diff --git a/src/vs/workbench/api/common/extHostDocumentData.ts b/src/vs/workbench/api/common/extHostDocumentData.ts
index 3a166503923e6ac6a479ba49cb56cf8f6fccbb5b..064cbbb0426db2fd3040a0c6e1ae0b81fb61b55d 100644
--- a/src/vs/workbench/api/common/extHostDocumentData.ts
+++ b/src/vs/workbench/api/common/extHostDocumentData.ts
@@ -239,8 +239,7 @@ export class ExtHostDocumentData extends MirrorTextModel {
 
 		} else if (regExpLeadsToEndlessLoop(regexp)) {
 			// use default when custom-regexp is bad
-			console.warn(`[getWordRangeAtPosition]: ignoring custom regexp '${regexp.source}' because it matches the empty string.`);
-			regexp = getWordDefinitionFor(this._languageId);
+			throw new Error(`[getWordRangeAtPosition]: ignoring custom regexp '${regexp.source}' because it matches the empty string.`);
 		}
 
 		const wordAtText = getWordAtText(