diff --git a/Makefile b/Makefile
index 1a594c8..4bebee9 100644
--- a/Makefile
+++ b/Makefile
@@ -39,9 +39,14 @@ aoctest: newt.js
 
 # Misc
 
+# build / install old vscode extension
 vscode:
 	cd newt-vscode && vsce package && code --install-extension *.vsix
 
+# build / install new LSP vscode extension
+vscode-lsp:
+	cd newt-vscode-lsp && vsce package && code --install-extension *.vsix
+
 playground: .PHONY
 	cd playground && ./build
 
diff --git a/newt-vscode-lsp/src/extension.ts b/newt-vscode-lsp/src/extension.ts
index b80292d..a95a7f7 100644
--- a/newt-vscode-lsp/src/extension.ts
+++ b/newt-vscode-lsp/src/extension.ts
@@ -7,6 +7,10 @@ import {
   TransportKind
 } from 'vscode-languageclient/node';
 
+function getIndent(text: string) {
+  return text.match(/\S/)?.index ?? 0
+}
+
 // They put this at module level for deactivate below.
 let client: LanguageClient
 
@@ -86,6 +90,84 @@ export function activate(context: vscode.ExtensionContext) {
       }
     }
   });
+
+  // HACK Temporarily copied from non-LSP version, until code actions are implemented
+  context.subscriptions.push(
+    vscode.languages.registerCodeActionsProvider(
+      { language: "newt" },
+      {
+        provideCodeActions(document, range, context, token) {
+          const actions: vscode.CodeAction[] = [];
+          for (const diagnostic of context.diagnostics) {
+            let {message,range} = diagnostic;
+            let m = message.match(/missing cases: \[(.*)\]/);
+            if (m) {
+              // A lot of this logic would also apply to case split.
+              let cons = m[1].split(', ');
+              let line = range.start.line;
+              let lineText = document.lineAt(line).text;
+              // this isn't going to work for let.
+              // and I think I relaxed the indent for `|`
+              const indent = getIndent(lineText)
+              let m2 = lineText.match(/(.*=>?)/);
+              if (!m2) continue;
+              let s = range.start.character;
+              let e = range.end.character;
+              let a = lineText.slice(0,s);
+              let b = lineText.slice(e,m2[0].length);
+              let parens = a.endsWith('(') && b.startsWith(')');
+              let lines = cons.map(con =>
+                !parens && con.includes('_')
+                ? `${a}(${con})${b} ?`
+                : `${a}${con}${b} ?`);
+                const fix = new vscode.CodeAction(
+                  "Add missing cases",
+                  vscode.CodeActionKind.QuickFix
+                );
+                fix.edit = new vscode.WorkspaceEdit();
+                // skip indented lines
+                while (1) {
+                  line = line + 1
+                  lineText = document.lineAt(line).text
+                  if (!lineText.trim() || getIndent(lineText) <= indent) break
+                }
+                const insertPos = new vscode.Position(line, 0);
+                let text = lines.join('\n') + '\n';
+                if (insertPos.line === document.lineCount) {
+                  text = "\n" + text;
+                }
+                fix.edit.insert(document.uri, insertPos, text);
+                fix.diagnostics = [diagnostic];
+                fix.isPreferred = true;
+                actions.push(fix);
+            }
+            m = message.match(/try importing: (.*)/);
+            if (m) {
+              let mods = m[1].split(', ')
+              let insertLine = 0;
+              for (let i = 0; i < document.lineCount; i++) {
+                const line = document.lineAt(i).text;
+                if (/^(import|module)\b/.test(line)) insertLine = i + 1;
+              }
+              const insertPos = new vscode.Position(insertLine, 0);
+              for (let mod of mods) {
+                const fix = new vscode.CodeAction(
+                  `Import ${mod}`,
+                  vscode.CodeActionKind.QuickFix
+                );
+                fix.edit = new vscode.WorkspaceEdit();
+                fix.edit.insert(document.uri, insertPos, `import ${mod}\n`);
+                fix.diagnostics = [diagnostic];
+                // fix.isPreferred = true;  // they're all preferred?
+                actions.push(fix);
+              }
+            }
+          }
+          return actions;
+        }
+      }
+    )
+  );
   return;
 
 }