Fix TS compile errors

src/vs/editor/common/model/pieceTreeTextBuffer/pieceTreeBase.ts

@@ -35,7 +35,7 @@ export class LineStarts {
 	) { }
 }
 
-export function createLineStartsFast(str: string, readonly: boolean = true): Uint32Array | number[] {
+export function createLineStartsFast(str: string, readonly: boolean = true): Uint32Array | Uint16Array | number[] {
 	let r: number[] = [0], rLength = 1;
 
 	for (let i = 0, len = str.length; i < len; i++) {

src/vs/editor/common/model/textModelTokens.ts

@@ -25,7 +25,7 @@ function getDefaultMetadata(topLevelLanguageId: LanguageId): number {
 	) >>> 0;
 }
 
-const EMPTY_LINE_TOKENS = new Uint32Array(0);
+const EMPTY_LINE_TOKENS = (new Uint32Array(0)).buffer;
 
 class ModelLineTokens {
 	_state: IState;

src/vs/editor/contrib/snippet/snippetParser.ts

@@ -568,7 +568,7 @@ export class SnippetParser {
 			if (marker instanceof Placeholder) {
 				placeholderCount += 1;
 				if (marker.isFinalTabstop) {
-					placeholderDefaultValues.set(0);
+					placeholderDefaultValues.set(0, undefined);
 				} else if (!placeholderDefaultValues.has(marker.index) && marker.children.length > 0) {
 					placeholderDefaultValues.set(marker.index, marker.children);
 				} else {