diff --git a/editors/code/src/commands.ts b/editors/code/src/commands.ts
deleted file mode 100644
index c7e27781e0..0000000000
--- a/editors/code/src/commands.ts
+++ /dev/null
@@ -1,17 +0,0 @@
-import * as applySourceChange from './commands/apply_source_change';
-import * as extendSelection from './commands/extend_selection';
-import * as joinLines from './commands/join_lines';
-import * as matchingBrace from './commands/matching_brace';
-import * as parentModule from './commands/parent_module';
-import * as runnables from './commands/runnables';
-import * as syntaxTree from './commands/syntaxTree';
-
-export {
-    applySourceChange,
-    extendSelection,
-    joinLines,
-    matchingBrace,
-    parentModule,
-    runnables,
-    syntaxTree,
-};
diff --git a/editors/code/src/commands/apply_source_change.ts b/editors/code/src/commands/apply_source_change.ts
index f011cbe12e..67765e5a3c 100644
--- a/editors/code/src/commands/apply_source_change.ts
+++ b/editors/code/src/commands/apply_source_change.ts
@@ -18,7 +18,6 @@ export interface SourceChange {
 }
 
 export async function handle(change: SourceChange) {
-    console.log(`applySOurceChange ${JSON.stringify(change)}`);
     const wsEdit = new vscode.WorkspaceEdit();
     for (const sourceEdit of change.sourceFileEdits) {
         const uri = Server.client.protocol2CodeConverter.asUri(sourceEdit.textDocument.uri);
@@ -28,17 +27,18 @@ export async function handle(change: SourceChange) {
     let created;
     let moved;
     for (const fsEdit of change.fileSystemEdits) {
-        if (fsEdit.type == 'createFile') {
-            const uri = vscode.Uri.parse(fsEdit.uri!);
-            wsEdit.createFile(uri);
-            created = uri;
-        } else if (fsEdit.type == 'moveFile') {
-            const src = vscode.Uri.parse(fsEdit.src!);
-            const dst = vscode.Uri.parse(fsEdit.dst!);
-            wsEdit.renameFile(src, dst);
-            moved = dst;
-        } else {
-            console.error(`unknown op: ${JSON.stringify(fsEdit)}`);
+        switch (fsEdit.type) {
+            case 'createFile':
+                const uri = vscode.Uri.parse(fsEdit.uri!);
+                wsEdit.createFile(uri);
+                created = uri;
+                break;
+            case 'moveFile':
+                const src = vscode.Uri.parse(fsEdit.src!);
+                const dst = vscode.Uri.parse(fsEdit.dst!);
+                wsEdit.renameFile(src, dst);
+                moved = dst;
+                break;
         }
     }
     const toOpen = created || moved;
@@ -51,7 +51,7 @@ export async function handle(change: SourceChange) {
         const uri = Server.client.protocol2CodeConverter.asUri(toReveal.textDocument.uri);
         const position = Server.client.protocol2CodeConverter.asPosition(toReveal.position);
         const editor = vscode.window.activeTextEditor;
-        if (!editor || editor.document.uri.toString() != uri.toString()) { return; }
+        if (!editor || editor.document.uri.toString() !== uri.toString()) { return; }
         if (!editor.selection.isEmpty) { return; }
         editor!.selection = new vscode.Selection(position, position);
     }
diff --git a/editors/code/src/commands/extend_selection.ts b/editors/code/src/commands/extend_selection.ts
index b722ac1722..cdc3d10fb3 100644
--- a/editors/code/src/commands/extend_selection.ts
+++ b/editors/code/src/commands/extend_selection.ts
@@ -14,7 +14,7 @@ interface ExtendSelectionResult {
 
 export async function handle() {
     const editor = vscode.window.activeTextEditor;
-    if (editor == null || editor.document.languageId != 'rust') { return; }
+    if (editor == null || editor.document.languageId !== 'rust') { return; }
     const request: ExtendSelectionParams = {
         selections: editor.selections.map((s) => {
             return Server.client.code2ProtocolConverter.asRange(s);
diff --git a/editors/code/src/commands/index.ts b/editors/code/src/commands/index.ts
new file mode 100644
index 0000000000..dfdcd64545
--- /dev/null
+++ b/editors/code/src/commands/index.ts
@@ -0,0 +1,17 @@
+import * as applySourceChange from './apply_source_change';
+import * as extendSelection from './extend_selection';
+import * as joinLines from './join_lines';
+import * as matchingBrace from './matching_brace';
+import * as parentModule from './parent_module';
+import * as runnables from './runnables';
+import * as syntaxTree from './syntaxTree';
+
+export {
+    applySourceChange,
+    extendSelection,
+    joinLines,
+    matchingBrace,
+    parentModule,
+    runnables,
+    syntaxTree,
+};
diff --git a/editors/code/src/commands/join_lines.ts b/editors/code/src/commands/join_lines.ts
index 80ad4460ba..526b698ccd 100644
--- a/editors/code/src/commands/join_lines.ts
+++ b/editors/code/src/commands/join_lines.ts
@@ -11,7 +11,7 @@ interface JoinLinesParams {
 
 export async function handle() {
     const editor = vscode.window.activeTextEditor;
-    if (editor == null || editor.document.languageId != 'rust') { return; }
+    if (editor == null || editor.document.languageId !== 'rust') { return; }
     const request: JoinLinesParams = {
         range: Server.client.code2ProtocolConverter.asRange(editor.selection),
         textDocument: { uri: editor.document.uri.toString() },
diff --git a/editors/code/src/commands/matching_brace.ts b/editors/code/src/commands/matching_brace.ts
index cf7f6bf8fa..a80446a8f5 100644
--- a/editors/code/src/commands/matching_brace.ts
+++ b/editors/code/src/commands/matching_brace.ts
@@ -10,7 +10,7 @@ interface FindMatchingBraceParams {
 
 export async function handle() {
     const editor = vscode.window.activeTextEditor;
-    if (editor == null || editor.document.languageId != 'rust') { return; }
+    if (editor == null || editor.document.languageId !== 'rust') { return; }
     const request: FindMatchingBraceParams = {
         textDocument: { uri: editor.document.uri.toString() },
         offsets: editor.selections.map((s) => {
diff --git a/editors/code/src/commands/parent_module.ts b/editors/code/src/commands/parent_module.ts
index 7d413c27a6..d66fb30264 100644
--- a/editors/code/src/commands/parent_module.ts
+++ b/editors/code/src/commands/parent_module.ts
@@ -5,7 +5,7 @@ import { Server } from '../server';
 
 export async function handle() {
     const editor = vscode.window.activeTextEditor;
-    if (editor == null || editor.document.languageId != 'rust') { return; }
+    if (editor == null || editor.document.languageId !== 'rust') { return; }
     const request: TextDocumentIdentifier = {
         uri: editor.document.uri.toString(),
     };
diff --git a/editors/code/src/commands/runnables.ts b/editors/code/src/commands/runnables.ts
index 37db6ea10a..40f590dceb 100644
--- a/editors/code/src/commands/runnables.ts
+++ b/editors/code/src/commands/runnables.ts
@@ -59,7 +59,7 @@ function createTask(spec: Runnable): vscode.Task {
 let prevRunnable: RunnableQuickPick | undefined;
 export async function handle() {
     const editor = vscode.window.activeTextEditor;
-    if (editor == null || editor.document.languageId != 'rust') { return; }
+    if (editor == null || editor.document.languageId !== 'rust') { return; }
     const textDocument: lc.TextDocumentIdentifier = {
         uri: editor.document.uri.toString(),
     };
@@ -73,7 +73,7 @@ export async function handle() {
         items.push(prevRunnable);
     }
     for (const r of runnables) {
-        if (prevRunnable && JSON.stringify(prevRunnable.runnable) == JSON.stringify(r)) {
+        if (prevRunnable && JSON.stringify(prevRunnable.runnable) === JSON.stringify(r)) {
             continue;
         }
         items.push(new RunnableQuickPick(r));
diff --git a/editors/code/src/events.ts b/editors/code/src/events.ts
deleted file mode 100644
index 8e2ac4a469..0000000000
--- a/editors/code/src/events.ts
+++ /dev/null
@@ -1,7 +0,0 @@
-import * as changeActiveTextEditor from './events/change_active_text_editor';
-import * as changeTextDocument from './events/change_text_document';
-
-export {
-    changeActiveTextEditor,
-    changeTextDocument,
-};
diff --git a/editors/code/src/events/change_active_text_editor.ts b/editors/code/src/events/change_active_text_editor.ts
index 96d61126c6..3440aa0c37 100644
--- a/editors/code/src/events/change_active_text_editor.ts
+++ b/editors/code/src/events/change_active_text_editor.ts
@@ -5,7 +5,7 @@ import { Decoration } from '../highlighting';
 import { Server } from '../server';
 
 export async function handle(editor: TextEditor | undefined) {
-    if (!Server.config.highlightingOn || !editor || editor.document.languageId != 'rust') { return; }
+    if (!Server.config.highlightingOn || !editor || editor.document.languageId !== 'rust') { return; }
     const params: TextDocumentIdentifier = {
         uri: editor.document.uri.toString(),
     };
diff --git a/editors/code/src/events/change_text_document.ts b/editors/code/src/events/change_text_document.ts
index 192fb1e8a8..b3000e0261 100644
--- a/editors/code/src/events/change_text_document.ts
+++ b/editors/code/src/events/change_text_document.ts
@@ -5,7 +5,7 @@ import { syntaxTreeUri, TextDocumentContentProvider } from '../commands/syntaxTr
 export function createHandler(textDocumentContentProvider: TextDocumentContentProvider) {
     return (event: vscode.TextDocumentChangeEvent) => {
         const doc = event.document;
-        if (doc.languageId != 'rust') { return; }
+        if (doc.languageId !== 'rust') { return; }
         afterLs(() => {
             textDocumentContentProvider.eventEmitter.fire(syntaxTreeUri);
         });
diff --git a/editors/code/src/events/index.ts b/editors/code/src/events/index.ts
new file mode 100644
index 0000000000..b570a7a926
--- /dev/null
+++ b/editors/code/src/events/index.ts
@@ -0,0 +1,7 @@
+import * as changeActiveTextEditor from './change_active_text_editor';
+import * as changeTextDocument from './change_text_document';
+
+export {
+    changeActiveTextEditor,
+    changeTextDocument,
+};
diff --git a/editors/code/src/highlighting.ts b/editors/code/src/highlighting.ts
index 71f8e5baa1..e2ac4d6290 100644
--- a/editors/code/src/highlighting.ts
+++ b/editors/code/src/highlighting.ts
@@ -9,17 +9,42 @@ export interface Decoration {
 }
 
 export class Highlighter {
-    private decorations: { [index: string]: vscode.TextEditorDecorationType };
-    constructor() {
-        this.decorations = {};
+    private static initDecorations(): Map<string, vscode.TextEditorDecorationType> {
+        const decor = (color: string) => vscode.window.createTextEditorDecorationType({ color });
+
+        const decorations: Iterable<[string, vscode.TextEditorDecorationType]> = [
+            ['background', decor('#3F3F3F')],
+            ['error', vscode.window.createTextEditorDecorationType({
+                borderColor: 'red',
+                borderStyle: 'none none dashed none',
+            })],
+            ['comment', decor('#7F9F7F')],
+            ['string', decor('#CC9393')],
+            ['keyword', decor('#F0DFAF')],
+            ['function', decor('#93E0E3')],
+            ['parameter', decor('#94BFF3')],
+            ['builtin', decor('#DD6718')],
+            ['text', decor('#DCDCCC')],
+            ['attribute', decor('#BFEBBF')],
+            ['literal', decor('#DFAF8F')],
+        ];
+
+        return new Map<string, vscode.TextEditorDecorationType>(decorations);
     }
 
+    private decorations: (Map<string, vscode.TextEditorDecorationType> | null) = null;
+
     public removeHighlights() {
-        for (const tag in this.decorations) {
-            this.decorations[tag].dispose();
+        if (this.decorations == null) {
+            return;
         }
 
-        this.decorations = {};
+        // Decorations are removed when the object is disposed
+        for (const decoration of this.decorations.values()) {
+            decoration.dispose();
+        }
+
+        this.decorations = null;
     }
 
     public setHighlights(
@@ -30,18 +55,17 @@ export class Highlighter {
         //
         // Note: decoration objects need to be kept around so we can dispose them
         // if the user disables syntax highlighting
-        if (Object.keys(this.decorations).length === 0) {
-            this.initDecorations();
+        if (this.decorations == null) {
+            this.decorations = Highlighter.initDecorations();
         }
 
         const byTag: Map<string, vscode.Range[]> = new Map();
-        for (const tag in this.decorations) {
+        for (const tag of this.decorations.keys()) {
             byTag.set(tag, []);
         }
 
         for (const d of highlights) {
             if (!byTag.get(d.tag)) {
-                console.log(`unknown tag ${d.tag}`);
                 continue;
             }
             byTag.get(d.tag)!.push(
@@ -50,29 +74,9 @@ export class Highlighter {
         }
 
         for (const tag of byTag.keys()) {
-            const dec: vscode.TextEditorDecorationType = this.decorations[tag];
+            const dec = this.decorations.get(tag) as vscode.TextEditorDecorationType;
             const ranges = byTag.get(tag)!;
             editor.setDecorations(dec, ranges);
         }
     }
-
-    private initDecorations() {
-        const decor = (obj: any) => vscode.window.createTextEditorDecorationType({ color: obj });
-        this.decorations = {
-            background: decor('#3F3F3F'),
-            error: vscode.window.createTextEditorDecorationType({
-                borderColor: 'red',
-                borderStyle: 'none none dashed none',
-            }),
-            comment: decor('#7F9F7F'),
-            string: decor('#CC9393'),
-            keyword: decor('#F0DFAF'),
-            function: decor('#93E0E3'),
-            parameter: decor('#94BFF3'),
-            builtin: decor('#DD6718'),
-            text: decor('#DCDCCC'),
-            attribute: decor('#BFEBBF'),
-            literal: decor('#DFAF8F'),
-        };
-    }
 }
diff --git a/editors/code/src/server.ts b/editors/code/src/server.ts
index 3857b00a53..325023e36a 100644
--- a/editors/code/src/server.ts
+++ b/editors/code/src/server.ts
@@ -34,7 +34,7 @@ export class Server {
                 'm/publishDecorations',
                 (params: PublishDecorationsParams) => {
                     const targetEditor = vscode.window.visibleTextEditors.find(
-                        (editor) => editor.document.uri.toString() == params.uri,
+                        (editor) => editor.document.uri.toString() === params.uri,
                     );
                     if (!Server.config.highlightingOn || !targetEditor) { return; }
                     Server.highlighter.setHighlights(
diff --git a/editors/code/tslint.json b/editors/code/tslint.json
index 466e1fa203..ce48dfc95e 100644
--- a/editors/code/tslint.json
+++ b/editors/code/tslint.json
@@ -1,5 +1,5 @@
 {
-    "defaultSeverity": "warning",
+    "defaultSeverity": "error",
     "extends": [
         "tslint:recommended"
     ],