Do not use the nullsafe operator in code downgraded to PHP 7.4

simple-downgrade leaves ?-> in place when it sits inside a larger
expression (a ternary arm, a concatenation, a method argument), so the
PHP 7.4 lint job parses those spots and fails. Spell the null checks out.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01GNLiox4nj8c7YstGfsuZ39

Author: ondrejmirtes

src/Analyser/ExprHandler/Helper/ClosureTypeResolver.php

@@ -416,8 +416,10 @@ private function closureContextCacheKey(MutatingScope $scope, Node\Expr\Closure|
 		// a closure whose body creates an unresolved template argument has the
 		// same key in both passes of the enclosing body; the resolutions installed
 		// for the second pass change its type
+		$frame = $scope->getCurrentTemplateArgumentFrame();
+
 		return $scope->getClosureScopeCacheKey($this->freeVariableRoots($expr)) . '/' . implode('|', $parts) . ($scope->nativeTypesPromoted ? '/native' : '/phpdoc')
-			. ($scope->getCurrentTemplateArgumentFrame()?->getResolutionCacheKeySuffix() ?? '');
+			. ($frame !== null ? $frame->getResolutionCacheKeySuffix() : '');
 	}
 
 	/**

src/Analyser/Generics/TemplateArgumentFrame.php

@@ -292,7 +292,7 @@ private function substituteMarker(UnresolvedTemplateArgumentType $marker): Type
 			return $this->resolveKey($key);
 		}
 
-		$resolved = $this->parent?->resolve($marker->getSite(), $marker->getTemplateName());
+		$resolved = $this->parent !== null ? $this->parent->resolve($marker->getSite(), $marker->getTemplateName()) : null;
 
 		return $resolved ?? $this->substituteResolutions($marker->getDelegate());
 	}

src/Analyser/NodeScopeResolver.php

@@ -3807,9 +3807,12 @@ public function observeReturnSend(MutatingScope $scope, ExpressionResult $return
 		if ($frame === null) {
 			return;
 		}
-		$declaredReturnType = $scope->isInAnonymousFunction()
-			? $scope->getAnonymousFunctionReturnType()
-			: $scope->getFunction()?->getReturnType();
+		if ($scope->isInAnonymousFunction()) {
+			$declaredReturnType = $scope->getAnonymousFunctionReturnType();
+		} else {
+			$function = $scope->getFunction();
+			$declaredReturnType = $function !== null ? $function->getReturnType() : null;
+		}
 		if ($declaredReturnType === null) {
 			return;
 		}

tests/PHPStan/Analyser/Generics/TemplateArgumentFrameTest.php

@@ -57,7 +57,7 @@ private static function frameWithA(?Type $initialType): array
 
 	private static function describe(?Type $type): ?string
 	{
-		return $type?->describe(VerbosityLevel::precise());
+		return $type !== null ? $type->describe(VerbosityLevel::precise()) : null;
 	}
 
 	public function testInvariantSendResolvesToTheFirstAcceptingSend(): void