/phpunit/Logger/JsonLoggerTest.php
+++ b/tests/phpunit/Logger/JsonLoggerTest.php
@@ -82,6 +82,7 @@ public function metricsProvider(): iterable
                     'notCoveredCount' => 0,
                     'escapedCount' => 0,
                     'errorCount' => 0,
+                    'syntaxErrorCount' => 0,
                     'skippedCount' => 0,
                     'timeOutCount' => 0,
                     'msi' => 0,
@@ -92,6 +93,7 @@ public function metricsProvider(): iterable
                 'timeouted' => [],
                 'killed' => [],
                 'errored' => [],
+                'syntaxErrors' => [],
                 'uncovered' => [],
             ],
         ];
@@ -102,16 +104,17 @@ public function metricsProvider(): iterable
             $this->createCompleteResultsCollector(),
             [
                 'stats' => [
-                    'totalMutantsCount' => 12,
+                    'totalMutantsCount' => 14,
                     'killedCount' => 2,
                     'notCoveredCount' => 2,
                     'escapedCount' => 2,
                     'errorCount' => 2,
+                    'syntaxErrorCount' => 2,
                     'skippedCount' => 2,
                     'timeOutCount' => 2,
-                    'msi' => 60,
-                    'mutationCodeCoverage' => 80,
-                    'coveredCodeMsi' => 75,
+                    'msi' => 50,
+                    'mutationCodeCoverage' => 83.33,
+                    'coveredCodeMsi' => 60,
                 ],
                 'escaped' => [
                     [
@@ -209,6 +212,30 @@ public function metricsProvider(): iterable
                         'processOutput' => 'process output',
                     ],
                 ],
+                'syntaxErrors' => [
+                    [
+                        'mutator' => [
+                            'mutatorName' => 'PregQuote',
+                            'originalSourceCode' => '<?php $a = 1;',
+                            'mutatedSourceCode' => '<?php $a = 2;',
+                            'originalFilePath' => 'foo/bar',
+                            'originalStartLine' => 9,
+                        ],
+                        'diff' => str_replace("\n", PHP_EOL, "--- Original\n+++ New\n@@ @@\n\n- echo 'original';\n+ echo 'syntaxError#1';"),
+                        'processOutput' => 'process output',
+                    ],
+                    [
+                        'mutator' => [
+                            'mutatorName' => 'For_',
+                            'originalSourceCode' => '<?php $a = 1;',
+                            'mutatedSourceCode' => '<?php $a = 2;',
+                            'originalFilePath' => 'foo/bar',
+                            'originalStartLine' => 10,
+                        ],
+                        'diff' => str_replace("\n", PHP_EOL, "--- Original\n+++ New\n@@ @@\n\n- echo 'original';\n+ echo 'syntaxError#0';"),
+                        'processOutput' => 'process output',
+                    ],
+                ],
                 'uncovered' => [],
             ],
         ];
@@ -224,6 +251,7 @@ public function metricsProvider(): iterable
                     'notCoveredCount' => 1,
                     'escapedCount' => 0,
                     'errorCount' => 0,
+                    'syntaxErrorCount' => 0,
                     'skippedCount' => 0,
                     'timeOutCount' => 0,
                     'msi' => 0,
@@ -234,6 +262,7 @@ public function metricsProvider(): iterable
                 'timeouted' => [],
                 'killed' => [],
                 'errored' => [],
+                'syntaxErrors' => [],
                 'uncovered' => [
                     [
                         'mutator' => [
@@ -261,6 +290,7 @@ public function metricsProvider(): iterable
                     'notCoveredCount' => 0,
                     'escapedCount' => 0,
                     'errorCount' => 0,
+                    'syntaxErrorCount' => 0,
                     'skippedCount' => 0,
                     'timeOutCount' => 0,
                     'msi' => 0,
@@ -271,6 +301,7 @@ public function metricsProvider(): iterable
                 'timeouted' => [],
                 'killed' => [],
                 'errored' => [],
+                'syntaxErrors' => [],
                 'uncovered' => [
                     [
                         'mutator' => [
diff --git a/tests/phpunit/Logger/PerMutatorLoggerTest.php b/tests/phpunit/Logger/PerMutatorLoggerTest.php
index 22e484004..d9a9262ba 100644
--- a/tests/phpunit/Logger/PerMutatorLoggerTest.php
+++ b/tests/phpunit/Logger/PerMutatorLoggerTest.php
@@ -66,8 +66,8 @@ public function metricsProvider(): iterable
             <<<'TXT'
 # Effects per Mutator
 
-| Mutator | Mutations | Killed | Escaped | Errors | Timed Out | Skipped | MSI (%s) | Covered MSI (%s) |
-| ------- | --------- | ------ | ------- | ------ | --------- | ------- | -------- | ---------------- |
+| Mutator | Mutations | Killed | Escaped | Errors | Syntax Errors | Timed Out | Skipped | MSI (%s) | Covered MSI (%s) |
+| ------- | --------- | ------ | ------- | ------ | ------------- | --------- | ------- | -------- | ---------------- |
 
 TXT
         ];
@@ -78,10 +78,10 @@ public function metricsProvider(): iterable
             <<<'TXT'
 # Effects per Mutator
 
-| Mutator   | Mutations | Killed | Escaped | Errors | Timed Out | Skipped | MSI (%s) | Covered MSI (%s) |
-| --------- | --------- | ------ | ------- | ------ | --------- | ------- | -------- | ---------------- |
-| For_      |         6 |      1 |       1 |      1 |         1 |       1 |    60.00 |            75.00 |
-| PregQuote |         6 |      1 |       1 |      1 |         1 |       1 |    60.00 |            75.00 |
+| Mutator   | Mutations | Killed | Escaped | Errors | Syntax Errors | Timed Out | Skipped | MSI (%s) | Covered MSI (%s) |
+| --------- | --------- | ------ | ------- | ------ | ------------- | --------- | ------- | -------- | ---------------- |
+| For_      |         7 |      1 |       1 |      1 |             1 |         1 |       1 |    50.00 |            60.00 |
+| PregQuote |         7 |      1 |       1 |      1 |             1 |         1 |       1 |    50.00 |            60.00 |
 
 TXT
         ];
diff --git a/tests/phpunit/Logger/SummaryFileLoggerTest.php b/tests/phpunit/Logger/SummaryFileLoggerTest.php
index 9cf38cb51..3abb453e5 100644
--- a/tests/phpunit/Logger/SummaryFileLoggerTest.php
+++ b/tests/phpunit/Logger/SummaryFileLoggerTest.php
@@ -65,6 +65,7 @@ public function metricsProvider(): iterable
 
 Killed: 0
 Errored: 0
+Syntax Errors: 0
 Escaped: 0
 Timed Out: 0
 Skipped: 0
@@ -76,10 +77,11 @@ public function metricsProvider(): iterable
         yield 'all mutations' => [
             $this->createCompleteMetricsCalculator(),
             <<<'TXT'
-Total: 12
+Total: 14
 
 Killed: 2
 Errored: 2
+Syntax Errors: 2
 Escaped: 2
 Timed Out: 2
 Skipped: 2
diff --git a/tests/phpunit/Logger/TextFileLoggerTest.php b/tests/phpunit/Logger/TextFileLoggerTest.php
index 1f51a393a..34bb866aa 100644
--- a/tests/phpunit/Logger/TextFileLoggerTest.php
+++ b/tests/phpunit/Logger/TextFileLoggerTest.php
@@ -124,6 +124,9 @@ public function emptyMetricsProvider(): iterable
 Errors mutants:
 ===============
 
+Syntax Errors mutants:
+======================
+
 Not Covered mutants:
 ====================
 
@@ -170,6 +173,9 @@ public function emptyMetricsProvider(): iterable
 Errors mutants:
 ===============
 
+Syntax Errors mutants:
+======================
+
 Not Covered mutants:
 ====================
 
@@ -213,6 +219,9 @@ public function emptyMetricsProvider(): iterable
 Errors mutants:
 ===============
 
+Syntax Errors mutants:
+======================
+
 TXT
         ];
 
@@ -253,6 +262,9 @@ public function emptyMetricsProvider(): iterable
 Errors mutants:
 ===============
 
+Syntax Errors mutants:
+======================
+
 TXT
         ];
     }
@@ -498,6 +510,33 @@ public function completeMetricsProvider(): iterable
   process output
 
 
+Syntax Errors mutants:
+======================
+
+1) foo/bar:9    [M] PregQuote
+
+--- Original
++++ New
+@@ @@
+
+- echo 'original';
++ echo 'syntaxError#1';
+
+  process output
+
+
+2) foo/bar:10    [M] For_
+
+--- Original
++++ New
+@@ @@
+
+- echo 'original';
++ echo 'syntaxError#0';
+
+  process output
+
+
 Not Covered mutants:
 ====================
 
@@ -792,6 +831,35 @@ public function completeMetricsProvider(): iterable
   process output
 
 
+Syntax Errors mutants:
+======================
+
+1) foo/bar:9    [M] PregQuote
+
+--- Original
++++ New
+@@ @@
+
+- echo 'original';
++ echo 'syntaxError#1';
+
+$ bin/phpunit --configuration infection-tmp-phpunit.xml --filter "tests/Acme/FooTest.php"
+  process output
+
+
+2) foo/bar:10    [M] For_
+
+--- Original
++++ New
+@@ @@
+
+- echo 'original';
++ echo 'syntaxError#0';
+
+$ bin/phpunit --configuration infection-tmp-phpunit.xml --filter "tests/Acme/FooTest.php"
+  process output
+
+
 Not Covered mutants:
 ====================
 
@@ -1038,6 +1106,33 @@ public function completeMetricsProvider(): iterable
 
   process output
 
+
+Syntax Errors mutants:
+======================
+
+1) foo/bar:9    [M] PregQuote
+
+--- Original
++++ New
+@@ @@
+
+- echo 'original';
++ echo 'syntaxError#1';
+
+  process output
+
+
+2) foo/bar:10    [M] For_
+
+--- Original
++++ New
+@@ @@
+
+- echo 'original';
++ echo 'syntaxError#0';
+
+  process output
+
 TXT
         ];
 
@@ -1275,6 +1370,35 @@ public function completeMetricsProvider(): iterable
 - echo 'original';
 + echo 'error#0';
 
+$ bin/phpunit --configuration infection-tmp-phpunit.xml --filter "tests/Acme/FooTest.php"
+  process output
+
+
+Syntax Errors mutants:
+======================
+
+1) foo/bar:9    [M] PregQuote
+
+--- Original
++++ New
+@@ @@
+
+- echo 'original';
++ echo 'syntaxError#1';
+
+$ bin/phpunit --configuration infection-tmp-phpunit.xml --filter "tests/Acme/FooTest.php"
+  process output
+
+
+2) foo/bar:10    [M] For_
+
+--- Original
++++ New
+@@ @@
+
+- echo 'original';
++ echo 'syntaxError#0';
+
 $ bin/phpunit --configuration infection-tmp-phpunit.xml --filter "tests/Acme/FooTest.php"
   process output
 
diff --git a/tests/phpunit/Metrics/CalculatorTest.php b/tests/phpunit/Metrics/CalculatorTest.php
index 7919f7cd0..cfd726cfa 100644
--- a/tests/phpunit/Metrics/CalculatorTest.php
+++ b/tests/phpunit/Metrics/CalculatorTest.php
@@ -174,9 +174,9 @@ public function metricsCalculatorProvider(): iterable
 
         yield 'nominal' => [
             $this->createCompleteMetricsCalculator(),
-            60.,
-            80.0,
-            75.0,
+            50.,  // 14 total mutations; 2 skipped; 6 of 12 are killed => 50%
+            83.33, // 14 total mutations; 2 skipped & 2 not covered; => 10 of 12 => 83.33%
+            60.0, // 14 total mutations; 2 skipped & 2 not covered; 6 of 10 are killed => 60%
         ];
     }
 }
diff --git a/tests/phpunit/Mutator/BaseMutatorTestCase.php b/tests/phpunit/Mutator/BaseMutatorTestCase.php
index 27a85b3e9..54cc9e150 100644
--- a/tests/phpunit/Mutator/BaseMutatorTestCase.php
+++ b/tests/phpunit/Mutator/BaseMutatorTestCase.php
@@ -70,7 +70,7 @@ protected function setUp(): void
      * @var string|string[]
      * @var mixed[] $settings
      */
-    final public function doTest(string $inputCode, $expectedCode = [], array $settings = []): void
+    final public function doTest(string $inputCode, $expectedCode = [], array $settings = [], bool $allowInvalidCode = false): void
     {
         $expectedCodeSamples = (array) $expectedCode;
 
@@ -106,7 +106,10 @@ final public function doTest(string $inputCode, $expectedCode = [], array $setti
                 StringNormalizer::normalizeString($expectedCodeSample),
                 StringNormalizer::normalizeString($realMutatedCode)
             );
-            $this->assertSyntaxIsValid($realMutatedCode);
+
+            if (!$allowInvalidCode) {
+                $this->assertSyntaxIsValid($realMutatedCode);
+            }
         }
     }
 
diff --git a/tests/phpunit/Mutator/ProfileListProvider.php b/tests/phpunit/Mutator/ProfileListProvider.php
index ada99f0ae..9dbc81850 100644
--- a/tests/phpunit/Mutator/ProfileListProvider.php
+++ b/tests/phpunit/Mutator/ProfileListProvider.php
@@ -44,6 +44,7 @@
 use Infection\Mutator\Mutator;
 use Infection\Mutator\NoopMutator;
 use Infection\Mutator\ProfileList;
+use Infection\Mutator\SyntaxError;
 use ReflectionClass;
 use function Safe\ksort;
 use function Safe\realpath;
@@ -98,7 +99,7 @@ public static function implementedMutatorProvider(): iterable
             $shortClassName = substr($file->getFilename(), 0, -4);
             $className = self::getMutatorClassNameFromPath($file->getPathname());
 
-            if (in_array($className, [IgnoreMutator::class, NoopMutator::class], true)) {
+            if (in_array($className, [IgnoreMutator::class, NoopMutator::class, SyntaxError::class], true)) {
                 continue;
             }
 
diff --git a/tests/phpunit/Mutator/SyntaxErrorTest.php b/tests/phpunit/Mutator/SyntaxErrorTest.php
new file mode 100644
index 000000000..5916197c4
--- /dev/null
+++ b/tests/phpunit/Mutator/SyntaxErrorTest.php
@@ -0,0 +1,66 @@
+<?php
+/**
+ * This code is licensed under the BSD 3-Clause License.
+ *
+ * Copyright (c) 2017, Maks Rafalko
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * * Redistributions of source code must retain the above copyright notice, this
+ *   list of conditions and the following disclaimer.
+ *
+ * * Redistributions in binary form must reproduce the above copyright notice,
+ *   this list of conditions and the following disclaimer in the documentation
+ *   and/or other materials provided with the distribution.
+ *
+ * * Neither the name of the copyright holder nor the names of its
+ *   contributors may be used to endorse or promote products derived from
+ *   this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+ * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+ * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+ * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+declare(strict_types=1);
+
+namespace Infection\Tests\Mutator;
+
+final class SyntaxErrorTest extends BaseMutatorTestCase
+{
+    /**
+     * @dataProvider mutationsProvider
+     *
+     * @param string|string[] $expected
+     */
+    public function test_it_can_mutate(string $input, $expected = []): void
+    {
+        $this->doTest($input, $expected, [], true);
+    }
+
+    public function mutationsProvider(): iterable
+    {
+        yield 'It mutates method call to invalid syntax' => [
+            <<<'PHP'
+<?php
+
+$this->methodCall();
+PHP
+            ,
+            <<<'PHP'
+<?php
+
+$->methodCall();
+PHP
+        ];
+    }
+}
diff --git a/tests/phpunit/TestFramework/PhpUnit/Adapter/PestAdapterTest.php b/tests/phpunit/TestFramework/PhpUnit/Adapter/PestAdapterTest.php
index bc5c85802..69ccfb90d 100644
--- a/tests/phpunit/TestFramework/PhpUnit/Adapter/PestAdapterTest.php
+++ b/tests/phpunit/TestFramework/PhpUnit/Adapter/PestAdapterTest.php
@@ -91,9 +91,9 @@ public function test_it_supports_junit_reports(): void
     }
 
     /**
-     * @dataProvider outputProvider
+     * @dataProvider passOutputProvider
      */
-    public function test_it_can_tell_the_outcome_of_the_tests_from_the_output(
+    public function test_it_can_tell_if_tests_pass_from_the_output(
         string $output,
         bool $expected
     ): void {
@@ -102,6 +102,18 @@ public function test_it_can_tell_the_outcome_of_the_tests_from_the_output(
         $this->assertSame($expected, $actual);
     }
 
+    /**
+     * @dataProvider syntaxErrorOutputProvider
+     */
+    public function test_it_can_tell_if_there_is_a_syntax_error_from_the_output(
+        string $output,
+        bool $expected
+    ): void {
+        $actual = $this->adapter->isSyntaxError($output);
+
+        $this->assertSame($expected, $actual);
+    }
+
     /**
      * @dataProvider memoryReportProvider
      */
@@ -266,7 +278,7 @@ public function test_it_provides_initial_test_run_command_line_when_coverage_rep
         );
     }
 
-    public function outputProvider(): iterable
+    public function passOutputProvider(): iterable
     {
         yield ['Tests:  1 risked', true];
 
@@ -275,6 +287,21 @@ public function outputProvider(): iterable
         yield ['Tests:  1 failed, 8 passed', false];
     }
 
+    public function syntaxErrorOutputProvider(): iterable
+    {
+        yield ['Tests:  1 risked', false];
+
+        yield [
+            <<<TXT
+'ParseError
+
+syntax error, unexpected ">"'
+TXT
+            ,
+            true,
+        ];
+    }
+
     public function memoryReportProvider(): iterable
     {
         yield ['Memory: 8.00MB', 8.0];
diff --git a/tests/phpunit/TestFramework/PhpUnit/Adapter/PhpUnitAdapterTest.php b/tests/phpunit/TestFramework/PhpUnit/Adapter/PhpUnitAdapterTest.php
index eb9d9b56e..ce718c2d0 100644
--- a/tests/phpunit/TestFramework/PhpUnit/Adapter/PhpUnitAdapterTest.php
+++ b/tests/phpunit/TestFramework/PhpUnit/Adapter/PhpUnitAdapterTest.php
@@ -91,9 +91,9 @@ public function test_it_supports_junit_reports(): void
     }
 
     /**
-     * @dataProvider outputProvider
+     * @dataProvider passOutputProvider
      */
-    public function test_it_can_tell_the_outcome_of_the_tests_from_the_output(
+    public function test_it_can_tell_if_tests_pass_from_the_output(
         string $output,
         bool $expected
     ): void {
@@ -102,6 +102,18 @@ public function test_it_can_tell_the_outcome_of_the_tests_from_the_output(
         $this->assertSame($expected, $actual);
     }
 
+    /**
+     * @dataProvider syntaxErrorOutputProvider
+     */
+    public function test_it_can_tell_if_there_is_a_syntax_error_from_the_output(
+        string $output,
+        bool $expected
+    ): void {
+        $actual = $this->adapter->isSyntaxError($output);
+
+        $this->assertSame($expected, $actual);
+    }
+
     /**
      * @dataProvider memoryReportProvider
      */
@@ -266,7 +278,7 @@ public function test_it_provides_initial_test_run_command_line_when_coverage_rep
         );
     }
 
-    public function outputProvider(): iterable
+    public function passOutputProvider(): iterable
     {
         yield ['OK, but incomplete, skipped, or risky tests!', true];
 
@@ -279,6 +291,13 @@ public function outputProvider(): iterable
         yield ['No tests executed!', true];
     }
 
+    public function syntaxErrorOutputProvider(): iterable
+    {
+        yield ['OK, but incomplete, skipped, or risky tests!', false];
+
+        yield ['ParseError: syntax error, unexpected ">"', true];
+    }
+
     public function memoryReportProvider(): iterable
     {
         yield ['Memory: 8.00MB', 8.0];