From f29d0102e180efae8d602df71e7aab39e9429326 Mon Sep 17 00:00:00 2001
From: Rahul Kumar <rahulkumar@berkeley.edu>
Date: Thu, 5 Mar 2026 15:01:20 -0800
Subject: [PATCH] fix(compiler): fix type equality check for cons fn

---
 core/compiler/src/compile.rs |  2 +-
 core/compiler/src/lib.rs     | 26 ++++++++++++++++++++++++++
 examples/seq_any/lib.ar      | 10 ++++++++++
 3 files changed, 37 insertions(+), 1 deletion(-)
 create mode 100644 examples/seq_any/lib.ar

diff --git a/core/compiler/src/compile.rs b/core/compiler/src/compile.rs
index 4c3d4ce..de66c38 100644
--- a/core/compiler/src/compile.rs
+++ b/core/compiler/src/compile.rs
@@ -1603,7 +1603,7 @@ impl<'a> AstTransformer for VarIdTyPass<'a> {
                     if args.posargs.len() == 2 {
                         let seqty = Ty::Seq(Box::new(args.posargs[0].ty()));
                         let tailty = args.posargs[1].ty();
-                        if !(tailty == Ty::SeqNil || tailty == seqty) {
+                        if !(tailty == Ty::SeqNil || self.is_eq_ty(&tailty, &seqty)) {
                             self.errors.push(StaticError {
                                 span: self.span(args.posargs[1].span()),
                                 kind: StaticErrorKind::IncorrectTy {
diff --git a/core/compiler/src/lib.rs b/core/compiler/src/lib.rs
index fc0f13d..a136604 100644
--- a/core/compiler/src/lib.rs
+++ b/core/compiler/src/lib.rs
@@ -49,6 +49,7 @@ mod tests {
     const ARGON_ROUNDING: &str = concatcp!(EXAMPLES_DIR, "/rounding/lib.ar");
     const ARGON_FLIPPED_RECT: &str = concatcp!(EXAMPLES_DIR, "/flipped_rect/lib.ar");
     const ARGON_SEQ_BASIC: &str = concatcp!(EXAMPLES_DIR, "/seq_basic/lib.ar");
+    const ARGON_SEQ_ANY: &str = concatcp!(EXAMPLES_DIR, "/seq_any/lib.ar");
     const ARGON_SEQ_FN: &str = concatcp!(EXAMPLES_DIR, "/seq_fn/lib.ar");
     const ARGON_SEQ_RECUR: &str = concatcp!(EXAMPLES_DIR, "/seq_recur/lib.ar");
     const ARGON_LUB_MATCH: &str = concatcp!(EXAMPLES_DIR, "/lub_match/lib.ar");
@@ -573,6 +574,31 @@ mod tests {
         assert_relative_eq!(r.y1.0, 200., epsilon = EPSILON);
     }
 
+    #[test]
+    fn argon_seq_any() {
+        let o = parse_workspace_with_std(ARGON_SEQ_ANY);
+        assert!(o.static_errors().is_empty());
+        let ast = o.ast();
+        let cells = compile(
+            &ast,
+            CompileInput {
+                cell: &["top"],
+                args: Vec::new(),
+                lyp_file: &PathBuf::from(BASIC_LYP),
+            },
+        );
+        println!("{cells:#?}");
+        let cells = cells.unwrap_valid();
+        let cell = &cells.cells[&cells.top];
+        assert_eq!(cell.objects.len(), 1);
+        let r = cell.objects.iter().find_map(|(_, v)| v.get_rect()).unwrap();
+        assert_eq!(r.layer.as_ref().unwrap(), "met1");
+        assert_relative_eq!(r.x0.0, 0., epsilon = EPSILON);
+        assert_relative_eq!(r.y0.0, 0., epsilon = EPSILON);
+        assert_relative_eq!(r.x1.0, 400., epsilon = EPSILON);
+        assert_relative_eq!(r.y1.0, 200., epsilon = EPSILON);
+    }
+
     #[test]
     fn argon_seq_fn() {
         let o = parse_workspace_with_std(ARGON_SEQ_FN);
diff --git a/examples/seq_any/lib.ar b/examples/seq_any/lib.ar
new file mode 100644
index 0000000..4848a47
--- /dev/null
+++ b/examples/seq_any/lib.ar
@@ -0,0 +1,10 @@
+fn prepend(lst: [Any]) -> [Float] {
+    cons(100., lst)
+}
+
+cell top() {
+    let r = rect("met1", x0=0., y0=0., x1=400.)!;
+    let lst = prepend(cons(500., cons(300., cons(800., cons(200., cons(1400., []))))));
+    let v = head(tail(tail(tail(tail(lst)))));
+    eq(r.y1, v);
+}