diff --git a/src/phase/type-unify.ts b/src/phase/type-unify.ts
index 58a71c9..dff4e44 100644
--- a/src/phase/type-unify.ts
+++ b/src/phase/type-unify.ts
@@ -256,7 +256,6 @@ const unify_ = (a: InferredType, b: InferredType, ctx: Context): InferredType =>
                 return b
             }
             switch (b.kind) {
-                // biome-ignore lint:
                 case 'identifier': {
                     if (a.def && a.def === b.def) {
                         if (a.typeArgs.length === b.typeArgs.length) {
@@ -273,6 +272,15 @@ const unify_ = (a: InferredType, b: InferredType, ctx: Context): InferredType =>
                             return u
                         }
                     }
+                    if (a.def?.kind === 'type-def' && b.def?.kind === 'type-def') {
+                        const e = makeErrorType(
+                            `failed unify [${[a, b].map(t => inferredTypeToString(t)).join(', ')}]`,
+                            'no-unify'
+                        )
+                        assign(a, e)
+                        assign(b, e)
+                        return e
+                    }
                     if (a.def?.kind === 'type-param') {
                         if (a.def.unified) {
                             const u = unify(a.def.unified, b, ctx)
@@ -285,17 +293,18 @@ const unify_ = (a: InferredType, b: InferredType, ctx: Context): InferredType =>
                             return b
                         }
                     }
+                    break
                 }
                 case 'inferred-fn':
                 case 'fn-type':
                 case 'name':
                     const e = makeErrorType(
-                        `failed unify [${[a, b].map(t => `${inferredTypeToString(t)} (${t.kind})`).join(', ')}]`,
+                        `failed unify [${[a, b].map(t => inferredTypeToString(t)).join(', ')}]`,
                         'no-unify'
                     )
                     assign(a, e)
                     assign(b, e)
-                    return a
+                    return e
             }
             break
         }
diff --git a/src/semantic/index.ts b/src/semantic/index.ts
index adc7a4d..6be3f70 100644
--- a/src/semantic/index.ts
+++ b/src/semantic/index.ts
@@ -27,11 +27,4 @@ export const semanticCheck = (ctx: Context): void => {
         unifyTypeBounds
     ]
     phases.forEach(f => eachModule(f, ctx))
-    // ;[collectTypeBounds, unifyTypeBounds].forEach(f =>
-    //     ctx.packages.at(-1)!.modules.forEach(m => {
-    //         ctx.moduleStack.push(m)
-    //         f(m, ctx)
-    //         ctx.moduleStack.pop()
-    //     })
-    // )
 }
diff --git a/src/typecheck/index.ts b/src/typecheck/index.ts
index 3b3404d..b42921f 100644
--- a/src/typecheck/index.ts
+++ b/src/typecheck/index.ts
@@ -135,7 +135,7 @@ export const inferredTypeToString = (t: InferredType, depth = 0): string => {
         case 'inferred':
             return `[${t.bounds.map(b => inferredTypeToString(b, depth + 1)).join(', ')}]`
         case 'inferred-fn':
-            const tps = t.typeParams.length > 0 ? `<${t.typeParams.map(typeParamToString)}>` : ''
+            const tps = t.typeParams.length > 0 ? `<${t.typeParams.map(typeParamToString).join(', ')}>` : ''
             const pts = t.params
                 .map(pt => `${pt.name ? `${pt.name}: ` : ''}${inferredTypeToString(pt.type)}`)
                 .join(', ')
@@ -162,7 +162,7 @@ export const typeToString = (t: Type): string => {
         case 'identifier':
             return idToString(t)
         case 'fn-type':
-            const tps = t.typeParams.length > 0 ? `<${t.typeParams.map(typeParamToString)}>` : ''
+            const tps = t.typeParams.length > 0 ? `<${t.typeParams.map(typeParamToString).join(', ')}>` : ''
             const pts = t.params
                 .map(pt => `${pt.name ? `${pt.name.value}: ` : ''}${typeToString(pt.paramType)}`)
                 .join(', ')