diff --git a/src/Analyser/ClassNode.php b/src/Analyser/ClassNode.php
index 592335e5..51f215b3 100644
--- a/src/Analyser/ClassNode.php
+++ b/src/Analyser/ClassNode.php
@@ -6,6 +6,7 @@
 
 use function array_filter;
 use function in_array;
+use function ltrim;
 use function preg_match;
 use function strcasecmp;
 use function strncasecmp;
@@ -92,6 +93,8 @@ public function __construct(
      */
     public function usesClass(string $class): bool
     {
+        $class = ltrim($class, '\\');
+
         if (! $this->dependsOn($class, isCaseSensitive: false)) {
             return false;
         }
@@ -111,6 +114,7 @@ public function usesClass(string $class): bool
      */
     public function usesConstant(string $constant): bool
     {
+        $constant          = ltrim($constant, '\\');
         $separatorPosition = strrpos($constant, '\\');
 
         // a constant name is case-sensitive
@@ -224,6 +228,8 @@ public function nameMatches(string $pattern, bool $isFullName = false): bool
      */
     public function implementsInterface(string $interface): bool
     {
+        $interface = ltrim($interface, '\\');
+
         return $this->matchesAnyClassLike($interface, $this->implements)
             || $this->matchesAnyClassLike($interface, $this->interfaceExtends)
             || $this->matchesAnyClassLike($interface, $this->parentInterfaces);
diff --git a/src/Analyser/NodeQueryTrait.php b/src/Analyser/NodeQueryTrait.php
index 5ab6d03d..6a97e281 100644
--- a/src/Analyser/NodeQueryTrait.php
+++ b/src/Analyser/NodeQueryTrait.php
@@ -5,11 +5,12 @@
 namespace Boundwize\StructArmed\Analyser;
 
 use function in_array;
-use function rtrim;
+use function ltrim;
 use function strcasecmp;
 use function strlen;
 use function strncasecmp;
 use function strtolower;
+use function trim;
 
 /**
  * Query helpers shared by {@see ClassNode}, {@see AnonymousClassNode},
@@ -35,6 +36,8 @@ public function isInLayer(string $layer): bool
 
     public function dependsOn(string $dependency, bool $isCaseSensitive = true): bool
     {
+        $dependency = ltrim($dependency, '\\');
+
         if ($isCaseSensitive) {
             return in_array($dependency, $this->dependencies, true);
         }
@@ -50,7 +53,7 @@ public function dependsOn(string $dependency, bool $isCaseSensitive = true): boo
 
     public function dependsOnNamespace(string $namespace): bool
     {
-        $prefix       = rtrim($namespace, '\\') . '\\';
+        $prefix       = trim($namespace, '\\') . '\\';
         $prefixLength = strlen($prefix);
 
         // namespace names are case-insensitive; only the prefix is compared,
@@ -78,6 +81,8 @@ public function setFunctionCalls(array $functionCalls): void
 
     public function callsFunction(string $function): bool
     {
+        $function = ltrim($function, '\\');
+
         foreach ($this->functionCalls as $functionCall) {
             if (strcasecmp($functionCall, $function) === 0) {
                 return true;
diff --git a/src/Analyser/RecursiveParentsTrait.php b/src/Analyser/RecursiveParentsTrait.php
index 4ddab395..dd663cbb 100644
--- a/src/Analyser/RecursiveParentsTrait.php
+++ b/src/Analyser/RecursiveParentsTrait.php
@@ -4,6 +4,7 @@
 
 namespace Boundwize\StructArmed\Analyser;
 
+use function ltrim;
 use function strcasecmp;
 
 /**
@@ -36,12 +37,16 @@ public function setRecursiveParents(array $parentClasses, array $parentInterface
      */
     public function implementsInterface(string $interface): bool
     {
+        $interface = ltrim($interface, '\\');
+
         return $this->matchesAnyClassLike($interface, $this->implements)
             || $this->matchesAnyClassLike($interface, $this->parentInterfaces);
     }
 
     public function extendsClass(string $class): bool
     {
+        $class = ltrim($class, '\\');
+
         if ($this->extends !== null && strcasecmp($this->extends, $class) === 0) {
             return true;
         }
diff --git a/tests/Analyser/AnonymousClassNodeTest.php b/tests/Analyser/AnonymousClassNodeTest.php
index aa1a5ea2..a468ec05 100644
--- a/tests/Analyser/AnonymousClassNodeTest.php
+++ b/tests/Analyser/AnonymousClassNodeTest.php
@@ -37,6 +37,8 @@ public function testParentChainQueriesAreCaseInsensitive(): void
 
         $this->assertSame(['App\\Support\\baseclass', 'App\\Support\\rootclass'], $anonymousClassNode->parentClasses);
         $this->assertTrue($anonymousClassNode->extendsClass('App\\Support\\RootClass'));
+        $this->assertTrue($anonymousClassNode->extendsClass('\\App\\Support\\RootClass'));
+        $this->assertTrue($anonymousClassNode->implementsInterface('\\App\\Contracts\\RootInterface'));
         $this->assertFalse($anonymousClassNode->extendsClass('App\\Support\\OtherClass'));
         $this->assertTrue($anonymousClassNode->implementsInterface('App\\Contracts\\RootInterface'));
         $this->assertFalse($anonymousClassNode->implementsInterface('App\\Contracts\\OtherInterface'));
diff --git a/tests/Analyser/ClassNodeTest.php b/tests/Analyser/ClassNodeTest.php
index 0ba97197..dab7276a 100644
--- a/tests/Analyser/ClassNodeTest.php
+++ b/tests/Analyser/ClassNodeTest.php
@@ -196,6 +196,7 @@ interfaceExtends:   ['App\\Contracts\\BaseOrderService'],
         $this->assertTrue($classNode->implementsInterface('App\\Contracts\\BaseOrderService'));
         $this->assertTrue($classNode->callsFunction('var_dump'));
         $this->assertTrue($classNode->callsFunction('VAR_DUMP'));
+        $this->assertTrue($classNode->callsFunction('\\var_dump'));
         $this->assertFalse($classNode->callsFunction('array_map'));
         $this->assertTrue($classNode->accessesSuperglobals());
         $this->assertTrue($classNode->usesLanguageConstruct('exit'));
@@ -318,6 +319,7 @@ className:        Foo::class,
 
         $this->assertTrue($classNode->implementsInterface('App\\Contracts\\FooInterface'));
         $this->assertTrue($classNode->implementsInterface('App\\Contracts\\RootInterface'));
+        $this->assertTrue($classNode->implementsInterface('\\App\\Contracts\\FooInterface'));
         $this->assertFalse($classNode->implementsInterface('App\\Contracts\\OtherInterface'));
     }
 
@@ -338,6 +340,8 @@ className:     Foo::class,
 
         $this->assertTrue($classNode->extendsClass('App\\Support\\BaseClass'));
         $this->assertTrue($classNode->extendsClass('App\\Support\\RootClass'));
+        $this->assertTrue($classNode->extendsClass('\\App\\Support\\BaseClass'));
+        $this->assertTrue($classNode->extendsClass('\\App\\Support\\RootClass'));
         $this->assertFalse($classNode->extendsClass('App\\Support\\OtherClass'));
     }
 
@@ -358,6 +362,7 @@ interfaceExtends: ['App\\Contracts\\baseinterface'],
         );
 
         $this->assertTrue($classNode->implementsInterface('App\\Contracts\\BaseInterface'));
+        $this->assertTrue($classNode->implementsInterface('\\App\\Contracts\\BaseInterface'));
         $this->assertTrue($classNode->implementsInterface('App\\Contracts\\RootInterface'));
         $this->assertFalse($classNode->implementsInterface('App\\Contracts\\OtherInterface'));
     }
@@ -514,6 +519,7 @@ className:    'App\\Domain\\OrderService',
 
         $this->assertFalse($classNode->dependsOn('datetimeimmutable'));
         $this->assertTrue($classNode->dependsOn('datetimeimmutable', isCaseSensitive: false));
+        $this->assertTrue($classNode->dependsOn('\\' . DateTimeImmutable::class));
         $this->assertFalse($classNode->dependsOn('datetime', isCaseSensitive: false));
     }
 
@@ -535,7 +541,9 @@ className:            'App\\Domain\\OrderService',
 
         $this->assertTrue($classNode->usesClass('datetimeimmutable'));
         $this->assertTrue($classNode->usesClass('DATETIMEIMMUTABLE'));
+        $this->assertTrue($classNode->usesClass('\\' . DateTimeImmutable::class));
         $this->assertFalse($classNode->usesClass('VENDOR\\HELPER'));
+        $this->assertFalse($classNode->usesClass('\\Vendor\\helper'));
     }
 
     public function testUsesClassIgnoresDependencyOnlyUsedAsFunctionOrConstant(): void
@@ -577,6 +585,8 @@ className:       'App\\Domain\\OrderService',
         );
 
         $this->assertTrue($classNode->usesConstant('STDIN'));
+        $this->assertTrue($classNode->usesConstant('\\STDIN'));
+        $this->assertTrue($classNode->usesConstant('\\Vendor\\Config\\DEBUG'));
         $this->assertFalse($classNode->usesConstant('stdin'));
         $this->assertTrue($classNode->usesConstant('vendor\\config\\DEBUG'));
         $this->assertFalse($classNode->usesConstant('Vendor\\Config\\debug'));
@@ -621,6 +631,8 @@ className:    'App\\Domain\\OrderService',
         );
 
         $this->assertTrue($classNode->dependsOnNamespace('App\\Bar'));
+        $this->assertTrue($classNode->dependsOnNamespace('\\App\\Bar'));
+        $this->assertTrue($classNode->dependsOnNamespace('\\App\\Bar\\'));
         $this->assertFalse($classNode->dependsOnNamespace('App\\Baz'));
     }