diff --git a/phpstan.neon.dist b/phpstan.neon.dist
new file mode 100644
index 00000000..3b5a67dd
--- /dev/null
+++ b/phpstan.neon.dist
@@ -0,0 +1,12 @@
+parameters:
+  level: 9
+  paths:
+    - src
+    - profile-command.php
+  scanDirectories:
+    - vendor/wp-cli/wp-cli/php
+  scanFiles:
+    - vendor/php-stubs/wordpress-stubs/wordpress-stubs.php
+    - tests/phpstan/scan-files.php
+
+  treatPhpDocTypesAsCertain: false
diff --git a/src/Command.php b/src/Command.php
index 8727938e..b27e082a 100644
--- a/src/Command.php
+++ b/src/Command.php
@@ -129,14 +129,22 @@ class Command {
 	 *
 	 * @skipglobalargcheck
 	 * @when before_wp_load
+	 *
+	 * @param array<string>       $args
+	 * @param array<string, mixed> $assoc_args
+	 * @return void
 	 */
 	public function stage( $args, $assoc_args ) {
 		global $wpdb;
 
-		$focus = Utils\get_flag_value( $assoc_args, 'all', isset( $args[0] ) ? $args[0] : null );
+		/** @var array<string, bool|string> $typed_assoc_args */
+		$typed_assoc_args = self::get_typed_assoc_args( $assoc_args );
+		$focus            = Utils\get_flag_value( $typed_assoc_args, 'all', isset( $args[0] ) ? $args[0] : null );
 
-		$order   = Utils\get_flag_value( $assoc_args, 'order', 'ASC' );
-		$orderby = Utils\get_flag_value( $assoc_args, 'orderby', null );
+		$order_val   = Utils\get_flag_value( $typed_assoc_args, 'order', 'ASC' );
+		$order       = is_string( $order_val ) ? $order_val : 'ASC';
+		$orderby_val = Utils\get_flag_value( $typed_assoc_args, 'orderby', null );
+		$orderby     = ( is_string( $orderby_val ) || is_null( $orderby_val ) ) ? $orderby_val : null;
 
 		$valid_stages = array( 'bootstrap', 'main_query', 'template' );
 		if ( $focus && ( true !== $focus && ! in_array( $focus, $valid_stages, true ) ) ) {
@@ -179,9 +187,10 @@ public function stage( $args, $assoc_args ) {
 			);
 		}
 		$fields    = array_merge( $base, $metrics );
-		$formatter = new Formatter( $assoc_args, $fields );
+		$formatter = new Formatter( $typed_assoc_args, $fields );
 		$loggers   = $profiler->get_loggers();
-		if ( Utils\get_flag_value( $assoc_args, 'spotlight' ) ) {
+		/** @var array<string, bool|string> $typed_assoc_args */
+		if ( Utils\get_flag_value( $typed_assoc_args, 'spotlight' ) ) {
 			$loggers = self::shine_spotlight( $loggers, $metrics );
 		}
 
@@ -257,13 +266,21 @@ public function stage( $args, $assoc_args ) {
 	 *
 	 * @skipglobalargcheck
 	 * @when before_wp_load
+	 *
+	 * @param array<string>       $args
+	 * @param array<string, mixed> $assoc_args
+	 * @return void
 	 */
 	public function hook( $args, $assoc_args ) {
 
-		$focus = Utils\get_flag_value( $assoc_args, 'all', isset( $args[0] ) ? $args[0] : null );
+		/** @var array<string, bool|string> $typed_assoc_args */
+		$typed_assoc_args = self::get_typed_assoc_args( $assoc_args );
+		$focus            = Utils\get_flag_value( $typed_assoc_args, 'all', isset( $args[0] ) ? $args[0] : null );
 
-		$order   = Utils\get_flag_value( $assoc_args, 'order', 'ASC' );
-		$orderby = Utils\get_flag_value( $assoc_args, 'orderby', null );
+		$order_val   = Utils\get_flag_value( $typed_assoc_args, 'order', 'ASC' );
+		$order       = is_string( $order_val ) ? $order_val : 'ASC';
+		$orderby_val = Utils\get_flag_value( $typed_assoc_args, 'orderby', null );
+		$orderby     = ( is_string( $orderby_val ) || is_null( $orderby_val ) ) ? $orderby_val : null;
 
 		$profiler = new Profiler( 'hook', $focus );
 		$profiler->run();
@@ -291,13 +308,16 @@ public function hook( $args, $assoc_args ) {
 			'request_count',
 		);
 		$fields    = array_merge( $base, $metrics );
-		$formatter = new Formatter( $assoc_args, $fields );
+		$formatter = new Formatter( $typed_assoc_args, $fields );
 		$loggers   = $profiler->get_loggers();
-		if ( Utils\get_flag_value( $assoc_args, 'spotlight' ) ) {
+		/** @var array<string, bool|string> $typed_assoc_args */
+		if ( Utils\get_flag_value( $typed_assoc_args, 'spotlight' ) ) {
 			$loggers = self::shine_spotlight( $loggers, $metrics );
 		}
-		$search = Utils\get_flag_value( $assoc_args, 'search', false );
-		if ( false !== $search && '' !== $search ) {
+		/** @var array<string, bool|string> $typed_assoc_args */
+		$search_val = Utils\get_flag_value( $typed_assoc_args, 'search', '' );
+		$search     = is_string( $search_val ) ? $search_val : '';
+		if ( '' !== $search ) {
 			if ( ! $focus ) {
 				WP_CLI::error( '--search requires --all or a specific hook.' );
 			}
@@ -357,16 +377,24 @@ public function hook( $args, $assoc_args ) {
 	 *     | 0.1009s | 100%        | 1             |
 	 *     +---------+-------------+---------------+
 	 *
+	 * @param array<string>       $args
+	 * @param array<string, mixed> $assoc_args
+	 * @return void
+	 *
 	 * @subcommand eval
 	 */
 	public function eval_( $args, $assoc_args ) {
 		$statement = $args[0];
 
-		$order   = Utils\get_flag_value( $assoc_args, 'order', 'ASC' );
-		$orderby = Utils\get_flag_value( $assoc_args, 'orderby', null );
+		/** @var array<string, bool|string> $typed_assoc_args */
+		$typed_assoc_args = self::get_typed_assoc_args( $assoc_args );
+		$order_val        = Utils\get_flag_value( $typed_assoc_args, 'order', 'ASC' );
+		$order            = is_string( $order_val ) ? $order_val : 'ASC';
+		$orderby_val      = Utils\get_flag_value( $typed_assoc_args, 'orderby', null );
+		$orderby          = ( is_string( $orderby_val ) || is_null( $orderby_val ) ) ? $orderby_val : null;
 
 		self::profile_eval_ish(
-			$assoc_args,
+			$typed_assoc_args,
 			function () use ( $statement ) {
 				eval( $statement ); // phpcs:ignore Squiz.PHP.Eval.Discouraged -- no other way around here
 			},
@@ -426,21 +454,30 @@ function () use ( $statement ) {
 	 *     | 0.1009s | 100%        | 1             |
 	 *     +---------+-------------+---------------+
 	 *
+	 * @param array<string>       $args
+	 * @param array<string, mixed> $assoc_args
+	 * @return void
+	 *
 	 * @subcommand eval-file
 	 */
 	public function eval_file( $args, $assoc_args ) {
 
 		$file = $args[0];
 
-		$order   = Utils\get_flag_value( $assoc_args, 'order', 'ASC' );
-		$orderby = Utils\get_flag_value( $assoc_args, 'orderby', null );
+		/** @var array<string, bool|string> $typed_assoc_args */
+		/** @var array<string, bool|string> $typed_assoc_args */
+		$typed_assoc_args = self::get_typed_assoc_args( $assoc_args );
+		$order_val        = Utils\get_flag_value( $typed_assoc_args, 'order', 'ASC' );
+		$order            = is_string( $order_val ) ? $order_val : 'ASC';
+		$orderby_val      = Utils\get_flag_value( $typed_assoc_args, 'orderby', null );
+		$orderby          = ( is_string( $orderby_val ) || is_null( $orderby_val ) ) ? $orderby_val : null;
 
 		if ( ! file_exists( $file ) ) {
 			WP_CLI::error( "'$file' does not exist." );
 		}
 
 		self::profile_eval_ish(
-			$assoc_args,
+			$typed_assoc_args,
 			function () use ( $file ) {
 				self::include_file( $file );
 			},
@@ -451,12 +488,20 @@ function () use ( $file ) {
 
 	/**
 	 * Profile an eval or eval-file statement.
+	 *
+	 * @param array<string, mixed> $assoc_args
+	 * @param callable             $profile_callback
+	 * @param string               $order
+	 * @param string|null          $orderby
+	 * @return void
 	 */
 	private static function profile_eval_ish( $assoc_args, $profile_callback, $order = 'ASC', $orderby = null ) {
-		$hook   = Utils\get_flag_value( $assoc_args, 'hook' );
-		$focus  = false;
-		$type   = false;
-		$fields = array();
+		/** @var array<string, bool|string> $typed_assoc_args */
+		$typed_assoc_args = self::get_typed_assoc_args( $assoc_args );
+		$hook             = Utils\get_flag_value( $typed_assoc_args, 'hook' );
+		$focus            = false;
+		$type             = false;
+		$fields           = array();
 		if ( $hook ) {
 			$type = 'hook';
 			if ( true !== $hook ) {
@@ -492,7 +537,7 @@ private static function profile_eval_ish( $assoc_args, $profile_callback, $order
 				'request_count',
 			)
 		);
-		$formatter = new Formatter( $assoc_args, $fields );
+		$formatter = new Formatter( $typed_assoc_args, $fields );
 		$formatter->display_items( $loggers, false, $order, $orderby );
 	}
 
@@ -500,6 +545,7 @@ private static function profile_eval_ish( $assoc_args, $profile_callback, $order
 	 * Include a file without exposing it to current scope
 	 *
 	 * @param string $file
+	 * @return void
 	 */
 	private static function include_file( $file ) {
 		include $file;
@@ -508,9 +554,9 @@ private static function include_file( $file ) {
 	/**
 	 * Filter loggers with zero-ish values.
 	 *
-	 * @param array $loggers
-	 * @param array $metrics
-	 * @return array
+	 * @param array<\WP_CLI\Profile\Logger> $loggers
+	 * @param array<string>                 $metrics
+	 * @return array<\WP_CLI\Profile\Logger>
 	 */
 	private static function shine_spotlight( $loggers, $metrics ) {
 
@@ -550,9 +596,9 @@ private static function shine_spotlight( $loggers, $metrics ) {
 	/**
 	 * Filter loggers to only those whose callback name matches a pattern.
 	 *
-	 * @param array  $loggers
-	 * @param string $pattern
-	 * @return array
+	 * @param array<\WP_CLI\Profile\Logger> $loggers
+	 * @param string                        $pattern
+	 * @return array<\WP_CLI\Profile\Logger>
 	 */
 	private static function filter_by_callback( $loggers, $pattern ) {
 		return array_filter(
@@ -562,4 +608,20 @@ function ( $logger ) use ( $pattern ) {
 			}
 		);
 	}
+
+	/**
+	 * Get typed assoc args for get_flag_value.
+	 *
+	 * @param array<string, mixed> $assoc_args
+	 * @return array<string, bool|string>
+	 */
+	private static function get_typed_assoc_args( $assoc_args ) {
+		$typed = array();
+		foreach ( $assoc_args as $k => $v ) {
+			if ( is_bool( $v ) || is_string( $v ) ) {
+				$typed[ $k ] = $v;
+			}
+		}
+		return $typed;
+	}
 }
diff --git a/src/Formatter.php b/src/Formatter.php
index 775db154..7c290c74 100644
--- a/src/Formatter.php
+++ b/src/Formatter.php
@@ -4,13 +4,32 @@
 
 class Formatter {
 
+	/**
+	 * @var \WP_CLI\Formatter
+	 */
 	private $formatter;
 
+	/**
+	 * @var array<string, mixed>
+	 */
 	private $args;
 
+	/**
+	 * @var int|null
+	 */
 	private $total_cell_index;
 
+	/**
+	 * Formatter constructor.
+	 *
+	 * @param array<mixed>         $assoc_args
+	 * @param array<string>|null   $fields
+	 * @param string|false          $prefix
+	 */
 	public function __construct( &$assoc_args, $fields = null, $prefix = false ) {
+		if ( null === $fields ) {
+			$fields = [];
+		}
 		$format_args = array(
 			'format' => 'table',
 			'fields' => $fields,
@@ -24,10 +43,19 @@ public function __construct( &$assoc_args, $fields = null, $prefix = false ) {
 		}
 
 		if ( ! is_array( $format_args['fields'] ) ) {
-			$format_args['fields'] = explode( ',', $format_args['fields'] );
+			$fields_val            = $format_args['fields'];
+			$fields_str            = is_scalar( $fields_val ) ? (string) $fields_val : '';
+			$format_args['fields'] = explode( ',', $fields_str );
 		}
 
-		$format_args['fields'] = array_filter( array_map( 'trim', $format_args['fields'] ) );
+		$format_args['fields'] = array_filter(
+			array_map(
+				function ( $val ) {
+					return trim( is_scalar( $val ) ? (string) $val : '' );
+				},
+				$format_args['fields']
+			)
+		);
 
 		if ( isset( $assoc_args['fields'] ) ) {
 			if ( empty( $format_args['fields'] ) ) {
@@ -39,9 +67,9 @@ public function __construct( &$assoc_args, $fields = null, $prefix = false ) {
 			}
 		}
 
-		if ( 'time' !== $fields[0] ) {
+		if ( ! empty( $fields ) && 'time' !== $fields[0] ) {
 			$index                  = array_search( $fields[0], $format_args['fields'], true );
-			$this->total_cell_index = ( false !== $index ) ? $index : null;
+			$this->total_cell_index = ( false !== $index ) ? (int) $index : null;
 		}
 
 		$this->args      = $format_args;
@@ -51,11 +79,17 @@ public function __construct( &$assoc_args, $fields = null, $prefix = false ) {
 	/**
 	 * Display multiple items according to the output arguments.
 	 *
-	 * @param array $items
+	 * @param array<\WP_CLI\Profile\Logger> $items
+	 * @param bool                         $include_total
+	 * @param string                       $order
+	 * @param string|null                  $orderby
+	 * @return void
 	 */
 	public function display_items( $items, $include_total, $order, $orderby ) {
 		if ( 'table' === $this->args['format'] && empty( $this->args['field'] ) ) {
-			$this->show_table( $order, $orderby, $items, $this->args['fields'], $include_total );
+			/** @var array<string> $fields */
+			$fields = $this->args['fields'];
+			$this->show_table( $order, $orderby, $items, $fields, $include_total );
 		} else {
 			$this->formatter->display_items( $items );
 		}
@@ -64,13 +98,14 @@ public function display_items( $items, $include_total, $order, $orderby ) {
 	/**
 	 * Function to compare floats.
 	 *
-	 * @param double $a Floating number.
-	 * @param double $b Floating number.
+	 * @param float $a Floating number.
+	 * @param float $b Floating number.
+	 * @return int
 	 */
 	private function compare_float( $a, $b ) {
-		$a = number_format( $a, 4 );
-		$b = number_format( $b, 4 );
-		if ( 0 === $a - $b ) {
+		$a = round( $a, 4 );
+		$b = round( $b, 4 );
+		if ( 0.0 === $a - $b ) {
 			return 0;
 		} elseif ( $a - $b < 0 ) {
 			return -1;
@@ -82,8 +117,12 @@ private function compare_float( $a, $b ) {
 	/**
 	 * Show items in a \cli\Table.
 	 *
-	 * @param array $items
-	 * @param array $fields
+	 * @param string                       $order
+	 * @param string|null                  $orderby
+	 * @param array<\WP_CLI\Profile\Logger> $items
+	 * @param array<string>                $fields
+	 * @param bool                         $include_total
+	 * @return void
 	 */
 	private function show_table( $order, $orderby, $items, $fields, $include_total ) {
 		$table = new \cli\Table();
@@ -109,7 +148,7 @@ function ( $a, $b ) use ( $order, $orderby ) {
 					list( $first, $second ) = $orderby_array;
 
 					if ( is_numeric( $first->$orderby ) && is_numeric( $second->$orderby ) ) {
-						return $this->compare_float( $first->$orderby, $second->$orderby );
+						return $this->compare_float( (float) $first->$orderby, (float) $second->$orderby );
 					}
 
 					return strcmp( $first->$orderby, $second->$orderby );
@@ -139,13 +178,17 @@ function ( $a, $b ) use ( $order, $orderby ) {
 				}
 				if ( stripos( $fields[ $i ], '_ratio' ) ) {
 					if ( ! is_null( $value ) ) {
+						assert( is_array( $totals[ $i ] ) );
 						$totals[ $i ][] = $value;
 					}
 				} else {
-					$totals[ $i ] += $value;
+					$current_total = is_numeric( $totals[ $i ] ) ? $totals[ $i ] : 0;
+					$add_value     = is_numeric( $value ) ? $value : 0;
+					$totals[ $i ]  = $current_total + $add_value;
 				}
 				if ( stripos( $fields[ $i ], '_time' ) || 'time' === $fields[ $i ] ) {
-					$values[ $i ] = round( $value, 4 ) . 's';
+					$value_num    = is_numeric( $value ) ? (float) $value : 0.0;
+					$values[ $i ] = round( $value_num, 4 ) . 's';
 				}
 			}
 			$table->addRow( $values );
@@ -156,11 +199,18 @@ function ( $a, $b ) use ( $order, $orderby ) {
 					continue;
 				}
 				if ( stripos( $fields[ $i ], '_time' ) || 'time' === $fields[ $i ] ) {
-					$totals[ $i ] = round( $value, 4 ) . 's';
+					assert( is_numeric( $value ) );
+					$totals[ $i ] = round( (float) $value, 4 ) . 's';
 				}
 				if ( is_array( $value ) ) {
 					if ( ! empty( $value ) ) {
-						$totals[ $i ] = round( ( array_sum( array_map( 'floatval', $value ) ) / count( $value ) ), 2 ) . '%';
+						$float_values = array_map(
+							function ( $val ) {
+								return floatval( is_scalar( $val ) ? $val : 0 );
+							},
+							$value
+						);
+						$totals[ $i ] = round( ( array_sum( $float_values ) / count( $value ) ), 2 ) . '%';
 					} else {
 						$totals[ $i ] = null;
 					}
diff --git a/src/Logger.php b/src/Logger.php
index 0c3ab116..f6e53ecb 100644
--- a/src/Logger.php
+++ b/src/Logger.php
@@ -2,36 +2,72 @@
 
 namespace WP_CLI\Profile;
 
+/**
+ * Logger class.
+ *
+ * @property string $callback
+ * @property string $location
+ */
 class Logger {
 
-	public $time                = 0;
-	public $query_count         = 0;
-	public $query_time          = 0;
-	public $cache_hits          = 0;
-	public $cache_misses        = 0;
-	public $cache_ratio         = null;
-	public $hook_count          = 0;
-	public $hook_time           = 0;
-	public $request_count       = 0;
-	public $request_time        = 0;
-	private $start_time         = null;
-	private $query_offset       = null;
-	private $cache_hit_offset   = null;
-	private $cache_miss_offset  = null;
-	private $hook_start_time    = null;
-	private $hook_depth         = 0;
+	/** @var float */
+	public $time = 0;
+	/** @var int */
+	public $query_count = 0;
+	/** @var float */
+	public $query_time = 0;
+	/** @var int */
+	public $cache_hits = 0;
+	/** @var int */
+	public $cache_misses = 0;
+	/** @var string|null */
+	public $cache_ratio = null;
+	/** @var int */
+	public $hook_count = 0;
+	/** @var float */
+	public $hook_time = 0;
+	/** @var int */
+	public $request_count = 0;
+	/** @var float */
+	public $request_time = 0;
+	/** @var float|null */
+	private $start_time = null;
+	/** @var int|null */
+	private $query_offset = null;
+	/** @var int|null */
+	private $cache_hit_offset = null;
+	/** @var int|null */
+	private $cache_miss_offset = null;
+	/** @var float|null */
+	private $hook_start_time = null;
+	/** @var int */
+	private $hook_depth = 0;
+	/** @var float|null */
 	private $request_start_time = null;
 
+	/** @var array<string, mixed> */
 	private $definitions = array();
 
+	/** @var array<\WP_CLI\Profile\Logger> */
 	public static $active_loggers = array();
 
+	/**
+	 * Logger constructor.
+	 *
+	 * @param array<string, mixed> $definition
+	 */
 	public function __construct( $definition = array() ) {
 		foreach ( $definition as $k => $v ) {
 			$this->definitions[ $k ] = $v;
 		}
 	}
 
+	/**
+	 * Magic getter for definitions.
+	 *
+	 * @param string $key
+	 * @return mixed
+	 */
 	public function __get( $key ) {
 		if ( isset( $this->definitions[ $key ] ) ) {
 			return $this->definitions[ $key ];
@@ -40,16 +76,31 @@ public function __get( $key ) {
 		return null;
 	}
 
+	/**
+	 * Magic setter for definitions.
+	 *
+	 * @param string $key
+	 * @param mixed  $value
+	 * @return void
+	 */
 	public function __set( $key, $value ) {
 		$this->definitions[ $key ] = $value;
 	}
 
+	/**
+	 * Magic isset for definitions.
+	 *
+	 * @param string $key
+	 * @return bool
+	 */
 	public function __isset( $key ) {
 		return isset( $this->definitions[ $key ] );
 	}
 
 	/**
 	 * Start this logger
+	 *
+	 * @return void
 	 */
 	public function start() {
 		global $wpdb, $wp_object_cache;
@@ -66,6 +117,8 @@ public function start() {
 
 	/**
 	 * Whether or not the logger is running
+	 *
+	 * @return bool
 	 */
 	public function running() {
 		return ! is_null( $this->start_time );
@@ -73,6 +126,8 @@ public function running() {
 
 	/**
 	 * Stop this logger
+	 *
+	 * @return void
 	 */
 	public function stop() {
 		global $wpdb, $wp_object_cache;
@@ -115,6 +170,8 @@ public function stop() {
 
 	/**
 	 * Start this logger's hook timer
+	 *
+	 * @return void
 	 */
 	public function start_hook_timer() {
 		++$this->hook_count;
@@ -128,6 +185,8 @@ public function start_hook_timer() {
 
 	/**
 	 * Stop this logger's hook timer
+	 *
+	 * @return void
 	 */
 	public function stop_hook_timer() {
 		if ( $this->hook_depth ) {
@@ -142,6 +201,8 @@ public function stop_hook_timer() {
 
 	/**
 	 * Start this logger's request timer
+	 *
+	 * @return void
 	 */
 	public function start_request_timer() {
 		++$this->request_count;
@@ -150,6 +211,8 @@ public function start_request_timer() {
 
 	/**
 	 * Stop this logger's request timer
+	 *
+	 * @return void
 	 */
 	public function stop_request_timer() {
 		if ( ! is_null( $this->request_start_time ) ) {
diff --git a/src/Profiler.php b/src/Profiler.php
index 2658441f..b224bcd9 100644
--- a/src/Profiler.php
+++ b/src/Profiler.php
@@ -6,9 +6,13 @@
 
 class Profiler {
 
+	/** @var string|false */
 	private $type;
+	/** @var string|bool|null */
 	private $focus;
-	private $loggers     = array();
+	/** @var array<string|int, \WP_CLI\Profile\Logger|array<string, mixed>> */
+	private $loggers = array();
+	/** @var array<string, array<string>> */
 	private $stage_hooks = array(
 		'bootstrap'  => array(
 			'muplugins_loaded',
@@ -35,26 +39,49 @@ class Profiler {
 		),
 	);
 
-	private $current_stage_hooks       = array();
-	private $running_hook              = null;
-	private $previous_filter           = null;
+	/** @var array<string> */
+	private $current_stage_hooks = array();
+	/** @var string|null */
+	private $running_hook = null;
+	/** @var string|null */
+	private $previous_filter = null;
+	/** @var array<mixed>|null */
 	private $previous_filter_callbacks = null;
-	private $filter_depth              = 0;
-
-	private $tick_callback          = null;
-	private $tick_location          = null;
-	private $tick_start_time        = null;
-	private $tick_query_offset      = null;
-	private $tick_cache_hit_offset  = null;
+	/** @var int */
+	private $filter_depth = 0;
+
+	/** @var string|null */
+	private $tick_callback = null;
+	/** @var string|null */
+	private $tick_location = null;
+	/** @var float|null */
+	private $tick_start_time = null;
+	/** @var int|null */
+	private $tick_query_offset = null;
+	/** @var int|null */
+	private $tick_cache_hit_offset = null;
+	/** @var int|null */
 	private $tick_cache_miss_offset = null;
 
+	/** @var bool */
 	private $is_admin_request = false;
 
+	/**
+	 * Profiler constructor.
+	 *
+	 * @param string|false     $type
+	 * @param string|bool|null $focus
+	 */
 	public function __construct( $type, $focus ) {
 		$this->type  = $type;
 		$this->focus = $focus;
 	}
 
+	/**
+	 * Get the loggers.
+	 *
+	 * @return array<\WP_CLI\Profile\Logger>
+	 */
 	public function get_loggers() {
 		foreach ( $this->loggers as $i => $logger ) {
 			if ( is_array( $logger ) ) {
@@ -72,11 +99,15 @@ public function get_loggers() {
 			$logger->location    = self::get_short_location( $logger->location );
 			$this->loggers[ $i ] = $logger;
 		}
-		return $this->loggers;
+		/** @var array<\WP_CLI\Profile\Logger> $loggers */
+		$loggers = $this->loggers;
+		return $loggers;
 	}
 
 	/**
 	 * Run the profiler against WordPress
+	 *
+	 * @return void
 	 */
 	public function run() {
 		$url  = WP_CLI::get_runner()->config['url'];
@@ -120,7 +151,7 @@ function () {
 		);
 		if (
 			'hook' === $this->type &&
-			$this->focus &&
+			is_string( $this->focus ) &&
 			':before' === substr( $this->focus, -7, 7 )
 		) {
 			$stage_hooks = array();
@@ -129,7 +160,7 @@ function () {
 			}
 			$end_hook = substr( $this->focus, 0, -7 );
 			$key      = array_search( $end_hook, $stage_hooks, true );
-			if ( isset( $stage_hooks[ $key - 1 ] ) ) {
+			if ( is_int( $key ) && isset( $stage_hooks[ $key - 1 ] ) ) {
 				$start_hook = $stage_hooks[ $key - 1 ];
 				WP_CLI::add_wp_hook( $start_hook, array( $this, 'wp_tick_profile_begin' ), 9999 );
 			} else {
@@ -138,7 +169,7 @@ function () {
 			WP_CLI::add_wp_hook( $end_hook, array( $this, 'wp_tick_profile_end' ), -9999 );
 		} elseif (
 			'hook' === $this->type &&
-			$this->focus &&
+			is_string( $this->focus ) &&
 			':after' === substr( $this->focus, -6, 6 )
 		) {
 			$start_hook = substr( $this->focus, 0, -6 );
@@ -153,6 +184,9 @@ function () {
 
 	/**
 	 * Start profiling function calls on the end of this filter
+	 *
+	 * @param mixed $value
+	 * @return mixed
 	 */
 	public function wp_tick_profile_begin( $value = null ) {
 
@@ -189,6 +223,9 @@ public function wp_tick_profile_begin( $value = null ) {
 
 	/**
 	 * Stop profiling function calls at the beginning of this filter
+	 *
+	 * @param mixed $value
+	 * @return mixed
 	 */
 	public function wp_tick_profile_end( $value = null ) {
 		unregister_tick_function( array( $this, 'handle_function_tick' ) );
@@ -198,6 +235,8 @@ public function wp_tick_profile_end( $value = null ) {
 
 	/**
 	 * Profiling verbosity at the beginning of every action and filter
+	 *
+	 * @return void
 	 */
 	public function wp_hook_begin() {
 
@@ -206,17 +245,23 @@ public function wp_hook_begin() {
 		}
 
 		$current_filter = current_filter();
+		if ( ! is_string( $current_filter ) ) {
+			return;
+		}
 		if ( ( 'stage' === $this->type && in_array( $current_filter, $this->current_stage_hooks, true ) )
 			|| ( 'hook' === $this->type && ! $this->focus ) ) {
 			$pseudo_hook = "{$current_filter}:before";
 			if ( isset( $this->loggers[ $pseudo_hook ] ) ) {
+				assert( $this->loggers[ $pseudo_hook ] instanceof Logger );
 				$this->loggers[ $pseudo_hook ]->stop();
 			}
 			$callback_count = 0;
 			$callbacks      = self::get_filter_callbacks( $current_filter );
 			if ( false !== $callbacks ) {
 				foreach ( $callbacks as $priority => $cbs ) {
-					$callback_count += count( $cbs );
+					if ( is_array( $cbs ) ) {
+						$callback_count += count( $cbs );
+					}
 				}
 			}
 			$this->loggers[ $current_filter ] = new Logger(
@@ -229,7 +274,8 @@ public function wp_hook_begin() {
 		}
 
 		if ( 0 === $this->filter_depth
-			&& ! is_null( $this->previous_filter_callbacks ) ) {
+			&& ! is_null( $this->previous_filter_callbacks )
+			&& ! is_null( $this->previous_filter ) ) {
 			self::set_filter_callbacks( $this->previous_filter, $this->previous_filter_callbacks );
 			$this->previous_filter_callbacks = null;
 		}
@@ -247,6 +293,9 @@ public function wp_hook_begin() {
 
 	/**
 	 * Wrap current filter callbacks with a timer
+	 *
+	 * @param string $current_filter
+	 * @return void
 	 */
 	private function wrap_current_filter_callbacks( $current_filter ) {
 
@@ -258,23 +307,38 @@ private function wrap_current_filter_callbacks( $current_filter ) {
 		$this->previous_filter_callbacks = $callbacks;
 
 		foreach ( $callbacks as $priority => $priority_callbacks ) {
-			foreach ( $priority_callbacks as $i => $the_ ) {
-				$callbacks[ $priority ][ $i ] = array(
-					'function'      => function () use ( $the_, $i ) {
-						if ( ! isset( $this->loggers[ $i ] ) ) {
-							$this->loggers[ $i ] = new Logger(
-								array(
-									'callback' => $the_['function'],
-								)
-							);
-						}
-						$this->loggers[ $i ]->start();
-						$value = call_user_func_array( $the_['function'], func_get_args() );
-						$this->loggers[ $i ]->stop();
-						return $value;
-					},
-					'accepted_args' => $the_['accepted_args'],
-				);
+			if ( is_array( $priority_callbacks ) ) {
+				$new_priority_callbacks = $priority_callbacks;
+				foreach ( $priority_callbacks as $i => $the_ ) {
+					if ( is_array( $the_ ) && isset( $the_['function'] ) && isset( $the_['accepted_args'] ) ) {
+						$func                         = $the_['function'];
+						$new_priority_callbacks[ $i ] = array(
+							'function'      => function () use ( $func, $i ) {
+								if ( ! isset( $this->loggers[ $i ] ) ) {
+									$this->loggers[ $i ] = new Logger(
+										array(
+											'callback' => $func,
+										)
+									);
+								}
+								assert( $this->loggers[ $i ] instanceof Logger );
+								$this->loggers[ $i ]->start();
+
+								$args = func_get_args();
+								if ( is_callable( $func ) ) {
+									$value = call_user_func_array( $func, $args );
+								} else {
+									$value = null;
+								}
+
+								$this->loggers[ $i ]->stop();
+								return $value;
+							},
+							'accepted_args' => $the_['accepted_args'],
+						);
+					}
+				}
+				$callbacks[ $priority ] = $new_priority_callbacks;
 			}
 		}
 		self::set_filter_callbacks( $current_filter, $callbacks );
@@ -282,6 +346,9 @@ private function wrap_current_filter_callbacks( $current_filter ) {
 
 	/**
 	 * Profiling verbosity at the end of every action and filter
+	 *
+	 * @param mixed $filter_value
+	 * @return mixed
 	 */
 	public function wp_hook_end( $filter_value = null ) {
 
@@ -292,10 +359,11 @@ public function wp_hook_end( $filter_value = null ) {
 		$current_filter = current_filter();
 		if ( ( 'stage' === $this->type && in_array( $current_filter, $this->current_stage_hooks, true ) )
 			|| ( 'hook' === $this->type && ! $this->focus ) ) {
+			assert( $this->loggers[ $current_filter ] instanceof Logger );
 			$this->loggers[ $current_filter ]->stop();
 			if ( 'stage' === $this->type ) {
 				$key = array_search( $current_filter, $this->current_stage_hooks, true );
-				if ( false !== $key && isset( $this->current_stage_hooks[ $key + 1 ] ) ) {
+				if ( is_int( $key ) && isset( $this->current_stage_hooks[ $key + 1 ] ) ) {
 					$pseudo_hook = "{$this->current_stage_hooks[$key+1]}:before";
 				} else {
 					$pseudo_hook        = "{$this->current_stage_hooks[$key]}:after";
@@ -313,6 +381,8 @@ public function wp_hook_end( $filter_value = null ) {
 
 	/**
 	 * Handle the tick of a function
+	 *
+	 * @return void
 	 */
 	public function handle_function_tick() {
 		global $wpdb, $wp_object_cache;
@@ -334,26 +404,41 @@ public function handle_function_tick() {
 				);
 			}
 
-			$this->loggers[ $callback_hash ]['time'] += $time;
-
-			if ( isset( $wpdb ) ) {
-				$total_queries = count( $wpdb->queries );
-				for ( $i = $this->tick_query_offset; $i < $total_queries; $i++ ) {
-					$this->loggers[ $callback_hash ]['query_time'] += $wpdb->queries[ $i ][1];
-					++$this->loggers[ $callback_hash ]['query_count'];
+			$logger_data = $this->loggers[ $callback_hash ];
+			if ( is_array( $logger_data ) ) {
+				$current_time        = isset( $logger_data['time'] ) && is_numeric( $logger_data['time'] ) ? $logger_data['time'] : 0.0;
+				$logger_data['time'] = (float) $current_time + $time;
+
+				if ( isset( $wpdb ) ) {
+					$total_queries = count( $wpdb->queries );
+					for ( $i = $this->tick_query_offset; $i < $total_queries; $i++ ) {
+						$q_time                    = isset( $wpdb->queries[ $i ][1] ) ? $wpdb->queries[ $i ][1] : 0.0;
+						$current_q_time            = isset( $logger_data['query_time'] ) && is_numeric( $logger_data['query_time'] ) ? $logger_data['query_time'] : 0.0;
+						$q_time_val                = is_numeric( $q_time ) ? $q_time : 0.0;
+						$logger_data['query_time'] = (float) $current_q_time + (float) $q_time_val;
+
+						$current_q_count            = isset( $logger_data['query_count'] ) && is_numeric( $logger_data['query_count'] ) ? $logger_data['query_count'] : 0;
+						$logger_data['query_count'] = (int) $current_q_count + 1;
+					}
 				}
-			}
 
-			if ( isset( $wp_object_cache ) ) {
-				$hits   = ! empty( $wp_object_cache->cache_hits ) ? $wp_object_cache->cache_hits : 0;
-				$misses = ! empty( $wp_object_cache->cache_misses ) ? $wp_object_cache->cache_misses : 0;
-				$this->loggers[ $callback_hash ]['cache_hits']   = ( $hits - $this->tick_cache_hit_offset ) + $this->loggers[ $callback_hash ]['cache_hits'];
-				$this->loggers[ $callback_hash ]['cache_misses'] = ( $misses - $this->tick_cache_miss_offset ) + $this->loggers[ $callback_hash ]['cache_misses'];
-				$total = $this->loggers[ $callback_hash ]['cache_hits'] + $this->loggers[ $callback_hash ]['cache_misses'];
-				if ( $total ) {
-					$ratio = ( $this->loggers[ $callback_hash ]['cache_hits'] / $total ) * 100;
-					$this->loggers[ $callback_hash ]['cache_ratio'] = round( $ratio, 2 ) . '%';
+				if ( isset( $wp_object_cache ) ) {
+					$hits   = ! empty( $wp_object_cache->cache_hits ) ? $wp_object_cache->cache_hits : 0;
+					$misses = ! empty( $wp_object_cache->cache_misses ) ? $wp_object_cache->cache_misses : 0;
+
+					$current_hits              = isset( $logger_data['cache_hits'] ) && is_numeric( $logger_data['cache_hits'] ) ? $logger_data['cache_hits'] : 0;
+					$logger_data['cache_hits'] = ( $hits - $this->tick_cache_hit_offset ) + (int) $current_hits;
+
+					$current_misses              = isset( $logger_data['cache_misses'] ) && is_numeric( $logger_data['cache_misses'] ) ? $logger_data['cache_misses'] : 0;
+					$logger_data['cache_misses'] = ( $misses - $this->tick_cache_miss_offset ) + (int) $current_misses;
+
+					$total = $logger_data['cache_hits'] + $logger_data['cache_misses'];
+					if ( $total ) {
+						$ratio                      = ( $logger_data['cache_hits'] / $total ) * 100;
+						$logger_data['cache_ratio'] = round( $ratio, 2 ) . '%';
+					}
 				}
+				$this->loggers[ $callback_hash ] = $logger_data;
 			}
 		}
 
@@ -366,7 +451,10 @@ public function handle_function_tick() {
 		$location = '';
 		$callback = '';
 		if ( in_array( strtolower( $frame['function'] ), array( 'include', 'require', 'include_once', 'require_once' ), true ) ) {
-			$callback = $frame['function'] . " '" . $frame['args'][0] . "'";
+			$callback = $frame['function'];
+			if ( isset( $frame['args'] ) && is_array( $frame['args'] ) && isset( $frame['args'][0] ) && is_scalar( $frame['args'][0] ) ) {
+				$callback .= " '" . (string) $frame['args'][0] . "'";
+			}
 		} elseif ( isset( $frame['object'] ) && method_exists( $frame['object'], $frame['function'] ) ) {
 			$callback = get_class( $frame['object'] ) . '->' . $frame['function'] . '()';
 		} elseif ( isset( $frame['class'] ) && method_exists( $frame['class'], $frame['function'] ) ) {
@@ -399,6 +487,9 @@ public function handle_function_tick() {
 
 	/**
 	 * Profiling request time for any active Loggers
+	 *
+	 * @param mixed $filter_value
+	 * @return mixed
 	 */
 	public function wp_request_begin( $filter_value = null ) {
 		foreach ( Logger::$active_loggers as $logger ) {
@@ -409,6 +500,9 @@ public function wp_request_begin( $filter_value = null ) {
 
 	/**
 	 * Profiling request time for any active Loggers
+	 *
+	 * @param mixed $filter_value
+	 * @return mixed
 	 */
 	public function wp_request_end( $filter_value = null ) {
 		foreach ( Logger::$active_loggers as $logger ) {
@@ -419,6 +513,8 @@ public function wp_request_end( $filter_value = null ) {
 
 	/**
 	 * Runs through the entirety of the WP bootstrap process
+	 *
+	 * @return void
 	 */
 	private function load_wordpress_with_template() {
 
@@ -439,21 +535,22 @@ private function load_wordpress_with_template() {
 			if ( 'bootstrap' === $this->focus ) {
 				$this->set_stage_hooks( $this->stage_hooks['bootstrap'] );
 			} elseif ( ! $this->focus ) {
-				$logger = new Logger( array( 'stage' => 'bootstrap' ) );
-				$logger->start();
+				$bootstrap_logger = new Logger( array( 'stage' => 'bootstrap' ) );
+				$bootstrap_logger->start();
 			}
 		}
 		WP_CLI::get_runner()->load_wordpress();
 		if ( $this->running_hook ) {
+			assert( $this->loggers[ $this->running_hook ] instanceof Logger );
 			$this->loggers[ $this->running_hook ]->stop();
 			$this->running_hook = null;
 		}
 		if ( 'hook' === $this->type && 'wp_loaded:after' === $this->focus ) {
 			$this->wp_tick_profile_end();
 		}
-		if ( 'stage' === $this->type && ! $this->focus ) {
-			$logger->stop();
-			$this->loggers[] = $logger;
+		if ( 'stage' === $this->type && ! $this->focus && isset( $bootstrap_logger ) ) {
+			$bootstrap_logger->stop();
+			$this->loggers[] = $bootstrap_logger;
 		}
 
 		// Skip main_query and template stages for admin requests.
@@ -466,21 +563,22 @@ private function load_wordpress_with_template() {
 			if ( 'main_query' === $this->focus ) {
 				$this->set_stage_hooks( $this->stage_hooks['main_query'] );
 			} elseif ( ! $this->focus ) {
-				$logger = new Logger( array( 'stage' => 'main_query' ) );
-				$logger->start();
+				$main_query_logger = new Logger( array( 'stage' => 'main_query' ) );
+				$main_query_logger->start();
 			}
 		}
 		wp();
 		if ( $this->running_hook ) {
+			assert( $this->loggers[ $this->running_hook ] instanceof Logger );
 			$this->loggers[ $this->running_hook ]->stop();
 			$this->running_hook = null;
 		}
 		if ( 'hook' === $this->type && 'wp:after' === $this->focus ) {
 			$this->wp_tick_profile_end();
 		}
-		if ( 'stage' === $this->type && ! $this->focus ) {
-			$logger->stop();
-			$this->loggers[] = $logger;
+		if ( 'stage' === $this->type && ! $this->focus && isset( $main_query_logger ) ) {
+			$main_query_logger->stop();
+			$this->loggers[] = $main_query_logger;
 		}
 
 		define( 'WP_USE_THEMES', true );
@@ -496,28 +594,32 @@ private function load_wordpress_with_template() {
 			if ( 'template' === $this->focus ) {
 				$this->set_stage_hooks( $this->stage_hooks['template'] );
 			} elseif ( ! $this->focus ) {
-				$logger = new Logger( array( 'stage' => 'template' ) );
-				$logger->start();
+				$template_logger = new Logger( array( 'stage' => 'template' ) );
+				$template_logger->start();
 			}
 		}
 		ob_start();
 		require_once ABSPATH . WPINC . '/template-loader.php';
 		ob_get_clean();
 		if ( $this->running_hook ) {
+			assert( $this->loggers[ $this->running_hook ] instanceof Logger );
 			$this->loggers[ $this->running_hook ]->stop();
 			$this->running_hook = null;
 		}
 		if ( 'hook' === $this->type && 'wp_footer:after' === $this->focus ) {
 			$this->wp_tick_profile_end();
 		}
-		if ( 'stage' === $this->type && ! $this->focus ) {
-			$logger->stop();
-			$this->loggers[] = $logger;
+		if ( 'stage' === $this->type && ! $this->focus && isset( $template_logger ) ) {
+			$template_logger->stop();
+			$this->loggers[] = $template_logger;
 		}
 	}
 
 	/**
 	 * Get a human-readable name from a callback
+	 *
+	 * @param mixed $callback
+	 * @return array{0: string, 1: string}
 	 */
 	private static function get_name_location_from_callback( $callback ) {
 		$location   = '';
@@ -526,9 +628,11 @@ private static function get_name_location_from_callback( $callback ) {
 		if ( is_array( $callback ) && is_object( $callback[0] ) ) {
 			$reflection = new \ReflectionMethod( $callback[0], $callback[1] );
 			$name       = get_class( $callback[0] ) . '->' . $callback[1] . '()';
-		} elseif ( is_array( $callback ) && method_exists( $callback[0], $callback[1] ) ) {
+		} elseif ( is_array( $callback ) && isset( $callback[0] ) && isset( $callback[1] ) && ( is_object( $callback[0] ) || is_string( $callback[0] ) ) && is_string( $callback[1] ) && method_exists( $callback[0], $callback[1] ) ) {
 			$reflection = new \ReflectionMethod( $callback[0], $callback[1] );
-			$name       = $callback[0] . '::' . $callback[1] . '()';
+			/** @var string $class_name */
+			$class_name = $callback[0];
+			$name       = $class_name . '::' . $callback[1] . '()';
 		} elseif ( is_object( $callback ) && is_a( $callback, 'Closure' ) ) {
 			$reflection = new \ReflectionFunction( $callback );
 			$name       = 'function(){}';
@@ -549,7 +653,8 @@ private static function get_name_location_from_callback( $callback ) {
 	 * @return string
 	 */
 	private static function get_short_location( $location ) {
-		$abspath = rtrim( realpath( ABSPATH ), '/' ) . '/';
+		$real_abspath = realpath( ABSPATH );
+		$abspath      = rtrim( false !== $real_abspath ? $real_abspath : ABSPATH, '/' ) . '/';
 		if ( defined( 'WP_PLUGIN_DIR' ) && 0 === stripos( $location, WP_PLUGIN_DIR ) ) {
 			$location = str_replace( trailingslashit( WP_PLUGIN_DIR ), '', $location );
 		} elseif ( defined( 'WPMU_PLUGIN_DIR' ) && 0 === stripos( $location, WPMU_PLUGIN_DIR ) ) {
@@ -566,6 +671,9 @@ private static function get_short_location( $location ) {
 
 	/**
 	 * Set the hooks for the current stage
+	 *
+	 * @param array<string> $hooks
+	 * @return void
 	 */
 	private function set_stage_hooks( $hooks ) {
 		$this->current_stage_hooks     = $hooks;
@@ -577,8 +685,8 @@ private function set_stage_hooks( $hooks ) {
 	/**
 	 * Get the callbacks for a given filter
 	 *
-	 * @param string
-	 * @return array|false
+	 * @param string $filter
+	 * @return array<mixed>|false
 	 */
 	private static function get_filter_callbacks( $filter ) {
 		global $wp_filter;
@@ -602,7 +710,8 @@ private static function get_filter_callbacks( $filter ) {
 	 * Set the callbacks for a given filter
 	 *
 	 * @param string $filter
-	 * @param mixed $callbacks
+	 * @param mixed  $callbacks
+	 * @return void
 	 */
 	private static function set_filter_callbacks( $filter, $callbacks ) {
 		global $wp_filter;
@@ -612,6 +721,7 @@ private static function set_filter_callbacks( $filter, $callbacks ) {
 		}
 
 		if ( is_a( $wp_filter[ $filter ], 'WP_Hook' ) ) {
+			/** @var array<mixed> $callbacks */
 			$wp_filter[ $filter ]->callbacks = $callbacks;
 		} else {
 			$wp_filter[ $filter ] = $callbacks; // phpcs:ignore
diff --git a/tests/phpstan/scan-files.php b/tests/phpstan/scan-files.php
new file mode 100644
index 00000000..81f3d91b
--- /dev/null
+++ b/tests/phpstan/scan-files.php
@@ -0,0 +1,6 @@
+<?php
+// phpcs:ignoreFile
+
+namespace {
+	define( 'WPINC', 'wp-includes' );
+}