Don't auto-resolve conditional types

Auto-resolving seems very useful, but doesn't allow inspecting the original type

src/PhpDoc/TypeNodeResolver.php

@@ -453,7 +453,7 @@ private function resolveIntersectionTypeNode(IntersectionTypeNode $typeNode, Nam
 
 	private function resolveConditionalTypeNode(ConditionalTypeNode $typeNode, NameScope $nameScope): Type
 	{
-		return ConditionalType::create(
+		return new ConditionalType(
 			$this->resolve($typeNode->subjectType, $nameScope),
 			$this->resolve($typeNode->targetType, $nameScope),
 			$this->resolve($typeNode->if, $nameScope),

src/Reflection/ResolvedFunctionVariant.php

@@ -3,13 +3,10 @@
 namespace PHPStan\Reflection;
 
 use PHPStan\Reflection\Php\DummyParameter;
-use PHPStan\Type\ConditionalTypeForParameter;
 use PHPStan\Type\Generic\TemplateTypeHelper;
 use PHPStan\Type\Generic\TemplateTypeMap;
 use PHPStan\Type\Type;
-use PHPStan\Type\TypeTraverser;
 use PHPStan\Type\TypeUtils;
-use function array_key_exists;
 use function array_map;
 
 class ResolvedFunctionVariant implements ParametersAcceptor, SingleParametersAcceptor
@@ -76,13 +73,12 @@ public function getReturnType(): Type
 		$type = $this->returnType;
 
 		if ($type === null) {
-			$type = TemplateTypeHelper::resolveTemplateTypes(
+			$type = TypeUtils::resolveTypes(
 				$this->parametersAcceptor->getReturnType(),
 				$this->resolvedTemplateTypeMap,
+				$this->passedArgs,
 			);
 
-			$type = $this->resolveConditionalTypes($type);
-
 			$this->returnType = $type;
 		}
 
@@ -105,15 +101,4 @@ public function flattenConditionalsInReturnType(): SingleParametersAcceptor
 		return $result;
 	}
 
-	private function resolveConditionalTypes(Type $type): Type
-	{
-		return TypeTraverser::map($type, function (Type $type, callable $traverse): Type {
-			while ($type instanceof ConditionalTypeForParameter && array_key_exists($type->getParameterName(), $this->passedArgs)) {
-				$type = $type->toConditional($this->passedArgs[$type->getParameterName()]);
-			}
-
-			return $traverse($type);
-		});
-	}
-
 }

src/Type/ConditionalType.php

@@ -16,7 +16,7 @@ final class ConditionalType implements CompoundType
 	use ConditionalTypeTrait;
 	use NonGeneralizableTypeTrait;
 
-	private function __construct(
+	public function __construct(
 		private Type $subject,
 		private Type $target,
 		Type $if,
@@ -69,18 +69,7 @@ public function describe(VerbosityLevel $level): string
 		);
 	}
 
-	public static function create(
-		Type $subject,
-		Type $target,
-		Type $if,
-		Type $else,
-		bool $negated,
-	): Type
-	{
-		return (new self($subject, $target, $if, $else, $negated))->resolve();
-	}
-
-	private function resolve(): Type
+	public function resolve(): Type
 	{
 		$isSuperType = $this->target->isSuperTypeOf($this->subject);
 
@@ -108,7 +97,7 @@ public function traverse(callable $cb): Type
 			return $this;
 		}
 
-		return self::create($subject, $target, $if, $else, $this->negated);
+		return new self($subject, $target, $if, $else, $this->negated);
 	}
 
 	private function isResolved(): bool

src/Type/ConditionalTypeForParameter.php

@@ -34,7 +34,7 @@ public function getParameterName(): string
 
 	public function toConditional(Type $subject): Type
 	{
-		return ConditionalType::create(
+		return new ConditionalType(
 			$subject,
 			$this->target,
 			$this->if,

src/Type/TypeUtils.php

@@ -7,6 +7,9 @@
 use PHPStan\Type\Constant\ConstantArrayType;
 use PHPStan\Type\Constant\ConstantIntegerType;
 use PHPStan\Type\Constant\ConstantStringType;
+use PHPStan\Type\Generic\TemplateType;
+use PHPStan\Type\Generic\TemplateTypeMap;
+use function array_key_exists;
 use function array_merge;
 
 /** @api */
@@ -348,4 +351,43 @@ public static function flattenConditionals(Type $type): Type
 		});
 	}
 
+	/**
+	 * Replaces template types with standin types, and conditional types with their resolved types
+	 *
+	 * @param array<string, Type> $passedArgs
+	 */
+	public static function resolveTypes(Type $type, TemplateTypeMap $standins, array $passedArgs, bool $keepErrorTypes = false): Type
+	{
+		return TypeTraverser::map($type, static function (Type $type, callable $traverse) use ($standins, $passedArgs, $keepErrorTypes): Type {
+			if ($type instanceof TemplateType && !$type->isArgument()) {
+				$newType = $standins->getType($type->getName());
+				if ($newType === null) {
+					return $traverse($type);
+				}
+
+				if ($newType instanceof ErrorType && !$keepErrorTypes) {
+					return $traverse($type->getBound());
+				}
+
+				return $newType;
+			}
+
+			if ($type instanceof ConditionalTypeForParameter || $type instanceof ConditionalType) {
+				$type = $traverse($type);
+
+				if ($type instanceof ConditionalTypeForParameter && array_key_exists($type->getParameterName(), $passedArgs)) {
+					$type = $type->toConditional($passedArgs[$type->getParameterName()]);
+				}
+
+				if ($type instanceof ConditionalType) {
+					return $type->resolve();
+				}
+
+				return $type;
+			}
+
+			return $traverse($type);
+		});
+	}
+
 }

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

@@ -112,9 +112,9 @@ public function testDeterministicReturnValue(): void
 	 */
 	public function testDeterministicParameter($foo, $bar, $baz): void
 	{
-		assertType('string', $foo);
-		assertType('string', $bar);
-		assertType('string', $baz);
+		assertType('(true is true ? string : bool)', $foo);
+		assertType('(5 is int<4, 6> ? string : bool)', $bar);
+		assertType('(5 is not int<0, 4> ? (4 is bool ? float : string) : bool)', $baz);
 	}
 
 	/**