Workaround for #16909 (#17088)

* Workaround for #16909

Fixes #16909

Worksaround TS2.1+ returning strings in the occurrences response we use for highlighting occurrences in documents

The workaround is to look at the text surrounding the first occurrence to see if it is a string literal.

* Small cleanup

* Add gate for ts 2.1.x

* Added check to make sure we don't compare the same character

extensions/typescript/src/features/documentHighlightProvider.ts

@@ -34,7 +34,18 @@ export default class TypeScriptDocumentHighlightProvider implements DocumentHigh
 		}
 		return this.client.execute('occurrences', args, token).then((response): DocumentHighlight[] => {
 			let data = response.body;
-			if (data) {
+			if (data && data.length) {
+				// Workaround for https://github.com/Microsoft/TypeScript/issues/12780
+				// Don't highlight string occurrences
+				const firstOccurrence = data[0];
+				if (this.client.apiVersion.has213Features() && firstOccurrence.start.offset > 1) {
+					// Check to see if contents around first occurrence are string delimiters
+					const contents = resource.getText(new Range(firstOccurrence.start.line - 1, firstOccurrence.start.offset - 1 - 1, firstOccurrence.end.line - 1, firstOccurrence.end.offset - 1 + 1));
+					const stringDelimiters = ['"', '\'', '`'];
+					if (contents && contents.length > 2 && stringDelimiters.indexOf(contents[0]) >= 0 && contents[0] === contents[contents.length - 1]) {
+						return [];
+					}
+				}
 				return data.map((item) => {
 					return new DocumentHighlight(new Range(item.start.line - 1, item.start.offset - 1, item.end.line - 1, item.end.offset - 1),
 						item.isWriteAccess ? DocumentHighlightKind.Write : DocumentHighlightKind.Read);