diff --git a/.github/workflows/checks.yml b/.github/workflows/checks.yml
index 58cd2d23..4bd07bf4 100644
--- a/.github/workflows/checks.yml
+++ b/.github/workflows/checks.yml
@@ -5,8 +5,6 @@ on: [ push, pull_request ]
 jobs:
   test:
     runs-on: ubuntu-latest
-    strategy:
-      fail-fast: true
 
     name: Code Checks
     steps:
@@ -29,5 +27,36 @@ jobs:
         run: composer install --prefer-dist --no-interaction --no-suggest
       - name: Run PHP Code Sniffer
         run: ./vendor/bin/phpcs
+
+  phpstan:
+    runs-on: ubuntu-latest
+    strategy:
+      fail-fast: false
+      matrix:
+        php:
+          - "7.4"
+          - "8.0"
+          - "8.1"
+          - "8.2"
+    name: PHPStan on PHP ${{ matrix.php }}
+    steps:
+      - name: Checkout code
+        uses: actions/checkout@v2
+
+      - name: Cache dependencies
+        uses: actions/cache@v2
+        with:
+          path: ~/.composer/cache/files
+          key: dependencies-code-checks
+
+      - name: Setup PHP
+        uses: shivammathur/setup-php@v2
+        with:
+          php-version: ${{ matrix.php }}
+          coverage: none
+          tools: "cs2pr"
+
+      - name: Install dependencies
+        run: composer install --prefer-dist --no-interaction --no-suggest
       - name: Run PHPStan
-        run: php vendor/bin/phpstan analyse --autoload-file tests/bootstrap.php
+        run: "vendor/bin/phpstan analyse --autoload-file tests/bootstrap.php --error-format=checkstyle | cs2pr"
diff --git a/phpstan.neon.dist b/phpstan.neon.dist
index b1fe7a07..8121c416 100644
--- a/phpstan.neon.dist
+++ b/phpstan.neon.dist
@@ -1,10 +1,8 @@
+includes:
+    - phpstan/include-by-php-version.php
+
 parameters:
     level: 8
     paths:
         - src
         - tests
-    reportUnmatchedIgnoredErrors: false
-    ignoreErrors:
-        -
-            # REDIS stuff only runs with it available
-            '#Constant REDIS_HOST not found\.#'
diff --git a/phpstan/include-by-php-version.php b/phpstan/include-by-php-version.php
new file mode 100644
index 00000000..cdb2c194
--- /dev/null
+++ b/phpstan/include-by-php-version.php
@@ -0,0 +1,15 @@
+<?php
+
+declare(strict_types=1);
+
+$includes = [];
+
+if (PHP_VERSION_ID >= 70400) {
+    $includes[] = __DIR__ . '/php-74.neon';
+}
+
+$config = [];
+$config['includes'] = $includes;
+$config['parameters']['phpVersion'] = PHP_VERSION_ID;
+
+return $config;
diff --git a/phpstan/php-74.neon b/phpstan/php-74.neon
new file mode 100644
index 00000000..5a413315
--- /dev/null
+++ b/phpstan/php-74.neon
@@ -0,0 +1,6 @@
+parameters:
+    ignoreErrors:
+        -
+            message: "#^Strict comparison using === between non\\-empty\\-array\\<int, string\\> and false will always evaluate to false\\.$#"
+            count: 1
+            path: ../src/Prometheus/Storage/RedisNg.php
diff --git a/src/Prometheus/RenderTextFormat.php b/src/Prometheus/RenderTextFormat.php
index c285bb30..98ee73ea 100644
--- a/src/Prometheus/RenderTextFormat.php
+++ b/src/Prometheus/RenderTextFormat.php
@@ -67,7 +67,6 @@ private function escapeAllLabels(array $labelNames, Sample $sample): array
 
         $labels = array_combine(array_merge($labelNames, $sample->getLabelNames()), $sample->getLabelValues());
 
-        /** @phpstan-ignore-next-line */
         if ($labels === false) {
             throw new RuntimeException('Unable to combine labels.');
         }
diff --git a/src/Prometheus/Storage/RedisNg.php b/src/Prometheus/Storage/RedisNg.php
index 990d0cf8..40061e2c 100644
--- a/src/Prometheus/Storage/RedisNg.php
+++ b/src/Prometheus/Storage/RedisNg.php
@@ -291,8 +291,7 @@ public function updateSummary(array $data): void
         if (false === $json) {
             throw new RuntimeException(json_last_error_msg());
         }
-        $this->redis->setNx($metaKey, $json);
-        /** @phpstan-ignore-line */
+        $this->redis->setnx($metaKey, $json);
 
         // store value key
         $valueKey = $summaryKey . ':' . $this->valueKey($data);
@@ -301,8 +300,7 @@ public function updateSummary(array $data): void
         if (false === $json) {
             throw new RuntimeException(json_last_error_msg());
         }
-        $this->redis->setNx($valueKey, $json);
-        /** @phpstan-ignore-line */
+        $this->redis->setnx($valueKey, $json);
 
         // trick to handle uniqid collision
         $done = false;
@@ -528,10 +526,15 @@ private function collectSummaries(): array
                 }
             }
             if (count($samples) === 0) {
-                $this->redis->del($valueKey);
+                if (isset($valueKey)) {
+                    $this->redis->del($valueKey);
+                }
+
                 continue;
             }
 
+            assert(isset($decodedLabelValues));
+
             // Compute quantiles
             sort($samples);
             foreach ($data['quantiles'] as $quantile) {
@@ -560,11 +563,7 @@ private function collectSummaries(): array
             ];
 
 
-            if (count($data['samples']) > 0) {
-                $summaries[] = $data;
-            } else {
-                $this->redis->del($metaKey);
-            }
+            $summaries[] = $data;
         }
         return $summaries;
     }