From 80da028aeb7fc9f9676ed7d0c4032c0c041c287c Mon Sep 17 00:00:00 2001
From: Calvin Rose <calsrose@gmail.com>
Date: Sun, 4 Jan 2026 08:18:23 -0600
Subject: [PATCH] Add linting to address #1688

Warn when defining macros on inner scopes, and also point out unused
metadata as well.
---
 src/core/specials.c | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/src/core/specials.c b/src/core/specials.c
index 35b06966..94a6e36c 100644
--- a/src/core/specials.c
+++ b/src/core/specials.c
@@ -464,12 +464,24 @@ static int varleaf(
     }
 }
 
+static void check_metadata_lint(JanetCompiler *c, JanetTable *attr_table) {
+    if (!(c->scope->flags & JANET_SCOPE_TOP) && attr_table && attr_table->count) {
+        /* A macro is a normal lint, other metadata is a strict lint */
+        if (janet_truthy(janet_table_get(attr_table, janet_ckeywordv("macro")))) {
+            janetc_lintf(c, JANET_C_LINT_NORMAL, "macro tag is ignored in inner scopes");
+        } else {
+            janetc_lintf(c, JANET_C_LINT_STRICT, "unused metadata %j in inner scope", janet_wrap_table(attr_table));
+        }
+    }
+}
+
 static JanetSlot janetc_var(JanetFopts opts, int32_t argn, const Janet *argv) {
     JanetCompiler *c = opts.compiler;
     JanetTable *attr_table = handleattr(c, "var", argn, argv);
     if (c->result.status == JANET_COMPILE_ERROR) {
         return janetc_cslot(janet_wrap_nil());
     }
+    check_metadata_lint(c, attr_table);
     SlotHeadPair *into = NULL;
     into = dohead_destructure(c, into, opts, argv[0], argv[argn - 1]);
     if (c->result.status == JANET_COMPILE_ERROR) {
@@ -530,6 +542,7 @@ static JanetSlot janetc_def(JanetFopts opts, int32_t argn, const Janet *argv) {
     if (c->result.status == JANET_COMPILE_ERROR) {
         return janetc_cslot(janet_wrap_nil());
     }
+    check_metadata_lint(c, attr_table);
     opts.flags &= ~JANET_FOPTS_HINT;
     SlotHeadPair *into = NULL;
     into = dohead_destructure(c, into, opts, argv[0], argv[argn - 1]);