Remove some ErrorType check

Author: VincentLanglet

src/Analyser/NodeScopeResolver.php

@@ -5628,10 +5628,9 @@ private function processAssignVar(
 			$varNativeType = $scope->getNativeType($var);
 
 			// 4. compose types
-			if ($varType instanceof ErrorType) {
+			$isImplicitArrayCreation = $this->isImplicitArrayCreation($dimFetchStack, $scope);
+			if ($isImplicitArrayCreation->yes()) {
 				$varType = new ConstantArrayType([], []);
-			}
-			if ($varNativeType instanceof ErrorType) {
 				$varNativeType = new ConstantArrayType([], []);
 			}
 			$offsetValueType = $varType;
@@ -6018,6 +6017,27 @@ static function (): void {
 		return new ExpressionResult($scope, $hasYield, $isAlwaysTerminating, $throwPoints, $impurePoints);
 	}
 
+	/**
+	 * @param list<ArrayDimFetch> $dimFetchStack
+	 */
+	private function isImplicitArrayCreation(array $dimFetchStack, Scope $scope): TrinaryLogic
+	{
+		if (count($dimFetchStack) === 0) {
+			return TrinaryLogic::createNo();
+		}
+
+		$varNode = $dimFetchStack[0]->var;
+		if (!$varNode instanceof Variable) {
+			return TrinaryLogic::createNo();
+		}
+
+		if (!is_string($varNode->name)) {
+			return TrinaryLogic::createNo();
+		}
+
+		return $scope->hasVariableType($varNode->name)->negate();
+	}
+
 	/**
 	 * @param list<ArrayDimFetch> $dimFetchStack
 	 * @param list<Type|null> $offsetTypes

tests/PHPStan/Analyser/nsrt/bug-12447-bis.php

@@ -0,0 +1,22 @@
+<?php declare(strict_types = 1);
+
+namespace Bug12447Bis;
+
+use function PHPStan\Testing\assertType;
+
+interface Foo
+{
+
+}
+
+class HelloWorld
+{
+
+	public function __invoke(Foo $foo): void
+	{
+		$a = $foo->doFoo();
+		assertType('*ERROR*', $a);
+		$a[] = 5;
+		assertType('mixed', $a);
+	}
+}