[TypeDeclaration] Fix return type union with null/mixed (#1565)

rectorphp · Dec 25, 2021 · a5624ca · a5624ca
1 parent 9b51302
commit a5624ca
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Showing 2 changed files with 26 additions and 3 deletions.
diff --git a/...or/FunctionLike/ReturnTypeDeclarationRector/FixtureForPhp80/skip_union_null_mixed.php.inc b/...or/FunctionLike/ReturnTypeDeclarationRector/FixtureForPhp80/skip_union_null_mixed.php.inc
@@ -0,0 +1,20 @@
+<?php
+
+namespace Rector\Tests\TypeDeclaration\Rector\FunctionLike\ReturnTypeDeclarationRector\FixtureForPhp80;
+
+final class SkipUnionNullMixed
+{
+    /**
+     * @var mixed[]
+     */
+    private $values = [];
+
+    public function get($key)
+    {
+        if (isset($this->values[$key])) {
+            return $this->values[$key];
+        }
+
+        return null;
+    }
+}
diff --git a/rules/TypeDeclaration/Rector/FunctionLike/ReturnTypeDeclarationRector.php b/rules/TypeDeclaration/Rector/FunctionLike/ReturnTypeDeclarationRector.php
@@ -118,11 +118,14 @@ public function refactor(Node $node): ?Node
             return $this->processType($node, $inferedReturnType);
         }
 
-        if (! $inferedReturnType->isSuperTypeOf(new MixedType())->yes()) {
-            return $this->processType($node, $inferedReturnType);
+        foreach ($inferedReturnType->getTypes() as $unionedType) {
+            // mixed type cannot be joined with another types
+            if ($unionedType instanceof MixedType) {
+                return null;
+            }
         }
 
-        return null;
+        return $this->processType($node, $inferedReturnType);
     }
 
     public function provideMinPhpVersion(): int