diff --git a/lib/Compilation.js b/lib/Compilation.js
index 6fcbf42e00f..c3e34ba70ca 100644
--- a/lib/Compilation.js
+++ b/lib/Compilation.js
@@ -1007,45 +1007,44 @@ class Compilation extends Tapable {
 	}
 
 	assignDepth(module) {
-		const assignDepthToModule = (module, depth) => {
-			// enter module
-			if(typeof module.depth === "number" && module.depth <= depth) return;
-			module.depth = depth;
+		const queue = new Set([module]);
+		let depth;
 
-			// enter it as block
-			assignDepthToDependencyBlock(module, depth + 1);
+		module.depth = 0;
+
+		const enqueueJob = module => {
+			const d = module.depth;
+			if(typeof d === "number" && d <= depth) return;
+			queue.add(module);
+			module.depth = depth;
 		};
 
 		const assignDepthToDependency = (dependency, depth) => {
 			if(dependency.module) {
-				queue.push(() => assignDepthToModule(dependency.module, depth));
+				enqueueJob(dependency.module);
 			}
 		};
 
-		const assignDepthToDependencyBlock = (block, depth) => {
-			const iteratorDependency = d => assignDepthToDependency(d, depth);
-
-			const iteratorBlock = b => assignDepthToDependencyBlock(b, depth);
-
+		const assignDepthToDependencyBlock = block => {
 			if(block.variables) {
-				iterationBlockVariable(block.variables, iteratorDependency);
+				iterationBlockVariable(block.variables, assignDepthToDependency);
 			}
 
 			if(block.dependencies) {
-				iterationOfArrayCallback(block.dependencies, iteratorDependency);
+				iterationOfArrayCallback(block.dependencies, assignDepthToDependency);
 			}
 
 			if(block.blocks) {
-				iterationOfArrayCallback(block.blocks, iteratorBlock);
+				iterationOfArrayCallback(block.blocks, assignDepthToDependencyBlock);
 			}
 		};
 
-		const queue = [() => {
-			assignDepthToModule(module, 0);
-		}];
+		for(module of queue) {
+			queue.delete(module);
+			depth = module.depth;
 
-		while(queue.length) {
-			queue.pop()();
+			depth++;
+			assignDepthToDependencyBlock(module);
 		}
 	}