diff --git a/src/vs/workbench/services/search/node/textSearchManager.ts b/src/vs/workbench/services/search/node/textSearchManager.ts
index 0f15a7709beb40d928ee0b16fb2d6d3fbabb2ad5..2d1d7ba49e4906f1901ed09e773b27c22b1170f4 100644
--- a/src/vs/workbench/services/search/node/textSearchManager.ts
+++ b/src/vs/workbench/services/search/node/textSearchManager.ts
@@ -12,7 +12,7 @@ import * as resources from 'vs/base/common/resources';
 import { URI } from 'vs/base/common/uri';
 import { toCanonicalName } from 'vs/base/node/encoding';
 import * as extfs from 'vs/base/node/extfs';
-import { IExtendedExtensionSearchOptions, IFileMatch, IFolderQuery, IPatternInfo, ISearchCompleteStats, ITextQuery, ITextSearchMatch, ITextSearchContext, ITextSearchResult } from 'vs/platform/search/common/search';
+import { IExtendedExtensionSearchOptions, IFileMatch, IFolderQuery, IPatternInfo, ISearchCompleteStats, ITextQuery, ITextSearchContext, ITextSearchMatch, ITextSearchResult } from 'vs/platform/search/common/search';
 import { QueryGlobTester, resolvePatternsForProvider } from 'vs/workbench/services/search/node/search';
 import * as vscode from 'vscode';
 
@@ -79,7 +79,9 @@ export class TextSearchManager {
 		const testingPs: Promise<void>[] = [];
 		const progress = {
 			report: (result: vscode.TextSearchResult) => {
-				// TODO: validate result.ranges vs result.preview.matches
+				if (!this.validateProviderResult(result)) {
+					return;
+				}
 
 				const hasSibling = folderQuery.folder.scheme === 'file' ?
 					glob.hasSiblingPromiseFn(() => {
@@ -107,6 +109,29 @@ export class TextSearchManager {
 			});
 	}
 
+	private validateProviderResult(result: vscode.TextSearchResult): boolean {
+		if (extensionResultIsMatch(result)) {
+			if (Array.isArray(result.ranges)) {
+				if (!Array.isArray(result.preview.matches)) {
+					console.warn('INVALID - A text search provider match\'s`ranges` and`matches` properties must have the same type.');
+					return false;
+				}
+
+				if ((<vscode.Range[]>result.preview.matches).length !== result.ranges.length) {
+					console.warn('INVALID - A text search provider match\'s`ranges` and`matches` properties must have the same length.');
+					return false;
+				}
+			} else {
+				if (Array.isArray(result.preview.matches)) {
+					console.warn('INVALID - A text search provider match\'s`ranges` and`matches` properties must have the same length.');
+					return false;
+				}
+			}
+		}
+
+		return true;
+	}
+
 	private readdir(dirname: string): Promise<string[]> {
 		return new Promise((resolve, reject) => {
 			this._extfs.readdir(dirname, (err, files) => {