Implement TypeSpecifierContext->getReturnType()

Author: staabm

Diff for: src/Analyser/TypeSpecifier.php

@@ -331,21 +331,6 @@ public function specifyTypesInCondition(
 				}
 			}
 
-			if (
-				!$context->null()
-				&& $expr->right instanceof FuncCall
-				&& count($expr->right->getArgs()) >= 3
-				&& $expr->right->name instanceof Name
-				&& in_array(strtolower((string) $expr->right->name), ['preg_match'], true)
-				&& IntegerRangeType::fromInterval(0, null)->isSuperTypeOf($leftType)->yes()
-			) {
-				return $this->specifyTypesInCondition(
-					$scope,
-					new Expr\BinaryOp\NotIdentical($expr->right, new ConstFetch(new Name('false'))),
-					$context,
-				)->setRootExpr($expr);
-			}
-
 			if (
 				!$context->null()
 				&& $expr->right instanceof FuncCall
@@ -466,6 +451,27 @@ public function specifyTypesInCondition(
 				}
 			}
 
+			if (
+				!$context->null()
+				&& $expr->left instanceof Node\Scalar
+				&& $expr->right instanceof Expr\FuncCall
+				&& $expr->right->name instanceof Name
+				&& in_array(strtolower((string) $expr->right->name), ['preg_match'], true)
+			) {
+				if (!$scope instanceof MutatingScope) {
+					throw new ShouldNotHappenException();
+				}
+				$newScope = $scope->filterBySpecifiedTypes($result);
+				$callType = $newScope->getType($expr->right);
+				$newContext = $context->newWithReturnType($callType);
+
+				$result = $result->unionWith($this->specifyTypesInCondition(
+					$scope,
+					$expr->right,
+					$newContext,
+				)->setRootExpr($expr));
+			}
+
 			return $result;
 
 		} elseif ($expr instanceof Node\Expr\BinaryOp\Greater) {

Diff for: src/Analyser/TypeSpecifierContext.php

@@ -3,6 +3,7 @@
 namespace PHPStan\Analyser;
 
 use PHPStan\ShouldNotHappenException;
+use PHPStan\Type\Type;
 
 /**
  * @api
@@ -21,6 +22,8 @@ final class TypeSpecifierContext
 	/** @var self[] */
 	private static array $registry;
 
+	private ?Type $returnType = null;
+
 	private function __construct(private ?int $value)
 	{
 	}
@@ -89,4 +92,16 @@ public function null(): bool
 		return $this->value === null;
 	}
 
+	public function newWithReturnType(Type $type): self
+	{
+		$new = self::create($this->value);
+		$new->returnType = $type;
+		return $new;
+	}
+
+	public function getReturnType(): ?Type
+	{
+		return $this->returnType;
+	}
+
 }