Give a more helpful error message when users try decorating using expressions that take no arguments.

src/compiler/checker.ts

@@ -16381,6 +16381,11 @@ namespace ts {
                 return resolveUntypedCall(node);
             }
 
+            if (callSignatures.length === 1 && callSignatures[0].parameters.length === 0) {
+                error(node, Diagnostics.A_decorator_function_must_accept_some_number_of_arguments_but_this_expression_takes_none_Did_you_mean_to_call_it_first);
+                return resolveErrorCall(node);
+            }
+
             const headMessage = getDiagnosticHeadMessageForDecoratorResolution(node);
             if (!callSignatures.length) {
                 let errorInfo: DiagnosticMessageChain;

src/compiler/diagnosticMessages.json

@@ -907,6 +907,10 @@
         "category": "Error",
         "code": 1328
     },
+    "A decorator function must accept some number of arguments, but this expression takes none. Did you mean to call it first?": {
+        "category": "Error",
+        "code": 1329
+    },
 
     "Duplicate identifier '{0}'.": {
         "category": "Error",