diff --git a/src/tsconfig.base.json b/src/tsconfig.base.json
index 045b0b85e4f..9a44ab45393 100644
--- a/src/tsconfig.base.json
+++ b/src/tsconfig.base.json
@@ -2,7 +2,8 @@
 	"compilerOptions": {
 		"module": "amd",
 		"moduleResolution": "node",
-		"noImplicitAny": false,
+		"noImplicitAny": true,
+		"suppressImplicitAnyIndexErrors": true,
 		"target": "es5",
 		"experimentalDecorators": true,
 		"noImplicitReturns": true,
diff --git a/src/vs/editor/contrib/hover/modesContentHover.ts b/src/vs/editor/contrib/hover/modesContentHover.ts
index dedf4c10fad..f66e00856f0 100644
--- a/src/vs/editor/contrib/hover/modesContentHover.ts
+++ b/src/vs/editor/contrib/hover/modesContentHover.ts
@@ -41,6 +41,7 @@ import { Action } from 'vs/base/common/actions';
 import { CodeActionKind } from 'vs/editor/contrib/codeAction/codeActionTrigger';
 import { IModeService } from 'vs/editor/common/services/modeService';
 import { withNullAsUndefined } from 'vs/base/common/types';
+import { IIdentifiedSingleEditOperation } from 'vs/editor/common/model';
 
 const $ = dom.$;
 
@@ -385,10 +386,10 @@ export class ModesContentHoverWidget extends ContentHoverWidget {
 					model.guessColorPresentation(color, originalText);
 
 					const updateEditorModel = () => {
-						let textEdits;
-						let newRange;
+						let textEdits: IIdentifiedSingleEditOperation[];
+						let newRange: Range;
 						if (model.presentation.textEdit) {
-							textEdits = [model.presentation.textEdit];
+							textEdits = [model.presentation.textEdit as IIdentifiedSingleEditOperation];
 							newRange = new Range(
 								model.presentation.textEdit.range.startLineNumber,
 								model.presentation.textEdit.range.startColumn,
@@ -405,7 +406,7 @@ export class ModesContentHoverWidget extends ContentHoverWidget {
 						this._editor.executeEdits('colorpicker', textEdits);
 
 						if (model.presentation.additionalTextEdits) {
-							textEdits = [...model.presentation.additionalTextEdits];
+							textEdits = [...model.presentation.additionalTextEdits as IIdentifiedSingleEditOperation[]];
 							this._editor.executeEdits('colorpicker', textEdits);
 							this.hide();
 						}
diff --git a/src/vs/workbench/contrib/extensions/electron-browser/extensionTipsService.ts b/src/vs/workbench/contrib/extensions/electron-browser/extensionTipsService.ts
index 8273bfb8a2e..c848a6cf74f 100644
--- a/src/vs/workbench/contrib/extensions/electron-browser/extensionTipsService.ts
+++ b/src/vs/workbench/contrib/extensions/electron-browser/extensionTipsService.ts
@@ -1008,7 +1008,7 @@ export class ExtensionTipsService extends Disposable implements IExtensionTipsSe
 			(experiments || []).forEach(experiment => {
 				const action = experiment.action;
 				if (action && experiment.state === ExperimentState.Run && action.properties && Array.isArray(action.properties.recommendations) && action.properties.recommendationReason) {
-					action.properties.recommendations.forEach(id => {
+					action.properties.recommendations.forEach((id: string) => {
 						this._experimentalRecommendations[id] = action.properties.recommendationReason;
 					});
 				}
diff --git a/src/vs/workbench/services/extensions/node/proxyResolver.ts b/src/vs/workbench/services/extensions/node/proxyResolver.ts
index 6a9973426b9..9682a543d82 100644
--- a/src/vs/workbench/services/extensions/node/proxyResolver.ts
+++ b/src/vs/workbench/services/extensions/node/proxyResolver.ts
@@ -515,7 +515,7 @@ async function readLinuxCaCertificates() {
 	return undefined;
 }
 
-function derToPem(blob) {
+function derToPem(blob: Buffer) {
 	const lines = ['-----BEGIN CERTIFICATE-----'];
 	const der = blob.toString('base64');
 	for (let i = 0; i < der.length; i += 64) {