From 842891cbf4543f0a46e0ae092874042c08c5ac37 Mon Sep 17 00:00:00 2001
From: imaqtkatt <eduarda.so@proton.me>
Date: Tue, 2 Jul 2024 09:14:02 -0300
Subject: [PATCH] Add missing error message

---
 src/fun/parser.rs                               | 17 ++++++++---------
 src/fun/transform/lift_defs.rs                  |  4 ++--
 tests/golden_tests/parse_file/fun_def.bend      |  5 +++++
 tests/golden_tests/parse_file/fun_def_name.bend |  5 +++++
 tests/snapshots/parse_file__fun_def.bend.snap   |  5 +++++
 .../parse_file__fun_def_name.bend.snap          |  8 ++++++++
 6 files changed, 33 insertions(+), 11 deletions(-)
 create mode 100644 tests/golden_tests/parse_file/fun_def.bend
 create mode 100644 tests/golden_tests/parse_file/fun_def_name.bend
 create mode 100644 tests/snapshots/parse_file__fun_def.bend.snap
 create mode 100644 tests/snapshots/parse_file__fun_def_name.bend.snap

diff --git a/src/fun/parser.rs b/src/fun/parser.rs
index 1d6530cb..b1c3e177 100644
--- a/src/fun/parser.rs
+++ b/src/fun/parser.rs
@@ -495,27 +495,26 @@ impl<'a> TermParser<'a> {
         self.skip_trivia();
         let (cur_name, rule) = self.parse_rule()?;
         let mut rules = vec![rule];
-        let mut cur_idx = *self.index();
+        let mut nxt_term = *self.index();
         loop {
           self.skip_trivia();
-          let back_term = *self.index();
+          let nxt_def = *self.index();
           match self.parse_rule() {
             Ok((name, rule)) => {
               if name == "def" {
-                self.index = back_term;
+                self.index = nxt_def;
                 return Ok(Term::Def { nam: cur_name, rules, nxt: Box::new(self.parse_term()?) });
               }
               if name == cur_name {
                 rules.push(rule);
-                cur_idx = *self.index();
+                nxt_term = *self.index();
               } else {
-                panic!()
+                let cur = *self.index();
+                let msg = format!("Expected a rule with name '{cur_name}'.");
+                return self.with_ctx(Err(msg), nxt_def..cur);
               }
             }
-            Err(_) => {
-              self.index = cur_idx;
-              break;
-            }
+            Err(_) => break self.index = nxt_term,
           }
         }
         let nxt = self.parse_term()?;
diff --git a/src/fun/transform/lift_defs.rs b/src/fun/transform/lift_defs.rs
index 1671bee6..3d51a4a4 100644
--- a/src/fun/transform/lift_defs.rs
+++ b/src/fun/transform/lift_defs.rs
@@ -77,13 +77,13 @@ fn gen_use(
     fvs.iter().cloned().map(|nam| Term::Var { nam }).collect::<Vec<_>>(),
   );
 
-  let r#use = Term::Use { nam: Some(nam.clone()), val: Box::new(call.clone()), nxt: std::mem::take(nxt) };
-
   for rule in rules.iter_mut() {
     let slf = std::mem::take(&mut rule.body);
     rule.body = Term::Use { nam: Some(nam.clone()), val: Box::new(call.clone()), nxt: Box::new(slf) };
   }
 
+  let r#use = Term::Use { nam: Some(nam.clone()), val: Box::new(call.clone()), nxt: std::mem::take(nxt) };
+
   (r#use, fvs, rules)
 }
 
diff --git a/tests/golden_tests/parse_file/fun_def.bend b/tests/golden_tests/parse_file/fun_def.bend
new file mode 100644
index 00000000..0b85c7b9
--- /dev/null
+++ b/tests/golden_tests/parse_file/fun_def.bend
@@ -0,0 +1,5 @@
+main =
+  let base = 0
+  def aux [] = base
+      aux (List/Cons head tail) = (+ head (aux tail))
+  (aux [1, 2, 3])
diff --git a/tests/golden_tests/parse_file/fun_def_name.bend b/tests/golden_tests/parse_file/fun_def_name.bend
new file mode 100644
index 00000000..5befee3c
--- /dev/null
+++ b/tests/golden_tests/parse_file/fun_def_name.bend
@@ -0,0 +1,5 @@
+main =
+  let base = 0
+  def aux [] = base
+      aux2 (List/Cons head tail) = (+ head (aux tail))
+  (aux [1, 2, 3])
diff --git a/tests/snapshots/parse_file__fun_def.bend.snap b/tests/snapshots/parse_file__fun_def.bend.snap
new file mode 100644
index 00000000..e6107bf0
--- /dev/null
+++ b/tests/snapshots/parse_file__fun_def.bend.snap
@@ -0,0 +1,5 @@
+---
+source: tests/golden_tests.rs
+input_file: tests/golden_tests/parse_file/fun_def.bend
+---
+(main) = let base = 0; def (aux []) = base(aux (List/Cons head tail)) = (+ head (aux tail))(aux [1, 2, 3])
diff --git a/tests/snapshots/parse_file__fun_def_name.bend.snap b/tests/snapshots/parse_file__fun_def_name.bend.snap
new file mode 100644
index 00000000..996c633f
--- /dev/null
+++ b/tests/snapshots/parse_file__fun_def_name.bend.snap
@@ -0,0 +1,8 @@
+---
+source: tests/golden_tests.rs
+input_file: tests/golden_tests/parse_file/fun_def_name.bend
+---
+Errors:
+In tests/golden_tests/parse_file/fun_def_name.bend :
+Expected a rule with name 'aux'.
+  4 |       aux2 (List/Cons head tail) = (+ head (aux tail))