diff --git a/compiler/forget/src/CompilerError.ts b/compiler/forget/src/CompilerError.ts
index ba4b85b7a2..9d072725e0 100644
--- a/compiler/forget/src/CompilerError.ts
+++ b/compiler/forget/src/CompilerError.ts
@@ -1,11 +1,13 @@
 import { Node, NodePath } from "@babel/traverse";
-import { SourceLocation } from "@babel/types";
+import { SourceLocation as BabelSourceLocation } from "@babel/types";
+import { SourceLocation } from "./HIR";
 import { ExtractClassProperties } from "./Utils/types";
 import { assertExhaustive } from "./Utils/utils";
 
 export enum ErrorSeverity {
   InvalidInput = "InvalidInput",
   Todo = "Todo",
+  Invariant = "Invariant",
 }
 
 export type CompilerErrorOptions = {
@@ -23,6 +25,8 @@ function mapSeverityToErrorCtor(severity: ErrorSeverity): CompilerErrorKind {
       return InvalidInputError;
     case ErrorSeverity.Todo:
       return TodoError;
+    case ErrorSeverity.Invariant:
+      return InvariantError;
     default:
       assertExhaustive(severity, `Unhandled severity level: ${severity}`);
   }
@@ -39,6 +43,12 @@ class TodoError extends Error {
     this.name = `${ErrorSeverity.Todo}Error`;
   }
 }
+class InvariantError extends Error {
+  constructor(message: string) {
+    super(message);
+    this.name = `${ErrorSeverity.Invariant}Error`;
+  }
+}
 
 export function tryPrintCodeFrame(
   options: CompilerErrorOptions
@@ -64,7 +74,7 @@ export class CompilerErrorDetail {
   reason: string;
   severity: ErrorSeverity;
   codeframe: string | null;
-  loc: SourceLocation | null;
+  loc: BabelSourceLocation | null;
 
   constructor(options: CompilerErrorDetailOptions) {
     this.reason = options.reason;
@@ -92,6 +102,19 @@ export class CompilerErrorDetail {
 export class CompilerError extends Error {
   details: CompilerErrorDetail[] = [];
 
+  static invariant(reason: string, loc: SourceLocation): never {
+    const errors = new CompilerError();
+    errors.pushErrorDetail(
+      new CompilerErrorDetail({
+        codeframe: null,
+        loc: typeof loc === "symbol" ? null : loc,
+        reason,
+        severity: ErrorSeverity.Invariant,
+      })
+    );
+    throw errors;
+  }
+
   constructor(...args: any[]) {
     super(...args);
   }
diff --git a/compiler/forget/src/HIR/BuildHIR.ts b/compiler/forget/src/HIR/BuildHIR.ts
index 599ddccfdf..cdb1680f80 100644
--- a/compiler/forget/src/HIR/BuildHIR.ts
+++ b/compiler/forget/src/HIR/BuildHIR.ts
@@ -1044,6 +1044,8 @@ function lowerExpression(
       const operator = expr.node.operator;
 
       if (builder.currentBlockKind() === "value") {
+        // try lowering the RHS in case it also contains errors
+        lowerExpressionToPlace(builder, expr.get("right"));
         builder.errors.push({
           reason: `(BuildHIR::lowerExpression) Handle AssignmentExpression within a LogicalExpression or ConditionalExpression`,
           severity: ErrorSeverity.Todo,
diff --git a/compiler/forget/src/Inference/InferReferenceEffects.ts b/compiler/forget/src/Inference/InferReferenceEffects.ts
index cde4340860..40fdaddfc9 100644
--- a/compiler/forget/src/Inference/InferReferenceEffects.ts
+++ b/compiler/forget/src/Inference/InferReferenceEffects.ts
@@ -6,6 +6,7 @@
  */
 
 import invariant from "invariant";
+import { CompilerError } from "../CompilerError";
 import {
   BasicBlock,
   BlockId,
@@ -199,10 +200,14 @@ class Environment {
       const kind = this.#values.get(value)!;
       mergedKind = mergedKind !== null ? mergeValues(mergedKind, kind) : kind;
     }
-    invariant(
-      mergedKind !== null,
-      `Expected at least one value at ${printPlace(place)}`
-    );
+    if (mergedKind === null) {
+      CompilerError.invariant(
+        `InferReferenceEffects::kind: Expected at least one value at '${printPlace(
+          place
+        )}'`,
+        place.loc
+      );
+    }
     return mergedKind;
   }