diff --git a/packages/vitest/src/node/pools/forks.ts b/packages/vitest/src/node/pools/forks.ts
index 84bdd83f930e..37c832970901 100644
--- a/packages/vitest/src/node/pools/forks.ts
+++ b/packages/vitest/src/node/pools/forks.ts
@@ -152,7 +152,7 @@ export function createForksPool(
       // Cancel pending tasks from pool when possible
       ctx.onCancel(() => pool.cancelPendingTasks())
 
-      const configs = new Map<WorkspaceProject, SerializedConfig>()
+      const configs = new WeakMap<WorkspaceProject, SerializedConfig>()
       const getConfig = (project: WorkspaceProject): SerializedConfig => {
         if (configs.has(project)) {
           return configs.get(project)!
@@ -165,15 +165,6 @@ export function createForksPool(
         return config
       }
 
-      const workspaceMap = new Map<string, WorkspaceProject[]>()
-      for (const spec of specs) {
-        const file = spec.moduleId
-        const project = spec.project.workspaceProject
-        const workspaceFiles = workspaceMap.get(file) ?? []
-        workspaceFiles.push(project)
-        workspaceMap.set(file, workspaceFiles)
-      }
-
       const singleFork = specs.filter(
         spec => spec.project.config.poolOptions?.forks?.singleFork,
       )
diff --git a/packages/vitest/src/node/pools/rpc.ts b/packages/vitest/src/node/pools/rpc.ts
index 36a2b369921d..e382a1ca45f7 100644
--- a/packages/vitest/src/node/pools/rpc.ts
+++ b/packages/vitest/src/node/pools/rpc.ts
@@ -39,7 +39,7 @@ export function createMethodsRPC(project: WorkspaceProject, options: MethodsOpti
         return result
       }
       if ('id' in result && typeof result.id === 'string') {
-        return { id: result.id as string }
+        return { id: result.id }
       }
 
       if (code == null) {
diff --git a/packages/vitest/src/node/pools/threads.ts b/packages/vitest/src/node/pools/threads.ts
index 413914461712..5c7dd5024d32 100644
--- a/packages/vitest/src/node/pools/threads.ts
+++ b/packages/vitest/src/node/pools/threads.ts
@@ -151,7 +151,7 @@ export function createThreadsPool(
       // Cancel pending tasks from pool when possible
       ctx.onCancel(() => pool.cancelPendingTasks())
 
-      const configs = new Map<WorkspaceProject, SerializedConfig>()
+      const configs = new WeakMap<WorkspaceProject, SerializedConfig>()
       const getConfig = (project: WorkspaceProject): SerializedConfig => {
         if (configs.has(project)) {
           return configs.get(project)!
@@ -162,13 +162,6 @@ export function createThreadsPool(
         return config
       }
 
-      const workspaceMap = new Map<string, WorkspaceProject[]>()
-      for (const [project, file] of specs) {
-        const workspaceFiles = workspaceMap.get(file) ?? []
-        workspaceFiles.push(project)
-        workspaceMap.set(file, workspaceFiles)
-      }
-
       const singleThreads = specs.filter(
         spec => spec.project.config.poolOptions?.threads?.singleThread,
       )