diff --git a/src/Psalm/Codebase.php b/src/Psalm/Codebase.php
index cb72efa8b76..1de35369467 100644
--- a/src/Psalm/Codebase.php
+++ b/src/Psalm/Codebase.php
@@ -1669,7 +1669,7 @@ public function getCompletionItemsForPartialSymbol(
             ) {
                 $file_contents = $this->getFileContents($file_path);
 
-                $class_name = preg_replace('/^.*\\\/', '', $fq_class_name);
+                $class_name = preg_replace('/^.*\\\/', '', $fq_class_name, 1);
 
                 if ($aliases->uses_end) {
                     $position = self::getPositionFromOffset($aliases->uses_end, $file_contents);
diff --git a/src/Psalm/Config.php b/src/Psalm/Config.php
index 9ac69ea7d42..6dd9b63d125 100644
--- a/src/Psalm/Config.php
+++ b/src/Psalm/Config.php
@@ -1312,7 +1312,7 @@ public function setCustomErrorLevel(string $issue_key, string $error_level): voi
     private function loadFileExtensions(SimpleXMLElement $extensions): void
     {
         foreach ($extensions as $extension) {
-            $extension_name = preg_replace('/^\.?/', '', (string)$extension['name']);
+            $extension_name = preg_replace('/^\.?/', '', (string)$extension['name'], 1);
             $this->file_extensions[] = $extension_name;
 
             if (isset($extension['scanner'])) {
@@ -1506,7 +1506,7 @@ private function getPluginClassForPath(Codebase $codebase, string $path, string
     public function shortenFileName(string $to): string
     {
         if (!is_file($to)) {
-            return preg_replace('/^' . preg_quote($this->base_dir, '/') . '/', '', $to);
+            return preg_replace('/^' . preg_quote($this->base_dir, '/') . '/', '', $to, 1);
         }
 
         $from = $this->base_dir;
@@ -1678,7 +1678,7 @@ public static function getParentIssueType(string $issue_type): ?string
         }
 
         if (strpos($issue_type, 'Possibly') === 0) {
-            $stripped_issue_type = preg_replace('/^Possibly(False|Null)?/', '', $issue_type);
+            $stripped_issue_type = preg_replace('/^Possibly(False|Null)?/', '', $issue_type, 1);
 
             if (strpos($stripped_issue_type, 'Invalid') === false && strpos($stripped_issue_type, 'Un') !== 0) {
                 $stripped_issue_type = 'Invalid' . $stripped_issue_type;
@@ -1692,7 +1692,7 @@ public static function getParentIssueType(string $issue_type): ?string
         }
 
         if (preg_match('/^(False|Null)[A-Z]/', $issue_type) && !strpos($issue_type, 'Reference')) {
-            return preg_replace('/^(False|Null)/', 'Invalid', $issue_type);
+            return preg_replace('/^(False|Null)/', 'Invalid', $issue_type, 1);
         }
 
         if ($issue_type === 'UndefinedInterfaceMethod') {
diff --git a/src/Psalm/Config/Creator.php b/src/Psalm/Config/Creator.php
index f67eb5cf3cd..5a541dca888 100644
--- a/src/Psalm/Config/Creator.php
+++ b/src/Psalm/Config/Creator.php
@@ -242,7 +242,7 @@ private static function getPsr4Or0Paths(string $current_dir, array $composer_jso
                     continue;
                 }
 
-                $path = preg_replace('@[\\\\/]$@', '', $path);
+                $path = preg_replace('@[/\\\]$@', '', $path, 1);
 
                 if ($path !== 'tests') {
                     $nodes[] = '<directory name="' . $path . '" />';
diff --git a/src/Psalm/Config/FileFilter.php b/src/Psalm/Config/FileFilter.php
index 76f53d6be2e..de83e148285 100644
--- a/src/Psalm/Config/FileFilter.php
+++ b/src/Psalm/Config/FileFilter.php
@@ -421,7 +421,7 @@ function (): bool {
      */
     protected static function slashify(string $str): string
     {
-        return preg_replace('/\/?$/', DIRECTORY_SEPARATOR, $str);
+        return rtrim( $str, DIRECTORY_SEPARATOR ) . DIRECTORY_SEPARATOR;
     }
 
     public function allows(string $file_name, bool $case_sensitive = false): bool
diff --git a/src/Psalm/Context.php b/src/Psalm/Context.php
index 73e642af92e..1acfb9d7d37 100644
--- a/src/Psalm/Context.php
+++ b/src/Psalm/Context.php
@@ -752,7 +752,7 @@ public function hasVariable(string $var_name): bool
             return false;
         }
 
-        $stripped_var = preg_replace('/(->|\[).*$/', '', $var_name);
+        $stripped_var = preg_replace('/(->|\[).*$/', '', $var_name, 1);
 
         if ($stripped_var !== '$this' || $var_name !== $stripped_var) {
             $this->referenced_var_ids[$var_name] = true;
diff --git a/src/Psalm/DocComment.php b/src/Psalm/DocComment.php
index ae3cd6ca32a..f9cbc8287c6 100644
--- a/src/Psalm/DocComment.php
+++ b/src/Psalm/DocComment.php
@@ -64,9 +64,9 @@ public static function parse(string $docblock, ?int $line_number = null, bool $p
     {
         // Strip off comments.
         $docblock = trim($docblock);
-        $docblock = preg_replace('@^/\*\*@', '', $docblock);
-        $docblock = preg_replace('@\*/$@', '', $docblock);
-        $docblock = preg_replace('@^[ \t]*\*@m', '', $docblock);
+        $docblock = preg_replace('@^/\*\*@', '', $docblock, 1);
+        $docblock = preg_replace('@\*/$@', '', $docblock, 1);
+        $docblock = preg_replace('@^[ \t]*\*@m', '', $docblock, 1);
 
         // Normalize multi-line @specials.
         $lines = explode("\n", $docblock);
@@ -157,7 +157,7 @@ public static function parse(string $docblock, ?int $line_number = null, bool $p
 
         // Trim any empty lines off the front, but leave the indent level if there
         // is one.
-        $docblock = preg_replace('/^\s*\n/', '', $docblock);
+        $docblock = preg_replace('/^\s*\n/', '', $docblock, 1);
 
         foreach ($special as $special_key => $_) {
             if (strpos($special_key, 'psalm-') === 0) {
diff --git a/src/Psalm/Internal/Analyzer/ClassLikeAnalyzer.php b/src/Psalm/Internal/Analyzer/ClassLikeAnalyzer.php
index 51387fc2cdf..c3c47b8c0db 100644
--- a/src/Psalm/Internal/Analyzer/ClassLikeAnalyzer.php
+++ b/src/Psalm/Internal/Analyzer/ClassLikeAnalyzer.php
@@ -231,7 +231,7 @@ public static function checkFullyQualifiedClassLikeName(
             return null;
         }
 
-        $fq_class_name = preg_replace('/^\\\/', '', $fq_class_name);
+        $fq_class_name = preg_replace('/^\\\/', '', $fq_class_name, 1);
 
         if (in_array($fq_class_name, ['callable', 'iterable', 'self', 'static', 'parent'], true)) {
             return true;
diff --git a/src/Psalm/Internal/Analyzer/NamespaceAnalyzer.php b/src/Psalm/Internal/Analyzer/NamespaceAnalyzer.php
index 06413e6bbbf..a3d658b6e01 100644
--- a/src/Psalm/Internal/Analyzer/NamespaceAnalyzer.php
+++ b/src/Psalm/Internal/Analyzer/NamespaceAnalyzer.php
@@ -221,7 +221,7 @@ public static function isWithinAny(string $calling_identifier, array $identifier
      */
     public static function getNameSpaceRoot(string $fullyQualifiedClassName): string
     {
-        $root_namespace = preg_replace('/^([^\\\]+).*/', '$1', $fullyQualifiedClassName);
+        $root_namespace = preg_replace('/^([^\\\]+).*/', '$1', $fullyQualifiedClassName, 1);
         if ($root_namespace === "") {
             throw new InvalidArgumentException("Invalid classname \"$fullyQualifiedClassName\"");
         }
diff --git a/src/Psalm/Internal/Analyzer/Statements/Expression/Call/FunctionCallAnalyzer.php b/src/Psalm/Internal/Analyzer/Statements/Expression/Call/FunctionCallAnalyzer.php
index d98cf1fc825..96f26a09497 100644
--- a/src/Psalm/Internal/Analyzer/Statements/Expression/Call/FunctionCallAnalyzer.php
+++ b/src/Psalm/Internal/Analyzer/Statements/Expression/Call/FunctionCallAnalyzer.php
@@ -735,7 +735,7 @@ private static function getAnalyzeNamedExpression(
                         if (strpos($var_type_part->value, '::')) {
                             $parts = explode('::', strtolower($var_type_part->value));
                             $fq_class_name = $parts[0];
-                            $fq_class_name = preg_replace('/^\\\\/', '', $fq_class_name);
+                            $fq_class_name = preg_replace('/^\\\/', '', $fq_class_name, 1);
                             $potential_method_id = new MethodIdentifier($fq_class_name, $parts[1]);
                         } else {
                             $function_call_info->new_function_name = new VirtualFullyQualified(
diff --git a/src/Psalm/Internal/Analyzer/Statements/Expression/CallAnalyzer.php b/src/Psalm/Internal/Analyzer/Statements/Expression/CallAnalyzer.php
index 9cc9d85098e..e5c7942365a 100644
--- a/src/Psalm/Internal/Analyzer/Statements/Expression/CallAnalyzer.php
+++ b/src/Psalm/Internal/Analyzer/Statements/Expression/CallAnalyzer.php
@@ -522,7 +522,7 @@ public static function getFunctionIdsFromCallableArg(
         }
 
         if ($callable_arg instanceof PhpParser\Node\Scalar\String_) {
-            $potential_id = preg_replace('/^\\\/', '', $callable_arg->value);
+            $potential_id = preg_replace('/^\\\/', '', $callable_arg->value, 1);
 
             if (preg_match('/^[A-Za-z0-9_]+(\\\[A-Za-z0-9_]+)*(::[A-Za-z0-9_]+)?$/', $potential_id)) {
                 return [$potential_id];
@@ -552,7 +552,7 @@ public static function getFunctionIdsFromCallableArg(
         }
 
         if ($class_arg instanceof PhpParser\Node\Scalar\String_) {
-            return [preg_replace('/^\\\/', '', $class_arg->value) . '::' . $method_name_arg->value];
+            return [preg_replace('/^\\\/', '', $class_arg->value, 1) . '::' . $method_name_arg->value];
         }
 
         if ($class_arg instanceof PhpParser\Node\Expr\ClassConstFetch
diff --git a/src/Psalm/Internal/Cli/LanguageServer.php b/src/Psalm/Internal/Cli/LanguageServer.php
index e8689ee968c..634cdee16a4 100644
--- a/src/Psalm/Internal/Cli/LanguageServer.php
+++ b/src/Psalm/Internal/Cli/LanguageServer.php
@@ -93,7 +93,7 @@ public static function run(array $argv): void
         array_map(
             function (string $arg) use ($valid_long_options): void {
                 if (strpos($arg, '--') === 0 && $arg !== '--') {
-                    $arg_name = preg_replace('/=.*$/', '', substr($arg, 2));
+                    $arg_name = preg_replace('/=.*$/', '', substr($arg, 2), 1);
 
                     if (!in_array($arg_name, $valid_long_options, true)
                         && !in_array($arg_name . ':', $valid_long_options, true)
diff --git a/src/Psalm/Internal/Cli/Psalm.php b/src/Psalm/Internal/Cli/Psalm.php
index 86031b7b614..a01a47aa05b 100644
--- a/src/Psalm/Internal/Cli/Psalm.php
+++ b/src/Psalm/Internal/Cli/Psalm.php
@@ -431,7 +431,7 @@ private static function validateCliArguments(array $args): void
         array_map(
             function (string $arg): void {
                 if (strpos($arg, '--') === 0 && $arg !== '--') {
-                    $arg_name = preg_replace('/=.*$/', '', substr($arg, 2));
+                    $arg_name = preg_replace('/=.*$/', '', substr($arg, 2), 1);
 
                     if (!in_array($arg_name, self::LONG_OPTIONS)
                         && !in_array($arg_name . ':', self::LONG_OPTIONS)
diff --git a/src/Psalm/Internal/Cli/Psalter.php b/src/Psalm/Internal/Cli/Psalter.php
index a29491475cf..7db204c5f61 100644
--- a/src/Psalm/Internal/Cli/Psalter.php
+++ b/src/Psalm/Internal/Cli/Psalter.php
@@ -432,7 +432,7 @@ private static function validateCliArguments(array $args): void
         array_map(
             function (string $arg): void {
                 if (strpos($arg, '--') === 0 && $arg !== '--') {
-                    $arg_name = preg_replace('/=.*$/', '', substr($arg, 2));
+                    $arg_name = preg_replace('/=.*$/', '', substr($arg, 2), 1);
 
                     if ($arg_name === 'alter') {
                         // valid option for psalm, ignored by psalter
diff --git a/src/Psalm/Internal/Cli/Refactor.php b/src/Psalm/Internal/Cli/Refactor.php
index 1c87f4e84a2..864e9d4aebd 100644
--- a/src/Psalm/Internal/Cli/Refactor.php
+++ b/src/Psalm/Internal/Cli/Refactor.php
@@ -82,7 +82,7 @@ public static function run(array $argv): void
         array_map(
             function (string $arg) use ($valid_long_options): void {
                 if (strpos($arg, '--') === 0 && $arg !== '--') {
-                    $arg_name = preg_replace('/=.*$/', '', substr($arg, 2));
+                    $arg_name = preg_replace('/=.*$/', '', substr($arg, 2), 1);
 
                     if ($arg_name === 'refactor') {
                         // valid option for psalm, ignored by psalter
diff --git a/src/Psalm/Internal/Codebase/Analyzer.php b/src/Psalm/Internal/Codebase/Analyzer.php
index 36c927131d3..a2d06d4eaaa 100644
--- a/src/Psalm/Internal/Codebase/Analyzer.php
+++ b/src/Psalm/Internal/Codebase/Analyzer.php
@@ -773,7 +773,7 @@ public function loadCachedResults(ProjectAnalyzer $project_analyzer): void
                     $method_param_uses[$member_id]
                 );
 
-                $member_stub = preg_replace('/::.*$/', '::*', $member_id);
+                $member_stub = preg_replace('/::.*$/', '::*', $member_id, 1);
 
                 if (isset($all_referencing_methods[$member_stub])) {
                     $newly_invalidated_methods = array_merge(
diff --git a/src/Psalm/Internal/Codebase/ClassLikes.php b/src/Psalm/Internal/Codebase/ClassLikes.php
index d19b202fef6..f81e888620f 100644
--- a/src/Psalm/Internal/Codebase/ClassLikes.php
+++ b/src/Psalm/Internal/Codebase/ClassLikes.php
@@ -185,7 +185,7 @@ private function collectPredefinedClassLikes(): void
         $predefined_classes = get_declared_classes();
 
         foreach ($predefined_classes as $predefined_class) {
-            $predefined_class = preg_replace('/^\\\/', '', $predefined_class);
+            $predefined_class = preg_replace('/^\\\/', '', $predefined_class, 1);
             /** @psalm-suppress ArgumentTypeCoercion */
             $reflection_class = new ReflectionClass($predefined_class);
 
@@ -201,7 +201,7 @@ private function collectPredefinedClassLikes(): void
         $predefined_interfaces = get_declared_interfaces();
 
         foreach ($predefined_interfaces as $predefined_interface) {
-            $predefined_interface = preg_replace('/^\\\/', '', $predefined_interface);
+            $predefined_interface = preg_replace('/^\\\/', '', $predefined_interface, 1);
             /** @psalm-suppress ArgumentTypeCoercion */
             $reflection_class = new ReflectionClass($predefined_interface);
 
diff --git a/src/Psalm/Internal/Codebase/Properties.php b/src/Psalm/Internal/Codebase/Properties.php
index 2a0137a5db6..ba5604ea850 100644
--- a/src/Psalm/Internal/Codebase/Properties.php
+++ b/src/Psalm/Internal/Codebase/Properties.php
@@ -83,8 +83,8 @@ public function propertyExists(
         ?Context $context = null,
         ?CodeLocation $code_location = null
     ): bool {
-        // remove trailing backslash if it exists
-        $property_id = preg_replace('/^\\\\/', '', $property_id);
+        // remove leading backslash if it exists
+        $property_id = ltrim( $property_id, '\\' );
 
         [$fq_class_name, $property_name] = explode('::$', $property_id);
         $fq_class_name_lc = strtolower($fq_class_name);
@@ -248,8 +248,8 @@ public function getAppearingClassForProperty(
 
     public function getStorage(string $property_id): PropertyStorage
     {
-        // remove trailing backslash if it exists
-        $property_id = preg_replace('/^\\\\/', '', $property_id);
+        // remove leading backslash if it exists
+        $property_id = ltrim( $property_id, '\\' );
 
         [$fq_class_name, $property_name] = explode('::$', $property_id);
 
@@ -269,8 +269,8 @@ public function getStorage(string $property_id): PropertyStorage
 
     public function hasStorage(string $property_id): bool
     {
-        // remove trailing backslash if it exists
-        $property_id = preg_replace('/^\\\\/', '', $property_id);
+        // remove leading backslash if it exists
+        $property_id = ltrim( $property_id, '\\' );
 
         [$fq_class_name, $property_name] = explode('::$', $property_id);
 
@@ -291,8 +291,8 @@ public function getPropertyType(
         ?StatementsSource $source = null,
         ?Context $context = null
     ): ?Union {
-        // remove trailing backslash if it exists
-        $property_id = preg_replace('/^\\\\/', '', $property_id);
+        // remove leading backslash if it exists
+        $property_id = ltrim( $property_id, '\\' );
 
         [$fq_class_name, $property_name] = explode('::$', $property_id);
 
diff --git a/src/Psalm/Internal/MethodIdentifier.php b/src/Psalm/Internal/MethodIdentifier.php
index cf4c81ba63d..1abb0ecded1 100644
--- a/src/Psalm/Internal/MethodIdentifier.php
+++ b/src/Psalm/Internal/MethodIdentifier.php
@@ -56,8 +56,8 @@ public static function fromMethodIdReference(string $method_id): self
         if (!static::isValidMethodIdReference($method_id)) {
             throw new InvalidArgumentException('Invalid method id reference provided: ' . $method_id);
         }
-        // remove trailing backslash if it exists
-        $method_id = preg_replace('/^\\\\/', '', $method_id);
+        // remove leading backslash if it exists
+        $method_id = ltrim($method_id, '\\');
         $method_id_parts = explode('::', $method_id);
         return new self($method_id_parts[0], strtolower($method_id_parts[1]));
     }
diff --git a/src/Psalm/Internal/PhpVisitor/Reflector/ClassLikeDocblockParser.php b/src/Psalm/Internal/PhpVisitor/Reflector/ClassLikeDocblockParser.php
index 4572df37da3..aa2adb811c0 100644
--- a/src/Psalm/Internal/PhpVisitor/Reflector/ClassLikeDocblockParser.php
+++ b/src/Psalm/Internal/PhpVisitor/Reflector/ClassLikeDocblockParser.php
@@ -506,7 +506,7 @@ protected static function addMagicPropertyToInfo(
                 ) {
                     $line_parts[1] = str_replace('&', '', $line_parts[1]);
 
-                    $line_parts[1] = preg_replace('/,$/', '', $line_parts[1]);
+                    $line_parts[1] = preg_replace('/,$/', '', $line_parts[1], 1);
 
                     $end = $offset + strlen($line_parts[0]);
 
diff --git a/src/Psalm/Internal/PhpVisitor/Reflector/ClassLikeNodeScanner.php b/src/Psalm/Internal/PhpVisitor/Reflector/ClassLikeNodeScanner.php
index 91fbfbfee14..656bab44db9 100644
--- a/src/Psalm/Internal/PhpVisitor/Reflector/ClassLikeNodeScanner.php
+++ b/src/Psalm/Internal/PhpVisitor/Reflector/ClassLikeNodeScanner.php
@@ -1838,8 +1838,8 @@ private static function getTypeAliasesFromCommentLines(
 
             $type_string = str_replace("\n", '', implode('', $var_line_parts));
 
-            $type_string = preg_replace('/>[^>^\}]*$/', '>', $type_string);
-            $type_string = preg_replace('/\}[^>^\}]*$/', '}', $type_string);
+            $type_string = preg_replace('/>[^>^\}]*$/', '>', $type_string, 1);
+            $type_string = preg_replace('/\}[^>^\}]*$/', '}', $type_string, 1);
 
             try {
                 $type_tokens = TypeTokenizer::getFullyQualifiedTokens(
diff --git a/src/Psalm/Internal/PhpVisitor/Reflector/FunctionLikeDocblockParser.php b/src/Psalm/Internal/PhpVisitor/Reflector/FunctionLikeDocblockParser.php
index 341d0f63918..2eb713b9458 100644
--- a/src/Psalm/Internal/PhpVisitor/Reflector/FunctionLikeDocblockParser.php
+++ b/src/Psalm/Internal/PhpVisitor/Reflector/FunctionLikeDocblockParser.php
@@ -76,7 +76,7 @@ public static function parse(
                     ) {
                         $line_parts[1] = str_replace('&', '', $line_parts[1]);
 
-                        $line_parts[1] = preg_replace('/,$/', '', $line_parts[1]);
+                        $line_parts[1] = preg_replace('/,$/', '', $line_parts[1], 1);
 
                         $end = $offset + strlen($line_parts[0]);
 
@@ -152,7 +152,7 @@ public static function parse(
                             throw new IncorrectDocblockException('Misplaced variable');
                         }
 
-                        $line_parts[1] = preg_replace('/,$/', '', $line_parts[1]);
+                        $line_parts[1] = preg_replace('/,$/', '', $line_parts[1], 1);
 
                         $info->params_out[] = [
                             'name' => trim($line_parts[1]),
@@ -340,7 +340,7 @@ public static function parse(
                             throw new IncorrectDocblockException('Misplaced variable');
                         }
 
-                        $line_parts[1] = preg_replace('/,$/', '', $line_parts[1]);
+                        $line_parts[1] = preg_replace('/,$/', '', $line_parts[1], 1);
 
                         $info->globals[] = [
                             'name' => $line_parts[1],
diff --git a/src/Psalm/Internal/Scanner/DocblockParser.php b/src/Psalm/Internal/Scanner/DocblockParser.php
index 2ddf134e62c..22ae1ed258f 100644
--- a/src/Psalm/Internal/Scanner/DocblockParser.php
+++ b/src/Psalm/Internal/Scanner/DocblockParser.php
@@ -111,7 +111,7 @@ public static function parse(string $docblock, int $offsetStart): ParsedDocblock
                 // Strip the leading *, if present.
                 $text = $lines[$k];
                 $text = str_replace("\t", ' ', $text);
-                $text = preg_replace('/^ *\*/', '', $text);
+                $text = preg_replace('/^ *\*/', '', $text, 1);
                 $lines[$k] = $text;
             }
 
@@ -142,7 +142,7 @@ public static function parse(string $docblock, int $offsetStart): ParsedDocblock
 
         // Trim any empty lines off the front, but leave the indent level if there
         // is one.
-        $docblock = preg_replace('/^\s*\n/', '', $docblock);
+        $docblock = preg_replace('/^\s*\n/', '', $docblock, 1);
 
         $parsed = new ParsedDocblock($docblock, $special, $first_line_padding ?: '');