tyck: Add testcases mentioned in #677

error/src/lib.rs

@@ -317,13 +317,6 @@ impl Display for Error {
     }
 }
 
-#[cfg(feature = "ffi")]
-impl std::convert::From<libloading::Error> for Error {
-    fn from(e: libloading::Error) -> Error {
-        Error::new(ErrKind::ExternFunc).with_msg(e.to_string())
-    }
-}
-
 impl std::convert::From<std::env::VarError> for Error {
     fn from(e: std::env::VarError) -> Self {
         Error::new(ErrKind::ExternFunc).with_msg(e.to_string())

fir/src/lib.rs

@@ -334,11 +334,9 @@ pub trait Pass<T: Debug, U: Debug, E> {
 
         // FIXME: Add a #[cfg(not(release))] here
         // otherwise just return `fir`
-        fir.map(|fir| {
+        fir.inspect(|fir| {
             Self::post_condition(&fir);
             fir.check();
-
-            fir
         })
     }
 }

typecheck/src/lib.rs

@@ -665,4 +665,62 @@ mod tests {
 
         assert!(fir.is_ok());
     }
+
+    #[test]
+    fn union_with_constant_valid() {
+        let ast = ast! {
+            type Nothing;
+            type NullableInt = int | Nothing;
+
+            func g(n: NullableInt) {}
+
+            where x = 16;
+
+            g(15);
+            g(x);
+            g(Nothing);
+        };
+
+        let fir = fir!(ast).type_check();
+
+        assert!(fir.is_ok());
+    }
+
+    #[test]
+    fn union_with_constant_invalid() {
+        let ast = ast! {
+            type Nothing;
+            type NullableInt = 15 | Nothing;
+
+            func g(n: NullableInt) {}
+
+            where x = 16;
+
+            g(15);
+            g(x);
+            g(Nothing);
+        };
+
+        let fir = fir!(ast).type_check();
+
+        assert!(fir.is_err());
+    }
+
+    #[test]
+    fn union_primitive_from_ext_fn() {
+        let ast = ast! {
+            ext func magic() -> int;
+
+            type Nothing;
+            type NullableInt = int | Nothing;
+
+            func g(n: NullableInt) {}
+
+            g(magic());
+        };
+
+        let fir = fir!(ast).type_check();
+
+        assert!(fir.is_ok());
+    }
 }