Introduce PHPStan

.travis.yml

@@ -66,6 +66,12 @@ install:
 script:
   - if [[ $TEST_COVERAGE == 'true' ]]; then composer test-coverage ; else composer test ; fi
   - if [[ $CS_CHECK == 'true' ]]; then composer cs-check ; fi
+  - |
+    if [[ $(phpenv version-name) == '7.3' ]]; then
+        composer require --dev "phpstan/phpstan:^0.12.7"
+        wget -qO- https://github.com/squizlabs/PHP_CodeSniffer/commit/2ecd8dc15364cdd6e5089e82ffef2b205c98c412.patch | patch -d vendor/squizlabs/php_codesniffer/ -p 1
+        vendor/bin/phpstan analyze
+    fi
 
 after_script:
   - if [[ $TEST_COVERAGE == 'true' ]]; then travis_retry php vendor/bin/php-coveralls -v ; fi

phpstan.neon.dist

@@ -0,0 +1,18 @@
+includes:
+    - phar://phpstan.phar/conf/bleedingEdge.neon
+parameters:
+    level: 2
+#    TODO Reach level MAX!
+#    level: 4
+#    level: max
+    inferPrivatePropertyTypeFromConstructor: true
+    paths:
+        - src/
+#        TODO Test tests!
+#        - test/
+    autoload_files:
+        - vendor/squizlabs/php_codesniffer/autoload.php
+    ignoreErrors:
+        # TODO These are way too easy to fix!
+        - '#^Access to an undefined property WebimpressCodingStandard\\\S+\.$#'
+        - '#^Variable \$\S+ might not be defined\.$#'

src/WebimpressCodingStandard/Sniffs/Functions/ReturnTypeSniff.php

@@ -96,7 +96,7 @@ class ReturnTypeSniff implements Sniff
     use MethodsTrait;
 
     /**
-     * @var string
+     * @var null|int
      */
     private $returnDoc;
 

src/WebimpressCodingStandard/Sniffs/Namespaces/AlphabeticallySortedUsesSniff.php

@@ -147,7 +147,7 @@ public function process(File $phpcsFile, $stackPtr)
     }
 
     /**
-     * @return string[][]
+     * @phpstan-return array<int, array{ptrUse:int, name:string, ptrEnd:int, string:string, type:string}>
      */
     private function getUseStatements(File $phpcsFile, int $scopePtr) : array
     {
@@ -231,7 +231,7 @@ private function clearName(string $name) : string
     }
 
     /**
-     * @param string[][] $uses
+     * @phpstan-param array<int, array{ptrUse:int, name:string, ptrEnd:int, string:string, type:string}> $uses
      */
     private function fixAlphabeticalOrder(File $phpcsFile, array $uses) : void
     {

src/WebimpressCodingStandard/Sniffs/PHP/DisallowFqnSniff.php

@@ -594,7 +594,7 @@ private function import(string $type, string $fqn, string $alias) : array
     }
 
     /**
-     * @param string[][] $references
+     * @phpstan-param array<string, string> $references
      */
     private function importReferences(File $phpcsFile, int $namespacePtr, array $references) : void
     {