Begin passing tests

dust-lang/src/abstract_tree/value_node.rs

@@ -151,24 +151,26 @@ impl AbstractNode for ValueNode {
 
             body.node.validate(&mut function_context, _manage_memory)?;
 
-            let (expected_return_type, expected_position) = if let Some(constructor) = return_type {
-                (constructor.construct(context)?, constructor.position())
-            } else {
-                return Err(ValidationError::ExpectedExpression(body.position));
-            };
-            let actual_return_type = if let Some(r#type) = body.node.expected_type(context)? {
-                r#type
-            } else {
-                return Err(ValidationError::ExpectedExpression(body.position));
-            };
+            let ((expected_return, expected_position), actual_return) =
+                match (return_type, body.node.expected_type(context)?) {
+                    (Some(constructor), Some(r#type)) => (
+                        (constructor.construct(context)?, constructor.position()),
+                        r#type,
+                    ),
+                    (None, Some(_)) => return Err(ValidationError::ExpectedValue(body.position)),
+                    (Some(constructor), None) => {
+                        return Err(ValidationError::ExpectedExpression(constructor.position()))
+                    }
+                    (None, None) => return Ok(()),
+                };
 
-            expected_return_type
-                .check(&actual_return_type)
-                .map_err(|conflict| ValidationError::TypeCheck {
+            expected_return.check(&actual_return).map_err(|conflict| {
+                ValidationError::TypeCheck {
                     conflict,
                     actual_position: body.position,
                     expected_position: Some(expected_position),
-                })?;
+                }
+            })?;
 
             return Ok(());
         }

dust-lang/src/parser/tests.rs

@@ -427,6 +427,29 @@ fn list_of_type() {
 
 #[test]
 fn function_type() {
+    assert_eq!(
+        parse(&lex("type Foo = fn |T| (int)").unwrap()).unwrap()[0],
+        Statement::TypeAlias(
+            TypeAlias::new(
+                Identifier::new("Foo").with_position((5, 8)),
+                TypeConstructor::Function(
+                    FunctionTypeConstructor {
+                        type_parameters: Some(vec![Identifier::new("T").with_position((15, 16))]),
+                        value_parameters: vec![TypeConstructor::Raw(
+                            RawTypeConstructor::Integer.with_position((19, 22))
+                        )],
+                        return_type: None
+                    }
+                    .with_position((11, 23))
+                )
+            )
+            .with_position((0, 23))
+        )
+    );
+}
+
+#[test]
+fn function_type_with_return() {
     assert_eq!(
         parse(&lex("type Foo = fn |T| (int) -> T").unwrap()).unwrap()[0],
         Statement::TypeAlias(
@@ -666,7 +689,7 @@ fn map() {
                 ),
             ])
             .with_position((0, 15))
-        ),)
+        ))
     );
 }