Fix duplicate errors in AssertRuleHelper

Author: ondrejmirtes

src/Rules/MissingTypehintCheck.php

@@ -85,7 +85,11 @@ public function getIterableTypesWithMissingValueTypehint(Type $type): array
 				if ($iterableValue instanceof MixedType && !$iterableValue->isExplicitMixed()) {
 					$iterablesWithMissingValueTypehint[] = $type;
 				}
-				if ($type instanceof IntersectionType && !$type->isList()->yes()) {
+				if ($type instanceof IntersectionType) {
+					if ($type->isList()->yes()) {
+						return $traverse($type->getIterableValueType());
+					}
+
 					return $type;
 				}
 			}

tests/PHPStan/Rules/PhpDoc/FunctionAssertRuleTest.php

@@ -70,6 +70,11 @@ public function testRule(): void
 				'Asserted negated type string for $i with type int does not narrow down the type.',
 				70,
 			],
+			[
+				'PHPDoc tag @phpstan-assert for $array has no value type specified in iterable type array<int, mixed>.',
+				88,
+				'See: https://phpstan.org/blog/solving-phpstan-no-value-type-specified-in-iterable-type',
+			],
 		]);
 	}
 

tests/PHPStan/Rules/PhpDoc/data/function-assert.php

@@ -76,3 +76,18 @@ function negate1(int $i): void
 function negate2(int $i): void
 {
 }
+
+/**
+ * @param array<mixed> $array
+ * @param string $message
+ *
+ * @phpstan-impure
+ *
+ * @psalm-assert list $array
+ */
+function isList($array, $message = ''): void
+{
+	if (!array_is_list($array)) {
+
+	}
+}