From e5eccf0a22104f2242cebbf636e6ad2336d328f1 Mon Sep 17 00:00:00 2001
From: Daniel Rosenwasser <Daniel.Rosenwasser@microsoft.com>
Date: Sat, 30 Sep 2017 00:58:09 -0700
Subject: [PATCH 1/2] Added test.

---
 .../codeFixAddForgottenDecoratorCall01.ts          | 14 ++++++++++++++
 1 file changed, 14 insertions(+)
 create mode 100644 tests/cases/fourslash/codeFixAddForgottenDecoratorCall01.ts

diff --git a/tests/cases/fourslash/codeFixAddForgottenDecoratorCall01.ts b/tests/cases/fourslash/codeFixAddForgottenDecoratorCall01.ts
new file mode 100644
index 0000000000000..17ae7f626f069
--- /dev/null
+++ b/tests/cases/fourslash/codeFixAddForgottenDecoratorCall01.ts
@@ -0,0 +1,14 @@
+/// <reference path='fourslash.ts' />
+
+////declare function foo(): (...args: any[]) => void;
+////class C {
+////    [|@foo|]
+////    bar() {
+////
+////    }
+////}
+
+verify.codeFix({
+    description: "Call decorator expression.",
+    newRangeContent: `@foo()`
+});

From ea2021dd3e49a016dac58de326601e24c02f8a09 Mon Sep 17 00:00:00 2001
From: Daniel Rosenwasser <Daniel.Rosenwasser@microsoft.com>
Date: Sat, 30 Sep 2017 00:58:46 -0700
Subject: [PATCH 2/2] Create fix for uninvoked decorators.

---
 src/compiler/diagnosticMessages.json          |  4 ++++
 .../addMissingInvocationForDecorator.ts       | 20 +++++++++++++++++++
 src/services/codefixes/fixes.ts               |  1 +
 3 files changed, 25 insertions(+)
 create mode 100644 src/services/codefixes/addMissingInvocationForDecorator.ts

diff --git a/src/compiler/diagnosticMessages.json b/src/compiler/diagnosticMessages.json
index 17c2366082035..f3d6d4fcc4706 100644
--- a/src/compiler/diagnosticMessages.json
+++ b/src/compiler/diagnosticMessages.json
@@ -3709,6 +3709,10 @@
         "category": "Message",
         "code": 90027
     },
+    "Call decorator expression.": {
+        "category": "Message",
+        "code": 90028
+    },
 
     "Convert function to an ES2015 class": {
         "category": "Message",
diff --git a/src/services/codefixes/addMissingInvocationForDecorator.ts b/src/services/codefixes/addMissingInvocationForDecorator.ts
new file mode 100644
index 0000000000000..7f17aab6db2a8
--- /dev/null
+++ b/src/services/codefixes/addMissingInvocationForDecorator.ts
@@ -0,0 +1,20 @@
+/* @internal */
+namespace ts.codefix {
+    registerCodeFix({
+        errorCodes: [Diagnostics._0_accepts_too_few_arguments_to_be_used_as_a_decorator_here_Did_you_mean_to_call_it_first_and_write_0.code],
+        getCodeActions: (context: CodeFixContext) => {
+            const sourceFile = context.sourceFile;
+            const token = getTokenAtPosition(sourceFile, context.span.start, /*includeJsDocComment*/ false);
+            const decorator = getAncestor(token, SyntaxKind.Decorator) as Decorator;
+            Debug.assert(!!decorator, "Expected position to be owned by a decorator.");
+            const replacement = createCall(decorator.expression, /*typeArguments*/ undefined, /*argumentsArray*/ undefined);
+            const changeTracker = textChanges.ChangeTracker.fromContext(context);
+            changeTracker.replaceNode(sourceFile, decorator.expression, replacement);
+
+            return [{
+                description: getLocaleSpecificMessage(Diagnostics.Call_decorator_expression),
+                changes: changeTracker.getChanges()
+            }];
+        }
+    });
+}
diff --git a/src/services/codefixes/fixes.ts b/src/services/codefixes/fixes.ts
index 9bc80cad69117..b024dfae7cd82 100644
--- a/src/services/codefixes/fixes.ts
+++ b/src/services/codefixes/fixes.ts
@@ -1,3 +1,4 @@
+/// <reference path="addMissingInvocationForDecorator.ts" />
 /// <reference path="correctQualifiedNameToIndexedAccessType.ts" />
 /// <reference path="fixClassIncorrectlyImplementsInterface.ts" />
 /// <reference path="fixAddMissingMember.ts" />