From 83226621e3d57bee6e3f97bb94f4b05a12bdae00 Mon Sep 17 00:00:00 2001
From: Sam Vervaeck <samvv@pm.me>
Date: Thu, 15 Sep 2022 16:04:02 +0200
Subject: [PATCH] Add support for inferring kinds from ArrowTypeExpression

---
 src/checker.ts | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/src/checker.ts b/src/checker.ts
index d5a572c33..8867d0a92 100644
--- a/src/checker.ts
+++ b/src/checker.ts
@@ -867,6 +867,14 @@ export class Checker {
 
   private inferKindFromTypeExpression(node: TypeExpression, env: KindEnv): Kind {
     switch (node.kind) {
+      case SyntaxKind.ArrowTypeExpression:
+      {
+        for (const param of node.paramTypeExprs) {
+          this.unifyKind(this.inferKindFromTypeExpression(param, env), new KStar(), node);
+        }
+        this.unifyKind(this.inferKindFromTypeExpression(node.returnTypeExpr, env), new KStar(), node);
+        return new KStar();
+      }
       case SyntaxKind.VarTypeExpression:
       case SyntaxKind.ReferenceTypeExpression:
       {