Fix #3419 - don’t add null to return type when template/conditional return is used

src/Psalm/Internal/PhpVisitor/ReflectorVisitor.php

@@ -2689,6 +2689,8 @@ class ReflectorVisitor extends PhpParser\NodeVisitorAbstract implements PhpParse
 
                     if ($storage->signature_return_type->isNullable()
                         && !$storage->return_type->isNullable()
+                        && !$storage->return_type->hasTemplate()
+                        && !$storage->return_type->hasConditional()
                     ) {
                         $storage->return_type->addType(new Type\Atomic\TNull());
                     }

src/Psalm/Type/Union.php

@@ -956,6 +956,19 @@ class Union implements TypeNode
         );
     }
 
+    /**
+     * @return bool
+     */
+    public function hasConditional()
+    {
+        return (bool) array_filter(
+            $this->types,
+            function (Atomic $type) : bool {
+                return $type instanceof Type\Atomic\TConditional;
+            }
+        );
+    }
+
     /**
      * @return bool
      */

tests/Template/ConditionalReturnTypeTest.php

@@ -476,6 +476,18 @@ class ConditionalReturnTypeTest extends TestCase
                         return $s;
                     }',
             ],
+            'nullableReturnType' => [
+                '<?php
+                    /**
+                     * @psalm-return ($name is "foo" ? string : null)
+                     */
+                    function get(string $name) {
+                        if ($name === "foo") {
+                            return "hello";
+                        }
+                        return null;
+                    }'
+            ],
         ];
     }
 }