diff --git a/build/package.json b/build/package.json
index a224242b6e7cb5038235e360f9fb6845551698c1..8f89abbc23d2a43bf4d5c178618f764878f4e8da 100644
--- a/build/package.json
+++ b/build/package.json
@@ -14,7 +14,7 @@
     "documentdb": "1.13.0",
     "mime": "^1.3.4",
     "minimist": "^1.2.0",
-    "typescript": "2.8.3",
+    "typescript": "2.9.1",
     "xml2js": "^0.4.17",
     "github-releases": "^0.4.1",
     "request": "^2.85.0"
diff --git a/build/yarn.lock b/build/yarn.lock
index 69ed0de667d7c3ca40608acccb2d51fa015d6899..ac6150fcf605df8d18f47857ca6f6c2499373bec 100644
--- a/build/yarn.lock
+++ b/build/yarn.lock
@@ -652,9 +652,9 @@ tweetnacl@^0.14.3, tweetnacl@~0.14.0:
   version "0.14.5"
   resolved "https://registry.yarnpkg.com/tweetnacl/-/tweetnacl-0.14.5.tgz#5ae68177f192d4456269d108afa93ff8743f4f64"
 
-typescript@2.8.3:
-  version "2.8.3"
-  resolved "https://registry.yarnpkg.com/typescript/-/typescript-2.8.3.tgz#5d817f9b6f31bb871835f4edf0089f21abe6c170"
+typescript@2.9.1:
+  version "2.9.1"
+  resolved "https://registry.yarnpkg.com/typescript/-/typescript-2.9.1.tgz#fdb19d2c67a15d11995fd15640e373e09ab09961"
 
 underscore@1.8.3, underscore@~1.8.3:
   version "1.8.3"
diff --git a/package.json b/package.json
index 1d95b31bc669c2bc1c88b2ad53b0e12f87e9b352..47785f6e2ba9d0f6db835bf5b6e61e2c4e2fa2f5 100644
--- a/package.json
+++ b/package.json
@@ -115,7 +115,7 @@
     "sinon": "^1.17.2",
     "source-map": "^0.4.4",
     "tslint": "^5.9.1",
-    "typescript": "2.8.3",
+    "typescript": "2.9.1",
     "typescript-formatter": "7.1.0",
     "uglify-es": "^3.0.18",
     "underscore": "^1.8.2",
diff --git a/src/vs/base/common/objects.ts b/src/vs/base/common/objects.ts
index ab5c34250cb25901a40c567d5ebb25e1e0fd2649..31769c963f1a8943249b60f04eab48ee25bb1535 100644
--- a/src/vs/base/common/objects.ts
+++ b/src/vs/base/common/objects.ts
@@ -16,7 +16,7 @@ export function deepClone<T>(obj: T): T {
 		return obj as any;
 	}
 	const result: any = Array.isArray(obj) ? [] : {};
-	Object.keys(obj).forEach((key: keyof T) => {
+	Object.keys(obj).forEach((key: string) => {
 		if (obj[key] && typeof obj[key] === 'object') {
 			result[key] = deepClone(obj[key]);
 		} else {
diff --git a/src/vs/base/common/parsers.ts b/src/vs/base/common/parsers.ts
index 01f806d424e33e20f9cc9417e0b2f20eaabd82f1..e2ba887eb3f6c7d841d797efc90e322878a76af0 100644
--- a/src/vs/base/common/parsers.ts
+++ b/src/vs/base/common/parsers.ts
@@ -81,7 +81,7 @@ export abstract class Parser {
 	}
 
 	protected static merge<T>(destination: T, source: T, overwrite: boolean): void {
-		Object.keys(source).forEach((key: keyof T) => {
+		Object.keys(source).forEach((key: string) => {
 			let destValue = destination[key];
 			let sourceValue = source[key];
 			if (Types.isUndefined(sourceValue)) {
diff --git a/src/vs/monaco.d.ts b/src/vs/monaco.d.ts
index 2b42db1f6e97d3b8dd8d91a4e849c82d4afc9839..8fec749449aaf25d4d9298f66cec721be31c52de 100644
--- a/src/vs/monaco.d.ts
+++ b/src/vs/monaco.d.ts
@@ -364,7 +364,7 @@ declare namespace monaco {
 		 * Placed last to cover the length of the enum.
 		 * Please do not depend on this value!
 		 */
-		MAX_VALUE = 112,
+		MAX_VALUE = 112
 	}
 
 	export class KeyMod {
@@ -761,7 +761,7 @@ declare namespace monaco {
 		/**
 		 * The selection starts below where it ends.
 		 */
-		RTL = 1,
+		RTL = 1
 	}
 
 	export class Token {
@@ -1136,7 +1136,7 @@ declare namespace monaco.editor {
 	export enum ScrollbarVisibility {
 		Auto = 1,
 		Hidden = 2,
-		Visible = 3,
+		Visible = 3
 	}
 
 	export interface ThemeColor {
@@ -1150,7 +1150,7 @@ declare namespace monaco.editor {
 		Left = 1,
 		Center = 2,
 		Right = 4,
-		Full = 7,
+		Full = 7
 	}
 
 	/**
@@ -1313,7 +1313,7 @@ declare namespace monaco.editor {
 		/**
 		 * Use carriage return and line feed (\r\n) as the end of line character.
 		 */
-		CRLF = 2,
+		CRLF = 2
 	}
 
 	/**
@@ -1327,7 +1327,7 @@ declare namespace monaco.editor {
 		/**
 		 * Use carriage return and line feed (\r\n) as the end of line character.
 		 */
-		CRLF = 2,
+		CRLF = 2
 	}
 
 	/**
@@ -1341,7 +1341,7 @@ declare namespace monaco.editor {
 		/**
 		 * Use carriage return and line feed (\r\n) as the end of line character.
 		 */
-		CRLF = 1,
+		CRLF = 1
 	}
 
 	/**
@@ -1435,7 +1435,7 @@ declare namespace monaco.editor {
 		AlwaysGrowsWhenTypingAtEdges = 0,
 		NeverGrowsWhenTypingAtEdges = 1,
 		GrowsOnlyWhenTypingBefore = 2,
-		GrowsOnlyWhenTypingAfter = 3,
+		GrowsOnlyWhenTypingAfter = 3
 	}
 
 	/**
@@ -1991,7 +1991,7 @@ declare namespace monaco.editor {
 
 	export const enum ScrollType {
 		Smooth = 0,
-		Immediate = 1,
+		Immediate = 1
 	}
 
 	/**
@@ -2321,7 +2321,7 @@ declare namespace monaco.editor {
 		/**
 		 * There was a Redo.
 		 */
-		Redo = 6,
+		Redo = 6
 	}
 
 	/**
@@ -2961,7 +2961,7 @@ declare namespace monaco.editor {
 		Small = 1,
 		Large = 2,
 		SmallBlocks = 3,
-		LargeBlocks = 4,
+		LargeBlocks = 4
 	}
 
 	/**
@@ -2983,7 +2983,7 @@ declare namespace monaco.editor {
 		/**
 		 * DeepIndent => wrapped lines get +2 indentation toward the parent.
 		 */
-		DeepIndent = 3,
+		DeepIndent = 3
 	}
 
 	/**
@@ -3013,7 +3013,7 @@ declare namespace monaco.editor {
 		/**
 		 * No-Blinking
 		 */
-		Solid = 5,
+		Solid = 5
 	}
 
 	/**
@@ -3043,7 +3043,7 @@ declare namespace monaco.editor {
 		/**
 		 * As a thin horizontal line (sitting under a character).
 		 */
-		UnderlineThin = 6,
+		UnderlineThin = 6
 	}
 
 	export interface InternalEditorScrollbarOptions {
@@ -3091,7 +3091,7 @@ declare namespace monaco.editor {
 		On = 1,
 		Relative = 2,
 		Interval = 3,
-		Custom = 4,
+		Custom = 4
 	}
 
 	export interface InternalEditorViewOptions {
@@ -3420,7 +3420,7 @@ declare namespace monaco.editor {
 		/**
 		 * Place the content widget below a position
 		 */
-		BELOW = 2,
+		BELOW = 2
 	}
 
 	/**
@@ -3477,7 +3477,7 @@ declare namespace monaco.editor {
 		/**
 		 * Position the overlay widget in the top center
 		 */
-		TOP_CENTER = 2,
+		TOP_CENTER = 2
 	}
 
 	/**
@@ -3568,7 +3568,7 @@ declare namespace monaco.editor {
 		/**
 		 * Mouse is outside of the editor.
 		 */
-		OUTSIDE_EDITOR = 13,
+		OUTSIDE_EDITOR = 13
 	}
 
 	/**
@@ -4207,7 +4207,7 @@ declare namespace monaco.languages {
 		Color = 15,
 		File = 16,
 		Reference = 17,
-		Folder = 18,
+		Folder = 18
 	}
 
 	/**
@@ -4557,7 +4557,7 @@ declare namespace monaco.languages {
 		/**
 		 * Insert new line and outdent once (relative to the previous line's indentation).
 		 */
-		Outdent = 3,
+		Outdent = 3
 	}
 
 	/**
@@ -4628,7 +4628,7 @@ declare namespace monaco.languages {
 	export enum SuggestTriggerKind {
 		Invoke = 0,
 		TriggerCharacter = 1,
-		TriggerForIncompleteCompletions = 2,
+		TriggerForIncompleteCompletions = 2
 	}
 
 	export interface CodeAction {
@@ -4725,7 +4725,7 @@ declare namespace monaco.languages {
 		/**
 		 * Write-access of a symbol, like writing to a variable.
 		 */
-		Write = 2,
+		Write = 2
 	}
 
 	/**
@@ -4863,7 +4863,7 @@ declare namespace monaco.languages {
 		Struct = 22,
 		Event = 23,
 		Operator = 24,
-		TypeParameter = 25,
+		TypeParameter = 25
 	}
 
 	/**
diff --git a/yarn.lock b/yarn.lock
index cec0a8fd79b6ba954c022a70621313290b1eb7e3..b5128530cf6b3e62016dceb1dd34362b78133b7c 100644
--- a/yarn.lock
+++ b/yarn.lock
@@ -5879,9 +5879,9 @@ typescript-formatter@7.1.0:
     commandpost "^1.0.0"
     editorconfig "^0.15.0"
 
-typescript@2.8.3:
-  version "2.8.3"
-  resolved "https://registry.yarnpkg.com/typescript/-/typescript-2.8.3.tgz#5d817f9b6f31bb871835f4edf0089f21abe6c170"
+typescript@2.9.1:
+  version "2.9.1"
+  resolved "https://registry.yarnpkg.com/typescript/-/typescript-2.9.1.tgz#fdb19d2c67a15d11995fd15640e373e09ab09961"
 
 typescript@^2.6.2:
   version "2.6.2"