diff --git a/src/RequirementChecker/RequirementsBuilder.php b/src/RequirementChecker/RequirementsBuilder.php
index d4518edc9..d8a5b4a2d 100644
--- a/src/RequirementChecker/RequirementsBuilder.php
+++ b/src/RequirementChecker/RequirementsBuilder.php
@@ -19,14 +19,36 @@
 use function array_map;
 use function array_unique;
 use function natsort;
+use function strcmp;
 use function strnatcmp;
 use function uksort;
+use function usort;
 
 final class RequirementsBuilder
 {
+    /**
+     * @var list<Requirement>
+     */
     private array $predefinedRequirements = [];
+
+    /**
+     * @var array<string, array<string|null>>
+     */
     private array $requiredExtensions = [];
+
+    /**
+     * @var array<string, array<string|null>>
+     */
     private array $providedExtensions = [];
+
+    /**
+     * @var array<string, array{string|null, RequirementType}>
+     */
+    private array $allExtensions = [];
+
+    /**
+     * @var array<string, array<string|null>>
+     */
     private array $conflictingExtensions = [];
 
     public function addRequirement(Requirement $requirement): void
@@ -37,11 +59,13 @@ public function addRequirement(Requirement $requirement): void
     public function addRequiredExtension(Extension $extension, ?string $source): void
     {
         $this->requiredExtensions[$extension->name][] = $source;
+        $this->allExtensions[$extension->name][$source] = [$source, RequirementType::EXTENSION];
     }
 
     public function addProvidedExtension(Extension $extension, ?string $source): void
     {
         $this->providedExtensions[$extension->name][] = $source;
+        $this->allExtensions[$extension->name][$source] = [$source, RequirementType::PROVIDED_EXTENSION];
     }
 
     public function addConflictingExtension(Extension $extension, ?string $source): void
@@ -53,21 +77,17 @@ public function all(): Requirements
     {
         $requirements = $this->predefinedRequirements;
 
-        foreach ($this->getUnfilteredSortedRequiredExtensions() as $extensionName => $sources) {
-            foreach ($sources as $source) {
-                $requirements[] = Requirement::forRequiredExtension(
-                    $extensionName,
-                    $source,
-                );
-            }
-        }
-
-        foreach ($this->getSortedProvidedExtensions() as $extensionName => $sources) {
-            foreach ($sources as $source) {
-                $requirements[] = Requirement::forProvidedExtension(
-                    $extensionName,
-                    $source,
-                );
+        foreach ($this->getSortedRequiredAndProvidedExtensions() as $extensionName => $sources) {
+            foreach ($sources as [$source, $type]) {
+                $requirements[] = RequirementType::EXTENSION === $type
+                    ? Requirement::forRequiredExtension(
+                        $extensionName,
+                        $source,
+                    )
+                    : Requirement::forProvidedExtension(
+                        $extensionName,
+                        $source,
+                    );
             }
         }
 
@@ -109,33 +129,28 @@ public function build(): Requirements
     }
 
     /**
-     * @return array<string, list<string>>
+     * @return array<string, list<array{string|null, RequirementType}>>
      */
-    private function getUnfilteredSortedRequiredExtensions(): array
+    private function getSortedRequiredAndProvidedExtensions(): array
     {
         return array_map(
-            self::createSortedDistinctList(...),
-            self::sortByExtensionName(
-                $this->requiredExtensions,
-            ),
-        );
-    }
+            static function (array $sources): array {
+                usort(
+                    $sources,
+                    static fn (array $sourceTypePairA, array $sourceTypePairB) => strcmp(
+                        $sourceTypePairA[0],
+                        (string) $sourceTypePairB[0],
+                    ),
+                );
 
-    /**
-     * @return array<string, list<string>>
-     */
-    private function getSortedProvidedExtensions(): array
-    {
-        return array_map(
-            self::createSortedDistinctList(...),
-            self::sortByExtensionName(
-                $this->providedExtensions,
-            ),
+                return $sources;
+            },
+            self::sortByExtensionName($this->allExtensions),
         );
     }
 
     /**
-     * @return array<string, list<string>>
+     * @return array<string, list<string|null>>
      */
     private function getSortedRequiredExtensions(): array
     {
@@ -151,7 +166,7 @@ private function getSortedRequiredExtensions(): array
     }
 
     /**
-     * @return array<string, list<string>>
+     * @return array<string, list<string|null>>
      */
     private function getSortedConflictedExtensions(): array
     {
diff --git a/tests/RequirementChecker/RequirementsBuilderTest.php b/tests/RequirementChecker/RequirementsBuilderTest.php
index 559c0ae71..f98cad507 100644
--- a/tests/RequirementChecker/RequirementsBuilderTest.php
+++ b/tests/RequirementChecker/RequirementsBuilderTest.php
@@ -68,6 +68,10 @@ public function test_it_can_build_requirements_from_required_extensions(): void
             new Extension('http'),
             'package2',
         );
+        $this->builder->addRequiredExtension(
+            new Extension('http'),
+            null,
+        );
         $this->builder->addRequiredExtension(
             new Extension('phar'),
             'package1',
@@ -83,6 +87,7 @@ public function test_it_can_build_requirements_from_required_extensions(): void
         );
 
         $expected = new Requirements([
+            Requirement::forRequiredExtension('http', null),
             Requirement::forRequiredExtension('http', 'package1'),
             Requirement::forRequiredExtension('http', 'package2'),
             Requirement::forRequiredExtension('openssl', 'package3'),
@@ -179,9 +184,9 @@ public function test_it_removes_extension_requirements_if_they_are_provided(): v
         $expectedAllRequirements = new Requirements([
             Requirement::forRequiredExtension('http', 'package1'),
             Requirement::forRequiredExtension('http', 'package2'),
+            Requirement::forProvidedExtension('http', 'package3'),
             Requirement::forRequiredExtension('openssl', 'package3'),
             Requirement::forRequiredExtension('phar', 'package1'),
-            Requirement::forProvidedExtension('http', 'package3'),
         ]);
 
         $this->assertBuiltRequirementsEquals($expectedBuiltRequirements);
@@ -218,9 +223,9 @@ public function test_it_does_not_remove_extension_conflicts_if_they_are_provided
         $expectedAllRequirements = new Requirements([
             Requirement::forRequiredExtension('http', 'package1'),
             Requirement::forRequiredExtension('http', 'package2'),
+            Requirement::forProvidedExtension('http', 'package3'),
             Requirement::forRequiredExtension('openssl', 'package3'),
             Requirement::forRequiredExtension('phar', 'package1'),
-            Requirement::forProvidedExtension('http', 'package3'),
         ]);
 
         $this->assertBuiltRequirementsEquals($expectedBuiltRequirements);