Fix most Psalm/PHPStan issues

.gitignore

@@ -1,3 +1,3 @@
 /vendor/
-.php_cs.cache
+.cache/
 composer.lock

.php_cs → .php-cs-fixer.dist.php

@@ -1,9 +1,10 @@
 <?php
-$finder = PhpCsFixer\Finder::create()
+$finder = (new PhpCsFixer\Finder())
     ->exclude('vendor')
     ->in(__DIR__);
-return PhpCsFixer\Config::create()
+return (new PhpCsFixer\Config())
     ->setUsingCache(true)
+    ->setCacheFile('.cache/php-cs-fixer/php-cs-fixer.cache')
     ->setRules([
         '@PSR2' => true,
         'encoding' => true,
@@ -14,7 +15,7 @@
         'indentation_type' => true,
         'blank_line_after_namespace' => true,
         'line_ending' => true,
-        'lowercase_constants' => true,
+        'constant_case' => ['case' => 'lower'],
         'lowercase_keywords' => true,
         'no_closing_tag' => true,
         'single_line_after_imports' => true,
@@ -23,16 +24,15 @@
         'whitespace_after_comma_in_array' => true,
         'blank_line_after_opening_tag' => true,
         'no_empty_statement' => true,
-        'no_extra_consecutive_blank_lines' => true,
+        'no_extra_blank_lines' => true,
         'function_typehint_space' => true,
         'no_leading_namespace_whitespace' => true,
         'no_blank_lines_after_class_opening' => true,
         'no_blank_lines_after_phpdoc' => true,
         'phpdoc_scalar' => true,
         'phpdoc_types' => true,
         'no_leading_import_slash' => true,
-        'no_extra_consecutive_blank_lines' => ['use'],
-        'blank_line_before_return' => true,
+        'blank_line_before_statement' => ['statements' => ['return']],
         'self_accessor' => false,
         'no_short_bool_cast' => true,
         'no_trailing_comma_in_singleline_array' => true,

composer.json

@@ -13,9 +13,11 @@
     "php": ">=7.1"
   },
   "require-dev": {
-    "friendsofphp/php-cs-fixer": "^2",
-    "phpunit/phpunit": "^5",
-    "giorgiosironi/eris": "^0.9"
+    "friendsofphp/php-cs-fixer": "^3.65",
+    "phpunit/phpunit": "^10.0",
+    "giorgiosironi/eris": "^1.0",
+    "phpstan/phpstan": "^2.0",
+    "vimeo/psalm": "^5.26"
   },
   "prefer-stable": true,
   "autoload": {
@@ -29,6 +31,8 @@
   "scripts": {
     "test": "phpunit --no-coverage",
     "fix-code": "php-cs-fixer fix --allow-risky=yes",
-    "check-code": "php-cs-fixer fix --verbose --diff --dry-run --allow-risky=yes"
+    "check-code": "php-cs-fixer fix --verbose --diff --dry-run --allow-risky=yes",
+    "phpstan": "phpstan analyse",
+    "psalm": "psalm"
   }
 }

phpstan-baseline.neon

@@ -0,0 +1,31 @@
+parameters:
+	ignoreErrors:
+		-
+			message: '#^Unable to resolve the template type b in call to function FunctionalPHP\\FantasyLand\\applicator$#'
+			identifier: argument.templateType
+			count: 1
+			path: src/FantasyLand/Helpful/ApplicativeLaws.php
+
+		-
+			message: '#^Variable \$ap in PHPDoc tag @var does not match assigned variable \$applicatorX\.$#'
+			identifier: varTag.differentVariable
+			count: 1
+			path: src/FantasyLand/Helpful/ApplicativeLaws.php
+
+		-
+			message: '#^Parameter \#1 \$f of function FunctionalPHP\\FantasyLand\\compose expects callable\(FunctionalPHP\\FantasyLand\\Functor\<b\>\)\: FunctionalPHP\\FantasyLand\\Functor\<c\>, \(callable\(FunctionalPHP\\FantasyLand\\Functor\<b\>\)\: FunctionalPHP\\FantasyLand\\Functor\<c\>\)\|FunctionalPHP\\FantasyLand\\Functor\<c\> given\.$#'
+			identifier: argument.type
+			count: 1
+			path: src/FantasyLand/Helpful/FunctorLaws.php
+
+		-
+			message: '#^Parameter \#2 \$g of function FunctionalPHP\\FantasyLand\\compose expects callable\(FunctionalPHP\\FantasyLand\\Functor\<a\>\)\: FunctionalPHP\\FantasyLand\\Functor\<b\>, \(callable\(FunctionalPHP\\FantasyLand\\Functor\<a\>\)\: FunctionalPHP\\FantasyLand\\Functor\<b\>\)\|FunctionalPHP\\FantasyLand\\Functor\<b\> given\.$#'
+			identifier: argument.type
+			count: 1
+			path: src/FantasyLand/Helpful/FunctorLaws.php
+
+		-
+			message: '#^Parameter \#4 \$f of static method FunctionalPHP\\FantasyLand\\Helpful\\MonadLaws\:\:test\(\) expects callable\(mixed\)\: FunctionalPHP\\FantasyLand\\Monad\<b\>, callable\(a\)\: FunctionalPHP\\FantasyLand\\Useful\\Identity\<b\> given\.$#'
+			identifier: argument.type
+			count: 1
+			path: src/FantasyLand/Helpful/Tests/MonadLawsTest.php

phpstan.neon.dist

@@ -0,0 +1,8 @@
+includes:
+    - phpstan-baseline.neon
+
+parameters:
+    level: 10
+    tmpDir: .cache/phpstan
+    paths:
+        - src

phpunit.xml.dist

@@ -1,14 +1,17 @@
 <?xml version="1.0" encoding="UTF-8"?>
-<phpunit xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
-         xsi:noNamespaceSchemaLocation="https://schema.phpunit.de/6.3/phpunit.xsd">
-    <testsuites>
-        <testsuite name="FantasyLand/Helpful/Tests">
-            <directory>./src/FantasyLand/Helpful/Tests</directory>
-        </testsuite>
-    </testsuites>
-    <filter>
-        <whitelist processUncoveredFilesFromWhitelist="true">
-            <directory suffix=".php">./src/</directory>
-        </whitelist>
-    </filter>
+<phpunit
+    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+    xsi:noNamespaceSchemaLocation="https://schema.phpunit.de/10.5/phpunit.xsd"
+    cacheDirectory=".cache/phpunit"
+>
+  <testsuites>
+    <testsuite name="FantasyLand/Helpful/Tests">
+      <directory>./src/FantasyLand/Helpful/Tests</directory>
+    </testsuite>
+  </testsuites>
+  <source>
+    <include>
+      <directory suffix=".php">./src/</directory>
+    </include>
+  </source>
 </phpunit>

psalm.baseline.xml

@@ -0,0 +1,9 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<files psalm-version="5.26.1@d747f6500b38ac4f7dfc5edbcae6e4b637d7add0">
+  <file src="src/FantasyLand/Helpful/FunctorLaws.php">
+    <PossiblyInvalidArgument>
+      <code><![CDATA[map($f)]]></code>
+      <code><![CDATA[map($g)]]></code>
+    </PossiblyInvalidArgument>
+  </file>
+</files>

psalm.xml

@@ -0,0 +1,47 @@
+<?xml version="1.0"?>
+<psalm
+    resolveFromConfigFile="true"
+    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+    xmlns="https://getpsalm.org/schema/config"
+    xsi:schemaLocation="https://getpsalm.org/schema/config vendor/vimeo/psalm/config.xsd"
+    cacheDirectory=".cache/psalm"
+    findUnusedBaselineEntry="true"
+    findUnusedCode="false"
+    errorBaseline="psalm.baseline.xml"
+>
+    <projectFiles>
+        <directory name="src" />
+        <ignoreFiles>
+            <directory name="vendor" />
+        </ignoreFiles>
+    </projectFiles>
+    <issueHandlers>
+        <!-- This is a stylistic preference from Psalm that we don't adhere to -->
+        <ParamNameMismatch errorLevel="suppress" />
+        <!--
+            This issue _may_ point to a valid issue, but more likely it's a
+            mismatch between what is possible to express in PHPDoc and what
+            the actual expectation is.
+
+            For example, if you have a `Maybe` monad, it will implement the
+            `bind` method with a more specific type than the `Monad` interface;
+            it will be `Maybe` instead of `Monad`. This is as expected, but
+            Psalm will complain about it because Psalm is assuming that a class
+            which implements an interface should always be subsitutable for any
+            other class which implements the same interface.
+
+            Ideally, that should be solvable with static parameter types and
+            static return types, but that doesn't seem to work as expected in
+            Psalm.
+        -->
+        <MoreSpecificImplementedParamType errorLevel="info" />
+        <!--
+            This issue is usually to do with extending a PHPUnit test class, so
+            usually a false positive. We should still report it, but at a lower
+            level so that we know to investigate all such instances.
+        -->
+        <PropertyNotSetInConstructor errorLevel="info" />
+        <!-- Psalm is complaining about being unable to load an internal PHPUnit class -->
+        <MissingDependency errorLevel="info" />
+    </issueHandlers>
+</psalm>

src/FantasyLand/Applicative.php

@@ -6,8 +6,8 @@
 
 /**
  * @template a
- * @template-extends Apply<a>
- * @template-extends Pointed<a>
+ * @extends Apply<a>
+ * @extends Pointed<a>
  */
 interface Applicative extends
     Apply,

src/FantasyLand/Apply.php

@@ -6,7 +6,7 @@
 
 /**
  * @template a
- * @template-extends Functor<a>
+ * @extends Functor<a>
  */
 interface Apply extends Functor
 {

src/FantasyLand/Chain.php

@@ -6,17 +6,16 @@
 
 /**
  * @template a
- * @template-extends Apply<a>
+ * @extends Apply<a>
  */
 interface Chain extends Apply
 {
     /**
      * bind :: Monad m => (a -> m b) -> m b
      *
      * @template b
-     * @template f of callable(a): Chain<b>
      *
-     * @param f $function
+     * @param callable(a): Chain<b> $function
      *
      * @return Chain<b>
      */

src/FantasyLand/Foldable.php

@@ -13,10 +13,9 @@ interface Foldable
      * reduce :: (b -> a -> b) -> b -> b
      *
      * @template b
-     * @template f of callable(b, a): b
      *
-     * @param f $function    Binary function ($accumulator, $value)
-     * @param b $accumulator Value to witch reduce
+     * @param callable(b, a): b $function    Binary function ($accumulator, $value)
+     * @param b                 $accumulator Value to witch reduce
      *
      * @return b Same type as $accumulator
      */

src/FantasyLand/Functor.php

@@ -13,11 +13,10 @@ interface Functor
      * map :: Functor f => (a -> b) -> f b
      *
      * @template b
-     * @template f of callable(a): b
      *
-     * @param f $function
+     * @param callable(a): b $function
      *
      * @return Functor<b>
      */
-    public function map(callable $function): Functor;
+    public function map(callable $function);
 }

src/FantasyLand/Helpful/ApplicativeLaws.php

@@ -15,23 +15,28 @@ class ApplicativeLaws
     /**
      * Generic test to verify if a type obey the applicative laws.
      *
-     * @param callable    $assertEqual Asserting function (Applicative $a1, Applicative $a2, $message)
-     * @param callable    $pure        Applicative "constructor"
-     * @param Applicative $u           Applicative f => f (a -> b)
-     * @param Applicative $v           Applicative f => f (a -> b)
-     * @param Applicative $w           Applicative f => f (a -> b)
-     * @param callable    $f           (a -> b)
-     * @param mixed       $x           Value to put into a applicative
+     * @template a
+     * @template b
+     * @template c
+     * @template d
+     *
+     * @param callable                            $assertEqual Asserting function (Applicative $a1, Applicative $a2, $message)
+     * @param a                                   $x           Value to put into a applicative
+     * @param callable(mixed): Applicative<mixed> $pure        Applicative "constructor"
+     * @param Applicative<callable(a): b>         $u           Applicative f => f (a -> b)
+     * @param Applicative<callable(b): c>         $v           Applicative f => f (a -> b)
+     * @param Applicative<callable(c): d>         $w           Applicative f => f (a -> b)
+     * @param callable(a): b                      $f           (a -> b)
      */
     public static function test(
         callable $assertEqual,
+        $x,
         callable $pure,
         Applicative $u,
         Applicative $v,
         Applicative $w,
-        callable $f,
-        $x
-    ) {
+        callable $f
+    ): void {
         // identity: pure id <*> v = v
         $assertEqual(
             $pure(identity)->ap($v),
@@ -47,9 +52,11 @@ public static function test(
         );
 
         // interchange: u <*> pure x = pure ($ x) <*> u
+        /** @var callable(callable(a): b): b $ap */
+        $applicatorX = applicator($x);
         $assertEqual(
             $u->ap($pure($x)),
-            $pure(applicator($x))->ap($u),
+            $pure($applicatorX)->ap($u),
             'interchange'
         );
 

src/FantasyLand/Helpful/FunctorLaws.php

@@ -5,7 +5,6 @@
 namespace FunctionalPHP\FantasyLand\Helpful;
 
 use FunctionalPHP\FantasyLand\Functor;
-use const FunctionalPHP\FantasyLand\identity;
 use function FunctionalPHP\FantasyLand\compose;
 use function FunctionalPHP\FantasyLand\map;
 
@@ -14,20 +13,33 @@ class FunctorLaws
     /**
      * Generic test to verify if a type obey the functor laws.
      *
-     * @param callable $assertEqual Asserting function (Functor $f1, Functor $f2, $message)
-     * @param callable $f           (a -> b)
-     * @param callable $g           (a -> b)
-     * @param Functor  $x           f a
+     * @template a
+     * @template b
+     * @template c
+     *
+     * @param callable       $assertEqual Asserting function (Functor $f1, Functor $f2, $message)
+     * @param callable(b): c $f           (a -> b)
+     * @param callable(a): b $g           (a -> b)
+     * @param Functor<a>     $x           f a
      */
     public static function test(
         callable $assertEqual,
         callable $f,
         callable $g,
         Functor $x
-    ) {
+    ): void {
+        $identity =
+            /**
+             * @param  a $x
+             * @return a
+             */
+            static function ($x) {
+                return $x;
+            };
+
         // identity: fmap id  ==  id
         $assertEqual(
-            map(identity, $x),
+            map($identity, $x),
             $x,
             'identity'
         );