From f814d0ca55f9bcca87dc400e928b5ddde9f2ac80 Mon Sep 17 00:00:00 2001
From: IsaacShelton <isaac.a.shelton@gmail.com>
Date: Sun, 26 Jan 2025 02:04:16 -0600
Subject: [PATCH] Added error test case for #[using] on trait functions, and
 made minor code improvements

---
 src/resolve/expr/call/infer_impl.rs           | 35 +++++++++++--------
 src/resolve/polymorph/matcher.rs              |  6 ++--
 .../using_trait_on_trait_func/main.adept      | 16 +++++++++
 3 files changed, 40 insertions(+), 17 deletions(-)
 create mode 100644 tests/error/using_trait_on_trait_func/main.adept

diff --git a/src/resolve/expr/call/infer_impl.rs b/src/resolve/expr/call/infer_impl.rs
index 8d70a94..274758e 100644
--- a/src/resolve/expr/call/infer_impl.rs
+++ b/src/resolve/expr/call/infer_impl.rs
@@ -25,24 +25,29 @@ pub fn infer_callee_missing_impl_args(
             continue;
         };
 
-        let from_env = caller.impl_params.params.iter().filter(|(_, param_trait)| {
-            if catalog
-                .extend_if_match_all_types(ctx, &expected_trait.args, &param_trait.args)
-                .is_err()
-            {
-                return false;
-            }
+        let from_env = caller
+            .impl_params
+            .params
+            .iter()
+            .filter_map(|(param_name, param_trait)| {
+                if catalog
+                    .extend_if_match_all_types(ctx, &expected_trait.args, &param_trait.args)
+                    .is_err()
+                {
+                    return None;
+                }
 
-            catalog
-                .resolver()
-                .resolve_trait(expected_trait)
-                .map_or(false, |expected_trait| {
-                    param_trait.trait_ref == expected_trait.trait_ref
-                })
-        });
+                catalog
+                    .resolver()
+                    .resolve_trait(expected_trait)
+                    .ok()
+                    .and_then(|expected_trait| {
+                        (param_trait.trait_ref == expected_trait.trait_ref).then_some(param_name)
+                    })
+            });
 
         match from_env.exactly_one() {
-            Ok((param_name, _)) => {
+            Ok(param_name) => {
                 if catalog
                     .polymorphs
                     .insert(expected_name.into(), PolyValue::PolyImpl(param_name.into()))
diff --git a/src/resolve/polymorph/matcher.rs b/src/resolve/polymorph/matcher.rs
index 45ec929..400af10 100644
--- a/src/resolve/polymorph/matcher.rs
+++ b/src/resolve/polymorph/matcher.rs
@@ -162,8 +162,10 @@ impl<'a, 'b, 'c> TypeMatcher<'a, 'b, 'c> {
             }
         }
 
-        self.partial
-            .insert(name.to_string(), PolyValue::Type(new_type.clone()));
+        assert!(self
+            .partial
+            .insert(name.to_string(), PolyValue::Type(new_type.clone()))
+            .is_none());
 
         Ok(())
     }
diff --git a/tests/error/using_trait_on_trait_func/main.adept b/tests/error/using_trait_on_trait_func/main.adept
new file mode 100644
index 0000000..3f2b9d6
--- /dev/null
+++ b/tests/error/using_trait_on_trait_func/main.adept
@@ -0,0 +1,16 @@
+
+pragma => adept(c"3.0")
+
+trait Example<$T> {
+    #[using Speak<$T>]
+    func invalidFunction(self $T) void
+}
+
+trait Speak<$T> {
+    func speak(self $T) void
+}
+
+func main {
+    
+}
+