diff --git a/tests/Fixer/Preload/ExplicitlyLoadClassTest.php b/tests/Fixer/Preload/ExplicitlyLoadClassTest.php
index 361925f3f14..d642075579c 100644
--- a/tests/Fixer/Preload/ExplicitlyLoadClassTest.php
+++ b/tests/Fixer/Preload/ExplicitlyLoadClassTest.php
@@ -44,16 +44,18 @@ public function provideFixCases()
 
         /** @var SplFileInfo $file */
         foreach ($finder as $file) {
-            $path = $file->getRealPath();
-            $output = file_get_contents($path);
+            $output = file_get_contents($file->getRealPath());
 
-            $input = null;
-            $inputFile = substr($path, 0, -7).'In.php';
-            if (is_file($inputFile)) {
-                $input = file_get_contents($inputFile);
+            $inputFilePattern = substr($file->getFilename(), 0, -7).'In*.php';
+            $inputFinder = new Finder();
+            $inputFinder->in($testDir)->name($inputFilePattern);
+
+            /** @var SplFileInfo $file */
+            foreach ($inputFinder as $input) {
+                yield sprintf('%s => %s', $input->getFilename(), $file->getFilename()) => [$output, file_get_contents($input->getRealPath())];
             }
 
-            yield $file->getFilename() => [$output, $input];
+            yield $file->getFilename() => [$output, null];
         }
     }
 }
diff --git a/tests/Fixtures/Preload/Case003_In.php b/tests/Fixtures/Preload/Case003_In.php
new file mode 100644
index 00000000000..240dc39b8ea
--- /dev/null
+++ b/tests/Fixtures/Preload/Case003_In.php
@@ -0,0 +1,15 @@
+<?php
+
+use App\Foo;
+
+/**
+ * Constructor with new Foo()
+ */
+class Case003
+{
+    private $foo;
+    public function __construct()
+    {
+        $this->foo = new Foo();
+    }
+}
diff --git a/tests/Fixtures/Preload/Case003_Out.php b/tests/Fixtures/Preload/Case003_Out.php
new file mode 100644
index 00000000000..dc71d812022
--- /dev/null
+++ b/tests/Fixtures/Preload/Case003_Out.php
@@ -0,0 +1,16 @@
+<?php
+
+use App\Foo;
+
+class_exists(Foo::class);
+/**
+ * Constructor with new Foo()
+ */
+class Case003
+{
+    private $foo;
+    public function __construct()
+    {
+        $this->foo = new Foo();
+    }
+}
diff --git a/tests/Fixtures/Preload/Case004_In.php b/tests/Fixtures/Preload/Case004_In.php
new file mode 100644
index 00000000000..828e6ae9894
--- /dev/null
+++ b/tests/Fixtures/Preload/Case004_In.php
@@ -0,0 +1,15 @@
+<?php
+
+use App\Foo;
+
+/**
+ * Constructor with class reference
+ */
+class Case004
+{
+    private $foo;
+    public function __construct()
+    {
+        $this->foo = Foo::class;
+    }
+}
diff --git a/tests/Fixtures/Preload/Case004_Out.php b/tests/Fixtures/Preload/Case004_Out.php
new file mode 100644
index 00000000000..7543f9570fc
--- /dev/null
+++ b/tests/Fixtures/Preload/Case004_Out.php
@@ -0,0 +1,16 @@
+<?php
+
+use App\Foo;
+
+class_exists(Foo::class);
+/**
+ * Constructor with class reference
+ */
+class Case004
+{
+    private $foo;
+    public function __construct()
+    {
+        $this->foo = Foo::class;
+    }
+}
diff --git a/tests/Fixtures/Preload/Case005_In.php b/tests/Fixtures/Preload/Case005_In.php
new file mode 100644
index 00000000000..7ee7df2ca77
--- /dev/null
+++ b/tests/Fixtures/Preload/Case005_In.php
@@ -0,0 +1,21 @@
+<?php
+
+use App\Foo;
+
+/**
+ * Constructor using more complex class references
+ */
+class Case005
+{
+    private $baz;
+    private $bazClass;
+    private $bar;
+    private $barClass;
+    public function __construct()
+    {
+        $this->bar = new Foo\Bar();
+        $this->barClass = Foo\BarClass::class;
+        $this->baz = new \Biz\Baz();
+        $this->bazClass = \Biz\BazClass::class;
+    }
+}
diff --git a/tests/Fixtures/Preload/Case005_Out.php b/tests/Fixtures/Preload/Case005_Out.php
new file mode 100644
index 00000000000..166bcd74f88
--- /dev/null
+++ b/tests/Fixtures/Preload/Case005_Out.php
@@ -0,0 +1,25 @@
+<?php
+
+use App\Foo;
+
+class_exists(Foo\Bar::class);
+class_exists(Foo\BarClass::class);
+class_exists(\Biz\Baz::class);
+class_exists(\Biz\BazClass::class);
+/**
+ * Constructor using more complex class references
+ */
+class Case005
+{
+    private $baz;
+    private $bazClass;
+    private $bar;
+    private $barClass;
+    public function __construct()
+    {
+        $this->bar = new Foo\Bar();
+        $this->barClass = Foo\BarClass::class;
+        $this->baz = new \Biz\Baz();
+        $this->bazClass = \Biz\BazClass::class;
+    }
+}
diff --git a/tests/Fixtures/Preload/Case006_In.php b/tests/Fixtures/Preload/Case006_In.php
new file mode 100644
index 00000000000..0547a87c2b1
--- /dev/null
+++ b/tests/Fixtures/Preload/Case006_In.php
@@ -0,0 +1,22 @@
+<?php
+
+use App\Foo;
+
+/**
+ * Constructor call to private method
+ */
+class Case006
+{
+    private $foo;
+    private $bar;
+    public function __construct()
+    {
+        $this->bar = 2;
+        $this->init();
+    }
+
+    private function init()
+    {
+        $this->foo = new Foo();
+    }
+}
diff --git a/tests/Fixtures/Preload/Case006_Out.php b/tests/Fixtures/Preload/Case006_Out.php
new file mode 100644
index 00000000000..9be2fdb5aa9
--- /dev/null
+++ b/tests/Fixtures/Preload/Case006_Out.php
@@ -0,0 +1,23 @@
+<?php
+
+use App\Foo;
+
+class_exists(Foo::class);
+/**
+ * Constructor call to private method
+ */
+class Case006
+{
+    private $foo;
+    private $bar;
+    public function __construct()
+    {
+        $this->bar = 2;
+        $this->init();
+    }
+
+    private function init()
+    {
+        $this->foo = new Foo();
+    }
+}
diff --git a/tests/Fixtures/Preload/Case007_In.php b/tests/Fixtures/Preload/Case007_In.php
new file mode 100644
index 00000000000..5b71b5c3d07
--- /dev/null
+++ b/tests/Fixtures/Preload/Case007_In.php
@@ -0,0 +1,22 @@
+<?php
+
+use App\Foo;
+
+/**
+ * Constructor call to public method
+ */
+class Case007
+{
+    private $foo;
+    private $bar;
+    public function __construct()
+    {
+        $this->bar = 2;
+        $this->init();
+    }
+
+    public function init()
+    {
+        $this->foo = new Foo();
+    }
+}
diff --git a/tests/Fixtures/Preload/Case007_Out.php b/tests/Fixtures/Preload/Case007_Out.php
new file mode 100644
index 00000000000..83e464b2ba6
--- /dev/null
+++ b/tests/Fixtures/Preload/Case007_Out.php
@@ -0,0 +1,23 @@
+<?php
+
+use App\Foo;
+
+class_exists(Foo::class);
+/**
+ * Constructor call to public method
+ */
+class Case007
+{
+    private $foo;
+    private $bar;
+    public function __construct()
+    {
+        $this->bar = 2;
+        $this->init();
+    }
+
+    public function init()
+    {
+        $this->foo = new Foo();
+    }
+}
diff --git a/tests/Fixtures/Preload/Case008_In.php b/tests/Fixtures/Preload/Case008_In.php
new file mode 100644
index 00000000000..487bcec9f46
--- /dev/null
+++ b/tests/Fixtures/Preload/Case008_In.php
@@ -0,0 +1,23 @@
+<?php
+
+use App\Foo;
+
+/**
+ * Constructor call to private method with parameter
+ */
+class Case008
+{
+    private $foo;
+    private $bar;
+    public function __construct()
+    {
+        $this->bar = 2;
+        $var = new Foo();
+        $this->init($var);
+    }
+
+    private function init(Foo $foo)
+    {
+        $this->foo = $foo;
+    }
+}
diff --git a/tests/Fixtures/Preload/Case008_Out.php b/tests/Fixtures/Preload/Case008_Out.php
new file mode 100644
index 00000000000..e6a165a62cf
--- /dev/null
+++ b/tests/Fixtures/Preload/Case008_Out.php
@@ -0,0 +1,24 @@
+<?php
+
+use App\Foo;
+
+class_exists(Foo::class);
+/**
+ * Constructor call to private method with parameter
+ */
+class Case008
+{
+    private $foo;
+    private $bar;
+    public function __construct()
+    {
+        $this->bar = 2;
+        $var = new Foo();
+        $this->init($var);
+    }
+
+    private function init(Foo $foo)
+    {
+        $this->foo = $foo;
+    }
+}
diff --git a/tests/Fixtures/Preload/Case009_Out.php b/tests/Fixtures/Preload/Case009_Out.php
new file mode 100644
index 00000000000..a55bb8d00eb
--- /dev/null
+++ b/tests/Fixtures/Preload/Case009_Out.php
@@ -0,0 +1,23 @@
+<?php
+
+use App\Foo;
+
+/**
+ * Constructor call to public method with parameter
+ */
+class Case009
+{
+    private $foo;
+    private $bar;
+    public function __construct()
+    {
+        $this->bar = 2;
+        $var = new Foo();
+        $this->init($var);
+    }
+
+    public function init(Foo $foo)
+    {
+        $this->foo = $foo;
+    }
+}
diff --git a/tests/Fixtures/Preload/Case010_In.php b/tests/Fixtures/Preload/Case010_In.php
new file mode 100644
index 00000000000..a46b39dc5cb
--- /dev/null
+++ b/tests/Fixtures/Preload/Case010_In.php
@@ -0,0 +1,26 @@
+<?php
+
+use App\Foo;
+
+/**
+ * Constructor using more complex class references
+ */
+class Case010
+{
+    private $baz;
+    private $bazClass;
+    private $bar;
+    private $barClass;
+    public function __construct()
+    {
+        $this->init();
+    }
+
+    private function init()
+    {
+        $this->bar = new Foo\Bar();
+        $this->barClass = Foo\BarClass::class;
+        $this->baz = new \Biz\Baz();
+        $this->bazClass = \Biz\BazClass::class;
+    }
+}
diff --git a/tests/Fixtures/Preload/Case010_Out.php b/tests/Fixtures/Preload/Case010_Out.php
new file mode 100644
index 00000000000..9bcb93b0381
--- /dev/null
+++ b/tests/Fixtures/Preload/Case010_Out.php
@@ -0,0 +1,30 @@
+<?php
+
+use App\Foo;
+
+class_exists(Foo\Bar::class);
+class_exists(Foo\BarClass::class);
+class_exists(\Biz\Baz::class);
+class_exists(\Biz\BazClass::class);
+/**
+ * Constructor using more complex class references
+ */
+class Case010
+{
+    private $baz;
+    private $bazClass;
+    private $bar;
+    private $barClass;
+    public function __construct()
+    {
+        $this->init();
+    }
+
+    private function init()
+    {
+        $this->bar = new Foo\Bar();
+        $this->barClass = Foo\BarClass::class;
+        $this->baz = new \Biz\Baz();
+        $this->bazClass = \Biz\BazClass::class;
+    }
+}
diff --git a/tests/Fixtures/Preload/Case011_In.php b/tests/Fixtures/Preload/Case011_In.php
new file mode 100644
index 00000000000..b9719023c2c
--- /dev/null
+++ b/tests/Fixtures/Preload/Case011_In.php
@@ -0,0 +1,19 @@
+<?php
+
+/**
+ * Return types of public functions
+ */
+class Case011
+{
+    private $foo;
+    public function __construct()
+    {
+        $this->init();
+    }
+
+    public function init(): Foo
+    {
+        $bar = new Bar();
+        return $bar->createFoo();
+    }
+}
diff --git a/tests/Fixtures/Preload/Case011_Out.php b/tests/Fixtures/Preload/Case011_Out.php
new file mode 100644
index 00000000000..f9e17dca753
--- /dev/null
+++ b/tests/Fixtures/Preload/Case011_Out.php
@@ -0,0 +1,20 @@
+<?php
+
+class_exists(Bar::class);
+/**
+ * Return types of public functions
+ */
+class Case011
+{
+    private $foo;
+    public function __construct()
+    {
+        $this->init();
+    }
+
+    public function init(): Foo
+    {
+        $bar = new Bar();
+        return $bar->createFoo();
+    }
+}
diff --git a/tests/Fixtures/Preload/Case012_In.php b/tests/Fixtures/Preload/Case012_In.php
new file mode 100644
index 00000000000..5b05c314c56
--- /dev/null
+++ b/tests/Fixtures/Preload/Case012_In.php
@@ -0,0 +1,19 @@
+<?php
+
+/**
+ * Return types of private functions
+ */
+class Case012
+{
+    private $foo;
+    public function __construct()
+    {
+        $this->init();
+    }
+
+    private function init(): Foo
+    {
+        $bar = new Bar();
+        return $bar->createFoo();
+    }
+}
diff --git a/tests/Fixtures/Preload/Case012_Out.php b/tests/Fixtures/Preload/Case012_Out.php
new file mode 100644
index 00000000000..d78f4fab57f
--- /dev/null
+++ b/tests/Fixtures/Preload/Case012_Out.php
@@ -0,0 +1,21 @@
+<?php
+
+class_exists(Foo::class);
+class_exists(Bar::class);
+/**
+ * Return types of private functions
+ */
+class Case012
+{
+    private $foo;
+    public function __construct()
+    {
+        $this->init();
+    }
+
+    private function init(): Foo
+    {
+        $bar = new Bar();
+        return $bar->createFoo();
+    }
+}
diff --git a/tests/Fixtures/Preload/Case013_In.php b/tests/Fixtures/Preload/Case013_In.php
new file mode 100644
index 00000000000..8986ffc3aa6
--- /dev/null
+++ b/tests/Fixtures/Preload/Case013_In.php
@@ -0,0 +1,19 @@
+<?php
+
+/**
+ * Return types of protected functions
+ */
+class Case013
+{
+    private $foo;
+    public function __construct()
+    {
+        $this->init();
+    }
+
+    protected function init(): Foo
+    {
+        $bar = new Bar();
+        return $bar->createFoo();
+    }
+}
diff --git a/tests/Fixtures/Preload/Case013_Out.php b/tests/Fixtures/Preload/Case013_Out.php
new file mode 100644
index 00000000000..20199aab3a2
--- /dev/null
+++ b/tests/Fixtures/Preload/Case013_Out.php
@@ -0,0 +1,21 @@
+<?php
+
+class_exists(Foo::class);
+class_exists(Bar::class);
+/**
+ * Return types of protected functions
+ */
+class Case013
+{
+    private $foo;
+    public function __construct()
+    {
+        $this->init();
+    }
+
+    protected function init(): Foo
+    {
+        $bar = new Bar();
+        return $bar->createFoo();
+    }
+}
diff --git a/tests/Fixtures/Preload/Case014_In.php b/tests/Fixtures/Preload/Case014_In.php
new file mode 100644
index 00000000000..27ae7f8253b
--- /dev/null
+++ b/tests/Fixtures/Preload/Case014_In.php
@@ -0,0 +1,19 @@
+<?php
+
+/**
+ * Return types of protected functions to return self
+ */
+class Case014
+{
+    private $foo;
+    public function __construct()
+    {
+        $this->init();
+    }
+
+    protected function init(): self
+    {
+        $bar = new Bar();
+        return $bar->createFoo();
+    }
+}
diff --git a/tests/Fixtures/Preload/Case014_Out.php b/tests/Fixtures/Preload/Case014_Out.php
new file mode 100644
index 00000000000..366e62ec644
--- /dev/null
+++ b/tests/Fixtures/Preload/Case014_Out.php
@@ -0,0 +1,20 @@
+<?php
+
+class_exists(Bar::class);
+/**
+ * Return types of protected functions to return self
+ */
+class Case014
+{
+    private $foo;
+    public function __construct()
+    {
+        $this->init();
+    }
+
+    protected function init(): self
+    {
+        $bar = new Bar();
+        return $bar->createFoo();
+    }
+}
diff --git a/tests/Fixtures/Preload/Case015_In.php b/tests/Fixtures/Preload/Case015_In.php
new file mode 100644
index 00000000000..daeb00272b3
--- /dev/null
+++ b/tests/Fixtures/Preload/Case015_In.php
@@ -0,0 +1,19 @@
+<?php
+
+/**
+ * Return types of protected functions to return primary type
+ */
+class Case015
+{
+    private $foo;
+    public function __construct()
+    {
+        $this->init();
+    }
+
+    protected function init(): string
+    {
+        $bar = new Bar();
+        return $bar->createFoo();
+    }
+}
diff --git a/tests/Fixtures/Preload/Case015_Out.php b/tests/Fixtures/Preload/Case015_Out.php
new file mode 100644
index 00000000000..483641e8765
--- /dev/null
+++ b/tests/Fixtures/Preload/Case015_Out.php
@@ -0,0 +1,20 @@
+<?php
+
+class_exists(Bar::class);
+/**
+ * Return types of protected functions to return primary type
+ */
+class Case015
+{
+    private $foo;
+    public function __construct()
+    {
+        $this->init();
+    }
+
+    protected function init(): string
+    {
+        $bar = new Bar();
+        return $bar->createFoo();
+    }
+}
diff --git a/tests/Fixtures/Preload/Case016_In.php b/tests/Fixtures/Preload/Case016_In.php
new file mode 100644
index 00000000000..bae0817c23e
--- /dev/null
+++ b/tests/Fixtures/Preload/Case016_In.php
@@ -0,0 +1,19 @@
+<?php
+
+/**
+ * Return types of protected functions to return nullable
+ */
+class Case016
+{
+    private $foo;
+    public function __construct()
+    {
+        $this->init();
+    }
+
+    protected function init(): ?Foo
+    {
+        $bar = new Bar();
+        return $bar->createFoo();
+    }
+}
diff --git a/tests/Fixtures/Preload/Case016_Out.php b/tests/Fixtures/Preload/Case016_Out.php
new file mode 100644
index 00000000000..56a78451385
--- /dev/null
+++ b/tests/Fixtures/Preload/Case016_Out.php
@@ -0,0 +1,21 @@
+<?php
+
+class_exists(Foo::class);
+class_exists(Bar::class);
+/**
+ * Return types of protected functions to return nullable
+ */
+class Case016
+{
+    private $foo;
+    public function __construct()
+    {
+        $this->init();
+    }
+
+    protected function init(): ?Foo
+    {
+        $bar = new Bar();
+        return $bar->createFoo();
+    }
+}
diff --git a/tests/Fixtures/Preload/Case017_In.php b/tests/Fixtures/Preload/Case017_In.php
new file mode 100644
index 00000000000..0c5eaddcbc6
--- /dev/null
+++ b/tests/Fixtures/Preload/Case017_In.php
@@ -0,0 +1,25 @@
+<?php
+
+/**
+ * Return types of protected functions.
+ * Foo found by argument to public function
+ */
+class Case017
+{
+    private $foo;
+    public function __construct()
+    {
+        $this->init();
+    }
+
+    protected function init(): Foo
+    {
+        $bar = new Bar();
+        return $bar->createFoo();
+    }
+
+    public function other(Foo $input)
+    {
+        // Nothing
+    }
+}
diff --git a/tests/Fixtures/Preload/Case017_Out.php b/tests/Fixtures/Preload/Case017_Out.php
new file mode 100644
index 00000000000..76618a854eb
--- /dev/null
+++ b/tests/Fixtures/Preload/Case017_Out.php
@@ -0,0 +1,26 @@
+<?php
+
+class_exists(Bar::class);
+/**
+ * Return types of protected functions.
+ * Foo found by argument to public function
+ */
+class Case017
+{
+    private $foo;
+    public function __construct()
+    {
+        $this->init();
+    }
+
+    protected function init(): Foo
+    {
+        $bar = new Bar();
+        return $bar->createFoo();
+    }
+
+    public function other(Foo $input)
+    {
+        // Nothing
+    }
+}
diff --git a/tests/Fixtures/Preload/Case018_In.php b/tests/Fixtures/Preload/Case018_In.php
new file mode 100644
index 00000000000..e5e1b918840
--- /dev/null
+++ b/tests/Fixtures/Preload/Case018_In.php
@@ -0,0 +1,25 @@
+<?php
+
+/**
+ * Return types of protected functions.
+ * Foo not found by argument to protected function
+ */
+class Case018
+{
+    private $foo;
+    public function __construct()
+    {
+        $this->init();
+    }
+
+    protected function init(): Foo
+    {
+        $bar = new Bar();
+        return $bar->createFoo();
+    }
+
+    protected function other(Foo $input)
+    {
+        // Nothing
+    }
+}
diff --git a/tests/Fixtures/Preload/Case018_Out.php b/tests/Fixtures/Preload/Case018_Out.php
new file mode 100644
index 00000000000..57a76498ba6
--- /dev/null
+++ b/tests/Fixtures/Preload/Case018_Out.php
@@ -0,0 +1,27 @@
+<?php
+
+class_exists(Foo::class);
+class_exists(Bar::class);
+/**
+ * Return types of protected functions.
+ * Foo not found by argument to protected function
+ */
+class Case018
+{
+    private $foo;
+    public function __construct()
+    {
+        $this->init();
+    }
+
+    protected function init(): Foo
+    {
+        $bar = new Bar();
+        return $bar->createFoo();
+    }
+
+    protected function other(Foo $input)
+    {
+        // Nothing
+    }
+}
diff --git a/tests/Fixtures/Preload/Case019_In.php b/tests/Fixtures/Preload/Case019_In.php
new file mode 100644
index 00000000000..871201e3580
--- /dev/null
+++ b/tests/Fixtures/Preload/Case019_In.php
@@ -0,0 +1,25 @@
+<?php
+
+/**
+ * Return types of protected functions.
+ * Foo not found by argument to private function
+ */
+class Case019
+{
+    private $foo;
+    public function __construct()
+    {
+        $this->init();
+    }
+
+    protected function init(): Foo
+    {
+        $bar = new Bar();
+        return $bar->createFoo();
+    }
+
+    private function other(Foo $input)
+    {
+        // Nothing
+    }
+}
diff --git a/tests/Fixtures/Preload/Case019_Out.php b/tests/Fixtures/Preload/Case019_Out.php
new file mode 100644
index 00000000000..27954ef16ec
--- /dev/null
+++ b/tests/Fixtures/Preload/Case019_Out.php
@@ -0,0 +1,27 @@
+<?php
+
+class_exists(Foo::class);
+class_exists(Bar::class);
+/**
+ * Return types of protected functions.
+ * Foo not found by argument to private function
+ */
+class Case019
+{
+    private $foo;
+    public function __construct()
+    {
+        $this->init();
+    }
+
+    protected function init(): Foo
+    {
+        $bar = new Bar();
+        return $bar->createFoo();
+    }
+
+    private function other(Foo $input)
+    {
+        // Nothing
+    }
+}