From 6f0d247e8331c9e36d97430c9619a8d4b5c59f66 Mon Sep 17 00:00:00 2001
From: Bogdan Popa <bogdan@defn.io>
Date: Wed, 6 Mar 2024 08:30:09 +0200
Subject: [PATCH] lint: track define-like identifier usages

---
 lint.rkt                              | 10 ++++++----
 tests/lint/define-syntax-rule.rkt     | 11 +++++++++++
 tests/lint/define-syntax-rule.rkt.out |  1 +
 3 files changed, 18 insertions(+), 4 deletions(-)
 create mode 100644 tests/lint/define-syntax-rule.rkt
 create mode 100644 tests/lint/define-syntax-rule.rkt.out

diff --git a/lint.rkt b/lint.rkt
index 3b5ca6b..7c98bc4 100644
--- a/lint.rkt
+++ b/lint.rkt
@@ -716,17 +716,19 @@
            #:do [(pop-scope!)
                  (pop-scope!)])
 
-  (pattern (_:define-like
+  (pattern (define-id:define-like
             name:define-identifier
             ~!
-            e:expression ...+))
+            e:expression ...+)
+           #:do [(track-binding-usage! (format-binding "~a" #'define-id))])
 
-  (pattern (_:define-like
+  (pattern (define-id:define-like
             hdr:function-header
             ~!
             (~do (push-scope!))
             e:expression ...+)
-           #:do [(for ([_ (in-range (add1 (attribute hdr.depth)))])
+           #:do [(track-binding-usage! (format-binding "~a" #'define-id))
+                 (for ([_ (in-range (add1 (attribute hdr.depth)))])
                    (pop-scope!))]))
 
 (define-syntax-class root-module-path
diff --git a/tests/lint/define-syntax-rule.rkt b/tests/lint/define-syntax-rule.rkt
new file mode 100644
index 0000000..85427f0
--- /dev/null
+++ b/tests/lint/define-syntax-rule.rkt
@@ -0,0 +1,11 @@
+#lang racket/base
+
+(require (for-syntax racket/base))
+
+(define-syntax-rule (define-keywords id ...)
+  (begin
+    (provide id ...)
+    (define-syntax (id stx)
+      (raise-syntax-error 'id "not allowed outside special form" stx)) ...))
+
+(define-keywords foo bar baz)
diff --git a/tests/lint/define-syntax-rule.rkt.out b/tests/lint/define-syntax-rule.rkt.out
new file mode 100644
index 0000000..1ee1f9b
--- /dev/null
+++ b/tests/lint/define-syntax-rule.rkt.out
@@ -0,0 +1 @@
+/define-syntax-rule.rkt:11:18:warning:identifier 'foo' is never used