diff --git a/build/package.json b/build/package.json
index a05a6b9a622..a99b2181cce 100644
--- a/build/package.json
+++ b/build/package.json
@@ -39,7 +39,7 @@
     "minimist": "^1.2.0",
     "request": "^2.85.0",
     "tslint": "^5.9.1",
-    "typescript": "3.3.1",
+    "typescript": "3.4.1",
     "vsce": "1.48.0",
     "xml2js": "^0.4.17"
   },
diff --git a/build/yarn.lock b/build/yarn.lock
index d5816c98f02..83ba3d2381c 100644
--- a/build/yarn.lock
+++ b/build/yarn.lock
@@ -1894,10 +1894,10 @@ typed-rest-client@^0.9.0:
     tunnel "0.0.4"
     underscore "1.8.3"
 
-typescript@3.3.1:
-  version "3.3.1"
-  resolved "https://registry.yarnpkg.com/typescript/-/typescript-3.3.1.tgz#6de14e1db4b8a006ac535e482c8ba018c55f750b"
-  integrity sha512-cTmIDFW7O0IHbn1DPYjkiebHxwtCMU+eTy30ZtJNBPF9j2O1ITu5XH2YnBeVRKWHqF+3JQwWJv0Q0aUgX8W7IA==
+typescript@3.4.1:
+  version "3.4.1"
+  resolved "https://registry.yarnpkg.com/typescript/-/typescript-3.4.1.tgz#b6691be11a881ffa9a05765a205cb7383f3b63c6"
+  integrity sha512-3NSMb2VzDQm8oBTLH6Nj55VVtUEpe/rgkIzMir0qVoLyjDZlnMBva0U6vDiV3IH+sl/Yu6oP5QwsAQtHPmDd2Q==
 
 uc.micro@^1.0.1, uc.micro@^1.0.5:
   version "1.0.5"
diff --git a/package.json b/package.json
index 6d51310b8b9..19008296c64 100644
--- a/package.json
+++ b/package.json
@@ -122,7 +122,7 @@
     "source-map": "^0.4.4",
     "ts-loader": "^4.4.2",
     "tslint": "^5.11.0",
-    "typescript": "3.3.1",
+    "typescript": "3.4.1",
     "typescript-formatter": "7.1.0",
     "typescript-tslint-plugin": "^0.0.7",
     "uglify-es": "^3.0.18",
diff --git a/src/vs/workbench/contrib/debug/browser/linkDetector.ts b/src/vs/workbench/contrib/debug/browser/linkDetector.ts
index 1b6f41c628f..f40b2470cb8 100644
--- a/src/vs/workbench/contrib/debug/browser/linkDetector.ts
+++ b/src/vs/workbench/contrib/debug/browser/linkDetector.ts
@@ -138,7 +138,7 @@ export class LinkDetector {
 
 	private onLinkClick(event: IMouseEvent, resource: uri, line: number, column: number = 0): void {
 		const selection = window.getSelection();
-		if (selection.type === 'Range') {
+		if (!selection || selection.type === 'Range') {
 			return; // do not navigate when user is selecting
 		}
 
diff --git a/src/vs/workbench/services/textfile/common/textFileService.ts b/src/vs/workbench/services/textfile/common/textFileService.ts
index 134e5222239..a5fed1254cb 100644
--- a/src/vs/workbench/services/textfile/common/textFileService.ts
+++ b/src/vs/workbench/services/textfile/common/textFileService.ts
@@ -292,7 +292,7 @@ export class TextFileService extends Disposable implements ITextFileService {
 	}
 
 	private backupBeforeShutdown(dirtyToBackup: URI[], textFileEditorModelManager: ITextFileEditorModelManager, reason: ShutdownReason): Promise<IBackupResult> {
-		return this.windowsService.getWindowCount().then(windowCount => {
+		return this.windowsService.getWindowCount().then<IBackupResult>(windowCount => {
 
 			// When quit is requested skip the confirm callback and attempt to backup all workspaces.
 			// When quit is not requested the confirm callback should be shown when the window being
diff --git a/yarn.lock b/yarn.lock
index bac73827f3c..b51cc01c312 100644
--- a/yarn.lock
+++ b/yarn.lock
@@ -8874,10 +8874,10 @@ typescript-tslint-plugin@^0.0.7:
     minimatch "^3.0.4"
     vscode-languageserver "^5.1.0"
 
-typescript@3.3.1:
-  version "3.3.1"
-  resolved "https://registry.yarnpkg.com/typescript/-/typescript-3.3.1.tgz#6de14e1db4b8a006ac535e482c8ba018c55f750b"
-  integrity sha512-cTmIDFW7O0IHbn1DPYjkiebHxwtCMU+eTy30ZtJNBPF9j2O1ITu5XH2YnBeVRKWHqF+3JQwWJv0Q0aUgX8W7IA==
+typescript@3.4.1:
+  version "3.4.1"
+  resolved "https://registry.yarnpkg.com/typescript/-/typescript-3.4.1.tgz#b6691be11a881ffa9a05765a205cb7383f3b63c6"
+  integrity sha512-3NSMb2VzDQm8oBTLH6Nj55VVtUEpe/rgkIzMir0qVoLyjDZlnMBva0U6vDiV3IH+sl/Yu6oP5QwsAQtHPmDd2Q==
 
 typescript@^2.6.2:
   version "2.6.2"