Skip conditional type search on types without late-resolvable types

`ConditionalReturnTypeRuleHelper::check()` walks every parameter type, out type, closure-this type and the return type with `TypeTraverser::map()` to collect `ConditionalType` and `ConditionalTypeForParameter` instances. Both are late-resolvable types, so a type whose `hasTemplateOrLateResolvableType()` is false can't contain one, and the traversal now gets skipped for those. When it does run, nothing changes: it still collects every occurrence without memoization, so this is independent from #6652, which keeps `map()` here on purpose.

On the symfony/ux-css array shape (847 keys, 144 of them a nested shape alias), this traversal visits the shared nested shape once per offset using it. With #6671, `hasTemplateOrLateResolvableType()` is memoized on `ConstantArrayType`, so the check costs almost nothing there.

For every `Type` whose `traverse()` visits children, `hasTemplateOrLateResolvableType()` checks those children too, except callable/closure parameter default values and `ObjectWithoutClassType`'s subtracted type, neither of which can hold a conditional type in a declared signature. I logged every traversal that found a conditional type while `hasTemplateOrLateResolvableType()` was false; that gave 0 cases over the full test suite and PHPStan's self-analysis.

Measured with the https://github.com/Kocal/sf-ux-css-phpstan-reproducer reproducer, `phpstan-nested.neon`, `--debug`, 6 interleaved runs with the first discarded:

| | before | after |
|---|---|---|
| 2.3.x, no turbo | 12.50-12.61 s | 12.12-12.17 s |
| 2.3.x + #6652 + #6671, no turbo | 2.58-2.65 s | 2.11-2.13 s |
| 2.3.x, turbo | 5.65-5.84 s | 5.46-5.50 s |

`make tests` passes with and without the turbo extension, `make phpstan` and `make cs` pass.

Refs phpstan/phpstan#15348

Author: Kocal

src/Rules/PhpDoc/ConditionalReturnTypeRuleHelper.php

@@ -30,15 +30,18 @@ public function check(ExtendedParametersAcceptor $acceptor): array
 		$conditionalTypes = [];
 		$parametersByName = [];
 		foreach ($acceptor->getParameters() as $parameter) {
-			TypeTraverser::map($parameter->getType(), static function (Type $type, callable $traverse) use (&$conditionalTypes): Type {
-				if ($type instanceof ConditionalType || $type instanceof ConditionalTypeForParameter) {
-					$conditionalTypes[] = $type;
-				}
+			// conditional types are late-resolvable, so a type without any cannot contain one
+			if ($parameter->getType()->hasTemplateOrLateResolvableType()) {
+				TypeTraverser::map($parameter->getType(), static function (Type $type, callable $traverse) use (&$conditionalTypes): Type {
+					if ($type instanceof ConditionalType || $type instanceof ConditionalTypeForParameter) {
+						$conditionalTypes[] = $type;
+					}
 
-				return $traverse($type);
-			});
+					return $traverse($type);
+				});
+			}
 
-			if ($parameter->getOutType() !== null) {
+			if ($parameter->getOutType() !== null && $parameter->getOutType()->hasTemplateOrLateResolvableType()) {
 				TypeTraverser::map($parameter->getOutType(), static function (Type $type, callable $traverse) use (&$conditionalTypes): Type {
 					if ($type instanceof ConditionalType || $type instanceof ConditionalTypeForParameter) {
 						$conditionalTypes[] = $type;
@@ -48,7 +51,7 @@ public function check(ExtendedParametersAcceptor $acceptor): array
 				});
 			}
 
-			if ($parameter->getClosureThisType() !== null) {
+			if ($parameter->getClosureThisType() !== null && $parameter->getClosureThisType()->hasTemplateOrLateResolvableType()) {
 				TypeTraverser::map($parameter->getClosureThisType(), static function (Type $type, callable $traverse) use (&$conditionalTypes): Type {
 					if ($type instanceof ConditionalType || $type instanceof ConditionalTypeForParameter) {
 						$conditionalTypes[] = $type;
@@ -61,13 +64,15 @@ public function check(ExtendedParametersAcceptor $acceptor): array
 			$parametersByName[$parameter->getName()] = $parameter;
 		}
 
-		TypeTraverser::map($acceptor->getReturnType(), static function (Type $type, callable $traverse) use (&$conditionalTypes): Type {
-			if ($type instanceof ConditionalType || $type instanceof ConditionalTypeForParameter) {
-				$conditionalTypes[] = $type;
-			}
+		if ($acceptor->getReturnType()->hasTemplateOrLateResolvableType()) {
+			TypeTraverser::map($acceptor->getReturnType(), static function (Type $type, callable $traverse) use (&$conditionalTypes): Type {
+				if ($type instanceof ConditionalType || $type instanceof ConditionalTypeForParameter) {
+					$conditionalTypes[] = $type;
+				}
 
-			return $traverse($type);
-		});
+				return $traverse($type);
+			});
+		}
 
 		$errors = [];
 		foreach ($conditionalTypes as $conditionalType) {