diff --git a/src/Composer/DependencyResolver/RuleSetGenerator.php b/src/Composer/DependencyResolver/RuleSetGenerator.php
index 6117c1d95..e8714a405 100644
--- a/src/Composer/DependencyResolver/RuleSetGenerator.php
+++ b/src/Composer/DependencyResolver/RuleSetGenerator.php
@@ -233,7 +233,7 @@ class RuleSetGenerator
         }
     }
 
-    protected function addConflictRules()
+    protected function addConflictRules($ignorePlatformReqs = false)
     {
         /** @var PackageInterface $package */
         foreach ($this->addedPackages as $package) {
@@ -242,6 +242,10 @@ class RuleSetGenerator
                     continue;
                 }
 
+                if ($ignorePlatformReqs && preg_match(PlatformRepository::PLATFORM_PACKAGE_REGEX, $link->getTarget())) {
+                    continue;
+                }
+
                 /** @var PackageInterface $possibleConflict */
                 foreach ($this->addedPackagesByNames[$link->getTarget()] as $possibleConflict) {
                     $conflictMatch = $this->pool->match($possibleConflict, $link->getTarget(), $link->getConstraint(), true);
@@ -362,7 +366,7 @@ class RuleSetGenerator
 
         $this->addRulesForJobs($ignorePlatformReqs);
 
-        $this->addConflictRules();
+        $this->addConflictRules($ignorePlatformReqs);
 
         // Remove references to packages
         $this->addedPackages = $this->addedPackagesByNames = null;