Merge pull request #9647 from tuqqu/match-branch-flattening

Flatten `match` arm conditions to check conditions independently

src/Psalm/Internal/Analyzer/Statements/Expression/MatchAnalyzer.php

@@ -128,18 +128,27 @@ class MatchAnalyzer
         }
 
         $arms = $stmt->arms;
+        $flattened_arms = [];
+        $last_arm = null;
 
-        foreach ($arms as $i => $arm) {
+        foreach ($arms as $arm) {
-            // move default to the end
             if ($arm->conds === null) {
-                unset($arms[$i]);
+                $last_arm = $arm;
-                $arms[] = $arm;
+                continue;
+            }
+
+            foreach ($arm->conds as $cond) {
+                $flattened_arms[] = new PhpParser\Node\MatchArm(
+                    [$cond],
+                    $arm->body,
+                    $arm->getAttributes(),
+                );
             }
         }
 
+        $arms = $flattened_arms;
         $arms = array_reverse($arms);
-
+        $last_arm ??= array_shift($arms);
-        $last_arm = array_shift($arms);
 
         if (!$last_arm) {
             IssueBuffer::maybeAdd(

tests/MatchTest.php

@@ -95,6 +95,44 @@ class MatchTest extends TestCase
                 'ignored_issues' => [],
                 'php_version' => '8.1',
             ],
+            'multipleInstanceOfConditionsInOneArm' => [
+                'code' => '<?php
+                    interface Foo {}
+                    class A implements Foo {}
+                    class B implements Foo {}
+                    class C {}
+
+                    function baz(A|B $_): int {
+                        return 1;
+                    }
+
+                    function bar(Foo $foo): int {
+                        return match (true) {
+                            $foo instanceof A, $foo instanceof B => baz($foo),
+                            $foo instanceof C => 3,
+                            default => 0,
+                        };
+                    }',
+                'assertions' => [],
+                'ignored_issues' => [],
+                'php_version' => '8.0',
+            ],
+            'multipleTypeCheckConditionsInOneArm' => [
+                'code' => '<?php
+                    function baz(int|string $_): int {
+                        return 1;
+                    }
+
+                    function bar(mixed $foo): int {
+                        return match (true) {
+                            is_string($foo), is_int($foo) => baz($foo),
+                            default => 0,
+                        };
+                    }',
+                'assertions' => [],
+                'ignored_issues' => [],
+                'php_version' => '8.0',
+            ],
         ];
     }
 
@@ -243,6 +281,28 @@ class MatchTest extends TestCase
                 'ignored_issues' => [],
                 'php_version' => '8.0',
             ],
+            'multipleInstanceOfConditionsNotMetInOneArm' => [
+                'code' => '<?php
+                    interface Foo {}
+                    class A implements Foo {}
+                    class B implements Foo {}
+                    class C {}
+
+                    function baz(C $_): int {
+                        return 1;
+                    }
+
+                    function bar(Foo $foo): int {
+                        return match (true) {
+                            $foo instanceof A, $foo instanceof B => baz($foo),
+                            $foo instanceof C => 3,
+                            default => 0,
+                        };
+                    }',
+                'error_message' => 'InvalidArgument',
+                'ignored_issues' => [],
+                'php_version' => '8.0',
+            ],
         ];
     }
 }