Fix solve tes

crates/compiler/derive_key/Cargo.toml

@@ -14,4 +14,4 @@ roc_types = { path = "../types" }
 
 [features]
 default = []
-debug-derived-symbols = []
+debug-derived-symbols = ["roc_module/debug-symbols"]

crates/compiler/solve/tests/solve_expr.rs

@@ -6998,9 +6998,10 @@ mod solve_expr {
 
                 after : Lazy a, (a -> Lazy b) -> Lazy b
                 after = \effect, map ->
-                    \{} ->
+                    thunk = \{} ->
                         when map (effect {}) is
                             b -> b {}
+                    thunk
 
                 f = \_ -> \_ -> ""
                 g = \{ s1 } -> \_ -> s1