Fix/9373 using enum property as const array key

src/Psalm/Internal/Codebase/ConstantTypeResolver.php

@@ -11,6 +11,9 @@
 use Psalm\Internal\Scanner\UnresolvedConstant\ArrayValue;
 use Psalm\Internal\Scanner\UnresolvedConstant\ClassConstant;
 use Psalm\Internal\Scanner\UnresolvedConstant\Constant;
+use Psalm\Internal\Scanner\UnresolvedConstant\EnumNameFetch;
+use Psalm\Internal\Scanner\UnresolvedConstant\EnumPropertyFetch;
+use Psalm\Internal\Scanner\UnresolvedConstant\EnumValueFetch;
 use Psalm\Internal\Scanner\UnresolvedConstant\ScalarValue;
 use Psalm\Internal\Scanner\UnresolvedConstant\UnresolvedAdditionOp;
 use Psalm\Internal\Scanner\UnresolvedConstant\UnresolvedBinaryOp;
@@ -331,6 +334,24 @@ public static function resolve(
             }
         }
 
+        if ($c instanceof EnumPropertyFetch) {
+            if ($classlikes->enumExists($c->fqcln)) {
+                $enum_storage = $classlikes->getStorageFor($c->fqcln);
+                if (isset($enum_storage->enum_cases[$c->case])) {
+                    if ($c instanceof EnumValueFetch) {
+                        $value = $enum_storage->enum_cases[$c->case]->value;
+                        if (is_string($value)) {
+                            return Type::getString($value)->getSingleAtomic();
+                        } elseif (is_int($value)) {
+                            return Type::getInt(false, $value)->getSingleAtomic();
+                        }
+                    } elseif ($c instanceof EnumNameFetch) {
+                        return Type::getString($c->case)->getSingleAtomic();
+                    }
+                }
+            }
+        }
+
         return new TMixed;
     }
 

src/Psalm/Internal/PhpVisitor/Reflector/ExpressionResolver.php

@@ -15,6 +15,8 @@
 use Psalm\Internal\Scanner\UnresolvedConstant\ArrayValue;
 use Psalm\Internal\Scanner\UnresolvedConstant\ClassConstant;
 use Psalm\Internal\Scanner\UnresolvedConstant\Constant;
+use Psalm\Internal\Scanner\UnresolvedConstant\EnumNameFetch;
+use Psalm\Internal\Scanner\UnresolvedConstant\EnumValueFetch;
 use Psalm\Internal\Scanner\UnresolvedConstant\KeyValuePair;
 use Psalm\Internal\Scanner\UnresolvedConstant\ScalarValue;
 use Psalm\Internal\Scanner\UnresolvedConstant\UnresolvedAdditionOp;
@@ -34,6 +36,7 @@
 use function class_exists;
 use function function_exists;
 use function implode;
+use function in_array;
 use function interface_exists;
 use function strtolower;
 
@@ -297,6 +300,24 @@ public static function getUnresolvedClassConstExpr(
             return new ArrayValue($items);
         }
 
+        if ($stmt instanceof PhpParser\Node\Expr\PropertyFetch
+            && $stmt->var instanceof PhpParser\Node\Expr\ClassConstFetch
+            && $stmt->var->class instanceof PhpParser\Node\Name
+            && $stmt->var->name instanceof PhpParser\Node\Identifier
+            && $stmt->name instanceof PhpParser\Node\Identifier
+            && in_array($stmt->name->name, ['name', 'value', true])
+        ) {
+            $enum_fq_class_name = ClassLikeAnalyzer::getFQCLNFromNameObject(
+                $stmt->var->class,
+                $aliases,
+            );
+            if ($stmt->name->name === 'value') {
+                return new EnumValueFetch($enum_fq_class_name, $stmt->var->name->name);
+            } elseif ($stmt->name->name === 'name') {
+                return new EnumNameFetch($enum_fq_class_name, $stmt->var->name->name);
+            }
+        }
+
         return null;
     }
 

src/Psalm/Internal/Scanner/UnresolvedConstant/EnumNameFetch.php

@@ -0,0 +1,11 @@
+<?php
+
+namespace Psalm\Internal\Scanner\UnresolvedConstant;
+
+/**
+ * @psalm-immutable
+ * @internal
+ */
+class EnumNameFetch extends EnumPropertyFetch
+{
+}

src/Psalm/Internal/Scanner/UnresolvedConstant/EnumPropertyFetch.php

@@ -0,0 +1,22 @@
+<?php
+
+namespace Psalm\Internal\Scanner\UnresolvedConstant;
+
+use Psalm\Internal\Scanner\UnresolvedConstantComponent;
+
+/**
+ * @psalm-immutable
+ * @internal
+ */
+abstract class EnumPropertyFetch extends UnresolvedConstantComponent
+{
+    public string $fqcln;
+
+    public string $case;
+
+    public function __construct(string $fqcln, string $case)
+    {
+        $this->fqcln = $fqcln;
+        $this->case = $case;
+    }
+}

src/Psalm/Internal/Scanner/UnresolvedConstant/EnumValueFetch.php

@@ -0,0 +1,11 @@
+<?php
+
+namespace Psalm\Internal\Scanner\UnresolvedConstant;
+
+/**
+ * @psalm-immutable
+ * @internal
+ */
+class EnumValueFetch extends EnumPropertyFetch
+{
+}