diff --git a/compiler/forget/src/HIR/BuildHIR.ts b/compiler/forget/src/HIR/BuildHIR.ts
index 9d38badad5..b2827a535f 100644
--- a/compiler/forget/src/HIR/BuildHIR.ts
+++ b/compiler/forget/src/HIR/BuildHIR.ts
@@ -11,6 +11,7 @@ import invariant from "invariant";
 import { CompilerError, ErrorSeverity } from "../CompilerError";
 import { Err, Ok, Result } from "../Utils/Result";
 import { assertExhaustive } from "../Utils/utils";
+import { Environment } from "./Environment";
 import {
   BlockId,
   BranchTerminal,
@@ -29,7 +30,7 @@ import {
   SourceLocation,
   ThrowTerminal,
 } from "./HIR";
-import HIRBuilder, { Environment } from "./HIRBuilder";
+import HIRBuilder from "./HIRBuilder";
 
 // *******************************************************************************************
 // *******************************************************************************************
diff --git a/compiler/forget/src/HIR/Environment.ts b/compiler/forget/src/HIR/Environment.ts
new file mode 100644
index 0000000000..4b72b43037
--- /dev/null
+++ b/compiler/forget/src/HIR/Environment.ts
@@ -0,0 +1,9 @@
+import { IdentifierId, makeIdentifierId } from "./HIR";
+
+export class Environment {
+  #nextIdentifer: number = 0;
+
+  get nextIdentifierId(): IdentifierId {
+    return makeIdentifierId(this.#nextIdentifer++);
+  }
+}
diff --git a/compiler/forget/src/HIR/HIR.ts b/compiler/forget/src/HIR/HIR.ts
index 6126f6c5cc..f320d2a5e5 100644
--- a/compiler/forget/src/HIR/HIR.ts
+++ b/compiler/forget/src/HIR/HIR.ts
@@ -7,7 +7,7 @@
 
 import * as t from "@babel/types";
 import invariant from "invariant";
-import { Environment } from "./HIRBuilder";
+import { Environment } from "./Environment";
 
 // *******************************************************************************************
 // *******************************************************************************************
diff --git a/compiler/forget/src/HIR/HIRBuilder.ts b/compiler/forget/src/HIR/HIRBuilder.ts
index 4cff0c0b83..58c8372870 100644
--- a/compiler/forget/src/HIR/HIRBuilder.ts
+++ b/compiler/forget/src/HIR/HIRBuilder.ts
@@ -11,6 +11,7 @@ import invariant from "invariant";
 import { CompilerError } from "../CompilerError";
 import { logHIR } from "../Utils/logger";
 import { assertExhaustive } from "../Utils/utils";
+import { Environment } from "./Environment";
 import { getOrAddGlobal } from "./Globals";
 import {
   BasicBlock,
@@ -20,10 +21,8 @@ import {
   GotoVariant,
   HIR,
   Identifier,
-  IdentifierId,
   Instruction,
   makeBlockId,
-  makeIdentifierId,
   makeInstructionId,
   makeType,
   Terminal,
@@ -71,14 +70,6 @@ function newBlock(id: BlockId, kind: BlockKind): WipBlock {
   return { id, kind, instructions: [] };
 }
 
-export class Environment {
-  #nextIdentifer: number = 0;
-
-  get nextIdentifierId(): IdentifierId {
-    return makeIdentifierId(this.#nextIdentifer++);
-  }
-}
-
 /**
  * Helper class for constructing a CFG
  */
diff --git a/compiler/forget/src/HIR/index.ts b/compiler/forget/src/HIR/index.ts
index 9c37e081cd..6918473071 100644
--- a/compiler/forget/src/HIR/index.ts
+++ b/compiler/forget/src/HIR/index.ts
@@ -6,9 +6,9 @@
  */
 
 export { lower } from "./BuildHIR";
+export { Environment } from "./Environment";
 export * from "./HIR";
 export {
-  Environment,
   markInstructionIds,
   markPredecessors,
   removeUnreachableFallthroughs,
diff --git a/compiler/forget/src/SSA/EnterSSA.ts b/compiler/forget/src/SSA/EnterSSA.ts
index 470f5454ae..f573134391 100644
--- a/compiler/forget/src/SSA/EnterSSA.ts
+++ b/compiler/forget/src/SSA/EnterSSA.ts
@@ -1,5 +1,6 @@
 import invariant from "invariant";
 import { CompilerError } from "../CompilerError";
+import { Environment } from "../HIR/Environment";
 import {
   BasicBlock,
   BlockId,
@@ -12,14 +13,12 @@ import {
   Phi,
   Place,
 } from "../HIR/HIR";
-import { Environment } from "../HIR/HIRBuilder";
 import { printIdentifier } from "../HIR/PrintHIR";
 import {
   eachTerminalSuccessor,
   mapInstructionOperands,
   mapTerminalOperands,
 } from "../HIR/visitors";
-import { todoInvariant } from "../Utils/todo";
 
 type IncompletePhi = {
   oldId: Identifier;