constrain the default

compiler/constrain/src/pattern.rs

@@ -246,7 +246,9 @@ pub fn constrain_pattern(
 
                         state.vars.push(*expr_var);
 
-                        constrain_expr(env, loc_expr.region, &loc_expr.value, expr_expected);
+                        let expr_con =
+                            constrain_expr(env, loc_expr.region, &loc_expr.value, expr_expected);
+                        state.constraints.push(expr_con);
 
                         RecordField::Optional(pat_type)
                     }

compiler/solve/tests/solve_expr.rs

@@ -2641,4 +2641,32 @@ mod solve_expr {
             "{ x : Num a, y ? Num a }* -> Num a",
         );
     }
+
+    #[test]
+    fn optional_field_let() {
+        infer_eq_without_problem(
+            indoc!(
+                r#"
+                { x, y ? 0 } = { x: 32 }
+
+                x + y
+                "#
+            ),
+            "Num *",
+        );
+    }
+
+    #[test]
+    fn optional_field_when() {
+        infer_eq_without_problem(
+            indoc!(
+                r#"
+                \r ->
+                    when r is
+                        { x, y ? 0 } -> x + y
+                "#
+            ),
+            "{ x : Num a, y ? Num a }* -> Num a",
+        );
+    }
 }