diff --git a/implementations/javascript/packages/schema/src/compiler/genunconverter.ts b/implementations/javascript/packages/schema/src/compiler/genunconverter.ts
index d9431be..3cbba75 100644
--- a/implementations/javascript/packages/schema/src/compiler/genunconverter.ts
+++ b/implementations/javascript/packages/schema/src/compiler/genunconverter.ts
@@ -58,7 +58,14 @@ function unconverterForAlternative(
         }
         return (cs.length === 1) ? cs[0] : seq(`_.merge`, parens(`(a, b) => (a === b) ? a : void 0`, ... cs));
     } else {
-        return unconverterFor(ctx, a.value, src, t);
+        try {
+            return unconverterFor(ctx, a.value, src, t);
+        } catch (e) {
+            if (e instanceof InsufficientInformationError) {
+                throw new Error(`Cannot produce unconverter for ${name}: ${e.message}`);
+            }
+            throw e;
+        }
     }
 }
 
@@ -82,7 +89,7 @@ function unconverterFor(ctx: FunctionContext, p: M.Pattern, src: string, t: Simp
     switch (p._variant) {
         case 'SimplePattern':
             return ((p: M.SimplePattern) => {
-                if (p._variant !== 'lit' && t.kind === 'record') {
+                if (p._variant !== 'lit' && (t.kind === 'record' || t.kind === 'unit')) {
                     throw new InsufficientInformationError(`A Cannot produce unconverter TODO ${src} ${formatItems([renderType(t)])}`);
                 }
                 switch (p._variant) {