Support conditional types in phpdoc asserts

Author: rvanvelzen

src/Analyser/TypeSpecifier.php

@@ -1313,6 +1313,17 @@ private function specifyTypesFromAsserts(TypeSpecifierContext $context, Expr\Cal
 				continue;
 			}
 
+			$assertedType = TypeTraverser::map($assert->getType(), static function (Type $type, callable $traverse) use ($argsMap, $scope): Type {
+				if ($type instanceof ConditionalTypeForParameter) {
+					$parameterName = substr($type->getParameterName(), 1);
+					if (array_key_exists($parameterName, $argsMap)) {
+						$type = $type->toConditional($scope->getType($argsMap[$parameterName]));
+					}
+				}
+
+				return $traverse($type);
+			});
+
 			$assertExpr = $assert->getParameter()->getExpr($parameterExpr);
 
 			$templateTypeMap = $parametersAcceptor->getResolvedTemplateTypeMap();
@@ -1334,19 +1345,19 @@ static function (Type $type, callable $traverse) use ($templateTypeMap, &$contai
 
 			$newTypes = $this->create(
 				$assertExpr,
-				$assert->getType(),
+				$assertedType,
 				$assert->isNegated() ? TypeSpecifierContext::createFalse() : TypeSpecifierContext::createTrue(),
 				false,
 				$scope,
 				$containsUnresolvedTemplate || $assert->isEquality() ? $call : null,
 			);
 			$types = $types !== null ? $types->unionWith($newTypes) : $newTypes;
 
-			if (!$context->null() || !$assert->getType() instanceof ConstantBooleanType) {
+			if (!$context->null() || !$assertedType instanceof ConstantBooleanType) {
 				continue;
 			}
 
-			$subContext = $assert->getType()->getValue() ? TypeSpecifierContext::createTrue() : TypeSpecifierContext::createFalse();
+			$subContext = $assertedType->getValue() ? TypeSpecifierContext::createTrue() : TypeSpecifierContext::createFalse();
 			if ($assert->isNegated()) {
 				$subContext = $subContext->negate();
 			}

tests/PHPStan/Analyser/NodeScopeResolverTest.php

@@ -1088,6 +1088,7 @@ public function dataFileAsserts(): iterable
 		yield from $this->gatherAssertTypes(__DIR__ . '/data/assert-methods.php');
 		yield from $this->gatherAssertTypes(__DIR__ . '/data/assert-intersected.php');
 		yield from $this->gatherAssertTypes(__DIR__ . '/data/assert-invariant.php');
+		yield from $this->gatherAssertTypes(__DIR__ . '/data/assert-conditional.php');
 		yield from $this->gatherAssertTypes(__DIR__ . '/../Rules/Comparison/data/docblock-assert-equality.php');
 		yield from $this->gatherAssertTypes(__DIR__ . '/data/bug-8008.php');
 		yield from $this->gatherAssertTypes(__DIR__ . '/data/assert-class-type.php');

tests/PHPStan/Analyser/data/assert-conditional.php

@@ -0,0 +1,37 @@
+<?php
+
+namespace AssertConditional;
+
+use function PHPStan\Testing\assertType;
+
+/**
+ * @phpstan-assert ($if is true ? true : false) $condition
+ */
+function assertIf(mixed $condition, bool $if)
+{
+}
+
+function (mixed $value1, mixed $value2) {
+	assertIf($value1, true);
+	assertType('true', $value1);
+
+	assertIf($value2, false);
+	assertType('false', $value2);
+};
+
+/**
+ * @template T of bool
+ * @param T $if
+ * @phpstan-assert (T is true ? true : false) $condition
+ */
+function assertIfTemplated(mixed $condition, bool $if)
+{
+}
+
+function (mixed $value1, mixed $value2) {
+	assertIfTemplated($value1, true);
+	assertType('true', $value1);
+
+	assertIfTemplated($value2, false);
+	assertType('false', $value2);
+};