endojs
diff --git a/‎packages/patterns/src/keys/checkKey.js
+1-1 b/‎packages/patterns/src/keys/checkKey.js
+1-1
@@ -588,7 +588,7 @@ const checkKeyInternal = (val, check) => {
     }
     case 'error':
     case 'promise': {
-      return check(false, X`A ${q(passStyle)} cannot be a key`);
+      return check(false, X`A ${q(passStyle)} cannot be a key: ${val}`);
     }
     default: {
       // Unexpected tags are just non-keys, but an unexpected passStyle
Original file line number	Diff line number	Diff line change
`@@ -588,7 +588,7 @@ const checkKeyInternal = (val, check) => {`
`588`	`588`	`}`
`589`	`589`	`case 'error':`
`590`	`590`	`case 'promise': {`
`591`		- return check(false, X`A ${q(passStyle)} cannot be a key`);
	`591`	+ return check(false, X`A ${q(passStyle)} cannot be a key: ${val}`);
`592`	`592`	`}`
`593`	`593`	`default: {`
`594`	`594`	`// Unexpected tags are just non-keys, but an unexpected passStyle`