diff --git a/src/Workers/Constructor.ts b/src/Workers/Constructor.ts
index 548283b..bdb568f 100644
--- a/src/Workers/Constructor.ts
+++ b/src/Workers/Constructor.ts
@@ -6,7 +6,7 @@ import { withdrawEnergy } from "../Actions/withdrawEnergy";
 import { WorkerDefinition } from "./worker";
 
 export const Constructor: WorkerDefinition = {
-    runAction: (creep: Creep) => runAction(creep, withdrawEnergy(<StructureContainer | null> creep.pos.findClosestByRange(FIND_STRUCTURES, { filter: { structureType: STRUCTURE_CONTAINER }})))
+    runAction: (creep: Creep) => runAction(creep, withdrawEnergy(creep.pos.findClosestByRange(FIND_STRUCTURES, { filter: { structureType: STRUCTURE_CONTAINER }}) as StructureContainer | null))
         .or(harvestFromClosestActiveSource())
         .andThen(buildConstructionSite())
         .or(creep.room.controller ? upgradeController(creep.room.controller) : Fail)
diff --git a/src/Workers/Miner.ts b/src/Workers/Miner.ts
index b8298d2..b49d71b 100644
--- a/src/Workers/Miner.ts
+++ b/src/Workers/Miner.ts
@@ -5,7 +5,7 @@ import { WorkerDefinition } from "./worker";
 
 export const Miner: WorkerDefinition = {
     runAction: (creep: Creep) => runAction(creep, harvestFromClosestActiveSource())
-        .andThen(transferEnergy(<StructureContainer | null> creep.pos.findClosestByRange(FIND_STRUCTURES, { filter: { structureType: STRUCTURE_CONTAINER }})))
+        .andThen(transferEnergy(creep.pos.findClosestByRange(FIND_STRUCTURES, { filter: { structureType: STRUCTURE_CONTAINER }}) as StructureContainer | null))
         .repeat(),
     name: 'miner',
     requiredCreeps: (room: Room) => room.find(FIND_STRUCTURES, { filter: { structureType: STRUCTURE_CONTAINER }}).length > 0 ? 4 : 0,
diff --git a/src/Workers/Upgrader.ts b/src/Workers/Upgrader.ts
index b721318..42791f0 100644
--- a/src/Workers/Upgrader.ts
+++ b/src/Workers/Upgrader.ts
@@ -6,10 +6,10 @@ import { withdrawEnergy } from "../Actions/withdrawEnergy";
 import { WorkerDefinition } from "./worker";
 
 export const Upgrader: WorkerDefinition = {
-    runAction: (creep: Creep, spawn: StructureSpawn) => runAction(creep, withdrawEnergy(<StructureContainer | null> creep.pos.findClosestByRange(FIND_STRUCTURES, { filter: { structureType: STRUCTURE_CONTAINER }})))
+    runAction: (creep: Creep, spawn: StructureSpawn) => runAction(creep, withdrawEnergy(creep.pos.findClosestByRange(FIND_STRUCTURES, { filter: { structureType: STRUCTURE_CONTAINER }}) as StructureContainer | null))
         .or(harvestFromClosestActiveSource())
         .andThen(transferEnergy(spawn))
-        .or(transferEnergy(<StructureExtension | null> creep.pos.findClosestByRange(FIND_MY_STRUCTURES, { filter: (structure: StructureExtension) => structure.structureType === STRUCTURE_EXTENSION && structure.store.getFreeCapacity(RESOURCE_ENERGY) > 0})))
+        .or(transferEnergy(creep.pos.findClosestByRange(FIND_MY_STRUCTURES, { filter: (structure: AnyOwnedStructure) => structure.structureType === STRUCTURE_EXTENSION && structure.store.getFreeCapacity(RESOURCE_ENERGY) > 0}) as StructureExtension | null))
         .or(creep.room.controller ? upgradeController(creep.room.controller) : Fail)
         .repeat(),
     name: 'upgrader',