From 4a63a4d86e9cbfc9987fb6910aef71087087911d Mon Sep 17 00:00:00 2001
From: Alex Crichton <alex@alexcrichton.com>
Date: Tue, 21 Apr 2020 12:43:05 -0500
Subject: [PATCH] Fix return value of `Func::param_arity` (#1566)

Accidentally forgot to subtract 2 to account for the two vmctx
parameters, so let's add a test here nad adjust it appropriately.
---
 crates/api/src/func.rs | 2 +-
 tests/all/func.rs      | 2 ++
 2 files changed, 3 insertions(+), 1 deletion(-)

diff --git a/crates/api/src/func.rs b/crates/api/src/func.rs
index b6a4dec62f..ade4917b99 100644
--- a/crates/api/src/func.rs
+++ b/crates/api/src/func.rs
@@ -502,7 +502,7 @@ impl Func {
             .signatures()
             .lookup(self.export.signature)
             .expect("failed to lookup signature");
-        sig.params.len()
+        sig.params.len() - 2 // skip the two vmctx leading parameters
     }
 
     /// Returns the number of results this function produces.
diff --git a/tests/all/func.rs b/tests/all/func.rs
index 1cbb3e0814..40616810ed 100644
--- a/tests/all/func.rs
+++ b/tests/all/func.rs
@@ -74,7 +74,9 @@ fn signatures_match() {
 
     let f = Func::wrap(&store, || {});
     assert_eq!(f.ty().params(), &[]);
+    assert_eq!(f.param_arity(), 0);
     assert_eq!(f.ty().results(), &[]);
+    assert_eq!(f.result_arity(), 0);
 
     let f = Func::wrap(&store, || -> i32 { loop {} });
     assert_eq!(f.ty().params(), &[]);